+/*************************************************
+* 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: Boolean success
+*/
+
+static void
+setup_proxy_protocol_host()
+{
+union {
+ struct {
+ uschar line[108];
+ } v1;
+ struct {
+ uschar sig[12];
+ uint8_t ver_cmd;
+ uint8_t fam;
+ uint16_t 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;
+
+/* Temp variables used in PPv2 address:port parsing */
+uint16_t tmpport;
+char tmpip[INET_ADDRSTRLEN];
+struct sockaddr_in tmpaddr;
+char tmpip6[INET6_ADDRSTRLEN];
+struct sockaddr_in6 tmpaddr6;
+
+/* We can't read "all data until end" because while SMTP is
+server-speaks-first, the TLS handshake is client-speaks-first, so for
+TLS-on-connect ports the proxy protocol header will usually be immediately
+followed by a TLS handshake, and with N TLS libraries, we can't reliably
+reinject data for reading by those. So instead we first read "enough to be
+safely read within the header, and figure out how much more to read".
+For v1 we will later read to the end-of-line, for v2 we will read based upon
+the stated length.
+
+The v2 sig is 12 octets, and another 4 gets us the length, so we know how much
+data is needed total. For v1, where the line looks like:
+PROXY TCPn L3src L3dest SrcPort DestPort \r\n
+
+However, for v1 there's also `PROXY UNKNOWN\r\n` which is only 15 octets.
+We seem to support that. So, if we read 14 octets then we can tell if we're
+v2 or v1. If we're v1, we can continue reading as normal.
+
+If we're v2, we can't slurp up the entire header. We need the length in the
+15th & 16th octets, then to read everything after that.
+
+So to safely handle v1 and v2, with client-sent-first supported correctly,
+we have to do a minimum of 3 read calls, not 1. Eww.
+*/
+
+#define PROXY_INITIAL_READ 14
+#define PROXY_V2_HEADER_SIZE 16
+#if PROXY_INITIAL_READ > PROXY_V2_HEADER_SIZE
+# error Code bug in sizes of data to read for proxy usage
+#endif
+
+int get_ok = 0;
+int size, ret;
+int fd = fileno(smtp_in);
+const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
+uschar * iptype; /* To display debug info */
+struct timeval tv;
+struct timeval tvtmp;
+socklen_t vslen = sizeof(struct timeval);
+BOOL yield = FALSE;
+
+/* Save current socket timeout values */
+get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
+
+/* 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;
+if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
+ goto bad;
+
+do
+ {
+ /* The inbound host was declared to be a Proxy Protocol host, so
+ don't do a PEEK into the data, actually slurp up enough to be
+ "safe". Can't take it all because TLS-on-connect clients follow
+ immediately with TLS handshake. */
+ ret = recv(fd, &hdr, PROXY_INITIAL_READ, 0);
+ }
+ while (ret == -1 && errno == EINTR);
+
+if (ret == -1)
+ goto proxyfail;
+
+/* For v2, handle reading the length, and then the rest. */
+if ((ret == PROXY_INITIAL_READ) && (memcmp(&hdr.v2, v2sig, sizeof(v2sig)) == 0))
+ {
+ int retmore;
+ uint8_t ver;
+
+ /* First get the length fields. */
+ do
+ {
+ retmore = recv(fd, (uschar*)&hdr + ret, PROXY_V2_HEADER_SIZE - PROXY_INITIAL_READ, 0);
+ } while (retmore == -1 && errno == EINTR);
+ if (retmore == -1)
+ goto proxyfail;
+ ret += retmore;
+
+ ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
+
+ /* May 2014: haproxy combined the version and command into one byte to
+ allow two full bytes for the length field in order to proxy SSL
+ connections. SSL Proxy is not supported in this version of Exim, but
+ must still separate values here. */
+
+ if (ver != 0x02)
+ {
+ DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
+ goto proxyfail;
+ }
+
+ /* The v2 header will always be 16 bytes per the spec. */
+ size = 16 + ntohs(hdr.v2.len);
+ DEBUG(D_receive) debug_printf("Detected PROXYv2 header, size %d (limit %d)\n",
+ size, (int)sizeof(hdr));
+
+ /* We should now have 16 octets (PROXY_V2_HEADER_SIZE), and we know the total
+ amount that we need. Double-check that the size is not unreasonable, then
+ get the rest. */
+ if (size > sizeof(hdr))
+ {
+ DEBUG(D_receive) debug_printf("PROXYv2 header size unreasonably large; security attack?\n");
+ goto proxyfail;
+ }
+
+ do
+ {
+ do
+ {
+ retmore = recv(fd, (uschar*)&hdr + ret, size-ret, 0);
+ } while (retmore == -1 && errno == EINTR);
+ if (retmore == -1)
+ goto proxyfail;
+ ret += retmore;
+ DEBUG(D_receive) debug_printf("PROXYv2: have %d/%d required octets\n", ret, size);
+ } while (ret < size);
+
+ } /* end scope for getting rest of data for v2 */
+
+/* At this point: if PROXYv2, we've read the exact size required for all data;
