avformat/sdp: Fix potential write beyond end of buffer

mkver · mkver · commit 9ee65bf88d6a · 2020-07-10T20:52:00.000+02:00
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> (cherry picked from commit 5d91b77) Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
diff --git a/libavformat/sdp.c b/libavformat/sdp.c
@@ -212,7 +212,7 @@ static char *extradata2psets(AVFormatContext *s, AVCodecParameters *par)
         p += strlen(p);
         r = r1;
     }
-    if (sps && sps_end - sps >= 4) {
+    if (sps && sps_end - sps >= 4 && p - psets <= MAX_PSET_SIZE - strlen(profile_string) - 7) {
         memcpy(p, profile_string, strlen(profile_string));
         p += strlen(p);
         ff_data_to_hex(p, sps + 1, 3, 0);

Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,7 @@ static char extradata2psets(AVFormatContext s, AVCodecParameters *par)`
`212`	`212`	`p += strlen(p);`
`213`	`213`	`r = r1;`
`214`	`214`	`}`
`215`		`- if (sps && sps_end - sps >= 4) {`
	`215`	`+ if (sps && sps_end - sps >= 4 && p - psets <= MAX_PSET_SIZE - strlen(profile_string) - 7) {`
`216`	`216`	`memcpy(p, profile_string, strlen(profile_string));`
`217`	`217`	`p += strlen(p);`
`218`	`218`	`ff_data_to_hex(p, sps + 1, 3, 0);`