diff options
| -rw-r--r-- | ChangeLog | 33 | ||||
| -rw-r--r-- | PROTOCOL | 23 | ||||
| -rw-r--r-- | PROTOCOL.agent | 24 | ||||
| -rw-r--r-- | PROTOCOL.certkeys | 191 | ||||
| -rw-r--r-- | addrmatch.c | 78 | ||||
| -rw-r--r-- | auth-options.c | 150 | ||||
| -rw-r--r-- | auth-options.h | 4 | ||||
| -rw-r--r-- | auth.h | 5 | ||||
| -rw-r--r-- | auth2-pubkey.c | 37 | ||||
| -rw-r--r-- | authfd.c | 24 | ||||
| -rw-r--r-- | dns.c | 8 | ||||
| -rw-r--r-- | dns.h | 6 | ||||
| -rw-r--r-- | hostfile.c | 31 | ||||
| -rw-r--r-- | hostfile.h | 4 | ||||
| -rw-r--r-- | kex.h | 5 | ||||
| -rw-r--r-- | kexdhs.c | 19 | ||||
| -rw-r--r-- | kexgexs.c | 20 | ||||
| -rw-r--r-- | key.c | 595 | ||||
| -rw-r--r-- | key.h | 32 | ||||
| -rw-r--r-- | match.h | 4 | ||||
| -rw-r--r-- | monitor.c | 5 | ||||
| -rw-r--r-- | myproposal.h | 6 | ||||
| -rw-r--r-- | servconf.c | 19 | ||||
| -rw-r--r-- | servconf.h | 5 | ||||
| -rw-r--r-- | ssh-add.c | 34 | ||||
| -rw-r--r-- | ssh-agent.c | 24 | ||||
| -rw-r--r-- | ssh-dss.c | 10 | ||||
| -rw-r--r-- | ssh-keygen.1 | 178 | ||||
| -rw-r--r-- | ssh-keygen.c | 433 | ||||
| -rw-r--r-- | ssh-rsa.c | 10 | ||||
| -rw-r--r-- | ssh.1 | 23 | ||||
| -rw-r--r-- | ssh.c | 71 | ||||
| -rw-r--r-- | ssh2.h | 5 | ||||
| -rw-r--r-- | sshconnect.c | 78 | ||||
| -rw-r--r-- | sshconnect2.c | 4 | ||||
| -rw-r--r-- | sshd.8 | 25 | ||||
| -rw-r--r-- | sshd.c | 117 | ||||
| -rw-r--r-- | sshd_config.5 | 12 |
38 files changed, 2164 insertions, 188 deletions
@@ -1,3 +1,36 @@ +20100226 + - OpenBSD CVS Sync + - djm@cvs.openbsd.org 2010/02/26 20:29:54 + [PROTOCOL PROTOCOL.agent PROTOCOL.certkeys addrmatch.c auth-options.c] + [auth-options.h auth.h auth2-pubkey.c authfd.c dns.c dns.h hostfile.c] + [hostfile.h kex.h kexdhs.c kexgexs.c key.c key.h match.h monitor.c] + [myproposal.h servconf.c servconf.h ssh-add.c ssh-agent.c ssh-dss.c] + [ssh-keygen.1 ssh-keygen.c ssh-rsa.c ssh.1 ssh.c ssh2.h sshconnect.c] + [sshconnect2.c sshd.8 sshd.c sshd_config.5] + Add support for certificate key types for users and hosts. + + OpenSSH certificate key types are not X.509 certificates, but a much + simpler format that encodes a public key, identity information and + some validity constraints and signs it with a CA key. CA keys are + regular SSH keys. This certificate style avoids the attack surface + of X.509 certificates and is very easy to deploy. + + Certified host keys allow automatic acceptance of new host keys + when a CA certificate is marked as trusted in ~/.ssh/known_hosts. + see VERIFYING HOST KEYS in ssh(1) for details. + + Certified user keys allow authentication of users when the signing + CA key is marked as trusted in authorized_keys. See "AUTHORIZED_KEYS + FILE FORMAT" in sshd(8) for details. + + Certificates are minted using ssh-keygen(1), documentation is in + the "CERTIFICATES" section of that manpage. + + Documentation on the format of certificates is in the file + PROTOCOL.certkeys + + feedback and ok markus@ + 20100224 - (djm) [pkcs11.h ssh-pkcs11-client.c ssh-pkcs11-helper.c ssh-pkcs11.c] [ssh-pkcs11.h] Add $OpenBSD$ RCS idents so we can sync portable @@ -31,7 +31,14 @@ The method is documented in: http://www.openssh.com/txt/draft-miller-secsh-compression-delayed-00.txt -3. connection: Channel write close extension "eow@openssh.com" +3. transport: New public key algorithms "ssh-rsa-cert-v00@openssh.com" and + "ssh-dsa-cert-v00@openssh.com" + +OpenSSH introduces two new public key algorithms to support certificate +authentication for users and hostkeys. These methods are documented in +the file PROTOCOL.certkeys + +4. connection: Channel write close extension "eow@openssh.com" The SSH connection protocol (rfc4254) provides the SSH_MSG_CHANNEL_EOF message to allow an endpoint to signal its peer that it will send no @@ -70,7 +77,7 @@ message is only sent to OpenSSH peers (identified by banner). Other SSH implementations may be whitelisted to receive this message upon request. -4. connection: disallow additional sessions extension +5. connection: disallow additional sessions extension "no-more-sessions@openssh.com" Most SSH connections will only ever request a single session, but a @@ -98,7 +105,7 @@ of this message, the no-more-sessions request is only sent to OpenSSH servers (identified by banner). Other SSH implementations may be whitelisted to receive this message upon request. -5. connection: Tunnel forward extension "tun@openssh.com" +6. connection: Tunnel forward extension "tun@openssh.com" OpenSSH supports layer 2 and layer 3 tunnelling via the "tun@openssh.com" channel type. This channel type supports forwarding of network packets @@ -159,7 +166,7 @@ The contents of the "data" field for layer 2 packets is: The "frame" field contains an IEEE 802.3 Ethernet frame, including header. -6. sftp: Reversal of arguments to SSH_FXP_SYMLINK +7. sftp: Reversal of arguments to SSH_FXP_SYMLINK When OpenSSH's sftp-server was implemented, the order of the arguments to the SSH_FXP_SYMLINK method was inadvertently reversed. Unfortunately, @@ -172,7 +179,7 @@ SSH_FXP_SYMLINK as follows: string targetpath string linkpath -7. sftp: Server extension announcement in SSH_FXP_VERSION +8. sftp: Server extension announcement in SSH_FXP_VERSION OpenSSH's sftp-server lists the extensions it supports using the standard extension announcement mechanism in the SSH_FXP_VERSION server @@ -193,7 +200,7 @@ ever changed in an incompatible way. The server MAY advertise the same extension with multiple versions (though this is unlikely). Clients MUST check the version number before attempting to use the extension. -8. sftp: Extension request "posix-rename@openssh.com" +9. sftp: Extension request "posix-rename@openssh.com" This operation provides a rename operation with POSIX semantics, which are different to those provided by the standard SSH_FXP_RENAME in @@ -210,7 +217,7 @@ rename(oldpath, newpath) and will respond with a SSH_FXP_STATUS message. This extension is advertised in the SSH_FXP_VERSION hello with version "1". -9. sftp: Extension requests "statvfs@openssh.com" and +10. sftp: Extension requests "statvfs@openssh.com" and "fstatvfs@openssh.com" These requests correspond to the statvfs and fstatvfs POSIX system @@ -251,4 +258,4 @@ The values of the f_flag bitmask are as follows: Both the "statvfs@openssh.com" and "fstatvfs@openssh.com" extensions are advertised in the SSH_FXP_VERSION hello with version "2". -$OpenBSD: PROTOCOL,v 1.14 2010/01/09 00:57:10 djm Exp $ +$OpenBSD: PROTOCOL,v 1.15 2010/02/26 20:29:54 djm Exp $ diff --git a/PROTOCOL.agent b/PROTOCOL.agent index 49adbdd5..b34fcd31 100644 --- a/PROTOCOL.agent +++ b/PROTOCOL.agent @@ -173,6 +173,15 @@ be added using the following request string key_comment constraint[] key_constraints +DSA certificates may be added with: + byte SSH2_AGENTC_ADD_IDENTITY or + SSH2_AGENTC_ADD_ID_CONSTRAINED + string "ssh-dss-cert-v00@openssh.com" + string certificate + mpint dsa_private_key + string key_comment + constraint[] key_constraints + RSA keys may be added with this request: byte SSH2_AGENTC_ADD_IDENTITY or @@ -187,6 +196,19 @@ RSA keys may be added with this request: string key_comment constraint[] key_constraints +RSA certificates may be added with this request: + + byte SSH2_AGENTC_ADD_IDENTITY or + SSH2_AGENTC_ADD_ID_CONSTRAINED + string "ssh-rsa-cert-v00@openssh.com" + string certificate + mpint rsa_d + mpint rsa_iqmp + mpint rsa_p + mpint rsa_q + string key_comment + constraint[] key_constraints + Note that the 'rsa_p' and 'rsa_q' parameters are sent in the reverse order to the protocol 1 add keys message. As with the corresponding protocol 1 "add key" request, the private key is overspecified to avoid @@ -513,4 +535,4 @@ Locking and unlocking affects both protocol 1 and protocol 2 keys. SSH_AGENT_CONSTRAIN_LIFETIME 1 SSH_AGENT_CONSTRAIN_CONFIRM 2 -$OpenBSD: PROTOCOL.agent,v 1.4 2008/07/01 23:12:47 stevesk Exp $ +$OpenBSD: PROTOCOL.agent,v 1.5 2010/02/26 20:29:54 djm Exp $ diff --git a/PROTOCOL.certkeys b/PROTOCOL.certkeys new file mode 100644 index 00000000..0b887a24 --- /dev/null +++ b/PROTOCOL.certkeys @@ -0,0 +1,191 @@ +This document describes a simple public-key certificate authentication +system for use by SSH. + +Background +---------- + +The SSH protocol currently supports a simple public key authentication +mechanism. Unlike other public key implementations, SSH eschews the +use of X.509 certificates and uses raw keys. This approach has some +benefits relating to simplicity of configuration and minimisation +of attack surface, but it does not support the important use-cases +of centrally managed, passwordless authentication and centrally +certified host keys. + +These protocol extensions build on the simple public key authentication +system already in SSH to allow certificate-based authentication. +The certificates used are not traditional X.509 certificates, with +numerous options and complex encoding rules, but something rather +more minimal: a key, some identity information and usage constraints +that have been signed with some other trusted key. + +A sshd server may be configured to allow authentication via certified +keys, by extending the existing ~/.ssh/authorized_keys mechanism +to allow specification of certification authority keys in addition +to raw user keys. The ssh client will support automatic verification +of acceptance of certified host keys, by adding a similar ability +to specify CA keys in ~/.ssh/known_hosts. + +Certified keys are represented using two new key types: +ssh-rsa-cert-v00@openssh.com and ssh-dss-cert-v00@openssh.com that +include certification information along with the public key that is used +to sign challenges. ssh-keygen performs the CA signing operation. + +Protocol extensions +------------------- + +The SSH wire protocol includes several extensibility mechanisms. +These modifications shall take advantage of namespaced public key +algorithm names to add support for certificate authentication without +breaking the protocol - implementations that do not support the +extensions will simply ignore them. + +Authentication using the new key formats described below proceeds +using the existing SSH "publickey" authentication method described +in RFC4252 section 7. + +New public key formats +---------------------- + +The ssh-rsa-cert-v00@openssh.com and ssh-dss-cert-v00@openssh.com key +types take a similar same high-level format (note: data types and +encoding are as per RFC4251 section 5). The serialised wire encoding of +these certificates is also used for storing them on disk. + +#define SSH_CERT_TYPE_USER 1 +#define SSH_CERT_TYPE_HOST 2 + +RSA certificate + + string "ssh-rsa-cert-v00@openssh.com" + mpint e + mpint n + uint32 type + string key id + string valid principals + uint64 valid after + uint64 valid before + string constraints + string nonce + string reserved + string signature key + string signature + +DSA certificate + + string "ssh-dss-cert-v00@openssh.com" + mpint p + mpint q + mpint g + mpint y + uint32 type + string key id + string valid principals + uint64 valid after + uint64 valid before + string constraints + string nonce + string reserved + string signature key + string signature + +e and n are the RSA exponent and public modulus respectively. + +p, q, g, y are the DSA parameters as described in FIPS-186-2. + +type specifies whether this certificate is for identification of a user +or a host using a SSH_CERT_TYPE_... value. + +key id is a free-form text field that is filled in by the CA at the time +of signing; the intention is that the contents of this field are used to +identify the identity principal in log messages. + +"valid principals" is a string containing zero or more principals as +strings packed inside it. These principals list the names for which this +certificate is valid; hostnames for SSH_CERT_TYPE_HOST certificates and +usernames for SSH_CERT_TYPE_USER certificates. As a special case, a +zero-length "valid principals" field means the certificate is valid for +any principal of the specified type. XXX DNS wildcards? + +"valid after" and "valid before" specify a validity period for the +certificate. Each represents a time in seconds since 1970-01-01 +00:00:00. A certificate is considered valid if: + valid after <= current time < valid before + +constraints is a set of zero or more key constraints encoded as below. + +The nonce field is a CA-provided random bitstring of arbitrary length +(but typically 16 or 32 bytes) included to make attacks that depend on +inducing collisions in the signature hash infeasible. + +The reserved field is current unused and is ignored in this version of +the protocol. + +signature key contains the CA key used to sign the certificate. +The valid key types for CA keys are ssh-rsa and ssh-dss. "Chained" +certificates, where the signature key type is a certificate type itself +are NOT supported. Note that it is possible for a RSA certificate key to +be signed by a DSS CA key and vice-versa. + +signature is computed over all preceding fields from the initial string +up to, and including the signature key. Signatures are computed and +encoded according to the rules defined for the CA's public key algorithm +(RFC4253 section 6.6 for ssh-rsa and ssh-dss). + +Constraints +----------- + +The constraints section of the certificate specifies zero or more +constraints on the certificates validity. The format of this field +is a sequence of zero or more tuples: + + string name + string data + +The name field identifies the constraint and the data field encodes +constraint-specific information (see below). All constraints are +"critical", if an implementation does not recognise a constraint +then the validating party should refuse to accept the certificate. + +The supported constraints and the contents and structure of their +data fields are: + +Name Format Description +----------------------------------------------------------------------------- +force-command string Specifies a command that is executed + (replacing any the user specified on the + ssh command-line) whenever this key is + used for authentication. + +permit-X11-forwarding empty Flag indicating that X11 forwarding + should be permitted. X11 