[FFmpeg-devel] [PATCH] avformat/whip: fix SDP ICE candidates parsing (PR #20423)

[FFmpeg-devel] [PATCH] avformat/whip: fix SDP ICE candidates parsing (PR #20423)

[Jack Lau via ffmpeg-devel]

PR #20423 opened by Jack Lau (JackLau)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20423
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20423.patch

fix issue #20407

Refer to RFC 5245 15.1,
the foundation may be any string up to 32 chars.
The old code could misread foundations as transport("udp").
This patch fully parse all these attr to avoid parsing error.

Signed-off-by: Jack Lau <jacklau1222@qq.com>


>From e1e7c6cca557a6d17b39a281efe077caf0455f07 Mon Sep 17 00:00:00 2001
From: Jack Lau <jacklau1222@qq.com>
Date: Thu, 4 Sep 2025 07:49:41 +0800
Subject: [PATCH] avformat/whip: fix SDP ICE candidates parsing

fix issue #20407

Refer to RFC 5245 15.1,
the foundation may be any string up to 32 chars.
The old code could misread foundations as transport("udp").
This patch fully parse all these attr to avoid parsing error.

Signed-off-by: Jack Lau <jacklau1222@qq.com>
---
 libavformat/whip.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libavformat/whip.c b/libavformat/whip.c
index 1fcf19aaa3..6a7b2bbc14 100644
--- a/libavformat/whip.c
+++ b/libavformat/whip.c
@@ -848,12 +848,12 @@ static int parse_answer(AVFormatContext *s)
                 goto end;
             }
         } else if (av_strstart(line, "a=candidate:", &ptr) && !whip->ice_protocol) {
-            ptr = av_stristr(ptr, "udp");
             if (ptr && av_stristr(ptr, "host")) {
-                char protocol[17], host[129];
-                int priority, port;
-                ret = sscanf(ptr, "%16s %d %128s %d typ host", protocol, &priority, host, &port);
-                if (ret != 4) {
+                /* Refer to RFC 5245 15.1 */
+                char foundation[33], protocol[17], host[129];
+                int component_id, priority, port;
+                ret = sscanf(ptr, "%32s %d %16s %d %128s %d typ host", foundation, &component_id, protocol, &priority, host, &port);
+                if (ret != 6) {
                     av_log(whip, AV_LOG_ERROR, "Failed %d to parse line %d %s from %s\n",
                         ret, i, line, whip->sdp_answer);
                     ret = AVERROR(EIO);
-- 
2.49.1

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