/* Process the SPA packet data
*/
void
incoming_spa(fko_srv_options_t *opts)
{
/* Always a good idea to initialize ctx to null if it will be used
* repeatedly (especially when using fko_new_with_data()).
*/
fko_ctx_t ctx = NULL;
char *spa_ip_demark, *gpg_id, *raw_digest = NULL;
time_t now_ts;
int res, status, ts_diff, enc_type, stanza_num=0;
int added_replay_digest = 0, pkt_data_len=0;
int is_err, cmd_exec_success = 0, attempted_decrypt = 0;
int conf_pkt_age = 0;
char dump_buf[CTX_DUMP_BUFSIZE];
spa_pkt_info_t *spa_pkt = &(opts->spa_pkt);
/* This will hold our pertinent SPA data.
*/
spa_data_t spadat;
/* Loop through all access stanzas looking for a match
*/
acc_stanza_t *acc = opts->acc_stanzas;
acc_string_list_t *gpg_id_ndx;
unsigned char is_gpg_match = 0;
inet_ntop(AF_INET, &(spa_pkt->packet_src_ip),
spadat.pkt_source_ip, sizeof(spadat.pkt_source_ip));
/* At this point, we want to validate and (if needed) preprocess the
* SPA data and/or to be reasonably sure we have a SPA packet (i.e
* try to eliminate obvious non-spa packets).
*/
pkt_data_len = spa_pkt->packet_data_len;
res = preprocess_spa_data(opts, spadat.pkt_source_ip);
if(res != FKO_SUCCESS)
{
log_msg(LOG_DEBUG, "[%s] preprocess_spa_data() returned error %i: '%s' for incoming packet.",
spadat.pkt_source_ip, res, get_errstr(res));
return;
}
if(opts->foreground == 1 && opts->verbose > 2)
{
printf("[+] candidate SPA packet payload:\n");
hex_dump(spa_pkt->packet_data, pkt_data_len);
}
if(strncasecmp(opts->config[CONF_ENABLE_SPA_PACKET_AGING], "Y", 1) == 0)
{
conf_pkt_age = strtol_wrapper(opts->config[CONF_MAX_SPA_PACKET_AGE],
0, RCHK_MAX_SPA_PACKET_AGE, NO_EXIT_UPON_ERR, &is_err);
if(is_err != FKO_SUCCESS)
{
log_msg(LOG_ERR, "[*] [%s] invalid MAX_SPA_PACKET_AGE", spadat.pkt_source_ip);
return;
}
}
if (is_src_match(opts->acc_stanzas, ntohl(spa_pkt->packet_src_ip)))
{
if(strncasecmp(opts->config[CONF_ENABLE_DIGEST_PERSISTENCE], "Y", 1) == 0)
{
/* Check for a replay attack
*/
res = get_raw_digest(&raw_digest, (char *)spa_pkt->packet_data);
if(res != FKO_SUCCESS)
{
if (raw_digest != NULL)
free(raw_digest);
return;
}
if (raw_digest == NULL)
return;
if (is_replay(opts, raw_digest) != SPA_MSG_SUCCESS)
{
free(raw_digest);
return;
}
}
}
else
{
log_msg(LOG_WARNING,
"No access data found for source IP: %s", spadat.pkt_source_ip
);
return;
}
/* Now that we know there is a matching access.conf stanza and the
* incoming SPA packet is not a replay, see if we should grant any
* access
*/
while(acc)
{
res = FKO_SUCCESS;
cmd_exec_success = 0;
attempted_decrypt = 0;
stanza_num++;
/* Start access loop with a clean FKO context
*/
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip, stanza_num, fko_errstr(res)
);
ctx = NULL;
}
/* Check for a match for the SPA source IP and the access stanza
*/
if(! compare_addr_list(acc->source_list, ntohl(spa_pkt->packet_src_ip)))
{
acc = acc->next;
continue;
}
log_msg(LOG_INFO, "(stanza #%d) SPA Packet from IP: %s received with access source match",
stanza_num, spadat.pkt_source_ip);
log_msg(LOG_DEBUG, "SPA Packet: '%s'", spa_pkt->packet_data);