forwarding will + be refused if this constraint is absent. + +permit-agent-forwarding empty Flag indicating that agent forwarding + should be allowed. Agent forwarding + must not be permitted unless this + constraint is present. + +permit-port-forwarding empty Flag indicating that port-forwarding + should be allowed. If this constraint is + not present then no port forwarding will + be allowed. + +permit-pty empty Flag indicating that PTY allocation + should be permitted. In the absence of + this constraint PTY allocation will be + disabled. + +permit-user-rc empty Flag indicating that execution of + ~/.ssh/rc should be permitted. Execution + of this script will not be permitted if + this constraint is not present. + +source-address string Comma-separated list of source addresses + from which this certificate is accepted + for authentication. Addresses are + specified in CIDR format (nn.nn.nn.nn/nn + or hhhh::hhhh/nn). + If this constraint is not present then + certificates may be presented from any + source address. diff --git a/addrmatch.c b/addrmatch.c index d39885b7..5b6773cc 100644 --- a/addrmatch.c +++ b/addrmatch.c @@ -1,4 +1,4 @@ -/* $OpenBSD: addrmatch.c,v 1.4 2008/12/10 03:55:20 stevesk Exp $ */ +/* $OpenBSD: addrmatch.c,v 1.5 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org> @@ -126,6 +126,8 @@ addr_netmask(int af, u_int l, struct xaddr *n) switch (af) { case AF_INET: n->af = AF_INET; + if (l == 0) + return 0; n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff); return 0; case AF_INET6: @@ -422,3 +424,77 @@ addr_match_list(const char *addr, const char *_list) return ret; } + +/* + * Match "addr" against list CIDR list "_list". Lexical wildcards and + * negation are not supported. If "addr" == NULL, will verify structure + * of "_list". + * + * Returns 1 on match found (never returned when addr == NULL). + * Returns 0 on if no match found, or no errors found when addr == NULL. + * Returns -1 on error + */ +int +addr_match_cidr_list(const char *addr, const char *_list) +{ + char *list, *cp, *o; + struct xaddr try_addr, match_addr; + u_int masklen; + int ret = 0, r; + + if (addr != NULL && addr_pton(addr, &try_addr) != 0) { + debug2("%s: couldn't parse address %.100s", __func__, addr); + return 0; + } + if ((o = list = strdup(_list)) == NULL) + return -1; + while ((cp = strsep(&list, ",")) != NULL) { + if (*cp == '\0') { + error("%s: empty entry in list \"%.100s\"", + __func__, o); + ret = -1; + break; + } + + /* + * NB. This function is called in pre-auth with untrusted data, + * so be extra paranoid about junk reaching getaddrino (via + * addr_pton_cidr). + */ + + /* Stop junk from reaching getaddrinfo. +3 is for masklen */ + if (strlen(cp) > INET6_ADDRSTRLEN + 3) { + error("%s: list entry \"%.100s\" too long", + __func__, cp); + ret = -1; + break; + } +#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/" + if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) { + error("%s: list entry \"%.100s\" contains invalid " + "characters", __func__, cp); + ret = -1; + } + + /* Prefer CIDR address matching */ + r = addr_pton_cidr(cp, &match_addr, &masklen); + if (r == -1) { + error("Invalid network entry \"%.100s\"", cp); + ret = -1; + break; + } else if (r == -2) { + error("Inconsistent mask length for " + "network \"%.100s\"", cp); + ret = -1; + break; + } else if (r == 0 && addr != NULL) { + if (addr_netmatch(&try_addr, &match_addr, + masklen) == 0) + ret = 1; + continue; + } + } + xfree(o); + + return ret; +} diff --git a/auth-options.c b/auth-options.c index ab085c23..396bda62 100644 --- a/auth-options.c +++ b/auth-options.c @@ -1,4 +1,4 @@ -/* $OpenBSD: auth-options.c,v 1.44 2009/01/22 10:09:16 djm Exp $ */ +/* $OpenBSD: auth-options.c,v 1.45 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -44,6 +44,7 @@ int no_agent_forwarding_flag = 0; int no_x11_forwarding_flag = 0; int no_pty_flag = 0; int no_user_rc = 0; +int key_is_cert_authority = 0; /* "command=" option. */ char *forced_command = NULL; @@ -64,6 +65,7 @@ auth_clear_options(void) no_pty_flag = 0; no_x11_forwarding_flag = 0; no_user_rc = 0; + key_is_cert_authority = 0; while (custom_environment) { struct envstring *ce = custom_environment; custom_environment = ce->next; @@ -96,6 +98,12 @@ auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum) return 1; while (*opts && *opts != ' ' && *opts != '\t') { + cp = "cert-authority"; + if (strncasecmp(opts, cp, strlen(cp)) == 0) { + key_is_cert_authority = 1; + opts += strlen(cp); + goto next_option; + } cp = "no-port-forwarding"; if (strncasecmp(opts, cp, strlen(cp)) == 0) { auth_debug_add("Port forwarding disabled."); @@ -374,3 +382,143 @@ bad_option: /* deny access */ return 0; } + +/* + * Set options from certificate constraints. These supersede user key options + * so this must be called after auth_parse_options(). + */ +int +auth_cert_constraints(Buffer *c_orig, struct passwd *pw) +{ + u_char *name = NULL, *data_blob = NULL; + u_int len; + Buffer c, data; + int ret = -1; + + int cert_no_port_forwarding_flag = 1; + int cert_no_agent_forwarding_flag = 1; + int cert_no_x11_forwarding_flag = 1; + int cert_no_pty_flag = 1; + int cert_no_user_rc = 1; + char *cert_forced_command = NULL; + int cert_source_address_done = 0; + + buffer_init(&data); + + /* Make copy to avoid altering original */ + buffer_init(&c); + buffer_append(&c, buffer_ptr(c_orig), buffer_len(c_orig)); + + while (buffer_len(&c) > 0) { + if ((name = buffer_get_string_ret(&c, NULL)) == NULL || + (data_blob = buffer_get_string_ret(&c, &len)) == NULL) { + error("Certificate constraints corrupt"); + goto out; + } + buffer_append(&data, data_blob, len); + debug3("found certificate constraint \"%.100s\" len %u", + name, len); + if (strcmp(name, "permit-X11-forwarding") == 0) + cert_no_x11_forwarding_flag = 0; + else if (strcmp(name, "permit-agent-forwarding") == 0) + cert_no_agent_forwarding_flag = 0; + else if (strcmp(name, "permit-port-forwarding") == 0) + cert_no_port_forwarding_flag = 0; + else if (strcmp(name, "permit-pty") == 0) + cert_no_pty_flag = 0; + else if (strcmp(name, "permit-user-rc") == 0) + cert_no_user_rc = 0; + else if (strcmp(name, "force-command") == 0) { + char *command = buffer_get_string_ret(&data, NULL); + + if (command == NULL) { + error("Certificate constraint \"%s\" corrupt", + name); + goto out; + } + if (cert_forced_command != NULL) { + error("Certificate has multiple " + "forced-command constraints"); + xfree(command); + goto out; + } + cert_forced_command = command; + } else if (strcmp(name, "source-address") == 0) { + char *allowed = buffer_get_string_ret(&data, NULL); + const char *remote_ip = get_remote_ipaddr(); + + if (allowed == NULL) { + error("Certificate constraint \"%s\" corrupt", + name); + goto out; + } + if (cert_source_address_done++) { + error("Certificate has multiple " + "source-address constraints"); + xfree(allowed); + goto out; + } + switch (addr_match_cidr_list(remote_ip, allowed)) { + case 1: + /* accepted */ + xfree(allowed); + break; + case 0: + /* no match */ + logit("Authentication tried for %.100s with " + "valid certificate but not from a " + "permitted host (ip=%.200s).", + pw->pw_name, remote_ip); + auth_debug_add("Your address '%.200s' is not " + "permitted to use this certificate for " + "login.", remote_ip); + xfree(allowed); + goto out; + case -1: + error("Certificate source-address contents " + "invalid"); + xfree(allowed); + goto out; + } + } else { + error("Certificate constraint \"%s\" is not supported", + name); + goto out; + } + + if (buffer_len(&data) != 0) { + error("Certificate constraint \"%s\" corrupt " + "(extra data)", name); + goto out; + } + buffer_clear(&data); + xfree(name); + xfree(data_blob); + name = data_blob = NULL; + } + + /* successfully parsed all constraints */ + ret = 0; + + no_port_forwarding_flag |= cert_no_port_forwarding_flag; + no_agent_forwarding_flag |= cert_no_agent_forwarding_flag; + no_x11_forwarding_flag |= cert_no_x11_forwarding_flag; + no_pty_flag |= cert_no_pty_flag; + no_user_rc |= cert_no_user_rc; + /* CA-specified forced command supersedes key option */ + if (cert_forced_command != NULL) { + if (forced_command != NULL) + xfree(forced_command); + forced_command = cert_forced_command; + } + + out: + if (name != NULL) + xfree(name); + if (data_blob != NULL) + xfree(data_blob); + buffer_free(&data); + buffer_free(&c); + return ret; +} + diff --git a/auth-options.h b/auth-options.h index 14488f72..694edc84 100644 --- a/auth-options.h +++ b/auth-options.h @@ -1,4 +1,4 @@ -/* $OpenBSD: auth-options.h,v 1.17 2008/03/26 21:28:14 djm Exp $ */ +/* $OpenBSD: auth-options.h,v 1.18 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> @@ -30,8 +30,10 @@ extern int no_user_rc; extern char *forced_command; extern struct envstring *custom_environment; extern int forced_tun_device; +extern int key_is_cert_authority; int auth_parse_options(struct passwd *, char *, char *, u_long); void auth_clear_options(void); +int auth_cert_constraints(Buffer *, struct passwd *); #endif @@ -1,4 +1,4 @@ -/* $OpenBSD: auth.h,v 1.63 2009/08/15 18:56:34 fgsch Exp $ */ +/* $OpenBSD: auth.h,v 1.64 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. @@ -178,7 +178,8 @@ check_key_in_hostfiles(struct passwd *, Key *, const char *, /* hostkey handling */ Key *get_hostkey_by_index(int); -Key *get_hostkey_by_type(int); +Key *get_hostkey_public_by_type(int); +Key *get_hostkey_private_by_type(int); int get_hostkey_index(Key *); int ssh1_session_key(BIGNUM *); diff --git a/auth2-pubkey.c b/auth2-pubkey.c index 2886f127..66ca5266 100644 --- a/auth2-pubkey.c +++ b/auth2-pubkey.c @@ -1,4 +1,4 @@ -/* $OpenBSD: auth2-pubkey.c,v 1.19 2008/07/03 21:46:58 otto Exp $ */ +/* $OpenBSD: auth2-pubkey.c,v 1.20 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -32,6 +32,8 @@ #include <pwd.h> #include <stdio.h> #include <stdarg.h> +#include <string.h> +#include <time.h> #include <unistd.h> #include "xmalloc.h" @@ -178,6 +180,7 @@ static int user_key_allowed2(struct passwd *pw, Key *key, char *file) { char line[SSH_MAX_PUBKEY_BYTES]; + const char *reason; int found_key = 0; FILE *f; u_long linenum = 0; @@ -196,11 +199,13 @@ user_key_allowed2(struct passwd *pw, Key *key, char *file) } found_key = 0; - found = key_new(key->type); + found = key_new(key_is_cert(key) ? KEY_UNSPEC : key->type); while (read_keyfile_line(f, file, line, sizeof(line), &linenum) != -1) { char *cp, *key_options = NULL; + auth_clear_options(); + /* Skip leading whitespace, empty and comment lines. */ for (cp = line; *cp == ' ' || *cp == '\t'; cp++) ; @@ -227,8 +232,32 @@ user_key_allowed2(struct passwd *pw, Key *key, char *file) continue; } } - if (key_equal(found, key) && - auth_parse_options(pw, key_options, file, linenum) == 1) { + if (auth_parse_options(pw, key_options, file, linenum) != 1) + continue; + if (key->type == KEY_RSA_CERT || key->type == KEY_DSA_CERT) { + if (!key_is_cert_authority) + continue; + if (!key_equal(found, key->cert->signature_key)) + continue; + debug("matching CA found: file %s, line %lu", + file, linenum); + fp = key_fingerprint(found, SSH_FP_MD5, + SSH_FP_HEX); + verbose("Found matching %s CA: %s", + key_type(found), fp); + xfree(fp); + if (key_cert_check_authority(key, 0, 0, pw->pw_name, + &reason) != 0) { + error("%s", reason); + auth_debug_add("%s", reason); + continue; + } + if (auth_cert_constraints(&key->cert->constraints, + pw) != 0) + continue; + found_key = 1; + break; + } else if (!key_is_cert_authority && key_equal(found, key)) { found_key = 1; debug("matching key found: file %s, line %lu", file, linenum); @@ -1,4 +1,4 @@ -/* $OpenBSD: authfd.c,v 1.81 2009/08/27 17:44:52 djm Exp $ */ +/* $OpenBSD: authfd.c,v 1.82 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -483,6 +483,16 @@ ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment) buffer_put_bignum2(b, key->rsa->p); buffer_put_bignum2(b, key->rsa->q); break; + case KEY_RSA_CERT: + if (key->cert == NULL || buffer_len(&key->cert->certblob) == 0) + fatal("%s: no cert/certblob", __func__); + buffer_put_string(b, buffer_ptr(&key->cert->certblob), + buffer_len(&key->cert->certblob)); + buffer_put_bignum2(b, key->rsa->d); + buffer_put_bignum2(b, key->rsa->iqmp); + buffer_put_bignum2(b, key->rsa->p); + buffer_put_bignum2(b, key->rsa->q); + break; case KEY_DSA: buffer_put_bignum2(b, key->dsa->p); buffer_put_bignum2(b, key->dsa->q); @@ -490,6 +500,13 @@ ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment) buffer_put_bignum2(b, key->dsa->pub_key); buffer_put_bignum2(b, key->dsa->priv_key); break; + case KEY_DSA_CERT: + if (key->cert == NULL || buffer_len(&key->cert->certblob) == 0) + fatal("%s: no cert/certblob", __func__); + buffer_put_string(b, buffer_ptr(&key->cert->certblob), + buffer_len(&key->cert->certblob)); + buffer_put_bignum2(b, key->dsa->priv_key); + break; } buffer_put_cstring(b, comment); } @@ -517,7 +534,9 @@ ssh_add_identity_constrained(AuthenticationConnection *auth, Key *key, ssh_encode_identity_rsa1(&msg, key->rsa, comment); break; case KEY_RSA: + case KEY_RSA_CERT: case KEY_DSA: + case KEY_DSA_CERT: type = constrained ? SSH2_AGENTC_ADD_ID_CONSTRAINED : SSH2_AGENTC_ADD_IDENTITY; @@ -565,7 +584,8 @@ ssh_remove_identity(AuthenticationConnection *auth, Key *key) buffer_put_int(&msg, BN_num_bits(key->rsa->n)); buffer_put_bignum(&msg, key->rsa->e); buffer_put_bignum(&msg, key->rsa->n); - } else if (key->type == KEY_DSA || key->type == KEY_RSA) { + } else if (key_type_plain(key->type) == KEY_DSA || + key_type_plain(key->type) == KEY_RSA) { key_to_blob(key, &blob, &blen); buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY); buffer_put_string(&msg, blob, blen); @@ -1,4 +1,4 @@ -/* $OpenBSD: dns.c,v 1.25 2008/06/12 00:03:49 dtucker Exp $ */ +/* $OpenBSD: dns.c,v 1.26 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2003 Wesley Griffin. All rights reserved. @@ -75,7 +75,7 @@ dns_result_totext(unsigned int res) */ static int dns_read_key(u_int8_t *algorithm, u_int8_t *digest_type, - u_char **digest, u_int *digest_len, const Key *key) + u_char **digest, u_int *digest_len, Key *key) { int success = 0; @@ -172,7 +172,7 @@ is_numeric_hostname(const char *hostname) */ int verify_host_key_dns(const char *hostname, struct sockaddr *address, - const Key *hostkey, int *flags) + Key *hostkey, int *flags) { u_int counter; int result; @@ -271,7 +271,7 @@ verify_host_key_dns(const char *hostname, struct sockaddr *address, * Export the fingerprint of a key as a DNS resource record */ int -export_dns_rr(const char *hostname, const Key *key, FILE *f, int generic) +export_dns_rr(const char *hostname, Key *key, FILE *f, int generic) { u_int8_t rdata_pubkey_algorithm = 0; u_int8_t rdata_digest_type = SSHFP_HASH_SHA1; @@ -1,4 +1,4 @@ -/* $OpenBSD: dns.h,v 1.10 2006/08/03 03:34:42 deraadt Exp $ */ +/* $OpenBSD: dns.h,v 1.11 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2003 Wesley Griffin. All rights reserved. @@ -46,7 +46,7 @@ enum sshfp_hashes { #define DNS_VERIFY_MATCH 0x00000002 #define DNS_VERIFY_SECURE 0x00000004 -int verify_host_key_dns(const char *, struct sockaddr *, const Key *, int *); -int export_dns_rr(const char *, const Key *, FILE *, int); +int verify_host_key_dns(const char *, struct sockaddr *, Key *, int *); +int export_dns_rr(const char *, Key *, FILE *, int); #endif /* DNS_H */ @@ -1,4 +1,4 @@ -/* $OpenBSD: hostfile.c,v 1.46 2009/10/11 23:03:15 djm Exp $ */ +/* $OpenBSD: hostfile.c,v 1.47 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -199,7 +199,7 @@ check_host_in_hostfile_by_key_or_type(const char *filename, { FILE *f; char line[8192]; - int linenum = 0; + int linenum = 0, want_cert = key_is_cert(key); u_int kbits; char *cp, *cp2, *hashed_host; HostStatus end_return; @@ -229,6 +229,23 @@ check_host_in_hostfile_by_key_or_type(const char *filename, if (!