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[FFmpeg-devel,3/5] avcodec/alsdec: Check for block_length <= 0 in read_var_block_data()

Message ID 20190726162608.22708-3-michael@niedermayer.cc
State Accepted
Commit be4fb282f9fb00d9c267dcc477745e2e468e758f
Headers show

Commit Message

Michael Niedermayer July 26, 2019, 4:26 p.m. UTC 
Fixes: left shift of negative value -1
Fixes: 15719/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5685731105701888

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/alsdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michael Niedermayer Aug. 5, 2019, 4:46 p.m. UTC | #1 
On Fri, Jul 26, 2019 at 06:26:06PM +0200, Michael Niedermayer wrote:
> Fixes: left shift of negative value -1
> Fixes: 15719/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5685731105701888
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/alsdec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

will apply

[...]
diff mbox

Patch

diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index ac3eca42c7..888e8d4cf8 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -657,7 +657,7 @@  static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
 
     // do not continue in case of a damaged stream since
     // block_length must be evenly divisible by sub_blocks
-    if (bd->block_length & (sub_blocks - 1)) {
+    if (bd->block_length & (sub_blocks - 1) || bd->block_length <= 0) {
         av_log(avctx, AV_LOG_WARNING,
                "Block length is not evenly divisible by the number of subblocks.\n");
         return AVERROR_INVALIDDATA;