Initial revision

1 files changed, 565 insertions, 0 deletions

diff --git a/authfd.c b/authfd.c
new file mode 100644
index 00000000..07893caf
--- /dev/null
+++ b/authfd.c
@@ -0,0 +1,565 @@
+/*
+
+authfd.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+                   All rights reserved
+
+Created: Wed Mar 29 01:30:28 1995 ylo
+
+Functions for connecting the local authentication agent.
+
+*/
+
+#include "includes.h"
+RCSID("$Id: authfd.c,v 1.1 1999/10/27 03:42:43 damien Exp $");
+
+#include "ssh.h"
+#include "rsa.h"
+#include "authfd.h"
+#include "buffer.h"
+#include "bufaux.h"
+#include "xmalloc.h"
+#include "getput.h"
+
+#include <openssl/rsa.h>
+
+/* Returns the number of the authentication fd, or -1 if there is none. */
+
+int
+ssh_get_authentication_socket()
+{
+  const char *authsocket;
+  int sock;
+  struct sockaddr_un sunaddr;
+
+  authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
+  if (!authsocket)
+    return -1;
+
+  sunaddr.sun_family = AF_UNIX;
+  strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
+  
+  sock = socket(AF_UNIX, SOCK_STREAM, 0);
+  if (sock < 0)
+    return -1;
+  
+  if (connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0)
+    {
+      close(sock);
+      return -1;
+    }
+
+  return sock;
+}
+
+/* Closes the agent socket if it should be closed (depends on how it was
+   obtained).  The argument must have been returned by 
+   ssh_get_authentication_socket(). */
+
+void ssh_close_authentication_socket(int sock)
+{
+  if (getenv(SSH_AUTHSOCKET_ENV_NAME))
+    close(sock);
+}
+
+/* Opens and connects a private socket for communication with the
+   authentication agent.  Returns the file descriptor (which must be
+   shut down and closed by the caller when no longer needed).
+   Returns NULL if an error occurred and the connection could not be
+   opened. */
+
+AuthenticationConnection *ssh_get_authentication_connection()
+{
+  AuthenticationConnection *auth;
+  int sock;
+  
+  sock = ssh_get_authentication_socket();
+
+  /* Fail if we couldn't obtain a connection.  This happens if we exited
+     due to a timeout. */
+  if (sock < 0)
+    return NULL;
+
+  /* Applocate the connection structure and initialize it. */
+  auth = xmalloc(sizeof(*auth));
+  auth->fd = sock;
+  buffer_init(&auth->packet);
+  buffer_init(&auth->identities);
+  auth->howmany = 0;
+
+  return auth;
+}
+
+/* Closes the connection to the authentication agent and frees any associated
+   memory. */
+
+void ssh_close_authentication_connection(AuthenticationConnection *ac)
+{
+  buffer_free(&ac->packet);
+  buffer_free(&ac->identities);
+  close(ac->fd);
+  /* Free the connection data structure. */
+  xfree(ac);
+}
+
+/* Returns the first authentication identity held by the agent.
+   Returns true if an identity is available, 0 otherwise.
+   The caller must initialize the integers before the call, and free the
+   comment after a successful call (before calling ssh_get_next_identity). */
+
+int
+ssh_get_first_identity(AuthenticationConnection *auth,
+		       int *bitsp, BIGNUM *e, BIGNUM *n, char **comment)
+{
+  unsigned char msg[8192];
+  int len, l;
+
+  /* Send a message to the agent requesting for a list of the identities
+     it can represent. */
+  msg[0] = 0;
+  msg[1] = 0;
+  msg[2] = 0;
+  msg[3] = 1;
+  msg[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
+  if (write(auth->fd, msg, 5) != 5)
+    {
+      error("write auth->fd: %.100s", strerror(errno));
+      return 0;
+    }
+
+  /* Read the length of the response.  XXX implement timeouts here. */
+  len = 4;
+  while (len > 0)
+    {
+      l = read(auth->fd, msg + 4 - len, len);
+      if (l <= 0)
+	{
+	  error("read auth->fd: %.100s", strerror(errno));
+	  return 0;
+	}
+      len -= l;
+    }
+
+  /* Extract the length, and check it for sanity.  (We cannot trust
+     authentication agents). */
+  len = GET_32BIT(msg);
+  if (len < 1 || len > 256*1024)
+    fatal("Authentication reply message too long: %d\n", len);