/* Make sure this access stanza has not expired
*/
if(acc->access_expire_time > 0)
{
if(acc->expired)
{
acc = acc->next;
continue;
}
else
{
if(time(NULL) > acc->access_expire_time)
{
log_msg(LOG_INFO, "[%s] (stanza #%d) Access stanza has expired",
spadat.pkt_source_ip, stanza_num);
acc->expired = 1;
acc = acc->next;
continue;
}
}
}
/* Get encryption type and try its decoding routine first (if the key
* for that type is set)
*/
enc_type = fko_encryption_type((char *)spa_pkt->packet_data);
if(acc->use_rijndael)
{
if (acc->key == NULL)
{
log_msg(LOG_ERR,
"[%s] (stanza #%d) No KEY for RIJNDAEL encrypted messages",
spadat.pkt_source_ip, stanza_num
);
acc = acc->next;
continue;
}
/* Command mode messages may be quite long
*/
if(acc->enable_cmd_exec || enc_type == FKO_ENCRYPTION_RIJNDAEL)
{
res = fko_new_with_data(&ctx, (char *)spa_pkt->packet_data,
acc->key, acc->key_len, acc->encryption_mode, acc->hmac_key,
acc->hmac_key_len, acc->hmac_type);
attempted_decrypt = 1;
if(res == FKO_SUCCESS)
cmd_exec_success = 1;
}
}
if(acc->use_gpg && enc_type == FKO_ENCRYPTION_GPG && cmd_exec_success == 0)
{
/* For GPG we create the new context without decrypting on the fly
* so we can set some GPG parameters first.
*/
if(acc->gpg_decrypt_pw != NULL || acc->gpg_allow_no_pw)
{
res = fko_new_with_data(&ctx, (char *)spa_pkt->packet_data, NULL,
0, FKO_ENC_MODE_ASYMMETRIC, acc->hmac_key,
acc->hmac_key_len, acc->hmac_type);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Error creating fko context (before decryption): %s",
spadat.pkt_source_ip, stanza_num, fko_errstr(res)
);
acc = acc->next;
continue;
}
/* Set whatever GPG parameters we have.
*/
if(acc->gpg_exe != NULL)
{
res = fko_set_gpg_exe(ctx, acc->gpg_exe);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Error setting GPG path %s: %s",
spadat.pkt_source_ip, stanza_num, acc->gpg_exe,
fko_errstr(res)
);
acc = acc->next;
continue;
}
}
if(acc->gpg_home_dir != NULL)
{
res = fko_set_gpg_home_dir(ctx, acc->gpg_home_dir);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Error setting GPG keyring path to %s: %s",
spadat.pkt_source_ip, stanza_num, acc->gpg_home_dir,
fko_errstr(res)
);
acc = acc->next;
continue;
}
}
if(acc->gpg_decrypt_id != NULL)
fko_set_gpg_recipient(ctx, acc->gpg_decrypt_id);
/* If GPG_REQUIRE_SIG is set for this acc stanza, then set
* the FKO context accordingly and check the other GPG Sig-
* related parameters. This also applies when REMOTE_ID is
* set.
*/
if(acc->gpg_require_sig)
{
fko_set_gpg_signature_verify(ctx, 1);
/* Set whether or not to ignore signature verification errors.
*/
fko_set_gpg_ignore_verify_error(ctx, acc->gpg_ignore_sig_error);
}
else
{
fko_set_gpg_signature_verify(ctx, 0);
fko_set_gpg_ignore_verify_error(ctx, 1);
}
/* Now decrypt the data.
*/
res = fko_decrypt_spa_data(ctx, acc->gpg_decrypt_pw, 0);
attempted_decrypt = 1;
}
}
if(attempted_decrypt == 0)
{
log_msg(LOG_ERR,
"(stanza #%d) No stanza encryption mode match for encryption type: %i.",
stanza_num, enc_type);
acc = acc->next;
continue;
}
/* Do we have a valid FKO context? Did the SPA decrypt properly?
