diff options
Diffstat (limited to 'auth/auth_digest.c')
| -rw-r--r-- | auth/auth_digest.c | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/auth/auth_digest.c b/auth/auth_digest.c new file mode 100644 index 0000000..2e29180 --- /dev/null +++ b/auth/auth_digest.c @@ -0,0 +1,475 @@ +/* Copyright 2009 Justin Erenkrantz and Greg Stein + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/*** Digest authentication ***/ + +#include <serf.h> +#include <serf_private.h> +#include <auth/auth.h> + +#include <apr.h> +#include <apr_base64.h> +#include <apr_strings.h> +#include <apr_uuid.h> +#include <apr_md5.h> + +/** Digest authentication, implements RFC 2617. **/ + +/* Stores the context information related to Digest authentication. + The context is per connection. */ +typedef struct digest_authn_info_t { + /* nonce-count for digest authentication */ + unsigned int digest_nc; + + const char *header; + + const char *ha1; + + const char *realm; + const char *cnonce; + const char *nonce; + const char *opaque; + const char *algorithm; + const char *qop; + const char *username; + + apr_pool_t *pool; +} digest_authn_info_t; + +static char +int_to_hex(int v) +{ + return (v < 10) ? '0' + v : 'a' + (v - 10); +} + +/** + * Convert a string if ASCII characters HASHVAL to its hexadecimal + * representation. + * + * The returned string will be allocated in the POOL and be null-terminated. + */ +static const char * +hex_encode(const unsigned char *hashval, + apr_pool_t *pool) +{ + int i; + char *hexval = apr_palloc(pool, (APR_MD5_DIGESTSIZE * 2) + 1); + for (i = 0; i < APR_MD5_DIGESTSIZE; i++) { + hexval[2 * i] = int_to_hex((hashval[i] >> 4) & 0xf); + hexval[2 * i + 1] = int_to_hex(hashval[i] & 0xf); + } + hexval[APR_MD5_DIGESTSIZE * 2] = '\0'; + return hexval; +} + +/** + * Returns a 36-byte long string of random characters. + * UUIDs are formatted as: 00112233-4455-6677-8899-AABBCCDDEEFF. + * + * The returned string will be allocated in the POOL and be null-terminated. + */ +static const char * +random_cnonce(apr_pool_t *pool) +{ + apr_uuid_t uuid; + char *buf = apr_palloc(pool, APR_UUID_FORMATTED_LENGTH + 1); + + apr_uuid_get(&uuid); + apr_uuid_format(buf, &uuid); + + return hex_encode((unsigned char*)buf, pool); +} + +static const char * +build_digest_ha1(const char *username, + const char *password, + const char *realm_name, + apr_pool_t *pool) +{ + const char *tmp; + unsigned char ha1[APR_MD5_DIGESTSIZE]; + apr_status_t status; + + /* calculate ha1: + MD5 hash of the combined user name, authentication realm and password */ + tmp = apr_psprintf(pool, "%s:%s:%s", + username, + realm_name, + password); + status = apr_md5(ha1, tmp, strlen(tmp)); + + return hex_encode(ha1, pool); +} + +static const char * +build_digest_ha2(const char *uri, + const char *method, + const char *qop, + apr_pool_t *pool) +{ + if (!qop || strcmp(qop, "auth") == 0) { + const char *tmp; + unsigned char ha2[APR_MD5_DIGESTSIZE]; + apr_status_t status; + + /* calculate ha2: + MD5 hash of the combined method and URI */ + tmp = apr_psprintf(pool, "%s:%s", + method, + uri); + status = apr_md5(ha2, tmp, strlen(tmp)); + + return hex_encode(ha2, pool); + } else { + /* TODO: auth-int isn't supported! */ + } + + return NULL; +} + +static const char * +build_auth_header(digest_authn_info_t *digest_info, + const char *path, + const char *method, + apr_pool_t *pool) +{ + char *hdr; + const char *ha2; + const char *response; + unsigned char response_hdr[APR_MD5_DIGESTSIZE]; + const char *response_hdr_hex; + apr_status_t status; + + ha2 = build_digest_ha2(path, method, digest_info->qop, pool); + + hdr = apr_psprintf(pool, + "Digest realm=\"%s\"," + " username=\"%s\"," + " nonce=\"%s\"," + " uri=\"%s\"", + digest_info->realm, digest_info->username, + digest_info->nonce, + path); + + if (digest_info->qop) { + if (! digest_info->cnonce) + digest_info->cnonce = random_cnonce(digest_info->pool); + + hdr = apr_psprintf(pool, "%s, nc=%08x, cnonce=\"%s\", qop=\"%s\"", + hdr, + digest_info->digest_nc, + digest_info->cnonce, + digest_info->qop); + + /* Build the response header: + MD5 hash