*cp || *cp == '#' || *cp == '\n') continue; + /* + * Ignore CA keys when looking for raw keys. + * Ignore raw keys when looking for CA keys. + */ + if (strncasecmp(cp, CA_MARKER, sizeof(CA_MARKER) - 1) == 0 && + (cp[sizeof(CA_MARKER) - 1] == ' ' || + cp[sizeof(CA_MARKER) - 1] == '\t')) { + if (want_cert) { + /* Skip the marker and following whitespace */ + cp += sizeof(CA_MARKER); + for (; *cp == ' ' || *cp == '\t'; cp++) + ; + } else + continue; + } else if (want_cert) + continue; + /* Find the end of the host name portion. */ for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) ; @@ -273,8 +290,14 @@ check_host_in_hostfile_by_key_or_type(const char *filename, continue; /* Check if the current key is the same as the given key. */ - if (key_equal(key, found)) { - /* Ok, they match. */ + if (want_cert && key_equal(key->cert->signature_key, found)) { + /* Found CA cert for key */ + debug3("check_host_in_hostfile: CA match line %d", + linenum); + fclose(f); + return HOST_OK; + } else if (!want_cert && key_equal(key, found)) { + /* Found identical key */ debug3("check_host_in_hostfile: match line %d", linenum); fclose(f); return HOST_OK; @@ -1,4 +1,4 @@ -/* $OpenBSD: hostfile.h,v 1.16 2006/03/25 22:22:43 djm Exp $ */ +/* $OpenBSD: hostfile.h,v 1.17 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> @@ -28,6 +28,8 @@ int lookup_key_in_hostfile_by_type(const char *, const char *, #define HASH_MAGIC "|1|" #define HASH_DELIM '|' +#define CA_MARKER "@cert-authority" + char *host_hash(const char *, const char *, u_int); #endif @@ -1,4 +1,4 @@ -/* $OpenBSD: kex.h,v 1.48 2009/10/24 11:13:54 andreas Exp $ */ +/* $OpenBSD: kex.h,v 1.49 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. @@ -126,7 +126,8 @@ struct Kex { char *client_version_string; char *server_version_string; int (*verify_host_key)(Key *); - Key *(*load_host_key)(int); + Key *(*load_host_public_key)(int); + Key *(*load_host_private_key)(int); int (*host_key_index)(Key *); void (*kex[KEX_MAX])(Kex *); }; @@ -1,4 +1,4 @@ -/* $OpenBSD: kexdhs.c,v 1.10 2009/06/21 07:37:15 dtucker Exp $ */ +/* $OpenBSD: kexdhs.c,v 1.11 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2001 Markus Friedl. All rights reserved. * @@ -50,7 +50,7 @@ kexdh_server(Kex *kex) { BIGNUM *shared_secret = NULL, *dh_client_pub = NULL; DH *dh; - Key *server_host_key; + Key *server_host_public, *server_host_private; u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; u_int sbloblen, klen, hashlen, slen; int kout; @@ -71,11 +71,16 @@ kexdh_server(Kex *kex) debug("expecting SSH2_MSG_KEXDH_INIT"); packet_read_expect(SSH2_MSG_KEXDH_INIT); - if (kex->load_host_key == NULL) + if (kex->load_host_public_key == NULL || + kex->load_host_private_key == NULL) fatal("Cannot load hostkey"); - server_host_key = kex->load_host_key(kex->hostkey_type); - if (server_host_key == NULL) + server_host_public = kex->load_host_public_key(kex->hostkey_type); + if (server_host_public == NULL) fatal("Unsupported hostkey type %d", kex->hostkey_type); + server_host_private = kex->load_host_private_key(kex->hostkey_type); + if (server_host_private == NULL) + fatal("Missing private key for hostkey type %d", + kex->hostkey_type); /* key, cert */ if ((dh_client_pub = BN_new()) == NULL) @@ -113,7 +118,7 @@ kexdh_server(Kex *kex) memset(kbuf, 0, klen); xfree(kbuf); - key_to_blob(server_host_key, &server_host_key_blob, &sbloblen); + key_to_blob(server_host_public, &server_host_key_blob, &sbloblen); /* calc H */ kex_dh_hash( @@ -137,7 +142,7 @@ kexdh_server(Kex *kex) } /* sign H */ - if (PRIVSEP(key_sign(server_host_key, &signature, &slen, hash, + if (PRIVSEP(key_sign(server_host_private, &signature, &slen, hash, hashlen)) < 0) fatal("kexdh_server: key_sign failed"); @@ -1,4 +1,4 @@ -/* $OpenBSD: kexgexs.c,v 1.12 2009/06/21 07:37:15 dtucker Exp $ */ +/* $OpenBSD: kexgexs.c,v 1.13 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Niels Provos. All rights reserved. * Copyright (c) 2001 Markus Friedl. All rights reserved. @@ -52,18 +52,24 @@ void kexgex_server(Kex *kex) { BIGNUM *shared_secret = NULL, *dh_client_pub = NULL; - Key *server_host_key; + Key *server_host_public, *server_host_private; DH *dh; u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL; u_int sbloblen, klen, slen, hashlen; int omin = -1, min = -1, omax = -1, max = -1, onbits = -1, nbits = -1; int type, kout; - if (kex->load_host_key == NULL) + if (kex->load_host_public_key == NULL || + kex->load_host_private_key == NULL) fatal("Cannot load hostkey"); - server_host_key = kex->load_host_key(kex->hostkey_type); - if (server_host_key == NULL) + server_host_public = kex->load_host_public_key(kex->hostkey_type); + if (server_host_public == NULL) fatal("Unsupported hostkey type %d", kex->hostkey_type); + server_host_private = kex->load_host_private_key(kex->hostkey_type); + if (server_host_private == NULL) + fatal("Missing private key for hostkey type %d", + kex->hostkey_type); + type = packet_read(); switch (type) { @@ -149,7 +155,7 @@ kexgex_server(Kex *kex) memset(kbuf, 0, klen); xfree(kbuf); - key_to_blob(server_host_key, &server_host_key_blob, &sbloblen); + key_to_blob(server_host_public, &server_host_key_blob, &sbloblen); if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD) omin = min = omax = max = -1; @@ -179,7 +185,7 @@ kexgex_server(Kex *kex) } /* sign H */ - if (PRIVSEP(key_sign(server_host_key, &signature, &slen, hash, + if (PRIVSEP(key_sign(server_host_private, &signature, &slen, hash, hashlen)) < 0) fatal("kexgex_server: key_sign failed"); @@ -1,4 +1,4 @@ -/* $OpenBSD: key.c,v 1.82 2010/01/13 01:10:56 dtucker Exp $ */ +/* $OpenBSD: key.c,v 1.83 2010/02/26 20:29:54 djm Exp $ */ /* * read_bignum(): * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -52,6 +52,21 @@ #include "uuencode.h" #include "buffer.h" #include "log.h" +#include "ssh2.h" + +static struct KeyCert * +cert_new(void) +{ + struct KeyCert *cert; + + cert = xcalloc(1, sizeof(*cert)); + buffer_init(&cert->certblob); + buffer_init(&cert->constraints); + cert->key_id = NULL; + cert->principals = NULL; + cert->signature_key = NULL; + return cert; +} Key * key_new(int type) @@ -63,9 +78,11 @@ key_new(int type) k->type = type; k->dsa = NULL; k->rsa = NULL; + k->cert = NULL; switch (k->type) { case KEY_RSA1: case KEY_RSA: + case KEY_RSA_CERT: if ((rsa = RSA_new()) == NULL) fatal("key_new: RSA_new failed"); if ((rsa->n = BN_new()) == NULL) @@ -75,6 +92,7 @@ key_new(int type) k->rsa = rsa; break; case KEY_DSA: + case KEY_DSA_CERT: if ((dsa = DSA_new()) == NULL) fatal("key_new: DSA_new failed"); if ((dsa->p = BN_new()) == NULL) @@ -93,16 +111,20 @@ key_new(int type) fatal("key_new: bad key type %d", k->type); break; } + + if (key_is_cert(k)) + k->cert = cert_new(); + return k; } -Key * -key_new_private(int type) +void +key_add_private(Key *k) { - Key *k = key_new(type); switch (k->type) { case KEY_RSA1: case KEY_RSA: + case KEY_RSA_CERT: if ((k->rsa->d = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); if ((k->rsa->iqmp = BN_new()) == NULL) @@ -117,6 +139,7 @@ key_new_private(int type) fatal("key_new_private: BN_new failed"); break; case KEY_DSA: + case KEY_DSA_CERT: if ((k->dsa->priv_key = BN_new()) == NULL) fatal("key_new_private: BN_new failed"); break; @@ -125,9 +148,34 @@ key_new_private(int type) default: break; } +} + +Key * +key_new_private(int type) +{ + Key *k = key_new(type); + + key_add_private(k); return k; } +static void +cert_free(struct KeyCert *cert) +{ + u_int i; + + buffer_free(&cert->certblob); + buffer_free(&cert->constraints); + if (cert->key_id != NULL) + xfree(cert->key_id); + for (i = 0; i < cert->nprincipals; i++) + xfree(cert->principals[i]); + if (cert->principals != NULL) + xfree(cert->principals); + if (cert->signature_key != NULL) + key_free(cert->signature_key); +} + void key_free(Key *k) { @@ -136,11 +184,13 @@ key_free(Key *k) switch (k->type) { case KEY_RSA1: case KEY_RSA: + case KEY_RSA_CERT: if (k->rsa != NULL) RSA_free(k->rsa); k->rsa = NULL; break; case KEY_DSA: + case KEY_DSA_CERT: if (k->dsa != NULL) DSA_free(k->dsa); k->dsa = NULL; @@ -151,20 +201,49 @@ key_free(Key *k) fatal("key_free: bad key type %d", k->type); break; } + if (key_is_cert(k)) { + if (k->cert != NULL) + cert_free(k->cert); + k->cert = NULL; + } + xfree(k); } +static int +cert_compare(struct KeyCert *a, struct KeyCert *b) +{ + if (a == NULL && b == NULL) + return 1; + if (a == NULL || b == NULL) + return 0; + if (buffer_len(&a->certblob) != buffer_len(&b->certblob)) + return 0; + if (memcmp(buffer_ptr(&a->certblob), buffer_ptr(&b->certblob), + buffer_len(&a->certblob)) != 0) + return 0; + return 1; +} + +/* + * Compare public portions of key only, allowing comparisons between + * certificates and plain keys too. + */ int -key_equal(const Key *a, const Key *b) +key_equal_public(const Key *a, const Key *b) { - if (a == NULL || b == NULL || a->type != b->type) + if (a == NULL || b == NULL || + key_type_plain(a->type) != key_type_plain(b->type)) return 0; + switch (a->type) { case KEY_RSA1: + case KEY_RSA_CERT: case KEY_RSA: return a->rsa != NULL && b->rsa != NULL && BN_cmp(a->rsa->e, b->rsa->e) == 0 && BN_cmp(a->rsa->n, b->rsa->n) == 0; + case KEY_DSA_CERT: case KEY_DSA: return a->dsa != NULL && b->dsa != NULL && BN_cmp(a->dsa->p, b->dsa->p) == 0 && @@ -177,16 +256,27 @@ key_equal(const Key *a, const Key *b) /* NOTREACHED */ } +int +key_equal(const Key *a, const Key *b) +{ + if (a == NULL || b == NULL || a->type != b->type) + return 0; + if (key_is_cert(a)) { + if (!cert_compare(a->cert, b->cert)) + return 0; + } + return key_equal_public(a, b); +} + u_char* -key_fingerprint_raw(const Key *k, enum fp_type dgst_type, - u_int *dgst_raw_length) +key_fingerprint_raw(Key *k, enum fp_type dgst_type, u_int *dgst_raw_length) { const EVP_MD *md = NULL; EVP_MD_CTX ctx; u_char *blob = NULL; u_char *retval = NULL; u_int len = 0; - int nlen, elen; + int nlen, elen, otype; *dgst_raw_length = 0; @@ -214,6 +304,14 @@ key_fingerprint_raw(const Key *k, enum fp_type dgst_type, case KEY_RSA: key_to_blob(k, &blob, &len); break; + case KEY_DSA_CERT: + case KEY_RSA_CERT: + /* We want a fingerprint of the _key_ not of the cert */ + otype = k->type; + k->type = key_type_plain(k->type); + key_to_blob(k, &blob, &len); + k->type = otype; + break; case KEY_UNSPEC: return retval; default: @@ -408,7 +506,7 @@ key_fingerprint_randomart(u_char *dgst_raw, u_int dgst_raw_len, const Key *k) } char * -key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep) +key_fingerprint(Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep) { char *retval = NULL; u_char *dgst_raw; @@ -533,6 +631,8 @@ key_read(Key *ret, char **cpp) case KEY_UNSPEC: case KEY_RSA: case KEY_DSA: + case KEY_DSA_CERT: + case KEY_RSA_CERT: space = strchr(cp, ' '); if (space == NULL) { debug3("key_read: missing whitespace"); @@ -577,25 +677,36 @@ key_read(Key *ret, char **cpp) return -1; } /*XXXX*/ - if (ret->type == KEY_RSA) { + if (key_is_cert(ret)) { + if (!key_is_cert(k)) { + error("key_read: loaded key is not a cert"); + key_free(k); + return -1; + } + if (ret->cert != NULL) + cert_free(ret->cert); + ret->cert = k->cert; + k->cert = NULL; + } + if (key_type_plain(ret->type) == KEY_RSA) { if (ret->rsa != NULL) RSA_free(ret->rsa); ret->rsa = k->rsa; k->rsa = NULL; - success = 1; #ifdef DEBUG_PK RSA_print_fp(stderr, ret->rsa, 8); #endif - } else { + } + if (key_type_plain(ret->type) == KEY_DSA) { if (ret->dsa != NULL) DSA_free(ret->dsa); ret->dsa = k->dsa; k->dsa = NULL; - success = 1; #ifdef DEBUG_PK DSA_print_fp(stderr, ret->dsa, 8); #endif } + success = 1; /*XXXX*/ key_free(k); if (success != 1) @@ -622,28 +733,53 @@ key_write(const Key *key, FILE *f) u_char *blob; char *uu; - if (key->type == KEY_RSA1 && key->rsa != NULL) { + if (key_is_cert(key)) { + if (key->cert == NULL) { + error("%s: no cert data", __func__); + return 0; + } + if (buffer_len(&key->cert->certblob) == 0) { + error("%s: no signed certificate blob", __func__); + return 0; + } + } + + switch (key->type) { + case KEY_RSA1: + if (key->rsa == NULL) + return 0; /* size of modulus 'n' */ bits = BN_num_bits(key->rsa->n); fprintf(f, "%u", bits); if (write_bignum(f, key->rsa->e) && - write_bignum(f, key->rsa->n)) { - success = 1; - } else { - error("key_write: failed for RSA key"); - } - } else if ((key->type == KEY_DSA && key->dsa != NULL) || - (key->type == KEY_RSA && key->rsa != NULL)) { - key_to_blob(key, &blob, &len); - uu = xmalloc(2*len); - n = uuencode(blob, len, uu, 2*len); - if (n > 0) { - fprintf(f, "%s %s", key_ssh_name(key), uu); - success = 