Remove use of strcpy() and sprintf().

[tinc] / src / sptps.c

diff --git a/src/sptps.c b/src/sptps.c
index e5946ed..712d50e 100644 (file)
--- a/src/sptps.c
+++ b/src/sptps.c
@@ -1,6 +1,6 @@
 /*
     sptps.c -- Simple Peer-to-Peer Security
-    Copyright (C) 2011-2014 Guus Sliepen <guus@tinc-vpn.org>,
+    Copyright (C) 2011-2015 Guus Sliepen <guus@tinc-vpn.org>,
                   2010      Brandon L. Black <blblack@gmail.com>
 
     This program is free software; you can redistribute it and/or modify
@@ -204,7 +204,7 @@ static bool generate_key_material(sptps_t *s, const char *shared, size_t len) {
 
        // Create the HMAC seed, which is "key expansion" + session label + server nonce + client nonce
        char seed[s->labellen + 64 + 13];
-       strcpy(seed, "key expansion");
+       memcpy(seed, "key expansion", 13);
        if(s->initiator) {
                memcpy(seed + 13, s->mykex + 1, 32);
                memcpy(seed + 45, s->hiskex + 1, 32);
@@ -384,10 +384,11 @@ static bool sptps_check_seqno(sptps_t *s, uint32_t seqno, bool update_state) {
                                if (update_state)
                                        s->farfuture++;
                                if(farfuture)
-                                       return error(s, EIO, "Packet is %d seqs in the future, dropped (%u)\n", seqno - s->inseqno, s->farfuture);
+                                       return update_state ? error(s, EIO, "Packet is %d seqs in the future, dropped (%u)\n", seqno - s->inseqno, s->farfuture) : false;
 
                                // Unless we have seen lots of them, in which case we consider the others lost.
-                               warning(s, "Lost %d packets\n", seqno - s->inseqno);
+                               if(update_state)
+                                       warning(s, "Lost %d packets\n", seqno - s->inseqno);
                                if (update_state) {
                                        // Mark all packets in the replay window as being late.
                                        memset(s->late, 255, s->replaywin);
@@ -395,7 +396,7 @@ static bool sptps_check_seqno(sptps_t *s, uint32_t seqno, bool update_state) {
                        } else if (seqno < s->inseqno) {
                                // If the sequence number is farther in the past than the bitmap goes, or if the packet was already received, drop it.
                                if((s->inseqno >= s->replaywin * 8 && seqno < s->inseqno - s->replaywin * 8) || !(s->late[(seqno / 8) % s->replaywin] & (1 << seqno % 8)))
-                                       return error(s, EIO, "Received late or replayed packet, seqno %d, last received %d\n", seqno, s->inseqno);
+                                       return update_state ? error(s, EIO, "Received late or replayed packet, seqno %d, last received %d\n", seqno, s->inseqno) : false;
                        } else if (update_state) {
                                // We missed some packets. Mark them in the bitmap as being late.
                                for(int i = s->inseqno; i < seqno; i++)
@@ -447,6 +448,7 @@ static bool sptps_receive_data_datagram(sptps_t *s, const char *data, size_t len
        uint32_t seqno;
        memcpy(&seqno, data, 4);
        seqno = ntohl(seqno);
+       data += 4; len -= 4;
 
        if(!s->instate) {
                if(seqno != s->inseqno)
@@ -454,38 +456,39 @@ static bool sptps_receive_data_datagram(sptps_t *s, const char *data, size_t len
 
                s->inseqno = seqno + 1;
 
-               uint8_t type = data[4];
+               uint8_t type = *(data++); len--;
 
                if(type != SPTPS_HANDSHAKE)
                        return error(s, EIO, "Application record received before handshake finished");
 
-               return receive_handshake(s, data + 5, len - 5);
+               return receive_handshake(s, data, len);
        }
 
        // Decrypt
 
        char buffer[len];
-
        size_t outlen;
-
-       if(!chacha_poly1305_decrypt(s->incipher, seqno, data + 4, len - 4, buffer, &outlen))
+       if(!chacha_poly1305_decrypt(s->incipher, seqno, data, len, buffer, &outlen))
                return error(s, EIO, "Failed to decrypt and verify packet");
 
        if(!sptps_check_seqno(s, seqno, true))
                return false;
 
        // Append a NULL byte for safety.
-       buffer[len - 20] = 0;
+       buffer[outlen] = 0;
+
+       data = buffer;
+       len = outlen;
 
-       uint8_t type = buffer[0];
+       uint8_t type = *(data++); len--;
 
        if(type < SPTPS_HANDSHAKE) {
                if(!s->instate)
                        return error(s, EIO, "Application record received before handshake finished");
-               if(!s->receive_record(s->handle, type, buffer + 1, len - 21))
+               if(!s->receive_record(s->handle, type, data, len))
                        return false;
        } else if(type == SPTPS_HANDSHAKE) {
-               if(!receive_handshake(s, buffer + 1, len - 21))
+               if(!receive_handshake(s, data, len))
                        return false;
        } else {
                return error(s, EIO, "Invalid record type %d", type);