Commit ce515e99 authored by Kamil Dudka's avatar Kamil Dudka
Browse files

ssh: move the fingerprint checking code to a separate fnc

parent a34197ef

lib/ssh.c

+39 −32
Original line number Diff line number Diff line
@@ -639,6 +639,43 @@ static CURLcode ssh_knownhost(struct connectdata *conn) 
  return result;

}



static bool ssh_check_fingerprint(struct connectdata *conn)

{

  struct ssh_conn *sshc = &conn->proto.sshc;

  struct SessionHandle *data = conn->data;

  const char *pubkey_md5 = data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5];

  char md5buffer[33];

  int i;



  const char *fingerprint = libssh2_hostkey_hash(sshc->ssh_session,

      LIBSSH2_HOSTKEY_HASH_MD5);



  /* The fingerprint points to static storage (!), don't free() it. */

  for(i = 0; i < 16; i++)

    snprintf(&md5buffer[i*2], 3, "%02x", (unsigned char) fingerprint[i]);

  infof(data, "SSH MD5 fingerprint: %s\n", md5buffer);



  /* Before we authenticate we check the hostkey's MD5 fingerprint

   * against a known fingerprint, if available.

   */

  if(pubkey_md5 && strlen(pubkey_md5) == 32) {

    if(!strequal(md5buffer, pubkey_md5)) {

      failf(data,

          "Denied establishing ssh session: mismatch md5 fingerprint. "

          "Remote %s is not equal to %s", md5buffer, pubkey_md5);

      state(conn, SSH_SESSION_FREE);

      sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;

      return sshc->actualcode;

    }

    else {

      infof(data, "MD5 checksum match!\n");

      /* as we already matched, we skip the check for known hosts */

      return CURLE_OK;

    }

  }

  else

    return ssh_knownhost(conn);

}



/*

 * ssh_statemach_act() runs the SSH state machine as far as it can without
@@ -654,10 +691,8 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block) 
  struct SSHPROTO *sftp_scp = data->state.proto.ssh;

  struct ssh_conn *sshc = &conn->proto.sshc;

  curl_socket_t sock = conn->sock[FIRSTSOCKET];

  const char *fingerprint;

  char md5buffer[33];

  char *new_readdir_line;

  int rc = LIBSSH2_ERROR_NONE, i;

  int rc = LIBSSH2_ERROR_NONE;

  int err;

  int seekerr = CURL_SEEKFUNC_OK;

  *block = 0; /* we're not blocking by default */
@@ -698,35 +733,7 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block) 
       * against our known hosts. How that is handled (reading from file,

       * whatever) is up to us.

       */

      fingerprint = libssh2_hostkey_hash(sshc->ssh_session,

                                         LIBSSH2_HOSTKEY_HASH_MD5);



      /* The fingerprint points to static storage (!), don't free() it. */

      for(i = 0; i < 16; i++)

        snprintf(&md5buffer[i*2], 3, "%02x", (unsigned char) fingerprint[i]);

      infof(data, "SSH MD5 fingerprint: %s\n", md5buffer);



      /* Before we authenticate we check the hostkey's MD5 fingerprint

       * against a known fingerprint, if available.

       */

      if(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5] &&

         strlen(data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]) == 32) {

        if(!strequal(md5buffer,

                     data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5])) {

          failf(data,

                "Denied establishing ssh session: mismatch md5 fingerprint. "

                "Remote %s is not equal to %s",

                md5buffer, data->set.str[STRING_SSH_HOST_PUBLIC_KEY_MD5]);

          state(conn, SSH_SESSION_FREE);

          result = sshc->actualcode = CURLE_PEER_FAILED_VERIFICATION;

        }

        else

          infof(data, "MD5 checksum match!\n");

        /* as we already matched, we skip the check for known hosts */

      }

      else

        result = ssh_knownhost(conn);



      result = ssh_check_fingerprint(conn);

      if(!result)

        state(conn, SSH_AUTHLIST);

      break;