1; - } - xfree(blob); - xfree(uu); + write_bignum(f, key->rsa->n)) + return 1; + error("key_write: failed for RSA key"); + return 0; + case KEY_DSA: + case KEY_DSA_CERT: + if (key->dsa == NULL) + return 0; + break; + case KEY_RSA: + case KEY_RSA_CERT: + if (key->rsa == NULL) + return 0; + break; + default: + return 0; } + + key_to_blob(key, &blob, &len); + uu = xmalloc(2*len); + n = uuencode(blob, len, uu, 2*len); + if (n > 0) { + fprintf(f, "%s %s", key_ssh_name(key), uu); + success = 1; + } + xfree(blob); + xfree(uu); + return success; } @@ -657,6 +793,10 @@ key_type(const Key *k) return "RSA"; case KEY_DSA: return "DSA"; + case KEY_RSA_CERT: + return "RSA-CERT"; + case KEY_DSA_CERT: + return "DSA-CERT"; } return "unknown"; } @@ -669,6 +809,10 @@ key_ssh_name(const Key *k) return "ssh-rsa"; case KEY_DSA: return "ssh-dss"; + case KEY_RSA_CERT: + return "ssh-rsa-cert-v00@openssh.com"; + case KEY_DSA_CERT: + return "ssh-dss-cert-v00@openssh.com"; } return "ssh-unknown"; } @@ -679,8 +823,10 @@ key_size(const Key *k) switch (k->type) { case KEY_RSA1: case KEY_RSA: + case KEY_RSA_CERT: return BN_num_bits(k->rsa->n); case KEY_DSA: + case KEY_DSA_CERT: return BN_num_bits(k->dsa->p); } return 0; @@ -723,6 +869,9 @@ key_generate(int type, u_int bits) case KEY_RSA1: k->rsa = rsa_generate_private_key(bits); break; + case KEY_RSA_CERT: + case KEY_DSA_CERT: + fatal("key_generate: cert keys cannot be generated directly"); default: fatal("key_generate: unknown type %d", type); } @@ -730,12 +879,55 @@ key_generate(int type, u_int bits) return k; } +void +key_cert_copy(const Key *from_key, struct Key *to_key) +{ + u_int i; + const struct KeyCert *from; + struct KeyCert *to; + + if (to_key->cert != NULL) { + cert_free(to_key->cert); + to_key->cert = NULL; + } + + if ((from = from_key->cert) == NULL) + return; + + to = to_key->cert = cert_new(); + + buffer_append(&to->certblob, buffer_ptr(&from->certblob), + buffer_len(&from->certblob)); + + buffer_append(&to->constraints, buffer_ptr(&from->constraints), + buffer_len(&from->constraints)); + + to->type = from->type; + to->key_id = from->key_id == NULL ? NULL : xstrdup(from->key_id); + to->valid_after = from->valid_after; + to->valid_before = from->valid_before; + to->signature_key = from->signature_key == NULL ? + NULL : key_from_private(from->signature_key); + + to->nprincipals = from->nprincipals; + if (to->nprincipals > CERT_MAX_PRINCIPALS) + fatal("%s: nprincipals (%u) > CERT_MAX_PRINCIPALS (%u)", + __func__, to->nprincipals, CERT_MAX_PRINCIPALS); + if (to->nprincipals > 0) { + to->principals = xcalloc(from->nprincipals, + sizeof(*to->principals)); + for (i = 0; i < to->nprincipals; i++) + to->principals[i] = xstrdup(from->principals[i]); + } +} + Key * key_from_private(const Key *k) { Key *n = NULL; switch (k->type) { case KEY_DSA: + case KEY_DSA_CERT: n = key_new(k->type); if ((BN_copy(n->dsa->p, k->dsa->p) == NULL) || (BN_copy(n->dsa->q, k->dsa->q) == NULL) || @@ -745,6 +937,7 @@ key_from_private(const Key *k) break; case KEY_RSA: case KEY_RSA1: + case KEY_RSA_CERT: n = key_new(k->type); if ((BN_copy(n->rsa->n, k->rsa->n) == NULL) || (BN_copy(n->rsa->e, k->rsa->e) == NULL)) @@ -754,6 +947,8 @@ key_from_private(const Key *k) fatal("key_from_private: unknown type %d", k->type); break; } + if (key_is_cert(k)) + key_cert_copy(k, n); return n; } @@ -770,6 +965,10 @@ key_type_from_name(char *name) return KEY_RSA; } else if (strcmp(name, "ssh-dss") == 0) { return KEY_DSA; + } else if (strcmp(name, "ssh-rsa-cert-v00@openssh.com") == 0) { + return KEY_RSA_CERT; + } else if (strcmp(name, "ssh-dss-cert-v00@openssh.com") == 0) { + return KEY_DSA_CERT; } debug2("key_type_from_name: unknown key type '%s'", name); return KEY_UNSPEC; @@ -797,6 +996,117 @@ key_names_valid2(const char *names) return 1; } +static int +cert_parse(Buffer *b, Key *key, const u_char *blob, u_int blen) +{ + u_char *principals, *constraints, *sig_key, *sig; + u_int signed_len, plen, clen, sklen, slen; + Buffer tmp; + char *principal; + int ret = -1; + + buffer_init(&tmp); + + /* Copy the entire key blob for verification and later serialisation */ + buffer_append(&key->cert->certblob, blob, blen); + + principals = constraints = sig_key = sig = NULL; + if (buffer_get_int_ret(&key->cert->type, b) != 0 || + (key->cert->key_id = buffer_get_string_ret(b, NULL)) == NULL || + (principals = buffer_get_string_ret(b, &plen)) == NULL || + buffer_get_int64_ret(&key->cert->valid_after, b) != 0 || + buffer_get_int64_ret(&key->cert->valid_before, b) != 0 || + (constraints = buffer_get_string_ret(b, &clen)) == NULL || + /* skip nonce */ buffer_get_string_ptr_ret(b, NULL) == NULL || + /* skip reserved */ buffer_get_string_ptr_ret(b, NULL) == NULL || + (sig_key = buffer_get_string_ret(b, &sklen)) == NULL) { + error("%s: parse error", __func__); + goto out; + } + + /* Signature is left in the buffer so we can calculate this length */ + signed_len = buffer_len(&key->cert->certblob) - buffer_len(b); + + if ((sig = buffer_get_string_ret(b, &slen)) == NULL) { + error("%s: parse error", __func__); + goto out; + } + + if (key->cert->type != SSH2_CERT_TYPE_USER && + key->cert->type != SSH2_CERT_TYPE_HOST) { + error("Unknown certificate type %u", key->cert->type); + goto out; + } + + buffer_append(&tmp, principals, plen); + while (buffer_len(&tmp) > 0) { + if (key->cert->nprincipals >= CERT_MAX_PRINCIPALS) { + error("Too many principals"); + goto out; + } + if ((principal = buffer_get_string_ret(&tmp, NULL)) == NULL) { + error("Principals data invalid"); + goto out; + } + key->cert->principals = xrealloc(key->cert->principals, + key->cert->nprincipals + 1, sizeof(*key->cert->principals)); + key->cert->principals[key->cert->nprincipals++] = principal; + } + + buffer_clear(&tmp); + + buffer_append(&key->cert->constraints, constraints, clen); + buffer_append(&tmp, constraints, clen); + /* validate structure */ + while (buffer_len(&tmp) != 0) { + if (buffer_get_string_ptr(&tmp, NULL) == NULL || + buffer_get_string_ptr(&tmp, NULL) == NULL) { + error("Constraints data invalid"); + goto out; + } + } + buffer_clear(&tmp); + + if ((key->cert->signature_key = key_from_blob(sig_key, + sklen)) == NULL) { + error("Signature key invalid"); + goto out; + } + if (key->cert->signature_key->type != KEY_RSA && + key->cert->signature_key->type != KEY_DSA) { + error("Invalid signature key type %s (%d)", + key_type(key->cert->signature_key), + key->cert->signature_key->type); + goto out; + } + + switch (key_verify(key->cert->signature_key, sig, slen, + buffer_ptr(&key->cert->certblob), signed_len)) { + case 1: + break; /* Good signature */ + case 0: + error("Invalid signature on certificate"); + goto out; + case -1: + error("Certificate signature verification failed"); + goto out; + } + + ret = 0; + + out: + buffer_free(&tmp); + if (principals != NULL) + xfree(principals); + if (constraints != NULL) + xfree(constraints); + if (sig_key != NULL) + xfree(sig_key); + if (sig != NULL) + xfree(sig); + return ret; +} + Key * key_from_blob(const u_char *blob, u_int blen) { @@ -819,10 +1129,12 @@ key_from_blob(const u_char *blob, u_int blen) switch (type) { case KEY_RSA: + case KEY_RSA_CERT: key = key_new(type); if (buffer_get_bignum2_ret(&b, key->rsa->e) == -1 || buffer_get_bignum2_ret(&b, key->rsa->n) == -1) { error("key_from_blob: can't read rsa key"); + badkey: key_free(key); key = NULL; goto out; @@ -832,15 +1144,14 @@ key_from_blob(const u_char *blob, u_int blen) #endif break; case KEY_DSA: + case KEY_DSA_CERT: key = key_new(type); if (buffer_get_bignum2_ret(&b, key->dsa->p) == -1 || buffer_get_bignum2_ret(&b, key->dsa->q) == -1 || buffer_get_bignum2_ret(&b, key->dsa->g) == -1 || buffer_get_bignum2_ret(&b, key->dsa->pub_key) == -1) { error("key_from_blob: can't read dsa key"); - key_free(key); - key = NULL; - goto out; + goto badkey; } #ifdef DEBUG_PK DSA_print_fp(stderr, key->dsa, 8); @@ -853,6 +1164,10 @@ key_from_blob(const u_char *blob, u_int blen) error("key_from_blob: cannot handle type %s", ktype); goto out; } + if (key_is_cert(key) && cert_parse(&b, key, blob, blen) == -1) { + error("key_from_blob: can't parse cert data"); + goto badkey; + } rlen = buffer_len(&b); if (key != NULL && rlen != 0) error("key_from_blob: remaining bytes in key blob %d", rlen); @@ -875,6 +1190,12 @@ key_to_blob(const Key *key, u_char **blobp, u_int *lenp) } buffer_init(&b); switch (key->type) { + case KEY_DSA_CERT: + case KEY_RSA_CERT: + /* Use the existing blob */ + buffer_append(&b, buffer_ptr(&key->cert->certblob), + buffer_len(&key->cert->certblob)); + break; case KEY_DSA: buffer_put_cstring(&b, key_ssh_name(key)); buffer_put_bignum2(&b, key->dsa->p); @@ -911,8 +1232,10 @@ key_sign( const u_char *data, u_int datalen) { switch (key->type) { + case KEY_DSA_CERT: case KEY_DSA: return ssh_dss_sign(key, sigp, lenp, data, datalen); + case KEY_RSA_CERT: case KEY_RSA: return ssh_rsa_sign(key, sigp, lenp, data, datalen); default: @@ -935,8 +1258,10 @@ key_verify( return -1; switch (key->type) { + case KEY_DSA_CERT: case KEY_DSA: return ssh_dss_verify(key, signature, signaturelen, data, datalen); + case KEY_RSA_CERT: case KEY_RSA: return ssh_rsa_verify(key, signature, signaturelen, data, datalen); default: @@ -958,6 +1283,9 @@ key_demote(const Key *k) pk->rsa = NULL; switch (k->type) { + case KEY_RSA_CERT: + key_cert_copy(k, pk); + /* FALLTHROUGH */ case KEY_RSA1: case KEY_RSA: if ((pk->rsa = RSA_new()) == NULL) @@ -967,6 +1295,9 @@ key_demote(const Key *k) if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL) fatal("key_demote: BN_dup failed"); break; + case KEY_DSA_CERT: + key_cert_copy(k, pk); + /* FALLTHROUGH */ case KEY_DSA: if ((pk->dsa = DSA_new()) == NULL) fatal("key_demote: DSA_new failed"); @@ -986,3 +1317,199 @@ key_demote(const Key *k) return (pk); } + +int +key_is_cert(const Key *k) +{ + return k != NULL && + (k->type == KEY_RSA_CERT || k->type == KEY_DSA_CERT); +} + +/* Return the cert-less equivalent to a certified key type */ +int +key_type_plain(int type) +{ + switch (type) { + case KEY_RSA_CERT: + return KEY_RSA; + case KEY_DSA_CERT: + return KEY_DSA; + default: + return type; + } +} + +/* Convert a KEY_RSA or KEY_DSA to their _CERT equivalent */ +int +key_to_certified(Key *k) +{ + switch (k->type) { + case KEY_RSA: + k->cert = cert_new(); + k->type = KEY_RSA_CERT; + return 0; + case KEY_DSA: + k->cert = cert_new(); + k->type = KEY_DSA_CERT; + return 0; + default: + error("%s: key has incorrect type %s", __func__, key_type(k)); + return -1; + } +} + +/* Convert a KEY_RSA_CERT or KEY_DSA_CERT to their raw key equivalent */ +int +key_drop_cert(Key *k) +{ + switch (k->type) { + case KEY_RSA_CERT: + cert_free(k->cert); + k->type = KEY_RSA; + return 0; + case KEY_DSA_CERT: + cert_free(k->cert); + k->type = KEY_DSA; + return 0; + default: + error("%s: key has incorrect type %s", __func__, key_type(k)); + return -1; + } +} + +/* Sign a KEY_RSA_CERT or KEY_DSA_CERT, (re-)generating the signed certblob */ +int +key_certify(Key *k, Key *ca) +{ + Buffer principals; + u_char *ca_blob, *sig_blob, nonce[32]; + u_int i, ca_len, sig_len; + + if (k->cert == NULL) { + error("%s: key lacks cert info", __func__); + return -1; + } + + if (!key_is_cert(k)) { + error("%s: certificate has unknown type %d", __func__, + k->cert->type); + return -1; + } + + if (ca->type != KEY_RSA && ca->type != KEY_DSA) { + error("%s: CA key has unsupported type %s", __func__, + key_type(ca)); + return -1; + } + + key_to_blob(ca, &ca_blob, &ca_len); + + buffer_clear(&k->cert->certblob); + buffer_put_cstring(&k->cert->certblob, key_ssh_name(k)); + + switch (k->type) { + case KEY_DSA_CERT: + buffer_put_bignum2(&k->cert->certblob, k->dsa->p); + buffer_put_bignum2(&k->cert->certblob, k->dsa->q); + buffer_put_bignum2(&k->cert->certblob, k->dsa->g); + buffer_put_bignum2(&k->cert->certblob, k->dsa->pub_key); + break; + case KEY_RSA_CERT: + buffer_put_bignum2(&k->cert->certblob, k->rsa->e); + buffer_put_bignum2(&k->cert->certblob, k->rsa->n); + break; + default: + error("%s: key has incorrect type %s", __func__, key_type(k)); + buffer_clear(&k->cert->certblob); + xfree(ca_blob); + return -1; + } + + buffer_put_int(&k->cert->certblob, k->cert->type); + buffer_put_cstring(&k->cert->certblob, k->cert->key_id); + + buffer_init(&principals); + for (i = 0; i < k->cert->nprincipals; i++) + buffer_put_cstring(&principals, k->cert->principals[i]); + buffer_put_string(&k->cert->certblob, buffer_ptr(&principals), + buffer_len(&principals)); + buffer_free(&principals); + + buffer_put_int64(&k->cert->certblob, k->cert->valid_after); + buffer_put_int64(&k->cert->certblob, k->cert->valid_before); + buffer_put_string(&k->cert->certblob, + buffer_ptr(&k->cert->constraints), + buffer_len(&k->cert->constraints)); + + arc4random_buf(&nonce, sizeof(nonce)); + buffer_put_string(&k->cert->certblob, nonce, sizeof(nonce)); + buffer_put_string(&k->cert->certblob, NULL, 0); /* reserved */ + buffer_put_string(&k->cert->certblob, ca_blob, ca_len); + xfree(ca_blob); + + /* Sign the whole mess */ + if (key_sign(ca, &sig_blob, &sig_len, buffer_ptr(&k->cert->certblob), + buffer_len(&k->cert->certblob)) != 0) { + error("%s: signature operation failed", __func__); + buffer_clear(&k->cert->certblob); + return -1; + } + /* Append signature and we are done */ + buffer_put_string(&k->cert->certblob, sig_blob, sig_len); + xfree(sig_blob); + + return 0; +} + +int +key_cert_check_authority(const Key *k, int want_host, int require_principal, + const char *name, const char **reason) +{ + u_int i, principal_matches; + time_t now = time(NULL); + + if (want_host) { + if (k->cert->type != SSH2_CERT_TYPE_HOST) { + *reason = "Certificate invalid: not a host certificate"; + return -1; + } + } else { + if (k->cert->type != SSH2_CERT_TYPE_USER) { + *reason = "Certificate invalid: not a user certificate"; + return -1; + } + } + if (now < 0) { + error("%s: system clock lies before epoch", __func__); + *reason = "Certificate invalid: not yet valid"; + return -1; + } + if ((u_int64_t)now < k->cert->valid_after) { + *reason = "Certificate invalid: not yet valid"; + return -1; + } + if ((u_int64_t)now >= k->cert->valid_before) { + *reason = "Certificate invalid: