[FFmpeg-cvslog] avcodec/iff: Check for overlap in cmap_read_palette()

Michael Niedermayer git at videolan.org
Sat Sep 7 00:38:37 EEST 2019


ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Wed Aug 21 23:22:39 2019 +0200| [6c583ec9bdcc241d1cbfc1c5b8a600c91f0770fc] | committer: Michael Niedermayer

avcodec/iff: Check for overlap in cmap_read_palette()

Fixes: undefined memcpy() use
Fixes: 16302/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5678750575886336

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 dfa5d1a3667fa38e07373becc2401175b31d8228)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6c583ec9bdcc241d1cbfc1c5b8a600c91f0770fc
---

 libavcodec/iff.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/iff.c b/libavcodec/iff.c
index fc7bfad731..c18bac1ea1 100644
--- a/libavcodec/iff.c
+++ b/libavcodec/iff.c
@@ -180,6 +180,10 @@ static int cmap_read_palette(AVCodecContext *avctx, uint32_t *pal)
             pal[i] = 0xFF000000 | gray2rgb((i * 255) >> avctx->bits_per_coded_sample);
     }
     if (s->masking == MASK_HAS_MASK) {
+        if ((1 << avctx->bits_per_coded_sample) < count) {
+            avpriv_request_sample(avctx, "overlapping mask");
+            return AVERROR_PATCHWELCOME;
+        }
         memcpy(pal + (1 << avctx->bits_per_coded_sample), pal, count * 4);
         for (i = 0; i < count; i++)
             pal[i] &= 0xFFFFFF;



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