[FFmpeg-devel] [PATCH] vp9: avoid infinite loop with broken files

wm4 nfxjfg at googlemail.com
Sat Jan 10 18:00:08 CET 2015


With a certain fuzzed file, the parser will always return 0 consumed
bytes, which makes calling code call the parser infinitely. Return the
full packet size on error instead. (Here it would be nice if parsers
could return errors at all.)

Additionally, _if_ there's some data left, return that too, which might
help with somewhat broken but still somehow playable files.

Fixes ticket #4242.
---
There might be a more elegant way to fix this.
Also, not sure if the change *out_size has any worth.
---
 libavcodec/vp9_parser.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavcodec/vp9_parser.c b/libavcodec/vp9_parser.c
index 922f36f..b188785 100644
--- a/libavcodec/vp9_parser.c
+++ b/libavcodec/vp9_parser.c
@@ -43,6 +43,7 @@ static int parse(AVCodecParserContext *ctx,
                  const uint8_t *data, int size)
 {
     VP9ParseContext *s = ctx->priv_data;
+    int full_size = size;
     int marker;
 
     if (size <= 0) {
@@ -77,12 +78,12 @@ static int parse(AVCodecParserContext *ctx,
                     idx += a; \
                     if (sz > size) { \
                         s->n_frames = 0; \
-                        *out_size = 0; \
+                        *out_size = size; \
                         *out_data = data; \
                         av_log(avctx, AV_LOG_ERROR, \
                                "Superframe packet size too big: %u > %d\n", \
                                sz, size); \
-                        return size; \
+                        return full_size; \
                     } \
                     if (first) { \
                         first = 0; \
-- 
2.1.4



More information about the ffmpeg-devel mailing list