From 88069ea6c958db2638dfbfe4b3053e831b0b5379 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 11 Jan 2023 23:26:06 +0100 Subject: avcodec/pngdec: Check deloco index more exactly Fixes: out of array access: Fixes: 48567/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PNG_fuzzer-6716193709096960 Alternatively it should be possible to limit this to 3 plane RGB 8 /16bit to ensure the size is what it should be Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit d5bae704068dc37191280e024eecb8d02b762b28) Signed-off-by: Michael Niedermayer --- libavcodec/pngdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index 647e7f0a74..8a75a2e1dc 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -311,7 +311,7 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type, static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \ { \ int i; \ - for (i = 0; i < size; i += 3 + alpha) { \ + for (i = 0; i < size - 2; i += 3 + alpha) { \ int g = dst [i + 1]; \ dst[i + 0] += g; \ dst[i + 2] += g; \ -- cgit v1.2.1