+
+  /* Read the packet itself. */
+  buffer_clear(&auth->identities);
+  while (len > 0)
+    {
+      l = len;
+      if (l > sizeof(msg))
+	l = sizeof(msg);
+      l = read(auth->fd, msg, l);
+      if (l <= 0)
+	fatal("Incomplete authentication reply.");
+      buffer_append(&auth->identities, (char *)msg, l);
+      len -= l;
+    }
+  
+  /* Get message type, and verify that we got a proper answer. */
+  buffer_get(&auth->identities, (char *)msg, 1);
+  if (msg[0] != SSH_AGENT_RSA_IDENTITIES_ANSWER)
+    fatal("Bad authentication reply message type: %d", msg[0]);
+  
+  /* Get the number of entries in the response and check it for sanity. */
+  auth->howmany = buffer_get_int(&auth->identities);
+  if (auth->howmany > 1024)
+    fatal("Too many identities in authentication reply: %d\n", auth->howmany);
+
+  /* Return the first entry (if any). */
+  return ssh_get_next_identity(auth, bitsp, e, n, comment);
+}
+
+/* Returns the next authentication identity for the agent.  Other functions
+   can be called between this and ssh_get_first_identity or two calls of this
+   function.  This returns 0 if there are no more identities.  The caller
+   must free comment after a successful return. */
+
+int
+ssh_get_next_identity(AuthenticationConnection *auth,
+		      int *bitsp, BIGNUM *e, BIGNUM *n, char **comment)
+{
+  /* Return failure if no more entries. */
+  if (auth->howmany <= 0)
+    return 0;
+
+  /* Get the next entry from the packet.  These will abort with a fatal
+     error if the packet is too short or contains corrupt data. */
+  *bitsp = buffer_get_int(&auth->identities);
+  buffer_get_bignum(&auth->identities, e);
+  buffer_get_bignum(&auth->identities, n);
+  *comment = buffer_get_string(&auth->identities, NULL);
+
+  /* Decrement the number of remaining entries. */
+  auth->howmany--;
+
+  return 1;
+}
+
+/* Generates a random challenge, sends it to the agent, and waits for response
+   from the agent.  Returns true (non-zero) if the agent gave the correct
+   answer, zero otherwise.  Response type selects the style of response
+   desired, with 0 corresponding to protocol version 1.0 (no longer supported)
+   and 1 corresponding to protocol version 1.1. */
+
+int
+ssh_decrypt_challenge(AuthenticationConnection *auth,
+		      int bits, BIGNUM *e, BIGNUM *n, BIGNUM *challenge,
+		      unsigned char session_id[16],
+		      unsigned int response_type,
+		      unsigned char response[16])
+{
+  Buffer buffer;
+  unsigned char buf[8192];
+  int len, l, i;
+
+  /* Response type 0 is no longer supported. */
+  if (response_type == 0)
+    fatal("Compatibility with ssh protocol version 1.0 no longer supported.");
+
+  /* Format a message to the agent. */
+  buf[0] = SSH_AGENTC_RSA_CHALLENGE;
+  buffer_init(&buffer);
+  buffer_append(&buffer, (char *)buf, 1);
+  buffer_put_int(&buffer, bits);
+  buffer_put_bignum(&buffer, e);
+  buffer_put_bignum(&buffer, n);
+  buffer_put_bignum(&buffer, challenge);
+  buffer_append(&buffer, (char *)session_id, 16);
+  buffer_put_int(&buffer, response_type);
+
+  /* Get the length of the message, and format it in the buffer. */
+  len = buffer_len(&buffer);
+  PUT_32BIT(buf, len);
+
+  /* Send the length and then the packet to the agent. */
+  if (write(auth->fd, buf, 4) != 4 ||
+      write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) !=
+        buffer_len(&buffer))
+    {
+      error("Error writing to authentication socket.");
+    error_cleanup:
+      buffer_free(&buffer);
+      return 0;
+    }
+
+  /* Wait for response from the agent.  First read the length of the
+     response packet. */
+  len = 4;
+  while (len > 0)
+    {
+      l = read(auth->fd, buf + 4 - len, len);
+      if (l <= 0)
+	{
+	  error("Error reading response length from authentication socket.");
+	  goto error_cleanup;
+	}
+      len -= l;
+    }
+
+  /* Extract the length, and check it for sanity. */
+  len = GET_32BIT(buf);
+  if (len > 256*1024)