*/
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) Error creating fko context: %s",
spadat.pkt_source_ip, stanza_num, fko_errstr(res));
if(IS_GPG_ERROR(res))
log_msg(LOG_WARNING, "[%s] (stanza #%d) - GPG ERROR: %s",
spadat.pkt_source_ip, stanza_num, fko_gpg_errstr(ctx));
acc = acc->next;
continue;
}
/* Add this SPA packet into the replay detection cache
*/
if (added_replay_digest == 0
&& strncasecmp(opts->config[CONF_ENABLE_DIGEST_PERSISTENCE], "Y", 1) == 0)
{
res = add_replay(opts, raw_digest);
if (res != SPA_MSG_SUCCESS)
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) Could not add digest to replay cache",
spadat.pkt_source_ip, stanza_num);
acc = acc->next;
continue;
}
added_replay_digest = 1;
}
/* At this point, we assume the SPA data is valid. Now we need to see
* if it meets our access criteria.
*/
log_msg(LOG_DEBUG, "[%s] (stanza #%d) SPA Decode (res=%i):",
spadat.pkt_source_ip, stanza_num, res);
res = dump_ctx_to_buffer(ctx, dump_buf, sizeof(dump_buf));
if (res == FKO_SUCCESS)
log_msg(LOG_DEBUG, "%s", dump_buf);
else
log_msg(LOG_WARNING, "Unable to dump FKO context: %s", fko_errstr(res));
/* First, if this is a GPG message, and GPG_REMOTE_ID list is not empty,
* then we need to make sure this incoming message is signer ID matches
* an entry in the list.
*/
if(enc_type == FKO_ENCRYPTION_GPG && acc->gpg_require_sig)
{
res = fko_get_gpg_signature_id(ctx, &gpg_id);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Error pulling the GPG signature ID from the context: %s",
spadat.pkt_source_ip, stanza_num, fko_gpg_errstr(ctx));
acc = acc->next;
continue;
}
log_msg(LOG_INFO, "[%s] (stanza #%d) Incoming SPA data signed by '%s'.",
spadat.pkt_source_ip, stanza_num, gpg_id);
if(acc->gpg_remote_id != NULL)
{
is_gpg_match = 0;
for(gpg_id_ndx = acc->gpg_remote_id_list;
gpg_id_ndx != NULL; gpg_id_ndx=gpg_id_ndx->next)
{
res = fko_gpg_signature_id_match(ctx,
gpg_id_ndx->str, &is_gpg_match);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Error in GPG siganture comparision: %s",
spadat.pkt_source_ip, stanza_num, fko_gpg_errstr(ctx));
acc = acc->next;
continue;
}
if(is_gpg_match)
break;
}
if(! is_gpg_match)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Incoming SPA packet signed by ID: %s, but that ID is not the GPG_REMOTE_ID list.",
spadat.pkt_source_ip, stanza_num, gpg_id);
acc = acc->next;
continue;
}
}
}
/* Populate our spa data struct for future reference.
*/
res = get_spa_data_fields(ctx, &spadat);
/* Figure out what our timeout will be. If it is specified in the SPA
* data, then use that. If not, try the FW_ACCESS_TIMEOUT from the
* access.conf file (if there is one). Otherwise use the default.
*/
if(spadat.client_timeout > 0)
spadat.fw_access_timeout = spadat.client_timeout;
else if(acc->fw_access_timeout > 0)
spadat.fw_access_timeout = acc->fw_access_timeout;
else
spadat.fw_access_timeout = DEF_FW_ACCESS_TIMEOUT;
if(res != FKO_SUCCESS)
{
log_msg(LOG_ERR, "[%s] (stanza #%d) Unexpected error pulling SPA data from the context: %s",
spadat.pkt_source_ip, stanza_num, fko_errstr(res));
acc = acc->next;
continue;
}
/* Check packet age if so configured.
*/
if(strncasecmp(opts->config[CONF_ENABLE_SPA_PACKET_AGING], "Y", 1) == 0)
{
time(&now_ts);
ts_diff = abs(now_ts - spadat.timestamp);
if(ts_diff > conf_pkt_age)
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) SPA data time difference is too great (%i seconds).",
spadat.pkt_source_ip, stanza_num, ts_diff);
acc = acc->next;
continue;
}
}
/* At this point, we have enough to check the embedded (or packet source)
* IP address against the defined access rights. We start by splitting
* the spa msg source IP from the remainder of the message.
