From 6a82412bf33108111eb3f63076fd5a51349ae114 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 9 Jun 2022 21:13:59 +0200 Subject: [PATCH] avcodec/jpeglsdec: fix end check for xfrm Fixes: out of array access Fixes: 47871/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AMV_fuzzer-5646305956855808 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/jpeglsdec.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/libavcodec/jpeglsdec.c b/libavcodec/jpeglsdec.c index 399837cf2f..ab663dc1fc 100644 --- a/libavcodec/jpeglsdec.c +++ b/libavcodec/jpeglsdec.c @@ -484,19 +484,19 @@ int ff_jpegls_decode_picture(MJpegDecodeContext *s, int near, for (i = 0; i < s->height; i++) { switch(s->xfrm) { case 1: - for (x = off; x < w; x += 3) { + for (x = off; x + 2 < w; x += 3) { src[x ] += src[x+1] + 128; src[x+2] += src[x+1] + 128; } break; case 2: - for (x = off; x < w; x += 3) { + for (x = off; x + 2 < w; x += 3) { src[x ] += src[x+1] + 128; src[x+2] += ((src[x ] + src[x+1])>>1) + 128; } break; case 3: - for (x = off; x < w; x += 3) { + for (x = off; x + 2 < w; x += 3) { int g = src[x+0] - ((src[x+2]+src[x+1])>>2) + 64; src[x+0] = src[x+2] + g + 128; src[x+2] = src[x+1] + g + 128; @@ -504,7 +504,7 @@ int ff_jpegls_decode_picture(MJpegDecodeContext *s, int near, } break; case 4: - for (x = off; x < w; x += 3) { + for (x = off; x + 2 < w; x += 3) { int r = src[x+0] - (( 359 * (src[x+2]-128) + 490) >> 8); int g = src[x+0] - (( 88 * (src[x+1]-128) - 183 * (src[x+2]-128) + 30) >> 8); int b = src[x+0] + ((454 * (src[x+1]-128) + 574) >> 8);