[FFmpeg-devel] [PATCH] Use CONFIG_FFRTMPCRYPT_PROTOCOL for conditional compilation...

[Ziemowit Laski <zlaski@ziemas.net>]

Use CONFIG_FFRTMPCRYPT_PROTOCOL for conditional compilation and NOT run-time evaluation.  If optimizations are disabled and CONFIG_FFRTMPCRYPT_PROTOCOL==0, the compiler may fail to get rid of the conditional blocks.  Alas, the blocks themselves contain calls to RTMPE functionality (ff_rtmpe_gen_pub_key, ff_rtmpe_compute_secret_key, etc.) that we have explicitly disabled by setting CONFIG_FFRTMPCRYPT_PROTOCOL to zero in the first place.

Signed-off-by: Ziemowit Łąski <15880281+zlaski@users.noreply.github.com>
---
 libavformat/rtmpproto.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/libavformat/rtmpproto.c b/libavformat/rtmpproto.c
index f0ef223f05..5ff0e0f443 100644
--- a/libavformat/rtmpproto.c
+++ b/libavformat/rtmpproto.c
@@ -1222,7 +1222,8 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
     for (i = 9; i <= RTMP_HANDSHAKE_PACKET_SIZE; i++)
         tosend[i] = av_lfg_get(&rnd) >> 24;
 
-    if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+    if (rt->encrypted) {
         /* When the client wants to use RTMPE, we have to change the command
          * byte to 0x06 which means to use encrypted data and we have to set
          * the flash version to at least 9.0.115.0. */
@@ -1237,6 +1238,7 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
         if ((ret = ff_rtmpe_gen_pub_key(rt->stream, tosend + 1)) < 0)
             return ret;
     }
+#endif
 
     client_pos = rtmp_handshake_imprint_with_digest(tosend + 1, rt->encrypted);
     if (client_pos < 0)
@@ -1300,7 +1302,8 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
         if (ret < 0)
             return ret;
 
-        if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+        if (rt->encrypted) {
             /* Compute the shared secret key sent by the server and initialize
              * the RC4 encryption. */
             if ((ret = ff_rtmpe_compute_secret_key(rt->stream, serverdata + 1,
@@ -1310,6 +1313,7 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
             /* Encrypt the signature received by the server. */
             ff_rtmpe_encrypt_sig(rt->stream, signature, digest, serverdata[0]);
         }
+#endif
 
         if (memcmp(signature, clientdata + RTMP_HANDSHAKE_PACKET_SIZE - 32, 32)) {
             av_log(s, AV_LOG_ERROR, "Signature mismatch\n");
@@ -1330,25 +1334,30 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
         if (ret < 0)
             return ret;
 
-        if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+        if (rt->encrypted) {
             /* Encrypt the signature to be send to the server. */
             ff_rtmpe_encrypt_sig(rt->stream, tosend +
                                  RTMP_HANDSHAKE_PACKET_SIZE - 32, digest,
                                  serverdata[0]);
         }
+#endif
 
         // write reply back to the server
         if ((ret = ffurl_write(rt->stream, tosend,
                                RTMP_HANDSHAKE_PACKET_SIZE)) < 0)
             return ret;
 
-        if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+        if (rt->encrypted) {
             /* Set RC4 keys for encryption and update the keystreams. */
             if ((ret = ff_rtmpe_update_keystream(rt->stream)) < 0)
                 return ret;
         }
+#endif
     } else {
-        if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+        if (rt->encrypted) {
             /* Compute the shared secret key sent by the server and initialize
              * the RC4 encryption. */
             if ((ret = ff_rtmpe_compute_secret_key(rt->stream, serverdata + 1,
@@ -1361,16 +1370,19 @@ static int rtmp_handshake(URLContext *s, RTMPContext *rt)
                                      serverdata[0]);
             }
         }
+#endif
 
         if ((ret = ffurl_write(rt->stream, serverdata + 1,
                                RTMP_HANDSHAKE_PACKET_SIZE)) < 0)
             return ret;
 
-        if (CONFIG_FFRTMPCRYPT_PROTOCOL && rt->encrypted) {
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
+        if (rt->encrypted) {
             /* Set RC4 keys for encryption and update the keystreams. */
             if ((ret = ff_rtmpe_update_keystream(rt->stream)) < 0)
                 return ret;
         }
+#endif        
     }
 
     return 0;
@@ -2643,6 +2655,8 @@ static int rtmp_open(URLContext *s, const char *uri, int flags, AVDictionary **o
         if (port < 0)
             port = RTMPS_DEFAULT_PORT;
         ff_url_join(buf, sizeof(buf), "tls", NULL, hostname, port, NULL);
+
+#if CONFIG_FFRTMPCRYPT_PROTOCOL
     } else if (!strcmp(proto, "rtmpe") || (!strcmp(proto, "rtmpte"))) {
         if (!strcmp(proto, "rtmpte"))
             av_dict_set(opts, "ffrtmpcrypt_tunneling", "1", 1);
@@ -2650,6 +2664,8 @@ static int rtmp_open(URLContext *s, const char *uri, int flags, AVDictionary **o
         /* open the encrypted connection */
         ff_url_join(buf, sizeof(buf), "ffrtmpcrypt", NULL, hostname, port, NULL);
         rt->encrypted = 1;
+#endif
+        
     } else {
         /* open the tcp connection */
         if (port < 0)
-- 
2.39.1.windows.1

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