From 158efc045c718054e3fbd7d0a19d8703e2c1b234 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 21 Apr 2019 11:05:17 +0200 Subject: [PATCH] avcodec/agm: Do not crash on invalid codes I do not know if such vlc trees are allowed in agm, I have no specification So i do not know if these should be treated as error, or not. But the code does contain a check for idx < 0 already ... Fixes: Stack-buffer-overflow in get_tree_codes Fixes: 14189/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AGM_fuzzer-5745747003179008 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Paul B Mahol Signed-off-by: Michael Niedermayer --- libavcodec/agm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/agm.c b/libavcodec/agm.c index f5fd5d065e..f3d81bf163 100644 --- a/libavcodec/agm.c +++ b/libavcodec/agm.c @@ -913,7 +913,7 @@ static void get_tree_codes(uint32_t *codes, Node *nodes, int idx, uint32_t pfx, { if (idx < 256 && idx >= 0) { codes[idx] = pfx; - } else { + } else if (idx >= 0) { get_tree_codes(codes, nodes, nodes[idx].child[0], pfx + (0 << bitpos), bitpos + 1); get_tree_codes(codes, nodes, nodes[idx].child[1], pfx + (1 << bitpos), bitpos + 1); }