*/
spa_ip_demark = strchr(spadat.spa_message, ',');
if(spa_ip_demark == NULL)
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) Error parsing SPA message string: %s",
spadat.pkt_source_ip, stanza_num, fko_errstr(res));
acc = acc->next;
continue;
}
if((spa_ip_demark-spadat.spa_message) < MIN_IPV4_STR_LEN-1
|| (spa_ip_demark-spadat.spa_message) > MAX_IPV4_STR_LEN)
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) Invalid source IP in SPA message, ignoring SPA packet",
spadat.pkt_source_ip, stanza_num, fko_errstr(res));
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip, stanza_num, fko_errstr(res)
);
ctx = NULL;
}
break;
}
strlcpy(spadat.spa_message_src_ip,
spadat.spa_message, (spa_ip_demark-spadat.spa_message)+1);
if(! is_valid_ipv4_addr(spadat.spa_message_src_ip))
{
log_msg(LOG_WARNING, "[%s] (stanza #%d) Invalid source IP in SPA message, ignoring SPA packet",
spadat.pkt_source_ip, stanza_num, fko_errstr(res));
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip, stanza_num, fko_errstr(res)
);
ctx = NULL;
}
break;
}
strlcpy(spadat.spa_message_remain, spa_ip_demark+1, MAX_DECRYPTED_SPA_LEN);
/* If use source IP was requested (embedded IP of 0.0.0.0), make sure it
* is allowed.
*/
if(strcmp(spadat.spa_message_src_ip, "0.0.0.0") == 0)
{
if(acc->require_source_address)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Got 0.0.0.0 when valid source IP was required.",
spadat.pkt_source_ip, stanza_num
);
acc = acc->next;
continue;
}
spadat.use_src_ip = spadat.pkt_source_ip;
}
else
spadat.use_src_ip = spadat.spa_message_src_ip;
/* If REQUIRE_USERNAME is set, make sure the username in this SPA data
* matches.
*/
if(acc->require_username != NULL)
{
if(strcmp(spadat.username, acc->require_username) != 0)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) Username in SPA data (%s) does not match required username: %s",
spadat.pkt_source_ip, stanza_num, spadat.username, acc->require_username
);
acc = acc->next;
continue;
}
}
/* Take action based on SPA message type.
*/
if(spadat.message_type == FKO_LOCAL_NAT_ACCESS_MSG
|| spadat.message_type == FKO_CLIENT_TIMEOUT_LOCAL_NAT_ACCESS_MSG
|| spadat.message_type == FKO_NAT_ACCESS_MSG
|| spadat.message_type == FKO_CLIENT_TIMEOUT_NAT_ACCESS_MSG)
{
#if FIREWALL_IPTABLES
if(strncasecmp(opts->config[CONF_ENABLE_IPT_FORWARDING], "Y", 1)!=0)
{
log_msg(LOG_WARNING,
"(stanza #%d) SPA packet from %s requested NAT access, but is not enabled",
stanza_num, spadat.pkt_source_ip
);
acc = acc->next;
continue;
}
#else
log_msg(LOG_WARNING,
"(stanza #%d) SPA packet from %s requested unsupported NAT access",
stanza_num, spadat.pkt_source_ip
);
acc = acc->next;
continue;
#endif
}
/* Command messages.
*/
if(spadat.message_type == FKO_COMMAND_MSG)
{
if(!acc->enable_cmd_exec)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) SPA Command message are not allowed in the current configuration.",
spadat.pkt_source_ip, stanza_num
);
acc = acc->next;
continue;
}
else
{
log_msg(LOG_INFO,
"[%s] (stanza #%d) Processing SPA Command message: command='%s'.",
spadat.pkt_source_ip, stanza_num, spadat.spa_message_remain
);
/* Do we need to become another user? If so, we call
* run_extcmd_as and pass the cmd_exec_uid.
*/
if(acc->cmd_exec_user != NULL && strncasecmp(acc->cmd_exec_user, "root", 4) != 0)
{
log_msg(LOG_INFO, "[%s] (stanza #%d) Setting effective user to %s (UID=%i) before running command.",
spadat.pkt_source_ip, stanza_num, acc->cmd_exec_user, acc->cmd_exec_uid);
res = run_extcmd_as(acc->cmd_exec_uid,
spadat.spa_message_remain, NULL, 0, 0);
}
else /* Just run it as we are (root that is). */
res = run_extcmd(spadat.spa_message_remain, NULL, 0, 5);
/* --DSS XXX: I have found that the status (and res for that
* matter) have been unreliable indicators of the
* actual exit status of some commands. Not sure
* why yet. For now, we will take what we get.
