[FFmpeg-cvslog] avcodec/tta: Check 24bit scaling for overflow
Michael Niedermayer
git at videolan.org
Sun Oct 9 23:07:30 EEST 2022
ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Sun Sep 11 00:11:20 2022 +0200| [9645062686b338eb5510eb917ab4f2b2e1430395] | committer: Michael Niedermayer
avcodec/tta: Check 24bit scaling for overflow
Fixes: signed integer overflow: -8427924 * 256 cannot be represented in type 'int'
Fixes: 48798/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TTA_fuzzer-5409428670644224
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 3993345f915bccceee315f44d412445346990e14)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9645062686b338eb5510eb917ab4f2b2e1430395
---
libavcodec/tta.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/libavcodec/tta.c b/libavcodec/tta.c
index 304f3a81df..b1ed8785c1 100644
--- a/libavcodec/tta.c
+++ b/libavcodec/tta.c
@@ -371,8 +371,15 @@ static int tta_decode_frame(AVCodecContext *avctx, void *data,
case 3: {
// shift samples for 24-bit sample format
int32_t *samples = (int32_t *)frame->data[0];
- for (i = 0; i < framelen * s->channels; i++)
- *samples++ *= 256;
+ int overflow = 0;
+
+ for (i = 0; i < framelen * s->channels; i++) {
+ int scaled = *samples * 256U;
+ overflow += (scaled >> 8 != *samples);
+ *samples++ = scaled;
+ }
+ if (overflow)
+ av_log(avctx, AV_LOG_WARNING, "%d overflows occurred on 24bit upscale\n", overflow);
// reset decode buffer
s->decode_buffer = NULL;
break;
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