of the combined HA1 result, server nonce (nonce), + request counter (nc), client nonce (cnonce), + quality of protection code (qop) and HA2 result. */ + response = apr_psprintf(pool, "%s:%s:%08x:%s:%s:%s", + digest_info->ha1, digest_info->nonce, + digest_info->digest_nc, + digest_info->cnonce, digest_info->qop, ha2); + } else { + /* Build the response header: + MD5 hash of the combined HA1 result, server nonce (nonce) + and HA2 result. */ + response = apr_psprintf(pool, "%s:%s:%s", + digest_info->ha1, digest_info->nonce, ha2); + } + + status = apr_md5(response_hdr, response, strlen(response)); + response_hdr_hex = hex_encode(response_hdr, pool); + + hdr = apr_psprintf(pool, "%s, response=\"%s\"", hdr, response_hdr_hex); + + if (digest_info->opaque) { + hdr = apr_psprintf(pool, "%s, opaque=\"%s\"", hdr, + digest_info->opaque); + } + if (digest_info->algorithm) { + hdr = apr_psprintf(pool, "%s, algorithm=\"%s\"", hdr, + digest_info->algorithm); + } + + return hdr; +} + +apr_status_t +serf__handle_digest_auth(int code, + serf_request_t *request, + serf_bucket_t *response, + const char *auth_hdr, + const char *auth_attr, + void *baton, + apr_pool_t *pool) +{ + char *attrs; + char *nextkv; + const char *realm_name = NULL; + const char *nonce = NULL; + const char *algorithm = NULL; + const char *qop = NULL; + const char *opaque = NULL; + const char *key; + serf_connection_t *conn = request->conn; + serf_context_t *ctx = conn->ctx; + serf__authn_info_t *authn_info = (code == 401) ? &ctx->authn_info : + &ctx->proxy_authn_info; + digest_authn_info_t *digest_info = (code == 401) ? conn->authn_baton : + conn->proxy_authn_baton; + apr_status_t status; + apr_pool_t *cred_pool; + char *username, *password; + + /* Can't do Digest authentication if there's no callback to get + username & password. */ + if (!ctx->cred_cb) { + return SERF_ERROR_AUTHN_FAILED; + } + + /* Need a copy cuz we're going to write NUL characters into the string. */ + attrs = apr_pstrdup(pool, auth_attr); + + /* We're expecting a list of key=value pairs, separated by a comma. + Ex. realm="SVN Digest", + nonce="f+zTl/leBAA=e371bd3070adfb47b21f5fc64ad8cc21adc371a5", + algorithm=MD5, qop="auth" */ + for ( ; (key = apr_strtok(attrs, ",", &nextkv)) != NULL; attrs = NULL) { + char *val; + + val = strchr(key, '='); + if (val == NULL) + continue; + *val++ = '\0'; + + /* skip leading spaces */ + while (*key && *key == ' ') + key++; + + /* If the value is quoted, then remove the quotes. */ + if (*val == '"') { + apr_size_t last = strlen(val) - 1; + + if (val[last] == '"') { + val[last] = '\0'; + val++; + } + } + + if (strcmp(key, "realm") == 0) + realm_name = val; + else if (strcmp(key, "nonce") == 0) + nonce = val; + else if (strcmp(key, "algorithm") == 0) + algorithm = val; + else if (strcmp(key, "qop") == 0) + qop = val; + else if (strcmp(key, "opaque") == 0) + opaque = val; + + /* Ignore all unsupported attributes. */ + } + + if (!realm_name) { + return SERF_ERROR_AUTHN_MISSING_ATTRIBUTE; + } + + authn_info->realm = apr_psprintf(conn->pool, "<%s://%s:%d> %s", + conn->host_info.scheme, + conn->host_info.hostname, + conn->host_info.port, + realm_name); + + /* Ask the application for credentials */ + apr_pool_create(&cred_pool, pool); + status = (*ctx->cred_cb)(&username, &password, request, baton, + code, authn_info->scheme->name, + authn_info->realm, cred_pool); + if (status) { + apr_pool_destroy(cred_pool); + return status; + } + + digest_info->header = (code == 401) ? "Authorization" : + "Proxy-Authorization"; + + /* Store the digest authentication parameters in the context relative + to this connection, so we can use it to create the Authorization header + when setting up requests. */ + digest_info->pool = conn->pool; + digest_info->qop = apr_pstrdup(digest_info->pool, qop); + digest_info->nonce = apr_pstrdup(digest_info->pool, nonce); + digest_info->cnonce = NULL; + digest_info->opaque = apr_pstrdup(digest_info->pool, opaque); + digest_info->algorithm = apr_pstrdup(digest_info->pool, algorithm); + digest_info->realm = apr_pstrdup(digest_info->pool, realm_name); + digest_info->username = apr_pstrdup(digest_info->pool, username); + digest_info->digest_nc++; + + digest_info->ha1 = build_digest_ha1(username, password, digest_info->realm, + digest_info->pool); + + apr_pool_destroy(cred_pool); + + /* If the handshake is finished tell serf it can send as much requests as it + likes. */ + serf_connection_set_max_outstanding_requests(conn, 0); + + return APR_SUCCESS; +} + +apr_status_t +serf__init_digest(int code, + serf_context_t *ctx, + apr_pool_t *pool) +{ + return APR_SUCCESS; +} + +apr_status_t +serf__init_digest_connection(int code, + serf_connection_t *conn, + apr_pool_t *pool) +{ + /* Digest authentication is done per connection, so keep all progress + information per connection. */ + if (code == 401) { + conn->authn_baton = apr_pcalloc(pool, sizeof(digest_authn_info_t)); + } else { + conn->proxy_authn_baton = apr_pcalloc(pool, sizeof(digest_authn_info_t)); + } + + /* Make serf send the initial requests one by one */ + serf_connection_set_max_outstanding_requests(conn, 1); + + return APR_SUCCESS; +} + +apr_status_t +serf__setup_request_digest_auth(int code, + serf_connection_t *conn, + const char *method, + const char *uri, + serf_bucket_t *hdrs_bkt) +{ + digest_authn_info_t *digest_info = (code == 401) ? conn->authn_baton : + conn->proxy_authn_baton; + apr_status_t status = APR_SUCCESS; + + if (digest_info && digest_info->realm) { + const char *value; + apr_uri_t parsed_uri; + + /* extract path from uri */ + status = apr_uri_parse(conn->pool, uri, &parsed_uri); + + /* Build a new Authorization header. */ + digest_info->header = (code == 401) ? "Authorization" : + "Proxy-Authorization"; + value = build_auth_header(digest_info, parsed_uri.path, method, + conn->pool); + + serf_bucket_headers_setn(hdrs_bkt, digest_info->header, + value); + digest_info->digest_nc++; + } + + return status; +} + +apr_status_t +serf__validate_response_digest_auth(int code, + serf_connection_t *conn, + serf_request_t *request, + serf_bucket_t *response, + apr_pool_t *pool) +{ + const char *key; + char *auth_attr; + char *nextkv; + const char *rspauth = NULL; + const char *qop = NULL; + const char *nc_str = NULL; + serf_bucket_t *hdrs; + digest_authn_info_t *digest_info = (code == 401) ? conn->authn_baton : + conn->proxy_authn_baton; + + hdrs = serf_bucket_response_get_headers(response); + + /* Need a copy cuz we're going to write NUL characters into the string. */ + if (code == 401) + auth_attr = apr_pstrdup(pool, + serf_bucket_headers_get(hdrs, "Authentication-Info")); + else + auth_attr = apr_pstrdup(pool, + serf_bucket_headers_get(hdrs, "Proxy-Authentication-Info")); + + /* If there's no Authentication-Info header there's nothing to validate. */ + if (! auth_attr) + return APR_SUCCESS; + + /* We're expecting a list of key=value pairs, separated by a comma. + Ex. rspauth="8a4b8451084b082be6b105e2b7975087", + cnonce="346531653132652d303033392d3435", nc=00000007, + qop=auth */ + for ( ; (key = apr_strtok(auth_attr, ",", &nextkv)) != NULL; auth_attr = NULL) { + char *val; + + val = strchr(key, '='); + if (val == NULL) + continue; + *val++ = '\0'; + + /* skip leading spaces */ + while (*key && *key == ' ') + key++; + + /* If the value is quoted, then remove the quotes. */ + if (*val == '"') { + apr_size_t last = strlen(val) - 1; + + if (val[last] == '"') { + val[last] = '\0'; + val++; + } + } + + if (strcmp(key, "rspauth") == 0) + rspauth = val; + else if (strcmp(key, "qop") == 0) + qop = val; + else if (strcmp(key, "nc") == 0) + nc_str = val; + } + + if (rspauth) { + const char *ha2, *tmp, *resp_hdr_hex; + unsigned char resp_hdr[APR_MD5_DIGESTSIZE]; + + ha2 = build_digest_ha2(conn->host_info.path, "", qop, pool); + tmp = apr_psprintf(pool, "%s:%s:%s:%s:%s:%s", + digest_info->ha1, digest_info->nonce, nc_str, + digest_info->cnonce, digest_info->qop, ha2); + apr_md5(resp_hdr, tmp, strlen(tmp)); + resp_hdr_hex = hex_encode(resp_hdr, pool); + + /* Incorrect response-digest in Authentication-Info header. */ + if (strcmp(rspauth, resp_hdr_hex) != 0) { + return SERF_ERROR_AUTHN_FAILED; + } + } + + return APR_SUCCESS; +} |