*/
status = WEXITSTATUS(res);
if(opts->verbose > 1)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) CMD_EXEC: command returned %i",
spadat.pkt_source_ip, stanza_num, status);
if(status != 0)
res = SPA_MSG_COMMAND_ERROR;
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip, stanza_num, fko_errstr(res)
);
ctx = NULL;
}
/* we processed the command on a matching access stanza, so we
* don't look for anything else to do with this SPA packet
*/
break;
}
}
/* From this point forward, we have some kind of access message. So
* we first see if access is allowed by checking access against
* restrict_ports and open_ports.
*
* --DSS TODO: We should add BLACKLIST support here as well.
*/
if(! acc_check_port_access(acc, spadat.spa_message_remain))
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) One or more requested protocol/ports was denied per access.conf.",
spadat.pkt_source_ip, stanza_num
);
acc = acc->next;
continue;
}
/* At this point, we process the SPA request and break out of the
* access stanza loop (first valid access stanza stops us looking
* for others).
*/
process_spa_request(opts, acc, &spadat);
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] (stanza #%d) fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip, stanza_num
);
ctx = NULL;
}
break;
}
if (raw_digest != NULL)
free(raw_digest);
if(ctx != NULL)
{
if(fko_destroy(ctx) == FKO_ERROR_ZERO_OUT_DATA)
log_msg(LOG_WARNING,
"[%s] fko_destroy() could not zero out sensitive data buffer.",
spadat.pkt_source_ip
);
ctx = NULL;
}
return;
}
/* Process command messages
*/
static int
process_cmd_msg(fko_srv_options_t *opts, acc_stanza_t *acc,
spa_data_t *spadat, const int stanza_num, int *res)
{
int pid_status=0;
char cmd_buf[MAX_SPA_CMD_LEN] = {0};
if(!acc->enable_cmd_exec)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) SPA Command messages are not allowed in the current configuration.",
spadat->pkt_source_ip, stanza_num
);
return 0;
}
else if(opts->test)
{
log_msg(LOG_WARNING,
"[%s] (stanza #%d) --test mode enabled, skipping command execution.",
spadat->pkt_source_ip, stanza_num
);
return 0;
}
else
{
log_msg(LOG_INFO,
"[%s] (stanza #%d) Processing SPA Command message: command='%s'.",
spadat->pkt_source_ip, stanza_num, spadat->spa_message_remain
);
memset(cmd_buf, 0x0, sizeof(cmd_buf));
if(acc->enable_cmd_sudo_exec)
{
/* Run the command via sudo - this allows sudo filtering
* to apply to the incoming command
*/
strlcpy(cmd_buf, opts->config[CONF_SUDO_EXE],
sizeof(cmd_buf));
if(acc->cmd_sudo_exec_user != NULL
&& strncasecmp(acc->cmd_sudo_exec_user, "root", 4) != 0)
{
strlcat(cmd_buf, " -u ", sizeof(cmd_buf));
strlcat(cmd_buf, acc->cmd_sudo_exec_user, sizeof(cmd_buf));
}
if(acc->cmd_exec_group != NULL
&& strncasecmp(acc->cmd_sudo_exec_group, "root", 4) != 0)
{
strlcat(cmd_buf, " -g ", sizeof(cmd_buf));
strlcat(cmd_buf,
acc->cmd_sudo_exec_group, sizeof(cmd_buf));
}
strlcat(cmd_buf, " ", sizeof(cmd_buf));
strlcat(cmd_buf, spadat->spa_message_remain, sizeof(cmd_buf));
}
else
strlcpy(cmd_buf, spadat->spa_message_remain, sizeof(cmd_buf));
if(acc->cmd_exec_user != NULL
&& strncasecmp(acc->cmd_exec_user, "root", 4) != 0)
{