+if PROXYv1 then we've read "less than required for any valid line" and should
+read the rest". */
+
+if (ret >= 16 && memcmp(&hdr.v2, v2sig, 12) == 0)
+ {
+ uint8_t cmd = (hdr.v2.ver_cmd & 0x0f);
+
+ switch (cmd)
+ {
+ case 0x01: /* PROXY command */
+ switch (hdr.v2.fam)
+ {
+ case 0x11: /* TCPv4 address type */
+ iptype = US"IPv4";
+ tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
+ inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
+ if (!string_is_ip_address(US tmpip, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
+ goto proxyfail;
+ }
+ proxy_local_address = sender_host_address;
+ sender_host_address = string_copy(US tmpip);
+ tmpport = ntohs(hdr.v2.addr.ip4.src_port);
+ proxy_local_port = sender_host_port;
+ sender_host_port = tmpport;
+ /* Save dest ip/port */
+ tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
+ inet_ntop(AF_INET, &tmpaddr.sin_addr, CS &tmpip, sizeof(tmpip));
+ if (!string_is_ip_address(US tmpip, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
+ goto proxyfail;
+ }
+ proxy_external_address = string_copy(US tmpip);
+ tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
+ proxy_external_port = tmpport;
+ goto done;
+ case 0x21: /* TCPv6 address type */
+ iptype = US"IPv6";
+ memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
+ inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
+ if (!string_is_ip_address(US tmpip6, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
+ goto proxyfail;
+ }
+ proxy_local_address = sender_host_address;
+ sender_host_address = string_copy(US tmpip6);
+ tmpport = ntohs(hdr.v2.addr.ip6.src_port);
+ proxy_local_port = sender_host_port;
+ sender_host_port = tmpport;
+ /* Save dest ip/port */
+ memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
+ inet_ntop(AF_INET6, &tmpaddr6.sin6_addr, CS &tmpip6, sizeof(tmpip6));
+ if (!string_is_ip_address(US tmpip6, NULL))
+ {
+ DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
+ goto proxyfail;
+ }
+ proxy_external_address = string_copy(US tmpip6);
+ tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
+ proxy_external_port = tmpport;
+ goto done;
+ default:
+ DEBUG(D_receive)
+ debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
+ hdr.v2.fam);
+ goto proxyfail;
+ }
+ /* Unsupported protocol, keep local connection address */
+ break;
+ case 0x00: /* LOCAL command */
+ /* Keep local connection address for LOCAL */
+ iptype = US"local";
+ break;
+ default:
+ DEBUG(D_receive)
+ debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
+ goto proxyfail;
+ }
+ }
+else if (ret >= 8 && memcmp(hdr.v1.line, "PROXY", 5) == 0)
+ {
+ uschar *p;
+ uschar *end;
+ uschar *sp; /* Utility variables follow */
+ int tmp_port;
+ int r2;
+ char *endc;
+
+ /* get the rest of the line */
+ r2 = swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
+ if (r2 == -1)
+ goto proxyfail;
+ ret += r2;
+
+ p = string_copy(hdr.v1.line);
+ end = memchr(p, '\r', ret - 1);
+
+ if (!end || (end == (uschar*)&hdr + ret) || end[1] != '\n')
+ {
+ DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
+ goto proxyfail;
+ }
+ *end = '\0'; /* Terminate the string */
+ size = end + 2 - p; /* Skip header + CRLF */
+ DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
+ DEBUG(D_receive) debug_printf("Bytes read not within PROXY header: %d\n", ret - size);
+ /* Step through the string looking for the required fields. Ensure
+ strict adherence 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_local_address = 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;
+ }
+ proxy_external_address = p;
+ 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_local_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;
+ }
+ proxy_external_port = tmp_port;
+ /* Already checked for /r /n above. Good V1 header received. */
+ }
+else
+ {
+ /* Wrong protocol */
+ DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
+ (void) swallow_until_crlf(fd, (uschar*)&hdr, ret, sizeof(hdr)-ret);
+ goto proxyfail;
+ }
+
+done:
+ DEBUG(D_receive)
+ debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
+ yield = proxy_session;
+
+/* Don't flush any potential buffer contents. Any input on proxyfail
+should cause a synchronization failure */
+
+proxyfail:
+ restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
+
+bad:
+ if (yield)
+ {
+ sender_host_name = NULL;
+ (void) host_name_lookup();
+ host_build_sender_fullhost();
+ }
+ else
+ {
+ f.proxy_session_failed = TRUE;
+ DEBUG(D_receive)
+ debug_printf("Failure to extract proxied host, only QUIT allowed\n");
+ }
git://git.exim.org / exim.git / blobdiff