QUIT_CMD, HELP_CMD,
+#ifdef EXPERIMENTAL_PROXY
+ PROXY_FAIL_IGNORE_CMD,
+#endif
+
/* These are specials that don't correspond to actual commands */
EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
+#ifdef EXPERIMENTAL_PROXY
+/*************************************************
+* Check if host is required proxy host *
+*************************************************/
+/* The function determines if inbound host will be a regular smtp host
+or if it is configured that it must use Proxy Protocol.
+
+Arguments: none
+Returns: bool
+*/
+
+static BOOL
+check_proxy_protocol_host()
+{
+int rc;
+/* Cannot configure local connection as a proxy inbound */
+if (sender_host_address == NULL) return proxy_session;
+
+rc = verify_check_this_host(&proxy_required_hosts, NULL, NULL,
+ sender_host_address, NULL);
+if (rc == OK)
+ {
+ DEBUG(D_receive)
+ debug_printf("Detected proxy protocol configured host\n");
+ proxy_session = TRUE;
+ }
+return proxy_session;
+}
+
+
+/*************************************************
+* Flush waiting input string *
+*************************************************/
+static void
+flush_input()
+{
+int rc;
+
+rc = smtp_getc();
+while (rc != '\n') /* End of input string */
+ {
+ rc = smtp_getc();
+ }
+}
+
+
+/*************************************************
+* Setup host for proxy protocol *
+*************************************************/
+/* The function configures the connection based on a header from the
+inbound host to use Proxy Protocol. The specification is very exact
+so exit with an error if do not find the exact required pieces. This
+includes an incorrect number of spaces separating args.
+
+Arguments: none
+Returns: int
+*/
+
+static BOOL
+setup_proxy_protocol_host()
+{
+union {
+ struct {
+ uschar line[108];
+ } v1;
+ struct {
+ uschar sig[12];
+ uschar ver;
+ uschar cmd;
+ uschar fam;
+ uschar len;
+ union {
+ struct { /* TCP/UDP over IPv4, len = 12 */
+ uint32_t src_addr;
+ uint32_t dst_addr;
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip4;
+ struct { /* TCP/UDP over IPv6, len = 36 */
+ uint8_t src_addr[16];
+ uint8_t dst_addr[16];
+ uint16_t src_port;
+ uint16_t dst_port;
+ } ip6;
+ struct { /* AF_UNIX sockets, len = 216 */
+ uschar src_addr[108];
+ uschar dst_addr[108];
+ } unx;
+ } addr;
+ } v2;
+} hdr;
+
+int size, ret, fd;
+uschar *tmpip;
+const char v2sig[13] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A\x02";
+uschar *iptype; /* To display debug info */
+struct timeval tv;
+
+fd = fileno(smtp_in);
+
+/* Proxy Protocol host must send header within a short time
+(default 3 seconds) or it's considered invalid */
+tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
+tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
+setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&tv,
+ sizeof(struct timeval));
+do
+ {
+ ret = recv(fd, &hdr, sizeof(hdr), MSG_PEEK);
+ }
+ while (ret == -1 && errno == EINTR);
+
+if (ret == -1)
+ return (errno == EAGAIN) ? 0 : ERRNO_PROXYFAIL;
+
+if (ret >= 16 &&
+ memcmp(&hdr.v2, v2sig, 13) == 0)
+ {
+ DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
+ size = 16 + hdr.v2.len;
+ if (ret < size)
+ {
+ DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header\n");
+ goto proxyfail;
+ }
+ switch (hdr.v2.cmd)
+ {
+ case 0x01: /* PROXY command */
+ switch (hdr.v2.fam)
+ {
+ case 0x11: /* TCPv4 */
+ tmpip = string_sprintf("%s", hdr.v2.addr.ip4.src_addr);
+ if (!string_is_ip_address(tmpip,NULL))
+ return ERRNO_PROXYFAIL;
+ sender_host_address = tmpip;
+ sender_host_port = hdr.v2.addr.ip4.src_port;
+ goto done;
+ case 0x21: /* TCPv6 */
+ tmpip = string_sprintf("%s", hdr.v2.addr.ip6.src_addr);
+ if (!string_is_ip_address(tmpip,NULL))
+ return ERRNO_PROXYFAIL;
+ sender_host_address = tmpip;
+ sender_host_port = hdr.v2.addr.ip6.src_port;
+ goto done;
+ }
+ /* Unsupported protocol, keep local connection address */
+ break;
+ case 0x00: /* LOCAL command */
+ /* Keep local connection address for LOCAL */
+ break;
+ default:
+ DEBUG(D_receive) debug_printf("Unsupported PROXYv2 command\n");
+ goto proxyfail;
+ }
+ }
+else if (ret >= 8 &&
+ memcmp(hdr.v1.line, "PROXY", 5) == 0)
+ {
+ uschar *p = string_copy(hdr.v1.line);
+ uschar *end = memchr(p, '\r', ret - 1);
+ uschar *sp; /* Utility variables follow */
+ int tmp_port;
+ char *endc;
+
+ if (!end || end[1] != '\n')
+ {
+ DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
+ goto proxyfail;
+ }
+ *end = '\0'; /* Terminate the string */
+ size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
+ DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
+ /* Step through the string looking for the required fields. Ensure