log_msg(LOG_INFO,
"[%s] (stanza #%d) Running command '%s' setuid/setgid user/group to %s/%s (UID=%i,GID=%i)",
spadat->pkt_source_ip, stanza_num, cmd_buf, acc->cmd_exec_user,
acc->cmd_exec_group == NULL ? acc->cmd_exec_user : acc->cmd_exec_group,
acc->cmd_exec_uid, acc->cmd_exec_gid);
*res = run_extcmd_as(acc->cmd_exec_uid, acc->cmd_exec_gid,
cmd_buf, NULL, 0, WANT_STDERR, NO_TIMEOUT,
&pid_status, opts);
}
else /* Just run it as we are (root that is). */
{
log_msg(LOG_INFO,
"[%s] (stanza #%d) Running command '%s'",
spadat->pkt_source_ip, stanza_num, cmd_buf);
*res = run_extcmd(cmd_buf, NULL, 0, WANT_STDERR,
5, &pid_status, opts);
}
/* should only call WEXITSTATUS() if WIFEXITED() is true
*/
log_msg(LOG_INFO,
"[%s] (stanza #%d) CMD_EXEC: command returned %i, pid_status: %d",
spadat->pkt_source_ip, stanza_num, *res,
WIFEXITED(pid_status) ? WEXITSTATUS(pid_status) : pid_status);
if(WIFEXITED(pid_status))
{
if(WEXITSTATUS(pid_status) != 0)
*res = SPA_MSG_COMMAND_ERROR;
}
else
*res = SPA_MSG_COMMAND_ERROR;
}
return 1;
}
/* Process the SPA packet data
*/
int
incoming_spa(fko_srv_options_t *opts)
{
/* Always a good idea to initialize ctx to null if it will be used
* repeatedly (especially when using fko_new_with_data().
*/
fko_ctx_t ctx = NULL;
char *spa_ip_demark, *gpg_id;
time_t now_ts;
int res, status, ts_diff, enc_type;
spa_pkt_info_t *spa_pkt = &(opts->spa_pkt);
/* This will hold our pertinent SPA data.
*/
spa_data_t spadat;
/* Get the access.conf data for the stanza that matches this incoming
* source IP address.
*/
acc_stanza_t *acc = acc_check_source(opts, spa_pkt->packet_src_ip);
inet_ntop(AF_INET, &(spa_pkt->packet_src_ip),
spadat.pkt_source_ip, sizeof(spadat.pkt_source_ip));
/* At this point, we want to validate and (if needed) preprocess the
* SPA data and/or to be reasonably sure we have a SPA packet (i.e
* try to eliminate obvious non-spa packets).
*/
res = preprocess_spa_data(opts, spadat.pkt_source_ip);
if(res != FKO_SUCCESS)
return(SPA_MSG_NOT_SPA_DATA);
log_msg(LOG_INFO, "SPA Packet from IP: %s received.", spadat.pkt_source_ip);
if(acc == NULL)
{
log_msg(LOG_WARNING,
"No access data found for source IP: %s", spadat.pkt_source_ip
);
return(SPA_MSG_ACCESS_DENIED);
}
if(opts->verbose > 1)
log_msg(LOG_INFO, "SPA Packet: '%s'\n", spa_pkt->packet_data);
/* Get encryption type and try its decoding routine first (if the key
* for that type is set)
*/
enc_type = fko_encryption_type((char *)spa_pkt->packet_data);
if(enc_type == FKO_ENCRYPTION_RIJNDAEL)
{
if(acc->key != NULL)
res = fko_new_with_data(&ctx, (char *)spa_pkt->packet_data, acc->key);
else
{
log_msg(LOG_ERR,
"No KEY for RIJNDAEL encrypted messages");
return(SPA_MSG_FKO_CTX_ERROR);
}
}
else if(enc_type == FKO_ENCRYPTION_GPG)
{
/* For GPG we create the new context without decrypting on the fly
* so we can set some GPG parameters first.
*/
if(acc->gpg_decrypt_pw != NULL)
{
res = fko_new_with_data(&ctx, (char *)spa_pkt->packet_data, NULL);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"Error creating fko context (before decryption): %s",
fko_errstr(res)
);
return(SPA_MSG_FKO_CTX_ERROR);
}
/* Set whatever GPG parameters we have.
