From 5c11cf98abdd728037553995bbf401d858b40aeb Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 17 Aug 2025 15:31:48 +0200 Subject: [PATCH] avcodec/sanm: Check w,h,left,top The setup code fow w,h,left,top is complex, the code using it also falls in at least 2 different classes, one using left/top the other not. To ensure no out of array access happens we add this clear check. Fixes: out of array access Fixes: 439261995/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SANM_fuzzer-5383455572819968 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 134fbfd1dcb59441e38d870ddd231772f4e8e127) Signed-off-by: Michael Niedermayer --- libavcodec/sanm.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c index 8b7c0d9556..abd7981ac6 100644 --- a/libavcodec/sanm.c +++ b/libavcodec/sanm.c @@ -974,6 +974,11 @@ static int process_frame_obj(SANMVideoContext *ctx) } bytestream2_skip(&ctx->gb, 4); + if (w + FFMAX(left, 0) > ctx->avctx->width || h + FFMAX(top, 0) > ctx->avctx->height) { + avpriv_request_sample(ctx->avctx, "overly large frame\n"); + return AVERROR_PATCHWELCOME; + } + switch (codec) { case 1: case 3: