2 new cvars: sv_gameplayfix_unstickentities and sv_gameplayfix_unstickplayers to...

[xonotic/darkplaces.git] / crypto.c

diff --git a/crypto.c b/crypto.c
index 4b9d3976ab29fbb9851b118f79dffc63405c9f3e..ef281462187b7bb9be90c2071c51f84d20330bfc 100644 (file)
--- a/crypto.c
+++ b/crypto.c
@@ -782,7 +782,7 @@ static void Crypto_LoadKeys(void)
                                                len2 = FP64_SIZE;
                                                if(qd0_blind_id_fingerprint64_public_id(pubkeys[i], pubkeys_priv_fp64[i], &len2)) // keeps final NUL
                                                {
-                                                       Con_Printf("Loaded private ID key_%d.d0si for key_%d.d0pk (fingerprint: %s)\n", i, i, pubkeys_priv_fp64[i]);
+                                                       Con_Printf("Loaded private ID key_%d.d0si for key_%d.d0pk (public key fingerprint: %s)\n", i, i, pubkeys_priv_fp64[i]);
                                                        pubkeys_havepriv[i] = true;
                                                        strlcat(crypto_idstring_buf, va(" %s@%s", pubkeys_priv_fp64[i], pubkeys_fp64[i]), sizeof(crypto_idstring_buf));
                                                }
@@ -1043,7 +1043,7 @@ static void Crypto_KeyGen_Finished(int code, size_t length_received, unsigned ch
        len2 = FP64_SIZE;
        if(qd0_blind_id_fingerprint64_public_id(pubkeys[keygen_i], pubkeys_priv_fp64[keygen_i], &len2)) // keeps final NUL
        {
-               Con_Printf("Received private ID key_%d.d0pk (fingerprint: %s)\n", keygen_i, pubkeys_priv_fp64[keygen_i]);
+               Con_Printf("Received private ID key_%d.d0pk (public key fingerprint: %s)\n", keygen_i, pubkeys_priv_fp64[keygen_i]);
                pubkeys_havepriv[keygen_i] = true;
                strlcat(crypto_idstring_buf, va(" %s@%s", pubkeys_priv_fp64[keygen_i], pubkeys_fp64[keygen_i]), sizeof(crypto_idstring_buf));
                crypto_idstring = crypto_idstring_buf;
@@ -1185,7 +1185,7 @@ static void Crypto_Keys_f(void)
                {
                        Con_Printf("%2d: public key key_%d.d0pk (fingerprint: %s)\n", i, i, pubkeys_fp64[i]);
                        if(pubkeys_havepriv[i])
-                               Con_Printf("    private ID key_%d.d0si (fingerprint: %s)\n", i, pubkeys_priv_fp64[i]);
+                               Con_Printf("    private ID key_%d.d0si (public key fingerprint: %s)\n", i, pubkeys_priv_fp64[i]);
                }
        }
 }
@@ -1309,9 +1309,14 @@ static void seacpy(unsigned char *key, const unsigned char *iv, unsigned char *d
        }
 }
 
+// NOTE: we MUST avoid the following begins of the packet:
+//   1. 0xFF, 0xFF, 0xFF, 0xFF
+//   2. 0x80, 0x00, length/256, length%256
+// this luckily does NOT affect AES mode, where the first byte always is in the range from 0x00 to 0x0F
 const void *Crypto_EncryptPacket(crypto_t *crypto, const void *data_src, size_t len_src, void *data_dst, size_t *len_dst, size_t len)
 {
        unsigned char h[32];
+       int i;
        if(crypto->authenticated)
        {
                if(crypto->use_aes)
@@ -1346,6 +1351,15 @@ const void *Crypto_EncryptPacket(crypto_t *crypto, const void *data_src, size_t
                        *len_dst = len_src + 16;
                        memcpy(data_dst, h, 16);
                        memcpy(((unsigned char *) data_dst) + 16, (unsigned char *) data_src, len_src);
+
+                       // handle the "avoid" conditions:
+                       i = BuffBigLong((unsigned char *) data_dst);
+                       if(
+                               (i == (int)0xFFFFFFFF) // avoid QW control packet
+                               ||
+                               (i == (int)0x80000000 + (int)*len_dst) // avoid NQ control packet
+                       )
+                               *(unsigned char *)data_dst ^= 0x80; // this will ALWAYS fix it
                }
                return data_dst;
        }
@@ -1359,6 +1373,17 @@ const void *Crypto_EncryptPacket(crypto_t *crypto, const void *data_src, size_t
 const void *Crypto_DecryptPacket(crypto_t *crypto, const void *data_src, size_t len_src, void *data_dst, size_t *len_dst, size_t len)
 {
        unsigned char h[32];
+       int i;
+
+       // silently handle non-crypto packets
+       i = BuffBigLong((unsigned char *) data_src);
+       if(
+               (i == (int)0xFFFFFFFF) // avoid QW control packet
+               ||
+               (i == (int)0x80000000 + (int)len_src) // avoid NQ control packet
+       )
+               return NULL;
+
        if(crypto->authenticated)
        {
                if(crypto->use_aes)
@@ -1413,11 +1438,31 @@ const void *Crypto_DecryptPacket(crypto_t *crypto, const void *data_src, size_t
                                Com_HexDumpToConsole((const unsigned char *) data_src, len_src);
                                return NULL;
                        }
+
                        if(memcmp((const unsigned char *) data_src, h, 16)) // ignore first byte, used for length
                        {
-                               Con_Printf("HMAC mismatch\n");
-                               Com_HexDumpToConsole((const unsigned char *) data_src, len_src);
-                               return NULL;
+                               // undo the "avoid conditions"
+                               if(
+                                               (i == (int)0x7FFFFFFF) // avoided QW control packet
+                                               ||
+                                               (i == (int)0x00000000 + (int)len_src) // avoided NQ control packet
+                                 )
+                               {
+                                       // do the avoidance on the hash too
+                                       h[0] ^= 0x80;
+                                       if(memcmp((const unsigned char *) data_src, h, 16)) // ignore first byte, used for length
+                                       {
+                                               Con_Printf("HMAC mismatch\n");
+                                               Com_HexDumpToConsole((const unsigned char *) data_src, len_src);
+                                               return NULL;
+                                       }
+                               }
+                               else
+                               {
+                                       Con_Printf("HMAC mismatch\n");
+                                       Com_HexDumpToConsole((const unsigned char *) data_src, len_src);
+                                       return NULL;
+                               }
                        }
                        return ((const unsigned char *) data_src) + 16; // no need to copy, so data_dst is not used
                }