*/
if(acc->gpg_home_dir != NULL)
res = fko_set_gpg_home_dir(ctx, acc->gpg_home_dir);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING,
"Error setting GPG keyring path to %s: %s",
acc->gpg_home_dir,
fko_errstr(res)
);
return(SPA_MSG_FKO_CTX_ERROR);
}
if(acc->gpg_decrypt_id != NULL)
fko_set_gpg_recipient(ctx, acc->gpg_decrypt_id);
/* If GPG_REQUIRE_SIG is set for this acc stanza, then set
* the FKO context accordingly and check the other GPG Sig-
* related parameters. This also applies when REMOTE_ID is
* set.
*/
if(acc->gpg_require_sig)
{
fko_set_gpg_signature_verify(ctx, 1);
/* Set whether or not to ignore signature verification errors.
*/
fko_set_gpg_ignore_verify_error(ctx, acc->gpg_ignore_sig_error);
}
else
{
fko_set_gpg_signature_verify(ctx, 0);
fko_set_gpg_ignore_verify_error(ctx, 1);
}
/* Now decrypt the data.
*/
res = fko_decrypt_spa_data(ctx, acc->gpg_decrypt_pw);
}
else
{
log_msg(LOG_ERR,
"No GPG_DECRYPT_PW for GPG encrypted messages");
return(SPA_MSG_FKO_CTX_ERROR);
}
}
else
{
log_msg(LOG_ERR, "Unable to determing encryption type. Got type=%i.",
enc_type);
return(SPA_MSG_FKO_CTX_ERROR);
}
/* Do we have a valid FKO context?
*/
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING, "Error creating fko context: %s",
fko_errstr(res));
if(IS_GPG_ERROR(res))
log_msg(LOG_WARNING, " - GPG ERROR: %s",
fko_gpg_errstr(ctx));
goto clean_and_bail;
}
/* At this point, we assume the SPA data is valid. Now we need to see
* if it meets our access criteria.
*/
if(opts->verbose > 2)
log_msg(LOG_INFO, "SPA Decode (res=%i):\n%s", res, dump_ctx(ctx));
/* First, if this is a GPG message, and GPG_REMOTE_ID list is not empty,
* then we need to make sure this incoming message is signer ID matches
* an entry in the list.
*/
if(enc_type == FKO_ENCRYPTION_GPG && acc->gpg_require_sig)
{
res = fko_get_gpg_signature_id(ctx, &gpg_id);
if(res != FKO_SUCCESS)
{
log_msg(LOG_WARNING, "Error pulling the GPG signature ID from the context: %s",
fko_gpg_errstr(ctx));
goto clean_and_bail;
}
if(opts->verbose)
log_msg(LOG_INFO, "Incoming SPA data signed by '%s'.", gpg_id);
if(acc->gpg_remote_id != NULL && !acc_check_gpg_remote_id(acc, gpg_id))
{
log_msg(LOG_WARNING,
"Incoming SPA packet signed by ID: %s, but that ID is not the GPG_REMOTE_ID list.",
gpg_id);
goto clean_and_bail;
}
}
/* Check for replays if so configured.
*/
if(strncasecmp(opts->config[CONF_ENABLE_DIGEST_PERSISTENCE], "Y", 1) == 0)
{
res = replay_check(opts, ctx);
if(res != 0) /* non-zero means we have seen this packet before. */
goto clean_and_bail;
}
/* Populate our spa data struct for future reference.
*/
res = get_spa_data_fields(ctx, &spadat);
/* Figure out what our timeout will be. If it is specified in the SPA
* data, then use that. If not, try the FW_ACCESS_TIMEOUT from the
* access.conf file (if there is one). Otherwise use the default.
*/
if(spadat.client_timeout > 0)
spadat.fw_access_timeout = spadat.client_timeout;
else if(acc->fw_access_timeout > 0)
spadat.fw_access_timeout = acc->fw_access_timeout;
else
spadat.fw_access_timeout = DEF_FW_ACCESS_TIMEOUT;
if(res != FKO_SUCCESS)
{
log_msg(LOG_ERR, "Unexpected error pulling SPA data from the context: %s",
fko_errstr(res));
res = SPA_MSG_ERROR;
goto clean_and_bail;
}
/* Check packet age if so configured.