+ strict adherance to required formatting, exit for any error. */
+ p += 5;
+ if (!isspace(*(p++)))
+ {
+ DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
+ goto proxyfail;
+ }
+ if (!Ustrncmp(p, CCS"TCP4", 4))
+ iptype = US"IPv4";
+ else if (!Ustrncmp(p,CCS"TCP6", 4))
+ iptype = US"IPv6";
+ else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
+ {
+ iptype = US"Unknown";
+ goto done;
+ }
+ else
+ {
+ DEBUG(D_receive) debug_printf("Invalid TCP type\n");
+ goto proxyfail;
+ }
+
+ p += Ustrlen(iptype);
+ if (!isspace(*(p++)))
+ {
+ DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
+ goto proxyfail;
+ }
+ /* Find the end of the arg */
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive)
+ debug_printf("Did not find proxied src %s\n", iptype);
+ goto proxyfail;
+ }
+ *sp = '\0';
+ if(!string_is_ip_address(p,NULL))
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxied src arg is not an %s address\n", iptype);
+ goto proxyfail;
+ }
+ proxy_host = sender_host_address;
+ sender_host_address = p;
+ p = sp + 1;
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive)
+ debug_printf("Did not find proxy dest %s\n", iptype);
+ goto proxyfail;
+ }
+ *sp = '\0';
+ if(!string_is_ip_address(p,NULL))
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxy dest arg is not an %s address\n", iptype);
+ goto proxyfail;
+ }
+ /* Should save dest ip somewhere? */
+ p = sp + 1;
+ if ((sp = Ustrchr(p, ' ')) == NULL)
+ {
+ DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
+ goto proxyfail;
+ }
+ *sp = '\0';
+ tmp_port = strtol(CCS p,&endc,10);
+ if (*endc || tmp_port == 0)
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxied src port '%s' not an integer\n", p);
+ goto proxyfail;
+ }
+ proxy_port = sender_host_port;
+ sender_host_port = tmp_port;
+ p = sp + 1;
+ if ((sp = Ustrchr(p, '\0')) == NULL)
+ {
+ DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
+ goto proxyfail;
+ }
+ tmp_port = strtol(CCS p,&endc,10);
+ if (*endc || tmp_port == 0)
+ {
+ DEBUG(D_receive)
+ debug_printf("Proxy dest port '%s' not an integer\n", p);
+ goto proxyfail;
+ }
+ /* Should save dest port somewhere? */
+ /* Already checked for /r /n above. Good V1 header received. */
+ goto done;
+ }
+else
+ {
+ /* Wrong protocol */
+ DEBUG(D_receive) debug_printf("Wrong proxy protocol specified\n");
+ goto proxyfail;
+ }
+
+proxyfail:
+/* Don't flush any potential buffer contents. Any input should cause a
+synchronization failure or we just don't want to speak SMTP to them */
+return FALSE;
+
+done:
+flush_input();
+DEBUG(D_receive)
+ debug_printf("Valid %s sender from Proxy Protocol header\n",
+ iptype);
+return proxy_session;
+}
+#endif
+
+
+
/*************************************************
* Read one command line *
*************************************************/
for (p = cmd_list; p < cmd_list_end; p++)
{
+ #ifdef EXPERIMENTAL_PROXY
+ /* Only allow QUIT command if Proxy Protocol parsing failed */
+ if (proxy_session && proxy_session_failed)
+ {
+ if (p->cmd != QUIT_CMD)
+ continue;
+ }
+ #endif
if (strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0 &&
(smtp_cmd_buffer[p->len-1] == ':' || /* "mail from:" or "rcpt to:" */
smtp_cmd_buffer[p->len] == 0 ||
}
}
+#ifdef EXPERIMENTAL_PROXY
+/* Only allow QUIT command if Proxy Protocol parsing failed */
+if (proxy_session && proxy_session_failed)
+ return PROXY_FAIL_IGNORE_CMD;
+#endif
+
/* Enforce synchronization for unknown commands */
if (smtp_inptr < smtp_inend && /* Outstanding input */
if (smtp_batched_input) return TRUE;
+#ifdef EXPERIMENTAL_PROXY
+/* If valid Proxy Protocol source is connecting, set up session.
+ * Failure will not allow any SMTP function other than QUIT. */
+proxy_session = FALSE;
+proxy_session_failed = FALSE;
+if (check_proxy_protocol_host())
+ {
+ if (setup_proxy_protocol_host() == FALSE)
+ {
+ proxy_session_failed = TRUE;
+ DEBUG(D_receive)
+ debug_printf("Failure to extract proxied host, only QUIT allowed\n");
+ }
+ else
+ {
+ sender_host_name = NULL;
+ (void)host_name_lookup();
+ host_build_sender_fullhost();
+ }
+ }
+#endif
+
/* Run the ACL if it exists */
user_msg = NULL;
-
/*************************************************
* Initialize for SMTP incoming message *
*************************************************/
done = 1; /* Pretend eof - drops connection */
break;
+ #ifdef EXPERIMENTAL_PROXY
+ case PROXY_FAIL_IGNORE_CMD:
+ smtp_printf("503 Command refused, required Proxy negotiation failed\r\n");
+ break;
+ #endif
default:
if (unknown_command_count++ >= smtp_max_unknown_commands)
git://git.exim.org / exim.git / blobdiff