Check return value of EVP_* functions, and check if length before en/decryption

[tinc] / src / net_packet.c

diff --git a/src/net_packet.c b/src/net_packet.c
index 8f47f23..00e36fc 100644 (file)
--- a/src/net_packet.c
+++ b/src/net_packet.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: net_packet.c,v 1.1.2.39 2003/08/22 11:18:42 guus Exp $
+    $Id: net_packet.c,v 1.1.2.42 2003/10/10 16:24:24 guus Exp $
 */
 
 #include "system.h"
@@ -114,10 +114,18 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
        vpn_packet_t *outpkt = pkt[0];
        int outlen, outpad;
        char hmac[EVP_MAX_MD_SIZE];
-       int i;
+       int i, result;
 
        cp();
 
+       /* Check packet length */
+
+       if(inpkt->len < sizeof(inpkt->seqno) + myself->maclength) {
+               ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Got too short packet from %s (%s)"),
+                                       n->name, n->hostname);
+               return;
+       }
+
        /* Check the message authentication code */
 
        if(myself->digest && myself->maclength) {
@@ -137,12 +145,18 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
        if(myself->cipher) {
                outpkt = pkt[nextpkt++];
 
-//             EVP_DecryptInit_ex(&packet_ctx, myself->cipher, NULL, myself->key,
-//                                             myself->key + myself->cipher->key_len);
                EVP_DecryptInit_ex(&packet_ctx, NULL, NULL, NULL, NULL);
-               EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
-                                                 (char *) &inpkt->seqno, inpkt->len);
-               EVP_DecryptFinal_ex(&packet_ctx, (char *) &outpkt->seqno + outlen, &outpad);
+               if(!EVP_DecryptUpdate(&packet_ctx, (char *) &outpkt->seqno, &outlen,
+                                       (char *) &inpkt->seqno, inpkt->len)) {
+                       ifdebug(TRAFFIC) logger(LOG_DEBUG, _("Error decrypting packet from %s (%s): %s"),
+                                               n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+                       return;
+               }
+               if(!EVP_DecryptFinal_ex(&packet_ctx, (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;
@@ -181,14 +195,17 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt)
                outpkt = pkt[nextpkt++];
 
                if((outpkt->len = uncompress_packet(outpkt->data, inpkt->data, inpkt->len, myself->compression)) < 0) {
-                       logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
-                                  n->name, n->hostname);
+                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while uncompressing packet from %s (%s)"),
+                                                n->name, n->hostname);
                        return;
                }
 
                inpkt = outpkt;
        }
 
+       if(n->connection)
+               n->connection->last_ping_time = now;
+
        receive_packet(n, inpkt);
 }
 
@@ -253,7 +270,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
                outpkt = pkt[nextpkt++];
 
                if((outpkt->len = compress_packet(outpkt->data, inpkt->data, inpkt->len, n->compression)) < 0) {
-                       logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
+                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while compressing packet to %s (%s)"),
                                   n->name, n->hostname);
                        return;
                }
@@ -271,11 +288,18 @@ static void send_udppacket(node_t *n, vpn_packet_t *inpkt)
        if(n->cipher) {
                outpkt = pkt[nextpkt++];
 
-//             EVP_EncryptInit_ex(&packet_ctx, n->cipher, NULL, n->key, n->key + n->cipher->key_len);
                EVP_EncryptInit_ex(&n->packet_ctx, NULL, NULL, NULL, NULL);
-               EVP_EncryptUpdate(&n->packet_ctx, (char *) &outpkt->seqno, &outlen,
-                                                 (char *) &inpkt->seqno, inpkt->len);
-               EVP_EncryptFinal_ex(&n->packet_ctx, (char *) &outpkt->seqno + outlen, &outpad);
+               if(!EVP_EncryptUpdate(&n->packet_ctx, (char *) &outpkt->seqno, &outlen,
+                                       (char *) &inpkt->seqno, inpkt->len)) {
+                       ifdebug(TRAFFIC) logger(LOG_ERR, _("Error while encrypting packet to %s (%s): %s"),
+                                               n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+                       return;
+               }
+               if(!EVP_EncryptFinal_ex(&n->packet_ctx, (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));
+                       return;
+               }
 
                outpkt->len = outlen + outpad;
                inpkt = outpkt;
@@ -367,7 +391,7 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet)
                           packet->len, from->name, from->hostname);
 
        for(node = connection_tree->head; node; node = node->next) {
-               c = (connection_t *) node->data;
+               c = node->data;
 
                if(c->status.active && c->status.mst && c != from->nexthop->connection)
                        send_packet(c->node, packet);
@@ -384,7 +408,7 @@ void flush_queue(node_t *n)
 
        for(node = n->queue->head; node; node = next) {
                next = node->next;
-               send_udppacket(n, (vpn_packet_t *) node->data);
+               send_udppacket(n, node->data);
                list_delete_node(n->queue, node);
        }
 }
@@ -401,7 +425,7 @@ void handle_incoming_vpn_data(int sock)
 
        pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-       if(pkt.len <= 0) {
+       if(pkt.len < 0) {
                logger(LOG_ERR, _("Receiving packet failed: %s"), strerror(errno));
                return;
        }
@@ -418,8 +442,5 @@ void handle_incoming_vpn_data(int sock)
                return;
        }
 
-       if(n->connection)
-               n->connection->last_ping_time = now;
-
        receive_udppacket(n, &pkt);
 }