From f1747c2c47e1c9b6b07ee52350ea6de85f2e41b2 Mon Sep 17 00:00:00 2001 From: turly221 Date: Wed, 11 Dec 2024 17:43:30 +0000 Subject: [PATCH] commit patch 17921065 --- src/net_packet.c | 3 + src/net_packet.c.orig | 703 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 706 insertions(+) create mode 100644 src/net_packet.c.orig diff --git a/src/net_packet.c b/src/net_packet.c index cd8d98ac0..0c78df9af 100644 --- a/src/net_packet.c +++ b/src/net_packet.c @@ -378,6 +378,9 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) { void receive_tcppacket(connection_t *c, const char *buffer, int len) { vpn_packet_t outpkt; + if(len > sizeof outpkt.data) + return; + outpkt.len = len; if(c->options & OPTION_TCPONLY) outpkt.priority = 0; diff --git a/src/net_packet.c.orig b/src/net_packet.c.orig new file mode 100644 index 000000000..cd8d98ac0 --- /dev/null +++ b/src/net_packet.c.orig @@ -0,0 +1,703 @@ +/* + net_packet.c -- Handles in- and outgoing VPN packets + Copyright (C) 1998-2005 Ivo Timmermans, + 2000-2012 Guus Sliepen + 2010 Timothy Redaelli + 2010 Brandon Black + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#include "system.h" + +#include +#include +#include +#include +#include + +#ifdef HAVE_ZLIB +#include +#endif + +#ifdef HAVE_LZO +#include LZO1X_H +#endif + +#include "avl_tree.h" +#include "conf.h" +#include "connection.h" +#include "device.h" +#include "ethernet.h" +#include "event.h" +#include "graph.h" +#include "logger.h" +#include "net.h" +#include "netutl.h" +#include "protocol.h" +#include "process.h" +#include "route.h" +#include "utils.h" +#include "xalloc.h" + +int keylifetime = 0; +int keyexpires = 0; +#ifdef HAVE_LZO +static char lzo_wrkmem[LZO1X_999_MEM_COMPRESS > LZO1X_1_MEM_COMPRESS ? LZO1X_999_MEM_COMPRESS : LZO1X_1_MEM_COMPRESS]; +#endif + +static void send_udppacket(node_t *, vpn_packet_t *); + +unsigned replaywin = 16; +bool localdiscovery = false; + +#define MAX_SEQNO 1073741824 + +/* mtuprobes == 1..30: initial discovery, send bursts with 1 second interval + mtuprobes == 31: sleep pinginterval seconds + mtuprobes == 32: send 1 burst, sleep pingtimeout second + mtuprobes == 33: no response from other side, restart PMTU discovery process + + Probes are sent in batches of three, with random sizes between the lower and + upper boundaries for the MTU thus far discovered. + + In case local discovery is enabled, a fourth packet is added to each batch, + which will be broadcast to the local network. +*/ + +void send_mtu_probe(node_t *n) { + vpn_packet_t packet; + int len, i; + int timeout = 1; + + n->mtuprobes++; + n->mtuevent = NULL; + + if(!n->status.reachable || !n->status.validkey) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname); + n->mtuprobes = 0; + return; + } + + if(n->mtuprobes > 32) { + if(!n->minmtu) { + n->mtuprobes = 31; + timeout = pinginterval; + goto end; + } + + ifdebug(TRAFFIC) logger(LOG_INFO, "%s (%s) did not respond to UDP ping, restarting PMTU discovery", n->name, n->hostname); + n->mtuprobes = 1; + n->minmtu = 0; + n->maxmtu = MTU; + } + + if(n->mtuprobes >= 10 && n->mtuprobes < 32 && !n->minmtu) { + ifdebug(TRAFFIC) logger(LOG_INFO, "No response to MTU probes from %s (%s)", n->name, n->hostname); + n->mtuprobes = 31; + } + + if(n->mtuprobes == 30 || (n->mtuprobes < 30 && n->minmtu >= n->maxmtu)) { + if(n->minmtu > n->maxmtu) + n->minmtu = n->maxmtu; + else + n->maxmtu = n->minmtu; + n->mtu = n->minmtu; + ifdebug(TRAFFIC) logger(LOG_INFO, "Fixing MTU of %s (%s) to %d after %d probes", n->name, n->hostname, n->mtu, n->mtuprobes); + n->mtuprobes = 31; + } + + if(n->mtuprobes == 31) { + timeout = pinginterval; + goto end; + } else if(n->mtuprobes == 32) { + timeout = pingtimeout; + } + + for(i = 0; i < 3 + localdiscovery; i++) { + if(n->maxmtu <= n->minmtu) + len = n->maxmtu; + else + len = n->minmtu + 1 + rand() % (n->maxmtu - n->minmtu); + + if(len < 64) + len = 64; + + memset(packet.data, 0, 14); + RAND_pseudo_bytes(packet.data + 14, len - 14); + packet.len = len; + if(i >= 3 && n->mtuprobes <= 10) + packet.priority = -1; + else + packet.priority = 0; + + ifdebug(TRAFFIC) logger(LOG_INFO, "Sending MTU probe length %d to %s (%s)", len, n->name, n->hostname); + + send_udppacket(n, &packet); + } + +end: + n->mtuevent = new_event(); + n->mtuevent->handler = (event_handler_t)send_mtu_probe; + n->mtuevent->data = n; + n->mtuevent->time = now + timeout; + event_add(n->mtuevent); +} + +void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Got MTU probe length %d from %s (%s)", packet->len, n->name, n->hostname); + + if(!packet->data[0]) { + packet->data[0] = 1; + send_udppacket(n, packet); + } else { + if(n->mtuprobes > 30) { + if(n->minmtu) + n->mtuprobes = 30; + else + n->mtuprobes = 1; + } + + if(len > n->maxmtu) + len = n->maxmtu; + if(n->minmtu < len) + n->minmtu = len; + } +} + +static length_t compress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) { + if(level == 0) { + memcpy(dest, source, len); + return len; + } else if(level == 10) { +#ifdef HAVE_LZO + lzo_uint lzolen = MAXSIZE; + lzo1x_1_compress(source, len, dest, &lzolen, lzo_wrkmem); + return lzolen; +#else + return -1; +#endif + } else if(level < 10) { +#ifdef HAVE_ZLIB + unsigned long destlen = MAXSIZE; + if(compress2(dest, &destlen, source, len, level) == Z_OK) + return destlen; + else +#endif + return -1; + } else { +#ifdef HAVE_LZO + lzo_uint lzolen = MAXSIZE; + lzo1x_999_compress(source, len, dest, &lzolen, lzo_wrkmem); + return lzolen; +#else + return -1; +#endif + } + + return -1; +} + +static length_t uncompress_packet(uint8_t *dest, const uint8_t *source, length_t len, int level) { + if(level == 0) { + memcpy(dest, source, len); + return len; + } else if(level > 9) { +#ifdef HAVE_LZO + lzo_uint lzolen = MAXSIZE; + if(lzo1x_decompress_safe(source, len, dest, &lzolen, NULL) == LZO_E_OK) + return lzolen; + else +#endif + return -1; + } +#ifdef HAVE_ZLIB + else { + unsigned long destlen = MAXSIZE; + if(uncompress(dest, &destlen, source, len) == Z_OK) + return destlen; + else + return -1; + } +#endif + + return -1; +} + +/* VPN packet I/O */ + +static void receive_packet(node_t *n, vpn_packet_t *packet) { + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Received packet of %d bytes from %s (%s)", + packet->len, n->name, n->hostname); + + route(n, packet); +} + +static bool try_mac(const node_t *n, const vpn_packet_t *inpkt) { + unsigned char hmac[EVP_MAX_MD_SIZE]; + + if(!n->indigest || !n->inmaclength || !n->inkey || inpkt->len < sizeof inpkt->seqno + n->inmaclength) + return false; + + HMAC(n->indigest, n->inkey, n->inkeylength, (unsigned char *) &inpkt->seqno, inpkt->len - n->inmaclength, (unsigned char *)hmac, NULL); + + return !memcmp(hmac, (char *) &inpkt->seqno + inpkt->len - n->inmaclength, n->inmaclength); +} + +static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) { + vpn_packet_t pkt1, pkt2; + vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 }; + int nextpkt = 0; + vpn_packet_t *outpkt = pkt[0]; + int outlen, outpad; + unsigned char hmac[EVP_MAX_MD_SIZE]; + int i; + + if(!n->inkey) { + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet", + n->name, n->hostname); + return; + } + + /* Check packet length */ + + if(inpkt->len < sizeof(inpkt->seqno) + n->inmaclength) { + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got too short packet from %s (%s)", + n->name, n->hostname); + return; + } + + /* Check