+    fatal("Authentication response too long: %d", len);
+
+  /* Read the rest of the response in tothe buffer. */
+  buffer_clear(&buffer);
+  while (len > 0)
+    {
+      l = len;
+      if (l > sizeof(buf))
+	l = sizeof(buf);
+      l = read(auth->fd, buf, l);
+      if (l <= 0)
+	{
+	  error("Error reading response from authentication socket.");
+	  goto error_cleanup;
+	}
+      buffer_append(&buffer, (char *)buf, l);
+      len -= l;
+    }
+
+  /* Get the type of the packet. */
+  buffer_get(&buffer, (char *)buf, 1);
+
+  /* Check for agent failure message. */
+  if (buf[0] == SSH_AGENT_FAILURE)
+    {
+      log("Agent admitted failure to authenticate using the key.");
+      goto error_cleanup;
+    }
+      
+  /* Now it must be an authentication response packet. */
+  if (buf[0] != SSH_AGENT_RSA_RESPONSE)
+    fatal("Bad authentication response: %d", buf[0]);
+
+  /* Get the response from the packet.  This will abort with a fatal error
+     if the packet is corrupt. */
+  for (i = 0; i < 16; i++)
+    response[i] = buffer_get_char(&buffer);
+
+  /* The buffer containing the packet is no longer needed. */
+  buffer_free(&buffer);
+
+  /* Correct answer. */
+  return 1;
+}  
+
+/* Adds an identity to the authentication server.  This call is not meant to
+   be used by normal applications. */
+
+int ssh_add_identity(AuthenticationConnection *auth,
+		     RSA *key, const char *comment)
+{
+  Buffer buffer;
+  unsigned char buf[8192];
+  int len, l, type;
+
+  /* Format a message to the agent. */
+  buffer_init(&buffer);
+  buffer_put_char(&buffer, SSH_AGENTC_ADD_RSA_IDENTITY);
+  buffer_put_int(&buffer, BN_num_bits(key->n));
+  buffer_put_bignum(&buffer, key->n);
+  buffer_put_bignum(&buffer, key->e);
+  buffer_put_bignum(&buffer, key->d);
+  /* To keep within the protocol: p < q for ssh. in SSL p > q */
+  buffer_put_bignum(&buffer, key->iqmp); /* ssh key->u */
+  buffer_put_bignum(&buffer, key->q); /* ssh key->p, SSL key->q */
+  buffer_put_bignum(&buffer, key->p); /* ssh key->q, SSL key->p */
+  buffer_put_string(&buffer, comment, strlen(comment));
+
+  /* Get the length of the message, and format it in the buffer. */
+  len = buffer_len(&buffer);
+  PUT_32BIT(buf, len);
+
+  /* Send the length and then the packet to the agent. */
+  if (write(auth->fd, buf, 4) != 4 ||
+      write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) !=
+        buffer_len(&buffer))
+    {
+      error("Error writing to authentication socket.");
+    error_cleanup:
+      buffer_free(&buffer);
+      return 0;
+    }
+
+  /* Wait for response from the agent.  First read the length of the
+     response packet. */
+  len = 4;
+  while (len > 0)
+    {
+      l = read(auth->fd, buf + 4 - len, len);
+      if (l <= 0)
+	{
+	  error("Error reading response length from authentication socket.");
+	  goto error_cleanup;
+	}
+      len -= l;
+    }
+
+  /* Extract the length, and check it for sanity. */
+  len = GET_32BIT(buf);
+  if (len > 256*1024)
+    fatal("Add identity response too long: %d", len);
+
+  /* Read the rest of the response in tothe buffer. */
+  buffer_clear(&buffer);
+  while (len > 0)
+    {
+      l = len;
+      if (l > sizeof(buf))
+	l = sizeof(buf);
+      l = read(auth->fd, buf, l);
+      if (l <= 0)
+	{
+	  error("Error reading response from authentication socket.");
+	  goto error_cleanup;
+	}
+      buffer_append(&buffer, (char *)buf, l);
+      len -= l;
+    }
+
+  /* Get the type of the packet. */
+  type = buffer_get_char(&buffer);
+  switch (type)
+    {
+    case SSH_AGENT_FAILURE:
+      buffer_free(&buffer);
+      return 0;
+    case SSH_AGENT_SUCCESS:
+      buffer_free(&buffer);
+      return 1;
+    default:
+      fatal("Bad response to add identity from authentication agent: %d", 
+	    type);
+    }
+  /*NOTREACHED*/
+  return 0;
+}  
+
+/* Removes an identity from the authentication server.  This call is not meant 
+   to be used by normal applications. */
+
+int ssh_remove_identity(AuthenticationConnection *auth, RSA *key)