*/
if(strncasecmp(opts->config[CONF_ENABLE_SPA_PACKET_AGING], "Y", 1) == 0)
{
time(&now_ts);
ts_diff = now_ts - spadat.timestamp;
if(ts_diff > atoi(opts->config[CONF_MAX_SPA_PACKET_AGE]))
{
log_msg(LOG_WARNING, "SPA data is too old (%i seconds).",
ts_diff);
res = SPA_MSG_TOO_OLD;
goto clean_and_bail;
}
}
/* At this point, we have enough to check the embedded (or packet source)
* IP address against the defined access rights. We start by splitting
* the spa msg source IP from the remainder of the message.
*/
spa_ip_demark = strchr(spadat.spa_message, ',');
if(spa_ip_demark == NULL)
{
log_msg(LOG_WARNING, "Error parsing SPA message string: %s",
fko_errstr(res));
res = SPA_MSG_ERROR;
goto clean_and_bail;
}
strlcpy(spadat.spa_message_src_ip, spadat.spa_message, (spa_ip_demark-spadat.spa_message)+1);
strlcpy(spadat.spa_message_remain, spa_ip_demark+1, 1024);
/* If use source IP was requested (embedded IP of 0.0.0.0), make sure it
* is allowed.
*/
if(strcmp(spadat.spa_message_src_ip, "0.0.0.0") == 0)
{
if(acc->require_source_address)
{
log_msg(LOG_WARNING,
"Got 0.0.0.0 when valid source IP was required."
);
res = SPA_MSG_ACCESS_DENIED;
goto clean_and_bail;
}
spadat.use_src_ip = spadat.pkt_source_ip;
}
else
spadat.use_src_ip = spadat.spa_message_src_ip;
/* If REQUIRE_USERNAME is set, make sure the username in this SPA data
* matches.
*/
if(acc->require_username != NULL)
{
if(strcmp(spadat.username, acc->require_username) != 0)
{
log_msg(LOG_WARNING,
"Username in SPA data (%s) does not match required username: %s",
spadat.username, acc->require_username
);
res = SPA_MSG_ACCESS_DENIED;
goto clean_and_bail;
}
}
/* Take action based on SPA message type. */
/* Command messages.
*/
if(spadat.message_type == FKO_COMMAND_MSG)
{
if(!acc->enable_cmd_exec)
{
log_msg(LOG_WARNING,
"SPA Command message are not allowed in the current configuration."
);
res = SPA_MSG_ACCESS_DENIED;
}
else
{
log_msg(LOG_INFO,
"Processing SPA Command message: command='%s'.",
spadat.spa_message_remain
);
/* Do we need to become another user? If so, we call
* run_extcmd_as and pass the cmd_exec_uid.
*/
if(acc->cmd_exec_user != NULL && strncasecmp(acc->cmd_exec_user, "root", 4) != 0)
{
if(opts->verbose)
log_msg(LOG_INFO, "Setting effective user to %s (UID=%i) before running command.",
acc->cmd_exec_user, acc->cmd_exec_uid);
res = run_extcmd_as(acc->cmd_exec_uid,
spadat.spa_message_remain, NULL, 0, 0);
}
else /* Just run it as we are (root that is). */
res = run_extcmd(spadat.spa_message_remain, NULL, 0, 5);
/* --DSS XXX: I have found that the status (and res for that
* matter) have been unreliable indicators of the
* actual exit status of some commands. Not sure
* why yet. For now, we will take what we get.
*/
status = WEXITSTATUS(res);
if(opts->verbose > 2)
log_msg(LOG_WARNING,
"CMD_EXEC: command returned %i", status);
if(status != 0)
res = SPA_MSG_COMMAND_ERROR;
}
goto clean_and_bail;
}
/* From this point forward, we have some kind of access message. So
* we first see if access is allowed by checking access against
* restrict_ports and open_ports.
*
* --DSS TODO: We should add BLACKLIST support here as well.
*/
if(! acc_check_port_access(acc, spadat.spa_message_remain))
{
log_msg(LOG_WARNING,
"One or more requested protocol/ports was denied per access.conf."
);
res = SPA_MSG_ACCESS_DENIED;
goto clean_and_bail;
}
/* At this point, we can process the SPA request.
*/
res = process_spa_request(opts, &spadat);
clean_and_bail:
if(ctx != NULL)
fko_destroy(ctx);
return(res);
}