expired"; + return -1; + } + if (k->cert->nprincipals == 0) { + if (require_principal) { + *reason = "Certificate lacks principal list"; + return -1; + } + } else { + principal_matches = 0; + for (i = 0; i < k->cert->nprincipals; i++) { + if (strcmp(name, k->cert->principals[i]) == 0) { + principal_matches = 1; + break; + } + } + if (!principal_matches) { + *reason = "Certificate invalid: name is not a listed " + "principal"; + return -1; + } + } + return 0; +} @@ -1,4 +1,4 @@ -/* $OpenBSD: key.h,v 1.27 2008/06/11 21:01:35 grunk Exp $ */ +/* $OpenBSD: key.h,v 1.28 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. @@ -26,6 +26,7 @@ #ifndef KEY_H #define KEY_H +#include "buffer.h" #include <openssl/rsa.h> #include <openssl/dsa.h> @@ -34,6 +35,8 @@ enum types { KEY_RSA1, KEY_RSA, KEY_DSA, + KEY_RSA_CERT, + KEY_DSA_CERT, KEY_UNSPEC }; enum fp_type { @@ -49,20 +52,35 @@ enum fp_rep { /* key is stored in external hardware */ #define KEY_FLAG_EXT 0x0001 +#define CERT_MAX_PRINCIPALS 256 +struct KeyCert { + Buffer certblob; /* Kept around for use on wire */ + u_int type; /* SSH2_CERT_TYPE_USER or SSH2_CERT_TYPE_HOST */ + char *key_id; + u_int nprincipals; + char **principals; + u_int64_t valid_after, valid_before; + Buffer constraints; + Key *signature_key; +}; + struct Key { int type; int flags; RSA *rsa; DSA *dsa; + struct KeyCert *cert; }; Key *key_new(int); +void key_add_private(Key *); Key *key_new_private(int); void key_free(Key *); Key *key_demote(const Key *); +int key_equal_public(const Key *, const Key *); int key_equal(const Key *, const Key *); -char *key_fingerprint(const Key *, enum fp_type, enum fp_rep); -u_char *key_fingerprint_raw(const Key *, enum fp_type, u_int *); +char *key_fingerprint(Key *, enum fp_type, enum fp_rep); +u_char *key_fingerprint_raw(Key *, enum fp_type, u_int *); const char *key_type(const Key *); int key_write(const Key *, FILE *); int key_read(Key *, char **); @@ -71,6 +89,14 @@ u_int key_size(const Key *); Key *key_generate(int, u_int); Key *key_from_private(const Key *); int key_type_from_name(char *); +int key_is_cert(const Key *); +int key_type_plain(int); +int key_to_certified(Key *); +int key_drop_cert(Key *); +int key_certify(Key *, Key *); +void key_cert_copy(const Key *, struct Key *); +int key_cert_check_authority(const Key *, int, int, const char *, + const char **); Key *key_from_blob(const u_char *, u_int); int key_to_blob(const Key *, u_char **, u_int *); @@ -1,4 +1,4 @@ -/* $OpenBSD: match.h,v 1.14 2008/06/10 03:57:27 djm Exp $ */ +/* $OpenBSD: match.h,v 1.15 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> @@ -23,5 +23,5 @@ char *match_list(const char *, const char *, u_int *); /* addrmatch.c */ int addr_match_list(const char *, const char *); - +int addr_match_cidr_list(const char *, const char *); #endif @@ -1,4 +1,4 @@ -/* $OpenBSD: monitor.c,v 1.104 2009/06/12 20:43:22 andreas Exp $ */ +/* $OpenBSD: monitor.c,v 1.105 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright 2002 Niels Provos <provos@citi.umich.edu> * Copyright 2002 Markus Friedl <markus@openbsd.org> @@ -1721,7 +1721,8 @@ mm_get_kex(Buffer *m) kex->flags = buffer_get_int(m); kex->client_version_string = buffer_get_string(m, NULL); kex->server_version_string = buffer_get_string(m, NULL); - kex->load_host_key=&get_hostkey_by_type; + kex->load_host_public_key=&get_hostkey_public_by_type; + kex->load_host_private_key=&get_hostkey_private_by_type; kex->host_key_index=&get_hostkey_index; return (kex); diff --git a/myproposal.h b/myproposal.h index 7bca3bca..98f27fd1 100644 --- a/myproposal.h +++ b/myproposal.h @@ -1,4 +1,4 @@ -/* $OpenBSD: myproposal.h,v 1.23 2009/01/23 07:58:11 djm Exp $ */ +/* $OpenBSD: myproposal.h,v 1.24 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. @@ -40,7 +40,9 @@ "diffie-hellman-group1-sha1" #endif -#define KEX_DEFAULT_PK_ALG "ssh-rsa,ssh-dss" +#define KEX_DEFAULT_PK_ALG "ssh-rsa-cert-v00@openssh.com," \ + "ssh-dss-cert-v00@openssh.com," \ + "ssh-rsa,ssh-dss" #define KEX_DEFAULT_ENCRYPT \ "aes128-ctr,aes192-ctr,aes256-ctr," \ @@ -1,4 +1,4 @@ -/* $OpenBSD: servconf.c,v 1.202 2010/01/13 03:48:12 djm Exp $ */ +/* $OpenBSD: servconf.c,v 1.203 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland * All rights reserved @@ -65,6 +65,7 @@ initialize_server_options(ServerOptions *options) options->listen_addrs = NULL; options->address_family = -1; options->num_host_key_files = 0; + options->num_host_cert_files = 0; options->pid_file = NULL; options->server_key_bits = -1; options->login_grace_time = -1; @@ -152,6 +153,7 @@ fill_default_server_options(ServerOptions *options) _PATH_HOST_DSA_KEY_FILE; } } + /* No certificates by default */ if (options->num_ports == 0) options->ports[options->num_ports++] = SSH_DEFAULT_PORT; if (options->listen_addrs == NULL) @@ -305,7 +307,7 @@ typedef enum { sGssAuthentication, sGssCleanupCreds, sAcceptEnv, sPermitTunnel, sMatch, sPermitOpen, sForceCommand, sChrootDirectory, sUsePrivilegeSeparation, sAllowAgentForwarding, - sZeroKnowledgePasswordAuthentication, + sZeroKnowledgePasswordAuthentication, sHostCertificate, sDeprecated, sUnsupported } ServerOpCodes; @@ -424,6 +426,7 @@ static struct { { "permitopen", sPermitOpen, SSHCFG_ALL }, { "forcecommand", sForceCommand, SSHCFG_ALL }, { "chrootdirectory", sChrootDirectory, SSHCFG_ALL }, + { "hostcertificate", sHostCertificate, SSHCFG_GLOBAL }, { NULL, sBadOption, 0 } }; @@ -816,6 +819,16 @@ process_server_config_line(ServerOptions *options, char *line, } break; + case sHostCertificate: + intptr = &options->num_host_cert_files; + if (*intptr >= MAX_HOSTKEYS) + fatal("%s line %d: too many host certificates " + "specified (max %d).", filename, linenum, + MAX_HOSTCERTS); + charptr = &options->host_cert_files[*intptr]; + goto parse_filename; + break; + case sPidFile: charptr = &options->pid_file; goto parse_filename; @@ -1651,6 +1664,8 @@ dump_config(ServerOptions *o) /* string array arguments */ dump_cfg_strarray(sHostKeyFile, o->num_host_key_files, o->host_key_files); + dump_cfg_strarray(sHostKeyFile, o->num_host_cert_files, + o->host_cert_files); dump_cfg_strarray(sAllowUsers, o->num_allow_users, o->allow_users); dump_cfg_strarray(sDenyUsers, o->num_deny_users, o->deny_users); dump_cfg_strarray(sAllowGroups, o->num_allow_groups, o->allow_groups); @@ -1,4 +1,4 @@ -/* $OpenBSD: servconf.h,v 1.90 2010/01/13 03:48:13 djm Exp $ */ +/* $OpenBSD: servconf.h,v 1.91 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> @@ -24,6 +24,7 @@ #define MAX_DENY_GROUPS 256 /* Max # groups on deny list. */ #define MAX_SUBSYSTEMS 256 /* Max # subsystems. */ #define MAX_HOSTKEYS 256 /* Max # hostkeys. */ +#define MAX_HOSTCERTS 256 /* Max # host certificates. */ #define MAX_ACCEPT_ENV 256 /* Max # of env vars. */ #define MAX_MATCH_GROUPS 256 /* Max # of groups for Match. */ @@ -49,6 +50,8 @@ typedef struct { int address_family; /* Address family used by the server. */ char *host_key_files[MAX_HOSTKEYS]; /* Files containing host keys. */ int num_host_key_files; /* Number of files for host keys. */ + char *host_cert_files[MAX_HOSTCERTS]; /* Files containing host certs. */ + int num_host_cert_files; /* Number of files for host certs. */ char *pid_file; /* Where to put our pid */ int server_key_bits;/* Size of the server key. */ int login_grace_time; /* Disconnect if no auth in this time @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-add.c,v 1.92 2010/02/08 10:50:20 markus Exp $ */ +/* $OpenBSD: ssh-add.c,v 1.93 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -138,9 +138,9 @@ delete_all(AuthenticationConnection *ac) static int add_file(AuthenticationConnection *ac, const char *filename) { - Key *private; + Key *private, *cert; char *comment = NULL; - char msg[1024]; + char msg[1024], *certpath; int fd, perms_ok, ret = -1; if ((fd = open(filename, O_RDONLY)) < 0) { @@ -199,6 +199,34 @@ add_file(AuthenticationConnection *ac, const char *filename) fprintf(stderr, "Could not add identity: %s\n", filename); } + + /* Now try to add the certificate flavour too */ + xasprintf(&certpath, "%s-cert.pub", filename); + if ((cert = key_load_public(certpath, NULL)) != NULL) { + /* Graft with private bits */ + if (key_to_certified(private) != 0) + fatal("%s: key_to_certified failed", __func__); + key_cert_copy(cert, private); + key_free(cert); + + if (ssh_add_identity_constrained(ac, private, comment, + lifetime, confirm)) { + fprintf(stderr, "Certificate added: %s (%s)\n", + certpath, private->cert->key_id); + if (lifetime != 0) + fprintf(stderr, "Lifetime set to %d seconds\n", + lifetime); + if (confirm != 0) + fprintf(stderr, "The user has to confirm each " + "use of the key\n"); + } else { + error("Certificate %s (%s) add failed", certpath, + private->cert->key_id); + } + } else + fprintf(stderr, "Unable to load certificate %s", certpath); + + xfree(certpath); xfree(comment); key_free(private); diff --git a/ssh-agent.c b/ssh-agent.c index 46a744f4..b5c56527 100644 --- a/ssh-agent.c +++ b/ssh-agent.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-agent.c,v 1.164 2010/02/09 00:50:36 djm Exp $ */ +/* $OpenBSD: ssh-agent.c,v 1.165 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -468,6 +468,8 @@ process_add_identity(SocketEntry *e, int version) int type, success = 0, death = 0, confirm = 0; char *type_name, *comment; Key *k = NULL; + u_char *cert; + u_int len; switch (version) { case 1: @@ -498,6 +500,14 @@ process_add_identity(SocketEntry *e, int version) buffer_get_bignum2(&e->request, k->dsa->pub_key); buffer_get_bignum2(&e->request, k->dsa->priv_key); break; + case KEY_DSA_CERT: + cert = buffer_get_string(&e->request, &len); + if ((k = key_from_blob(cert, len)) == NULL) + fatal("Certificate parse failed"); + xfree(cert); + key_add_private(k); + buffer_get_bignum2(&e->request, k->dsa->priv_key); + break; case KEY_RSA: k = key_new_private(type); buffer_get_bignum2(&e->request, k->rsa->n); @@ -510,6 +520,17 @@ process_add_identity(SocketEntry *e, int version) /* Generate additional parameters */ rsa_generate_additional_parameters(k->rsa); break; + case KEY_RSA_CERT: + cert = buffer_get_string(&e->request, &len); + if ((k = key_from_blob(cert, len)) == NULL) + fatal("Certificate parse failed"); + xfree(cert); + key_add_private(k); + buffer_get_bignum2(&e->request, k->rsa->d); + buffer_get_bignum2(&e->request, k->rsa->iqmp); + buffer_get_bignum2(&e->request, k->rsa->p); + buffer_get_bignum2(&e->request, k->rsa->q); + break; default: buffer_clear(&e->request); goto send; @@ -519,6 +540,7 @@ process_add_identity(SocketEntry *e, int version) /* enable blinding */ switch (k->type) { case KEY_RSA: + case KEY_RSA_CERT: case KEY_RSA1: if (RSA_blinding_on(k->rsa, NULL) != 1) { error("process_add_identity: RSA_blinding_on failed"); @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-dss.c,v 1.24 2006/11/06 21:25:28 markus Exp $ */ +/* $OpenBSD: ssh-dss.c,v 1.25 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -53,7 +53,9 @@ ssh_dss_sign(const Key *key, u_char **sigp, u_int *lenp, u_int rlen, slen, len, dlen; Buffer b; - if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) { + if (key == NULL || + (key->type != KEY_DSA && key->type != KEY_DSA_CERT) || + key->dsa == NULL) { error("ssh_dss_sign: no DSA key"); return -1; } @@ -116,7 +118,9 @@ ssh_dss_verify(const Key *key, const u_char *signature, u_int signaturelen, int rlen, ret; Buffer b; - if (key == NULL || key->type != KEY_DSA || key->dsa == NULL) { + if (key == NULL || + (key->type != KEY_DSA && key->type != KEY_DSA_CERT) || + key->dsa == NULL) { error("ssh_dss_verify: no DSA key"); return -1; } diff --git a/ssh-keygen.1 b/ssh-keygen.1 index f09e1a10..772caf7a 100644 --- a/ssh-keygen.1 +++ b/ssh-keygen.1 @@ -1,4 +1,4 @@ -.\" $OpenBSD: ssh-keygen.1,v 1.83 2010/02/10 23:20:38 markus Exp $ +.\" $OpenBSD: ssh-keygen.1,v 1.84 2010/02/26 20:29:54 djm Exp $ .\" .\" -*- nroff -*- .\" @@ -37,7 +37,7 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.Dd $Mdocdate: February 10 2010 $ +.Dd $Mdocdate: February 26 2010 $ .Dt SSH-KEYGEN 1 .Os .Sh NAME @@ -106,6 +106,14 @@ .Op Fl v .Op Fl a Ar num_trials .Op Fl W Ar generator +.Nm ssh-keygen +.Fl s Ar ca_key +.Fl I Ar certificate_identity +.Op Fl h +.Op Fl n Ar principals +.Op Fl O Ar constraint +.Op Fl V Ar validity_interval +.Ar .Sh DESCRIPTION .Nm generates, manages and converts authentication keys for @@ -245,6 +253,17 @@ but they do not reveal identifying information should the file's contents be disclosed. This option will not modify existing hashed hostnames and is therefore safe to use on files that mix hashed and non-hashed names. +.It Fl h +When signing a key, create a host certificate instead of a user +certificate. +Please see the +.Sx CERTIFICATES +section for details. +.It Fl I +Specify the key identity when signing a public key. +Please see the +.Sx CERTIFICATES +section for details. .It Fl i This option will read an unencrypted private (or public) key file in SSH2-compatible format and print an OpenSSH compatible private @@ -268,6 +287,67 @@ Specify the amount of memory to use (in megabytes) when generating candidate moduli for DH-GEX. .It Fl N Ar new_passphrase Provides the new passphrase. +.It Fl n Ar principals +Specify one or more principals (user or host names) to be included in +a certificate when signing a key. +Multiple principals may be specified, separated by commas. +Please see the +.Sx CERTIFICATES +section for details. +.It Fl O Ar constraint +Specify a certificate constraint when signing a key. +This option may be specified multiple times. +Please see the +.Sx CERTIFICATES +section for details. +The constraints that are valid for user certificates are: +.Bl -tag -width Ds +.It Ic no-x11-forwarding +Disable X11 forwarding. (permitted by default) +.It Ic no-agent-forwarding +Disable +.Xr ssh-agent 1 +forwarding. (permitted by default) +.It Ic no-port-forwarding +Disable port forwarding. (permitted by default) +.It Ic no-pty +Disable PTY allocation. (permitted by default) +.It Ic no-user-rc +Disable execution of +.Pa ~/.ssh/rc +by +.Xr sshd 8 . +(permitted by default) +.It Ic clear +Clear all enabled permissions. +This is useful for clearing the default set of permissions so