+{
+  Buffer buffer;
+  unsigned char buf[8192];
+  int len, l, type;
+
+  /* Format a message to the agent. */
+  buffer_init(&buffer);
+  buffer_put_char(&buffer, SSH_AGENTC_REMOVE_RSA_IDENTITY);
+  buffer_put_int(&buffer, BN_num_bits(key->n));
+  buffer_put_bignum(&buffer, key->e);
+  buffer_put_bignum(&buffer, key->n);
+
+  /* Get the length of the message, and format it in the buffer. */
+  len = buffer_len(&buffer);
+  PUT_32BIT(buf, len);
+
+  /* Send the length and then the packet to the agent. */
+  if (write(auth->fd, buf, 4) != 4 ||
+      write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) !=
+        buffer_len(&buffer))
+    {
+      error("Error writing to authentication socket.");
+    error_cleanup:
+      buffer_free(&buffer);
+      return 0;
+    }
+
+  /* Wait for response from the agent.  First read the length of the
+     response packet. */
+  len = 4;
+  while (len > 0)
+    {
+      l = read(auth->fd, buf + 4 - len, len);
+      if (l <= 0)
+	{
+	  error("Error reading response length from authentication socket.");
+	  goto error_cleanup;
+	}
+      len -= l;
+    }
+
+  /* Extract the length, and check it for sanity. */
+  len = GET_32BIT(buf);
+  if (len > 256*1024)
+    fatal("Remove identity response too long: %d", len);
+
+  /* Read the rest of the response in tothe buffer. */
+  buffer_clear(&buffer);
+  while (len > 0)
+    {
+      l = len;
+      if (l > sizeof(buf))
+	l = sizeof(buf);
+      l = read(auth->fd, buf, l);
+      if (l <= 0)
+	{
+	  error("Error reading response from authentication socket.");
+	  goto error_cleanup;
+	}
+      buffer_append(&buffer, (char *)buf, l);
+      len -= l;
+    }
+
+  /* Get the type of the packet. */
+  type = buffer_get_char(&buffer);
+  switch (type)
+    {
+    case SSH_AGENT_FAILURE:
+      buffer_free(&buffer);
+      return 0;
+    case SSH_AGENT_SUCCESS:
+      buffer_free(&buffer);
+      return 1;
+    default:
+      fatal("Bad response to remove identity from authentication agent: %d", 
+	    type);
+    }
+  /*NOTREACHED*/
+  return 0;
+}  
+
+/* Removes all identities from the agent.  This call is not meant 
+   to be used by normal applications. */
+
+int ssh_remove_all_identities(AuthenticationConnection *auth)
+{
+  Buffer buffer;
+  unsigned char buf[8192];
+  int len, l, type;
+
+  /* Get the length of the message, and format it in the buffer. */
+  PUT_32BIT(buf, 1);
+  buf[4] = SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES;
+
+  /* Send the length and then the packet to the agent. */
+  if (write(auth->fd, buf, 5) != 5)
+    {
+      error("Error writing to authentication socket.");
+      return 0;
+    }
+
+  /* Wait for response from the agent.  First read the length of the
+     response packet. */
+  len = 4;
+  while (len > 0)
+    {
+      l = read(auth->fd, buf + 4 - len, len);
+      if (l <= 0)
+	{
+	  error("Error reading response length from authentication socket.");
+	  return 0;
+	}
+      len -= l;
+    }
+
+  /* Extract the length, and check it for sanity. */
+  len = GET_32BIT(buf);
+  if (len > 256*1024)
+    fatal("Remove identity response too long: %d", len);
+
+  /* Read the rest of the response into the buffer. */
+  buffer_init(&buffer);
+  while (len > 0)
+    {
+      l = len;
+      if (l > sizeof(buf))
+	l = sizeof(buf);
+      l = read(auth->fd, buf, l);
+      if (l <= 0)
+	{
+	  error("Error reading response from authentication socket.");
+	  buffer_free(&buffer);
+	  return 0;
+	}
+      buffer_append(&buffer, (char *)buf, l);
+      len -= l;
+    }
+
+  /* Get the type of the packet. */
+  type = buffer_get_char(&buffer);
+  switch (type)
+    {
+    case SSH_AGENT_FAILURE:
+      buffer_free(&buffer);
+      return 0;
+    case SSH_AGENT_SUCCESS:
+      buffer_free(&buffer);
+      return 1;
+    default:
+      fatal("Bad response to remove identity from authentication agent: %d", 
+	    type);
+    }
+  /*NOTREACHED*/
+  return 0;
+}