the message authentication code */ + + if(n->indigest && n->inmaclength) { + inpkt->len -= n->inmaclength; + HMAC(n->indigest, n->inkey, n->inkeylength, + (unsigned char *) &inpkt->seqno, inpkt->len, (unsigned char *)hmac, NULL); + + if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, n->inmaclength)) { + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)", + n->name, n->hostname); + return; + } + } + + /* Decrypt the packet */ + + if(n->incipher) { + outpkt = pkt[nextpkt++]; + + if(!EVP_DecryptInit_ex(&n->inctx, NULL, NULL, NULL, NULL) + || !EVP_DecryptUpdate(&n->inctx, (unsigned char *) &outpkt->seqno, &outlen, + (unsigned char *) &inpkt->seqno, inpkt->len) + || !EVP_DecryptFinal_ex(&n->inctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) { + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s): %s", + n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL)); + return; + } + + outpkt->len = outlen + outpad; + inpkt = outpkt; + } + + /* Check the sequence number */ + + inpkt->len -= sizeof(inpkt->seqno); + inpkt->seqno = ntohl(inpkt->seqno); + + if(replaywin) { + if(inpkt->seqno != n->received_seqno + 1) { + if(inpkt->seqno >= n->received_seqno + replaywin * 8) { + if(n->farfuture++ < replaywin >> 2) { + logger(LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)", + n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture); + return; + } + logger(LOG_WARNING, "Lost %d packets from %s (%s)", + inpkt->seqno - n->received_seqno - 1, n->name, n->hostname); + memset(n->late, 0, replaywin); + } else if (inpkt->seqno <= n->received_seqno) { + if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) { + logger(LOG_WARNING, "Got late or replayed packet from %s (%s), seqno %d, last received %d", + n->name, n->hostname, inpkt->seqno, n->received_seqno); + return; + } + } else { + for(i = n->received_seqno + 1; i < inpkt->seqno; i++) + n->late[(i / 8) % replaywin] |= 1 << i % 8; + } + } + + n->farfuture = 0; + n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8); + } + + if(inpkt->seqno > n->received_seqno) + n->received_seqno = inpkt->seqno; + + if(n->received_seqno > MAX_SEQNO) + keyexpires = 0; + + /* Decompress the packet */ + + length_t origlen = inpkt->len; + + if(n->incompression) { + outpkt = pkt[nextpkt++]; + + if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, n->incompression)) < 0) { + ifdebug(TRAFFIC) logger(LOG_ERR, "Error while uncompressing packet from %s (%s)", + n->name, n->hostname); + return; + } + + inpkt = outpkt; + + origlen -= MTU/64 + 20; + } + + inpkt->priority = 0; + + if(!inpkt->data[12] && !inpkt->data[13]) + mtu_probe_h(n, inpkt, origlen); + else + receive_packet(n, inpkt); +} + +void receive_tcppacket(connection_t *c, const char *buffer, int len) { + vpn_packet_t outpkt; + + outpkt.len = len; + if(c->options & OPTION_TCPONLY) + outpkt.priority = 0; + else + outpkt.priority = -1; + memcpy(outpkt.data, buffer, len); + + receive_packet(c->node, &outpkt); +} + +static void send_udppacket(node_t *n, vpn_packet_t *origpkt) { + vpn_packet_t pkt1, pkt2; + vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 }; + vpn_packet_t *inpkt = origpkt; + int nextpkt = 0; + vpn_packet_t *outpkt; + int origlen; + int outlen, outpad; +#if defined(SOL_IP) && defined(IP_TOS) + static int priority = 0; +#endif + int origpriority; + + if(!n->status.reachable) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send UDP packet to unreachable node %s (%s)", n->name, n->hostname); + return; + } + + /* Make sure we have a valid key */ + + if(!n->status.validkey) { + ifdebug(TRAFFIC) logger(LOG_INFO, + "No valid key known yet for %s (%s), forwarding via TCP", + n->name, n->hostname); + + if(n->last_req_key + 10 <= now) { + send_req_key(n); + n->last_req_key = now; + } + + send_tcppacket(n->nexthop->connection, origpkt); + + return; + } + + if(n->options & OPTION_PMTU_DISCOVERY && inpkt->len > n->minmtu && (inpkt->data[12] | inpkt->data[13])) { + ifdebug(TRAFFIC) logger(LOG_INFO, + "Packet for %s (%s) larger than minimum MTU, forwarding via %s", + n->name, n->hostname, n != n->nexthop ? n->nexthop->name : "TCP"); + + if(n != n->nexthop) + send_packet(n->nexthop, origpkt); + else + send_tcppacket(n->nexthop->connection, origpkt); + + return; + } + + origlen = inpkt->len; + origpriority = inpkt->priority; + + /* Compress the packet */ + + if(n->outcompression) { + outpkt = pkt[nextpkt++]; + + if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->outcompression)) < 0) { + ifdebug(TRAFFIC) logger(LOG_ERR, "Error while compressing packet to %s (%s)", + n->name, n->hostname); + return; + } + + inpkt = outpkt; + } + + /* Add sequence number */ + + inpkt->seqno = htonl(++(n->sent_seqno)); + inpkt->len += sizeof(inpkt->seqno); + + /* Encrypt the packet */ + + if(n->outcipher) { + outpkt = pkt[nextpkt++]; + + if(!EVP_EncryptInit_ex(&n->outctx, NULL, NULL, NULL, NULL) + || !EVP_EncryptUpdate(&n->outctx, (unsigned char *) &outpkt->seqno, &outlen, + (unsigned char *) &inpkt->seqno, inpkt->len) + || !EVP_EncryptFinal_ex(&n->outctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) { + ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s): %s", + n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL)); + goto end; + } + + outpkt->len = outlen + outpad; + inpkt = outpkt; + } + + /* Add the message authentication code */ + + if(n->outdigest && n->outmaclength) { + HMAC(n->outdigest, n->outkey, n->outkeylength, (unsigned char *) &inpkt->seqno, + inpkt->len, (unsigned char *) &inpkt->seqno + inpkt->len, NULL); + inpkt->len += n->outmaclength; + } + + /* Determine which socket we have to use */ + + if(n->address.sa.sa_family != listen_socket[n->sock].sa.sa.sa_family) { + for(int sock = 0; sock < listen_sockets; sock++) { + if(n->address.sa.sa_family == listen_socket[sock].sa.sa.sa_family) { + n->sock = sock; + break; + } + } + } + + /* Send the packet */ + + struct sockaddr *sa; + socklen_t sl; + int sock; + + /* Overloaded use of priority field: -1 means local broadcast */ + + if(origpriority == -1 && n->prevedge) { + struct sockaddr_in in; + in.sin_family = AF_INET; + in.sin_addr.s_addr = -1; + in.sin_port = n->prevedge->address.in.sin_port; + sa = (struct sockaddr *)∈ + sl = sizeof in; + sock = 0; + } else { + if(origpriority == -1) + origpriority = 0; + + sa = &(n->address.sa); + sl = SALEN(n->address.sa); + sock = n->sock; + } + +#if defined(SOL_IP) && defined(IP_TOS) + if(priorityinheritance && origpriority != priority + && listen_socket[n->sock].sa.sa.sa_family == AF_INET) { + priority = origpriority; + ifdebug(TRAFFIC) logger(LOG_DEBUG, "Setting outgoing packet priority to %d", priority); + if(setsockopt(listen_socket[n->sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority))) /* SO_PRIORITY doesn't seem to work */ + logger(LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno)); + } +#endif + + if(sendto(listen_socket[sock].udp, (char *) &inpkt->seqno, inpkt->len, 0, sa, sl) < 0 && !sockwouldblock(sockerrno)) { + if(sockmsgsize(sockerrno)) { + if(n->maxmtu >= origlen) + n->maxmtu = origlen - 1; + if(n->mtu >= origlen) + n->mtu = origlen - 1; + } else + ifdebug(TRAFFIC) logger(LOG_WARNING, "Error sending packet to %s (%s): %s", n->name, n->hostname, sockstrerror(sockerrno)); + } + +end: + origpkt->len = origlen; +} + +/* + send a packet to the given vpn ip. +*/ +void send_packet(const node_t *n, vpn_packet_t *packet) { + node_t *via; + + if(n == myself) { + if(overwrite_mac) + memcpy(packet->data, mymac.x, ETH_ALEN); + devops.write(packet); + return; + } + + ifdebug(TRAFFIC) logger(LOG_ERR, "Sending packet of %d bytes to %s (%s)", + packet->len, n->name, n->hostname); + + if(!n->status.reachable) { + ifdebug(TRAFFIC) logger(LOG_INFO, "Node %s (%s) is not reachable", + n->name, n->hostname); + return; + } + + via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via; + + if(via != n) + ifdebug(TRAFFIC) logger(LOG_INFO, "Sending packet to %s via %s (%s)", + n->name, via->name, n->via->hostname); + + if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) { + if(!send_tcppacket(via->connection, packet)) + terminate_connection(via->connection, true); + } else + send_udppacket(via, packet); +} + +/* Broadcast a packet using the minimum spanning tree */ + +void broadcast_packet(const node_t *from, vpn_packet_t *packet) { + avl_node_t *node; + connection_t *c; + node_t *n; + + // Always give ourself a copy of the packet. + if(from != myself) + send_packet(myself, packet); + + // In TunnelServer mode, do not forward broadcast packets. + // The MST might not be valid and create loops. + if(tunnelserver || broadcast_mode == BMODE_NONE) + return; + + ifdebug(TRAFFIC) logger(LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)", + packet->len, from->name, from->hostname); + + switch(broadcast_mode) { + // In MST mode, broadcast packets travel via the Minimum Spanning Tree. + // This guarantees all nodes receive the broadcast packet, and + // usually distributes the sending of broadcast packets over all nodes. + case BMODE_MST: + for(node = connection_tree->head; node; node = node->next) { + c = node->data; + + if(c->status.active && c->status.mst && c != from->nexthop->connection) + send_packet(c->node, packet); + } + break; + + // In direct mode, we send copies to each node we know of. + // However, this only reaches nodes that can be reached in a single hop. + // We don't have enough information to forward broadcast packets in this case. + case BMODE_DIRECT: + if(from != myself) + break; + + for(node = node_udp_tree->head; node; node = node->next) { + n = node->data; + + if(n->status.reachable && ((n->via == myself && n->nexthop == n) || n->via == n)) + send_packet(n, packet); + } + break; + + default: + break; + } +} + +static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) { + avl_node_t *node; + edge_t *e; + node_t *n = NULL; + bool hard = false; + static time_t last_hard_try = 0; + + for(node = edge_weight_tree->head; node; node = node->next) { + e = node->data; + + if(e->to == myself) + continue; + + if(sockaddrcmp_noport(from, &e->address)) { + if(last_hard_try == now) + continue; + hard = true; + } + + if(!try_mac(e->to, pkt)) + continue; + + n = e->to; + break; + } + + if(hard) + last_hard_try = now; + + last_hard_try = now; + return n; +} + +void handle_incoming_vpn_data(int sock) { + vpn_packet_t pkt; + char *hostname; + sockaddr_t from; + socklen_t fromlen = sizeof(from); + node_t *n; + + pkt.len = recvfrom(listen_socket[sock].udp, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen); + + if(pkt.len < 0) { + if(!sockwouldblock(sockerrno)) + logger(LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno)); + return; + } + + sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */ + + n = lookup_node_udp(&from); + + if(!n) { + n = try_harder(&from, &pkt); + if(n) + update_node_udp(n, &from); + else ifdebug(PROTOCOL) { + hostname = sockaddr2hostname(&from); + logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname); + free(hostname); + return; + } + else + return; + } + + n->sock = sock; + + receive_udppacket(n, &pkt); +}