permissions may +be added individually. +.It Ic permit-x11-forwarding +Allows X11 forwarding. +.It Ic permit-port-forwarding +Allows port forwarding. +.It Ic permit-pty +Allows PTY allocation. +.It Ic permit-user-rc +Allows execution of +.Pa ~/.ssh/rc +by +.Xr sshd 8 . +.It Ic force-command=command +Forces the execution of +.Ar command +instead of any shell or command specified by the user when +the certificate is used for authentication. +.It Ic source-address=address_list +Restrict the source addresses from which the certificate is considered valid +from. +The +.Ar address_list +is a comma-separated list of one or more address/netmask pairs in CIDR +format. +.El +.Pp +At present, no constraints are valid for host keys. .It Fl P Ar passphrase Provides the (old) passphrase. .It Fl p @@ -297,6 +377,11 @@ Print the SSHFP fingerprint resource record named for the specified public key file. .It Fl S Ar start Specify start point (in hex) when generating candidate moduli for DH-GEX. +.It Fl s Ar ca_key +Certify (sign) a public key using the specified CA key. +Please see the +.Sx CERTIFICATES +section for details. .It Fl T Ar output_file Test DH group exchange candidate primes (generated using the .Fl G @@ -310,6 +395,29 @@ for protocol version 1 and or .Dq dsa for protocol version 2. +.It Fl V Ar validity_interval +Specify a validity interval when signing a certificate. +A validity interval may consist of a single time, indicating that the +certificate is valid beginning now and expiring at that time, or may consist +of two times separated by a colon to indicate an explicit time interval. +The start time may be specified as a date in YYYYMMDD format, a time +in YYYYMMDDHHMMSS format or a relative time (to the current time) consisting +of a minus sign followed by a relative time in the format described in the +.Sx TIME FORMATS +section of +.Xr ssh_config 5 . +The end time may be specified as a YYYYMMDD date, a YYYYMMDDHHMMSS time or +a relative time starting with a plus character. +.Pp +For example: +.Dq +52w1d +(valid from now to 52 weeks and one day from now), +.Dq -4w:+4w +(valid from four weeks ago to four weeks from now), +.Dq 20100101123000:20110101123000 +(valid from 12:30 PM, January 1st, 2010 to 12:30 PM, January 1st, 2011), +.Dq -1d:20110101 +(valid from yesterday to midnight, January 1st, 2011). .It Fl v Verbose mode. Causes @@ -380,6 +488,72 @@ Screened DH groups may be installed in .Pa /etc/moduli . It is important that this file contains moduli of a range of bit lengths and that both ends of a connection share common moduli. +.Sh CERTIFICATES +.Nm +supports signing of keys to produce certificates that may be used for +user or host authentication. +Certificates consist of a public key, some identity information, zero or +more principal (user or host) names and an optional set of constraints that +are signed by a Certification Authority (CA) key. +Clients or servers may then trust only the CA key and verify its signature +on a certificate rather than trusting many user/host keys. +Note that OpenSSH certificates are a different, and much simpler, format to +the X.509 certificates used in +.Xr ssl 8 . +.Pp +.Nm +supports two types of certificates: user and host. +User certificates authenticate users to servers, whereas host certificates +authenticate server hosts to users. To generate a user certificate: +.Pp +.Dl $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub +.Pp +The resultant certificate will be placed in +.Pa /path/to/user_key_cert.pub . +A host certificate requires the +.Fl h +option: +.Pp +.Dl $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub +.Pp +The host certificate will be output to +.Pa /path/to/host_key_cert.pub . +In both cases, +.Ar key_id +is a "key identifier" that is logged by the server when the certificate +is used for authentication. +.Pp +Certificates may be limited to be valid for a set of principal (user/host) +names. +By default, generated certificates are valid for all users or hosts. +To generate a certificate for a specified set of principals: +.Pp +.Dl $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub +.Dl $ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub +.Pp +Additional limitations on the validity and use of user certificates may +be specified through certificate constraints. +A constrained certificate may disable features of the SSH session, may be +valid only when presented from particular source addresses or may +force the use of a specific command. +For a list of valid certificate constraints, see the documentation for the +.Fl O +option above. +.Pp +Finally, certificates may be defined with a validity lifetime. +The +.Fl V +option allows specification of certificate start and end times. +A certificate that is presented at a time outside this range will not be +considered valid. +By default, certificates have a maximum validity interval. +.Pp +For certificates to be used for user or host authentication, the CA +public key must be trusted by +.Xr sshd 8 +or +.Xr ssh 1 . +Please refer to those manual pages for details. .Sh FILES .Bl -tag -width Ds .It Pa ~/.ssh/identity diff --git a/ssh-keygen.c b/ssh-keygen.c index b6b7a2d9..60261c21 100644 --- a/ssh-keygen.c +++ b/ssh-keygen.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-keygen.c,v 1.178 2010/02/09 00:50:59 djm Exp $ */ +/* $OpenBSD: ssh-keygen.c,v 1.179 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -48,6 +48,7 @@ #include "match.h" #include "hostfile.h" #include "dns.h" +#include "ssh2.h" #ifdef ENABLE_PKCS11 #include "ssh-pkcs11.h" @@ -98,6 +99,35 @@ char *identity_new_passphrase = NULL; /* This is set to the new comment if given on the command line. */ char *identity_comment = NULL; +/* Path to CA key when certifying keys. */ +char *ca_key_path = NULL; + +/* Key type when certifying */ +u_int cert_key_type = SSH2_CERT_TYPE_USER; + +/* "key ID" of signed key */ +char *cert_key_id = NULL; + +/* Comma-separated list of principal names for certifying keys */ +char *cert_principals = NULL; + +/* Validity period for certificates */ +u_int64_t cert_valid_from = 0; +u_int64_t cert_valid_to = ~0ULL; + +/* Certificate constraints */ +#define CONSTRAINT_X_FWD (1) +#define CONSTRAINT_AGENT_FWD (1<<1) +#define CONSTRAINT_PORT_FWD (1<<2) +#define CONSTRAINT_PTY (1<<3) +#define CONSTRAINT_USER_RC (1<<4) +#define CONSTRAINT_DEFAULT (CONSTRAINT_X_FWD|CONSTRAINT_AGENT_FWD| \ + CONSTRAINT_PORT_FWD|CONSTRAINT_PTY| \ + CONSTRAINT_USER_RC) +u_int32_t constraint_flags = CONSTRAINT_DEFAULT; +char *constraint_command = NULL; +char *constraint_src_addr = NULL; + /* Dump public key file in format used by real and the original SSH 2 */ int convert_to_ssh2 = 0; int convert_from_ssh2 = 0; @@ -591,7 +621,7 @@ do_fingerprint(struct passwd *pw) } static void -print_host(FILE *f, const char *name, Key *public, int hash) +printhost(FILE *f, const char *name, Key *public, int ca, int hash) { if (print_fingerprint) { enum fp_rep rep; @@ -611,7 +641,7 @@ print_host(FILE *f, const char *name, Key *public, int hash) } else { if (hash && (name = host_hash(name, NULL, 0)) == NULL) fatal("hash_host failed"); - fprintf(f, "%s ", name); + fprintf(f, "%s%s%s ", ca ? CA_MARKER : "", ca ? " " : "", name); if (!key_write(public, f)) fatal("key_write failed"); fprintf(f, "\n"); @@ -622,10 +652,11 @@ static void do_known_hosts(struct passwd *pw, const char *name) { FILE *in, *out = stdout; - Key *public; + Key *pub; char *cp, *cp2, *kp, *kp2; char line[16*1024], tmp[MAXPATHLEN], old[MAXPATHLEN]; int c, skip = 0, inplace = 0, num = 0, invalid = 0, has_unhashed = 0; + int ca; if (!have_identity) { cp = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid); @@ -681,9 +712,19 @@ do_known_hosts(struct passwd *pw, const char *name) fprintf(out, "%s\n", cp); continue; } + /* Check whether this is a CA key */ + if (strncasecmp(cp, CA_MARKER, sizeof(CA_MARKER) - 1) == 0 && + (cp[sizeof(CA_MARKER) - 1] == ' ' || + cp[sizeof(CA_MARKER) - 1] == '\t')) { + ca = 1; + cp += sizeof(CA_MARKER); + } else + ca = 0; + /* Find the end of the host name portion. */ for (kp = cp; *kp && *kp != ' ' && *kp != '\t'; kp++) ; + if (*kp == '\0' || *(kp + 1) == '\0') { error("line %d missing key: %.40s...", num, line); @@ -693,15 +734,15 @@ do_known_hosts(struct passwd *pw, const char *name) *kp++ = '\0'; kp2 = kp; - public = key_new(KEY_RSA1); - if (key_read(public, &kp) != 1) { + pub = key_new(KEY_RSA1); + if (key_read(pub, &kp) != 1) { kp = kp2; - key_free(public); - public = key_new(KEY_UNSPEC); - if (key_read(public, &kp) != 1) { + key_free(pub); + pub = key_new(KEY_UNSPEC); + if (key_read(pub, &kp) != 1) { error("line %d invalid key: %.40s...", num, line); - key_free(public); + key_free(pub); invalid = 1; continue; } @@ -719,43 +760,52 @@ do_known_hosts(struct passwd *pw, const char *name) c = (strcmp(cp2, cp) == 0); if (find_host && c) { printf("# Host %s found: " - "line %d type %s\n", name, - num, key_type(public)); - print_host(out, cp, public, 0); + "line %d type %s%s\n", name, + num, key_type(pub), + ca ? " (CA key)" : ""); + printhost(out, cp, pub, ca, 0); } - if (delete_host && !c) - print_host(out, cp, public, 0); + if (delete_host && !c && !ca) + printhost(out, cp, pub, ca, 0); } else if (hash_hosts) - print_host(out, cp, public, 0); + printhost(out, cp, pub, ca, 0); } else { if (find_host || delete_host) { c = (match_hostname(name, cp, strlen(cp)) == 1); if (find_host && c) { printf("# Host %s found: " - "line %d type %s\n", name, - num, key_type(public)); - print_host(out, name, public, - hash_hosts); + "line %d type %s%s\n", name, + num, key_type(pub), + ca ? " (CA key)" : ""); + printhost(out, name, pub, + ca, hash_hosts && !ca); } - if (delete_host && !c) - print_host(out, cp, public, 0); + if (delete_host && !c && !ca) + printhost(out, cp, pub, ca, 0); } else if (hash_hosts) { for (cp2 = strsep(&cp, ","); cp2 != NULL && *cp2 != '\0'; cp2 = strsep(&cp, ",")) { - if (strcspn(cp2, "*?!") != strlen(cp2)) + if (ca) { + fprintf(stderr, "Warning: " + "ignoring CA key for host: " + "%.64s\n", cp2); + printhost(out, cp2, pub, ca, 0); + } else if (strcspn(cp2, "*?!") != + strlen(cp2)) { fprintf(stderr, "Warning: " "ignoring host name with " "metacharacters: %.64s\n", cp2); - else - print_host(out, cp2, public, 1); + printhost(out, cp2, pub, ca, 0); + } else + printhost(out, cp2, pub, ca, 1); } has_unhashed = 1; } } - key_free(public); + key_free(pub); } fclose(in); @@ -1012,6 +1062,293 @@ do_change_comment(struct passwd *pw) exit(0); } +static const char * +fmt_validity(void) +{ + char from[32], to[32]; + static char ret[64]; + time_t tt; + struct tm *tm; + + *from = *to = '\0'; + if (cert_valid_from == 0 && + cert_valid_to == 0xffffffffffffffffULL) + return "forever"; + + if (cert_valid_from != 0) { + /* XXX revisit INT_MAX in 2038 :) */ + tt = cert_valid_from > INT_MAX ? INT_MAX : cert_valid_from; + tm = localtime(&tt); + strftime(from, sizeof(from), "%Y-%m-%dT%H:%M:%S", tm); + } + if (cert_valid_to != 0xffffffffffffffffULL) { + /* XXX revisit INT_MAX in 2038 :) */ + tt = cert_valid_to > INT_MAX ? INT_MAX : cert_valid_to; + tm = localtime(&tt); + strftime(to, sizeof(to), "%Y-%m-%dT%H:%M:%S", tm); + } + + if (cert_valid_from == 0) { + snprintf(ret, sizeof(ret), "before %s", to); + return ret; + } + if (cert_valid_to == 0xffffffffffffffffULL) { + snprintf(ret, sizeof(ret), "after %s", from); + return ret; + } + + snprintf(ret, sizeof(ret), "from %s to %s", from, to); + return ret; +} + +static void +add_flag_constraint(Buffer *c, const char *name) +{ + debug3("%s: %s", __func__, name); + buffer_put_cstring(c, name); + buffer_put_string(c, NULL, 0); +} + +static void +add_string_constraint(Buffer *c, const char *name, const char *value) +{ + Buffer b; + + debug3("%s: %s=%s", __func__, name, value); + buffer_init(&b); + buffer_put_cstring(&b, value); + + buffer_put_cstring(c, name); + buffer_put_string(c, buffer_ptr(&b), buffer_len(&b)); + + buffer_free(&b); +} + +static void +prepare_constraint_buf(Buffer *c) +{ + + buffer_clear(c); + if ((constraint_flags & CONSTRAINT_X_FWD) != 0) + add_flag_constraint(c, "permit-X11-forwarding"); + if ((constraint_flags & CONSTRAINT_AGENT_FWD) != 0) + add_flag_constraint(c, "permit-agent-forwarding"); + if ((constraint_flags & CONSTRAINT_PORT_FWD) != 0) + add_flag_constraint(c, "permit-port-forwarding"); + if ((constraint_flags & CONSTRAINT_PTY) != 0) + add_flag_constraint(c, "permit-pty"); + if ((constraint_flags & CONSTRAINT_USER_RC) != 0) + add_flag_constraint(c, "permit-user-rc"); + if (constraint_command != NULL) + add_string_constraint(c, "forced-command", constraint_command); + if (constraint_src_addr != NULL) + add_string_constraint(c, "source-address", constraint_src_addr); +} + +static void +do_ca_sign(struct passwd *pw, int argc, char **argv) +{ + int i, fd; + u_int n; + Key *ca, *public; + char *otmp, *tmp, *cp, *out, *comment, **plist = NULL; + FILE *f; + + tmp = tilde_expand_filename(ca_key_path, pw->pw_uid); + if ((ca = load_identity(tmp)) == NULL) + fatal("Couldn't load CA key \"%s\"", tmp); + xfree(tmp); + + for (i = 0; i < argc; i++) { + /* Split list of principals */ + n = 0; + if (cert_principals != NULL) { + otmp = tmp = xstrdup(cert_principals); + plist = NULL; + for (; (cp = strsep(&tmp, ",")) != NULL; n++) { + plist = xrealloc(plist, n + 1, sizeof(*plist)); + if (*(plist[n] = xstrdup(cp)) == '\0') + fatal("Empty principal name"); + } + xfree(otmp); + } + + tmp = tilde_expand_filename(argv[i], pw->pw_uid); + if ((public = key_load_public(tmp, &comment)) == NULL) + fatal("%s: unable to open \"%s\"", __func__, tmp); + if (public->type != KEY_RSA && public->type != KEY_DSA) + fatal("%s: key \"%s\" type %s cannot be certified", + __func__, tmp, key_type(public)); + + /* Prepare certificate to sign */ + if (key_to_certified(public) != 0) + fatal("Could not upgrade key %s to certificate", tmp); + public->cert->type = cert_key_type; + public->cert->key_id = xstrdup(cert_key_id); + public->cert->nprincipals = n; + public->cert->principals = plist; + public->cert->valid_after = cert_valid_from; + public->cert->valid_before = cert_valid_to; + prepare_constraint_buf(&public->cert->constraints); + public->cert->signature_key = key_from_private(ca); + + if (key_certify(public, ca) != 0) + fatal("Couldn't not certify key %s", tmp); + + if ((cp = strrchr(tmp, '.')) != NULL && strcmp(cp, ".pub") == 0) + *cp = '\0'; + xasprintf(&out, "%s-cert.pub", tmp); + xfree(tmp); + + if ((fd = open(out, O_WRONLY|O_CREAT|O_TRUNC, 0644)) == -1) + fatal("Could not open \"%s\" for writing: %s", out, + strerror(errno)); + if ((f = fdopen(fd, "w")) == NULL) + fatal("%s: fdopen: %s", __func__, strerror(errno)); + if (!key_write(public, f)) + fatal("Could not write certified key to %s", out); + fprintf(f, " %s\n", comment); + fclose(f); + + if (!quiet) + logit("Signed %s key %s: id \"%s\"%s%s valid %s", + cert_key_type == SSH2_CERT_TYPE_USER?"user":"host", + out, cert_key_id, + cert_principals != NULL ? " for " : "", + cert_principals != NULL ? cert_principals : "", + fmt_validity()); + + key_free(public); + xfree(out); + } + exit(0); +} + +static u_int64_t +parse_relative_time(const char *s, time_t now) +{ + int64_t mul, secs; + + mul = *s == '-' ? -1 : 1; + + if ((secs = convtime(s + 1)) == -1) + fatal("Invalid relative certificate time %s", s); + if (mul == -1 && secs > now) + fatal("Certificate time %s cannot be represented", s); + return now + (u_int64_t)(secs * mul); +} + +static u_int64_t +parse_absolute_time(const char *s) +{ + struct tm tm; + time_t tt; + + if (strlen(s) != 8 && strlen(s) != 14) + fatal("Invalid certificate time format %s", s); + + bzero(&tm, sizeof(tm)); + if (strptime(s, + strlen(s) == 8 ? "%Y%m%d" : "%Y%m%d%H%M%S", &tm) == NULL) + fatal("Invalid certificate time %s", s); + if ((tt = mktime(&tm)) < 0) + fatal("Certificate time %s cannot be represented", s); + return (u_int64_t)tt; +} + +static void +parse_cert_times(char *timespec) +{ + char *from, *to; + time_t now = time(NULL); + int64_t secs; + + /* +timespec relative to now */ + if (*timespec == '+' && strchr(timespec, ':') == NULL) { + if ((secs = convtime(timespec + 1)) == -1) + fatal("Invalid relative certificate life %s", timespec); + cert_valid_to = now + secs; + /* + * Backdate certificate one minute to avoid problems on hosts + * with poorly-synchronised clocks. + */ + cert_valid_from = ((now - 59)/ 60) * 60; + return; + } + + /* + * from:to, where + * from := [+-]timespec | YYYYMMDD | YYYYMMDDHHMMSS + * to := [+-]timespec | YYYYMMDD | YYYYMMDDHHMMSS + */ + from = xstrdup(timespec); + to = strchr(from, ':'); + if (to == NULL || from == to || *(to + 1) == '\0') + fatal("Invalid certificate life specification %s", optarg); + *to++ = '\0'; + + if (*from == '-' || *from == '+') + cert_valid_from = parse_relative_time(from, now); + else + cert_valid_from = parse_absolute_time(from); + + if (*to == '-' || *to == '+') + cert_valid_to = parse_relative_time(to, cert_valid_from); + else + cert_valid_to = parse_absolute_time(to); + + if (cert_valid_to <= cert_valid_from) + fatal("Empty certificate validity interval"); + xfree(from); +} + +static void +add_cert_constraint(char *opt) +{ + char *val; + + if (strcmp(opt, "clear") == 0) + constraint_flags = 0; + else if (strcasecmp(opt, "no-x11-forwarding") == 0) + constraint_flags &= ~CONSTRAINT_X_FWD; + else if (strcasecmp(opt, "permit-x11-forwarding") == 0) + constraint_flags |= CONSTRAINT_X_FWD; + else if (strcasecmp(opt, "no-agent-forwarding") == 0) + constraint_flags &= ~CONSTRAINT_AGENT_FWD; + else if (strcasecmp(opt, "permit-agent-forwarding") == 0) + constraint_flags |= CONSTRAINT_AGENT_FWD; + else if (strcasecmp(opt, "no-port-forwarding") == 0) + constraint_flags &= ~CONSTRAINT_PORT_FWD; + else if (strcasecmp(opt, "permit-port-forwarding") == 0) + constraint_flags |= CONSTRAINT_PORT_FWD; + else if (strcasecmp(opt, "no-pty") == 0) + constraint_flags &= ~CONSTRAINT_PTY; + else if (strcasecmp(opt, "permit-pty") == 0) + constraint_flags |= CONSTRAINT_PTY; + else if (strcasecmp(opt, "no-user-rc") == 0) + constraint_flags &= ~CONSTRAINT_USER_RC; + else if (strcasecmp(opt, "permit-user-rc") == 0) + constraint_flags |= CONSTRAINT_USER_RC; + else if (strncasecmp(opt, "force-command=", 14) == 0) { + val = opt + 14; + if (*val == '\0') + fatal("Empty force-command constraint"); + if (constraint_command != NULL) + fatal("force-command already specified"); + constraint_command = xstrdup(val); + } else if (strncasecmp(opt, "source-address=", 15) == 0) { + val = opt + 15; + if (*val == '\0') + fatal("Empty source-address constraint"); + if (constraint_src_addr != NULL) + fatal("source-address already specified"); + if (addr_match_cidr_list(NULL, val) != 0) + fatal("Invalid source-address list"); + constraint_src_addr = xstrdup(val); + } else + fatal("Unsupported certificate constraint \"%s\"", opt); +} + static void usage(void) { @@ -1031,18 +1368,24 @@ usage(void) fprintf(stderr, " -G file Generate candidates for DH-GEX moduli.\n"); fprintf(stderr, " -g Use generic DNS resource record format.\n"); fprintf(stderr, " -H Hash names in known_hosts file.\n"); + fprintf(stderr, " -h Generate host certificate instead of a user certificate.\n"); + fprintf(stderr, " -I key_id Key identifier to include in certificate.\n"); fprintf(stderr, " -i Convert RFC 4716 to OpenSSH key file.\n"); fprintf(stderr, " -l Show fingerprint of key file.\n"); fprintf(stderr, " -M memory Amount of memory (MB) to use for generating DH-GEX moduli.\n"); + fprintf(stderr, " -n name,... User/host principal names to include in certificate\n"); fprintf(stderr, " -N phrase Provide new passphrase.\n"); + fprintf(stderr, " -O cnstr Specify a certificate constraint.\n"); fprintf(stderr, " -P phrase Provide old passphrase.\n"); fprintf(stderr, " -p Change passphrase of private key file.\n"); fprintf(stderr, " -q Quiet.\n"); fprintf(stderr, " -R hostname Remove host from known_hosts file.\n"); fprintf(stderr, " -r hostname Print DNS resource record.\n"); + fprintf(stderr, " -s ca_key Certify keys with CA key.\n"); fprintf(stderr, " -S start Start point (hex) for generating DH-GEX moduli.\n"); fprintf(stderr, " -T file Screen candidates for DH-GEX moduli.\n"); fprintf(stderr, " -t type Specify type of key to create.\n"); + fprintf(stderr, " -V from:to Specify certificate validity interval.\n"); fprintf(stderr, " -v Verbose.\n"); fprintf(stderr, " -W gen Generator to use for generating DH-GEX moduli.\n"); fprintf(stderr, " -y Read private key file and print public key.\n"); @@ -1094,8 +1437,8 @@ main(int argc, char **argv) exit(1); } - while ((opt = getopt(argc, argv, - "degiqpclBHvxXyF:b:f:t:D:P:N:C:r:g:R:T:G:M:S:a:W:")) != -1) { + while ((opt = getopt(argc, argv, "degiqpclBHhvxXyF:b:f:t:D:I:P:N:n:" + "O:C:r:g:R:T:G:M:S:s:a:V:W:")) != -1) { switch (opt) { case 'b': bits = (u_int32_t)strtonum(optarg, 768, 32768, &errstr); @@ -1110,6 +1453,9 @@ main(int argc, char **argv) case 'H': hash_hosts = 1; break; + case 'I': + cert_key_id = optarg; + break; case 'R': delete_host = 1; rr_hostname = optarg; @@ -1120,6 +1466,9 @@ main(int argc, char **argv) case 'B': print_bubblebabble = 1; break; + case 'n': + cert_principals = optarg; + break; case 'p': change_passphrase = 1; break; @@ -1141,6 +1490,9 @@ main(int argc, char **argv) case 'N': identity_new_passphrase = optarg; break; + case 'O': + add_cert_constraint(optarg); + break; case 'C': identity_comment = optarg; break; @@ -1152,6 +1504,10 @@ main(int argc, char **argv) /* export key */ convert_to_ssh2 = 1; break; + case 'h': + cert_key_type = SSH2_CERT_TYPE_HOST; + constraint_flags = 0; + break; case 'i': case 'X': /* import key */ @@ -1163,6 +1519,9 @@ main(int argc, char **argv) case 'd': key_type_name = "dsa"; break; + case 's': + ca_key_path = optarg; + break; case 't': key_type_name = optarg; break; @@ -1217,6 +1576,9 @@ main(int argc, char **argv) if (BN_hex2bn(&start, optarg) == 0) fatal("Invalid start point."); break; + case 'V': + parse_cert_times(optarg); + break; case '?': default: usage(); @@ -1226,7 +1588,15 @@ main(int argc, char **argv) /* reinit */ log_init(argv[0], log_level, SYSLOG_FACILITY_USER, 1); - if (optind < argc) { + argv += optind; + argc -= optind; + + if (ca_key_path != NULL) { + if (argc < 1) { + printf("Too few arguments.\n"); + usage(); + } + } else if (argc > 0) { printf("Too many arguments.\n"); usage(); } @@ -1238,6 +1608,11 @@ main(int argc, char **argv) printf("Cannot use -l with -D or -R.\n"); usage(); } + if (ca_key_path != NULL) { + if (cert_key_id == NULL) + fatal("Must specify key id (-I) when certifying"); + do_ca_sign(pw, argc, argv); + } if (delete_host || hash_hosts || find_host) do_known_hosts(pw, rr_hostname); if (print_fingerprint || print_bubblebabble) @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-rsa.c,v 1.39 2006/08/03 03:34:42 deraadt Exp $ */ +/* $OpenBSD: ssh-rsa.c,v 1.40 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org> * @@ -46,7 +46,9 @@ ssh_rsa_sign(const Key *key, u_char **sigp, u_int *lenp, int ok, nid; Buffer b; - if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) { + if (key == NULL || + (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || + key->rsa == NULL) { error("ssh_rsa_sign: no RSA key"); return -1; } @@ -113,7 +115,9 @@ ssh_rsa_verify(const Key *key, const u_char *signature, u_int signaturelen, u_int len, dlen, modlen; int rlen, ret, nid; - if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) { + if (key == NULL || + (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || + key->rsa == NULL) { error("ssh_rsa_verify: no RSA key"); return -1; } @@ -34,8 +34,8 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.\" $OpenBSD: ssh.1,v 1.294 2010/02/11 13:23:29 jmc Exp $ -.Dd $Mdocdate: February 11 2010 $ +.\" $OpenBSD: ssh.1,v 1.295 2010/02/26 20:29:54 djm Exp $ +.Dd $Mdocdate: February 26 2010 $ .Dt SSH 1 .Os .Sh NAME @@ -1103,6 +1103,25 @@ See the option in .Xr ssh_config 5 for more information. +.Pp +Host keys may also be presented as certificates signed by a trusted +certification authority (CA). +In this case, trust of the CA key alone is sufficient for the host key +to be accepted. +To specify a public key as a trusted CA key in a known hosts file, +it should be added after a +.Dq @cert-authority +tag and a set of one or more domain-name wildcards separated by commas. +For example: +.Pp +.Dl @cert-authority *.mydomain.org,*.mydomain.com ssh-rsa AAAAB5W... +.Pp +See the +.Sx CERTIFICATES +section of +.Xr ssh-keygen 1 +for more details. +.Pp .Sh SSH-BASED VIRTUAL PRIVATE NETWORKS .Nm contains support for Virtual Private Network (VPN) tunnelling @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh.c,v 1.334 2010/02/08 22:03:05 jmc Exp $ */ +/* $OpenBSD: ssh.c,v 1.335 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -1306,34 +1306,35 @@ load_public_identity_files(void) int i = 0; Key *public; struct passwd *pw; + u_int n_ids; + char *identity_files[SSH_MAX_IDENTITY_FILES]; + Key *identity_keys[SSH_MAX_IDENTITY_FILES]; #ifdef ENABLE_PKCS11 Key **keys; int nkeys; +#endif /* PKCS11 */ + n_ids = 0; + bzero(identity_files, sizeof(identity_files)); + bzero(identity_keys, sizeof(identity_keys)); + +#ifdef ENABLE_PKCS11 if (options.pkcs11_provider != NULL && options.num_identity_files < SSH_MAX_IDENTITY_FILES && (pkcs11_init(!options.batch_mode) == 0) && (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, &keys)) > 0) { - int count = 0; for (i = 0; i < nkeys; i++) { - count++; - memmove(&options.identity_files[1], - &options.identity_files[0], - sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); - memmove(&options.identity_keys[1], - &options.identity_keys[0], - sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); - options.num_identity_files++; - options.identity_keys[0] = keys[i]; - options.identity_files[0] = + if (n_ids >= SSH_MAX_IDENTITY_FILES) { + key_free(keys[i]); + continue; + } + identity_keys[n_ids] = keys[i]; + identity_files[n_ids] = xstrdup(options.pkcs11_provider); /* XXX */ + n_ids++; } - if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) - options.num_identity_files = SSH_MAX_IDENTITY_FILES; - i = count; xfree(keys); - /* XXX leaks some keys */ } #endif /* ENABLE_PKCS11 */ if ((pw = getpwuid(original_real_uid)) == NULL) @@ -1343,7 +1344,11 @@ load_public_identity_files(void) if (gethostname(thishost, sizeof(thishost)) == -1) fatal("load_public_identity_files: gethostname: %s", strerror(errno)); - for (; i < options.num_identity_files; i++) { + for (i = 0; i < options.num_identity_files; i++) { + if (n_ids >= SSH_MAX_IDENTITY_FILES) { + xfree(options.identity_files[i]); + continue; + } cp = tilde_expand_filename(options.identity_files[i], original_real_uid); filename = percent_expand(cp, "d", pwdir, @@ -1354,9 +1359,37 @@ load_public_identity_files(void) debug("identity file %s type %d", filename, public ? public->type : -1); xfree(options.identity_files[i]); - options.identity_files[i] = filename; - options.identity_keys[i] = public; + identity_files[n_ids] = filename; + identity_keys[n_ids] = public; + + if (++n_ids >= SSH_MAX_IDENTITY_FILES) + continue; + + /* Try to add the certificate variant too */ + xasprintf(&cp, "%s-cert", filename); + public = key_load_public(cp, NULL); + debug("identity file %s type %d", cp, + public ? public->type : -1); + if (public == NULL) { + xfree(cp); + continue; + } + if (!key_is_cert(public)) { + debug("%s: key %s type %s is not a certificate", + __func__, cp, key_type(public)); + key_free(public); + xfree(cp); + continue; + } + identity_keys[n_ids] = public; + /* point to the original path, most likely the private key */ + identity_files[n_ids] = xstrdup(filename); + n_ids++; } + options.num_identity_files = n_ids; + memcpy(options.identity_files, identity_files, sizeof(identity_files)); + memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); + bzero(pwname, strlen(pwname)); xfree(pwname); bzero(pwdir, strlen(pwdir)); @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh2.h,v 1.12 2009/10/24 11:19:17 andreas Exp $ */ +/* $OpenBSD: ssh2.h,v 1.13 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. @@ -173,3 +173,6 @@ #define SSH2_MSG_KEX_ROAMING_AUTH_OK 33 #define SSH2_MSG_KEX_ROAMING_AUTH_FAIL 34 +/* Certificate types for OpenSSH certificate keys extension */ +#define SSH2_CERT_TYPE_USER 1 +#define SSH2_CERT_TYPE_HOST 2 diff --git a/sshconnect.c b/sshconnect.c index 63c4650f..35c2f49b 100644 --- a/sshconnect.c +++ b/sshconnect.