[FFmpeg-cvslog] avcodec/iff: Fix off by x error

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sat Jun 13 10:48:14 2020 +0200| [0e51c7b64a35478250c21efae14d68c50aea666c] | committer: Michael Niedermayer

avcodec/iff: Fix off by x error

Fixes: out of array access
Fixes: 23245/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5723121327013888.fuzz

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 51225dee0a6266780d26d43bd6802bbcf736327e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0e51c7b64a35478250c21efae14d68c50aea666c
---

 libavcodec/iff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/iff.c b/libavcodec/iff.c
index 66879cbf5d..79f6215c77 100644
--- a/libavcodec/iff.c
+++ b/libavcodec/iff.c
@@ -723,7 +723,7 @@ static void decode_deep_rle32(uint8_t *dst, const uint8_t *src, int src_size, in
         if (opcode >= 0) {
             int size = opcode + 1;
             for (i = 0; i < size; i++) {
-                int length = FFMIN(size - i, width);
+                int length = FFMIN(size - i, width - x);
                 if (src_end - src < length * 4)
                     return;
                 memcpy(dst + y*linesize + x * 4, src, length * 4);