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect.c,v 1.218 2010/01/13 00:19:04 dtucker Exp $ */ +/* $OpenBSD: sshconnect.c,v 1.219 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -58,6 +58,7 @@ #include "misc.h" #include "dns.h" #include "roaming.h" +#include "ssh2.h" #include "version.h" char *client_version_string = NULL; @@ -576,6 +577,23 @@ confirm(const char *prompt) } } +static int +check_host_cert(const char *host, const Key *host_key) +{ + const char *reason; + + if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) { + error("%s", reason); + return 0; + } + if (buffer_len(&host_key->cert->constraints) != 0) { + error("Certificate for %s contains unsupported constraint(s)", + host); + return 0; + } + return 1; +} + /* * check whether the supplied host key is valid, return -1 if the key * is not valid. the user_hostfile will not be updated if 'readonly' is true. @@ -588,13 +606,13 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, Key *host_key, int readonly, const char *user_hostfile, const char *system_hostfile) { - Key *file_key; - const char *type = key_type(host_key); + Key *file_key, *raw_key = NULL; + const char *type; char *ip = NULL, *host = NULL; char hostline[1000], *hostp, *fp, *ra; HostStatus host_status; HostStatus ip_status; - int r, local = 0, host_ip_differ = 0; + int r, want_cert, local = 0, host_ip_differ = 0; int salen; char ntop[NI_MAXHOST]; char msg[1024]; @@ -667,11 +685,15 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, host = put_host_port(hostname, port); } + retry: + want_cert = key_is_cert(host_key); + type = key_type(host_key); + /* * Store the host key from the known host file in here so that we can * compare it with the key for the IP address. */ - file_key = key_new(host_key->type); + file_key = key_new(key_is_cert(host_key) ? KEY_UNSPEC : host_key->type); /* * Check if the host key is present in the user's list of known @@ -687,9 +709,10 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, } /* * Also perform check for the ip address, skip the check if we are - * localhost or the hostname was an ip address to begin with + * localhost, looking for a certificate, or the hostname was an ip + * address to begin with. */ - if (options.check_host_ip) { + if (!want_cert && options.check_host_ip) { Key *ip_key = key_new(host_key->type); ip_file = user_hostfile; @@ -713,11 +736,14 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, switch (host_status) { case HOST_OK: /* The host is known and the key matches. */ - debug("Host '%.200s' is known and matches the %s host key.", - host, type); - debug("Found key in %s:%d", host_file, host_line); + debug("Host '%.200s' is known and matches the %s host %s.", + host, type, want_cert ? "certificate" : "key"); + debug("Found %s in %s:%d", + want_cert ? "certificate" : "key", host_file, host_line); + if (want_cert && !check_host_cert(hostname, host_key)) + goto fail; if (options.check_host_ip && ip_status == HOST_NEW) { - if (readonly) + if (readonly || want_cert) logit("%s host key for IP address " "'%.128s' not in list of known hosts.", type, ip); @@ -749,7 +775,7 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, break; } } - if (readonly) + if (readonly || want_cert) goto fail; /* The host is new. */ if (options.strict_host_key_checking == 1) { @@ -834,6 +860,17 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, "list of known hosts.", hostp, type); break; case HOST_CHANGED: + if (want_cert) { + /* + * This is only a debug() since it is valid to have + * CAs with wildcard DNS matches that don't match + * all hosts that one might visit. + */ + debug("Host certificate authority does not " + "match %s in %s:%d", CA_MARKER, + host_file, host_line); + goto fail; + } if (readonly == ROQUIET) goto fail; if (options.check_host_ip && host_ip_differ) { @@ -970,6 +1007,20 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, return 0; fail: + if (want_cert) { + /* + * No matching certificate. Downgrade cert to raw key and + * search normally. + */ + debug("No matching CA found. Retry with plain key"); + raw_key = key_from_private(host_key); + if (key_drop_cert(raw_key) != 0) + fatal("Couldn't drop certificate"); + host_key = raw_key; + goto retry; + } + if (raw_key != NULL) + key_free(raw_key); xfree(ip); xfree(host); return -1; @@ -982,7 +1033,8 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) struct stat st; int flags = 0; - if (options.verify_host_key_dns && + /* XXX certs are not yet supported for DNS */ + if (!key_is_cert(host_key) && options.verify_host_key_dns && verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { if (flags & DNS_VERIFY_FOUND) { diff --git a/sshconnect2.c b/sshconnect2.c index e81064da..2a5943e7 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect2.c,v 1.179 2010/01/13 01:20:20 dtucker Exp $ */ +/* $OpenBSD: sshconnect2.c,v 1.180 2010/02/26 20:29:54 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * Copyright (c) 2008 Damien Miller. All rights reserved. @@ -1311,6 +1311,8 @@ pubkey_prepare(Authctxt *authctxt) key = options.identity_keys[i]; if (key && key->type == KEY_RSA1) continue; + if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) + continue; options.identity_keys[i] = NULL; id = xcalloc(1, sizeof(*id)); id->key = key; @@ -34,8 +34,8 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.\" $OpenBSD: sshd.8,v 1.250 2010/01/30 21:08:33 djm Exp $ -.Dd $Mdocdate: January 30 2010 $ +.\" $OpenBSD: sshd.8,v 1.251 2010/02/26 20:29:54 djm Exp $ +.Dd $Mdocdate: February 26 2010 $ .Dt SSHD 8 .Os .Sh NAME @@ -47,6 +47,7 @@ .Op Fl 46DdeiqTt .Op Fl b Ar bits .Op Fl C Ar connection_spec +.Op Fl c Ar host_certificate_file .Op Fl f Ar config_file .Op Fl g Ar login_grace_time .Op Fl h Ar host_key_file @@ -101,6 +102,15 @@ to use IPv6 addresses only. .It Fl b Ar bits Specifies the number of bits in the ephemeral protocol version 1 server key (default 1024). +.It Fl c Ar host_certificate_file +Specifies a path to a certificate file to identify +.Nm +during key exchange. +The certificate file must match a host key file specified using the +.Fl -h +option or the +.Cm HostKey +configuration directive. .It Fl C Ar connection_spec Specify the connection parameters to use for the .Fl T @@ -498,6 +508,13 @@ No spaces are permitted, except within double quotes. The following option specifications are supported (note that option keywords are case-insensitive): .Bl -tag -width Ds +.It Cm from="cert-authority" +Specifies that the listed key is a certification authority (CA) that is +trusted to validate signed certificates for user authentication. +.Pp +Certificates may encode access restrictions similar to these key options. +If both certificate restrictions and key options are present, the most +restrictive union of the two is applied. .It Cm command="command" Specifies that the command is executed whenever this key is used for authentication. @@ -517,6 +534,10 @@ The command originally supplied by the client is available in the .Ev SSH_ORIGINAL_COMMAND environment variable. Note that this option applies to shell, command or subsystem execution. +Also note that this command may be superseded by either a +.Xr sshd_config 5 +.Cm ForceCommand +directive or a command embedded in a certificate. .It Cm environment="NAME=value" Specifies that the string is to be added to the environment when logging in using this key. @@ -1,4 +1,4 @@ -/* $OpenBSD: sshd.c,v 1.372 2010/01/29 00:20:41 djm Exp $ */ +/* $OpenBSD: sshd.c,v 1.373 2010/02/26 20:29:54 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -205,6 +205,7 @@ struct { Key *server_key; /* ephemeral server key */ Key *ssh1_host_key; /* ssh1 host key */ Key **host_keys; /* all private host keys */ + Key **host_certificates; /* all public host certificates */ int have_ssh1_key; int have_ssh2_key; u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; @@ -545,6 +546,10 @@ destroy_sensitive_data(void) key_free(sensitive_data.host_keys[i]); sensitive_data.host_keys[i] = NULL; } + if (sensitive_data.host_certificates[i]) { + key_free(sensitive_data.host_certificates[i]); + sensitive_data.host_certificates[i] = NULL; + } } sensitive_data.ssh1_host_key = NULL; memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); @@ -571,6 +576,7 @@ demote_sensitive_data(void) if (tmp->type == KEY_RSA1) sensitive_data.ssh1_host_key = tmp; } + /* Certs do not need demotion */ } /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ @@ -717,10 +723,11 @@ list_hostkey_types(void) const char *p; char *ret; int i; + Key *key; buffer_init(&b); for (i = 0; i < options.num_host_key_files; i++) { - Key *key = sensitive_data.host_keys[i]; + key = sensitive_data.host_keys[i]; if (key == NULL) continue; switch (key->type) { @@ -732,6 +739,19 @@ list_hostkey_types(void) buffer_append(&b, p, strlen(p)); break; } + /* If the private key has a cert peer, then list that too */ + key = sensitive_data.host_certificates[i]; + if (key == NULL) + continue; + switch (key->type) { + case KEY_RSA_CERT: + case KEY_DSA_CERT: + if (buffer_len(&b) > 0) + buffer_append(&b, ",", 1); + p = key_ssh_name(key); + buffer_append(&b, p, strlen(p)); + break; + } } buffer_append(&b, "\0", 1); ret = xstrdup(buffer_ptr(&b)); @@ -740,20 +760,37 @@ list_hostkey_types(void) return ret; } -Key * -get_hostkey_by_type(int type) +static Key * +get_hostkey_by_type(int type, int need_private) { int i; + Key *key; for (i = 0; i < options.num_host_key_files; i++) { - Key *key = sensitive_data.host_keys[i]; + if (type == KEY_RSA_CERT || type == KEY_DSA_CERT) + key = sensitive_data.host_certificates[i]; + else + key = sensitive_data.host_keys[i]; if (key != NULL && key->type == type) - return key; + return need_private ? + sensitive_data.host_keys[i] : key; } return NULL; } Key * +get_hostkey_public_by_type(int type) +{ + return get_hostkey_by_type(type, 0); +} + +Key * +get_hostkey_private_by_type(int type) +{ + return get_hostkey_by_type(type, 1); +} + +Key * get_hostkey_by_index(int ind) { if (ind < 0 || ind >= options.num_host_key_files) @@ -767,8 +804,13 @@ get_hostkey_index(Key *key) int i; for (i = 0; i < options.num_host_key_files; i++) { - if (key == sensitive_data.host_keys[i]) - return (i); + if (key_is_cert(key)) { + if (key == sensitive_data.host_certificates[i]) + return (i); + } else { + if (key == sensitive_data.host_keys[i]) + return (i); + } } return (-1); } @@ -807,9 +849,9 @@ usage(void) fprintf(stderr, "%s, %s\n", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); fprintf(stderr, -"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" -" [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" -" [-o option] [-p port] [-u len]\n" +"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n" +" [-f config_file] [-g login_grace_time] [-h host_key_file]\n" +" [-k key_gen_time] [-o option] [-p port] [-u len]\n" ); exit(1); } @@ -1236,7 +1278,7 @@ main(int ac, char **av) { extern char *optarg; extern int optind; - int opt, i, on = 1; + int opt, i, j, on = 1; int sock_in = -1, sock_out = -1, newsock = -1; const char *remote_ip; char *test_user = NULL, *test_host = NULL, *test_addr = NULL; @@ -1289,6 +1331,14 @@ main(int ac, char **av) case 'f': config_file_name = optarg; break; + case 'c': + if (options.num_host_cert_files >= MAX_HOSTCERTS) { + fprintf(stderr, "too many host certificates.\n"); + exit(1); + } + options.host_cert_files[options.num_host_cert_files++] = + derelativise_path(optarg); + break; case 'd': if (debug_flag == 0) { debug_flag = 1; @@ -1536,6 +1586,46 @@ main(int ac, char **av) exit(1); } + /* + * Load certificates. They are stored in an array at identical + * indices to the public keys that they relate to. + */ + sensitive_data.host_certificates = xcalloc(options.num_host_key_files, + sizeof(Key *)); + for (i = 0; i < options.num_host_key_files; i++) + sensitive_data.host_certificates[i] = NULL; + + for (i = 0; i < options.num_host_cert_files; i++) { + key = key_load_public(options.host_cert_files[i], NULL); + if (key == NULL) { + error("Could not load host certificate: %s", + options.host_cert_files[i]); + continue; + } + if (!key_is_cert(key)) { + error("Certificate file is not a certificate: %s", + options.host_cert_files[i]); + key_free(key); + continue; + } + /* Find matching private key */ + for (j = 0; j < options.num_host_key_files; j++) { + if (key_equal_public(key, + sensitive_data.host_keys[j])) { + sensitive_data.host_certificates[j] = key; + break; + } + } + if (j >= options.num_host_key_files) { + error("No matching private key for certificate: %s", + options.host_cert_files[i]); + key_free(key); + continue; + } + sensitive_data.host_certificates[j] = key; + debug("host certificate: #%d type %d %s", j, key->type, + key_type(key)); + } /* Check certain values for sanity. */ if (options.protocol & SSH_PROTO_1) { if (options.server_key_bits < 512 || @@ -2205,7 +2295,8 @@ do_ssh2_kex(void) kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; - kex->load_host_key=&get_hostkey_by_type; + kex->load_host_public_key=&get_hostkey_public_by_type; + kex->load_host_private_key=&get_hostkey_private_by_type; kex->host_key_index=&get_hostkey_index; xxx_kex = kex; diff --git a/sshd_config.5 b/sshd_config.5 index bf3319c4..00111465 100644 --- a/sshd_config.5 +++ b/sshd_config.5 @@ -34,8 +34,8 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" -.\" $OpenBSD: sshd_config.5,v 1.116 2010/01/09 23:04:13 dtucker Exp $ -.Dd $Mdocdate: January 9 2010 $ +.\" $OpenBSD: sshd_config.5,v 1.117 2010/02/26 20:29:54 djm Exp $ +.Dd $Mdocdate: February 26 2010 $ .Dt SSHD_CONFIG 5 .Os .Sh NAME @@ -411,6 +411,14 @@ uses the name supplied by the client rather than attempting to resolve the name from the TCP connection itself. The default is .Dq no . +.It Cm HostCertificate +Specifies a file containing a public host certificate. +The certificate's public key must match a private host key already specified +by +.Cm HostKey . +The default behaviour of +.Xr sshd 8 +is not to load any certificates. .It Cm HostKey Specifies a file containing a private host key used by SSH. |