From 04964bec430d61e89251e15b4cbb8400e4ea4af9 Mon Sep 17 00:00:00 2001 From: Dale Curtis Date: Fri, 2 Feb 2024 20:49:44 +0000 Subject: [PATCH] [mov] Avoid OOM for invalid STCO / CO64 constructions. The `entries` value is read directly from the stream and used to allocate memory. This change clamps `entries` to however many are possible in the remaining atom or file size (whichever is smallest). Fixes https://crbug.com/1429357 Signed-off-by: Dale Curtis --- libavformat/mov.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/libavformat/mov.c b/libavformat/mov.c index af95e1f662..9f012b24ae 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -2237,6 +2237,13 @@ static int mov_read_stco(MOVContext *c, AVIOContext *pb, MOVAtom atom) av_log(c->fc, AV_LOG_WARNING, "Ignoring duplicated STCO atom\n"); return 0; } + + // Clamp allocation size for `chunk_offsets` -- don't throw an error for an + // invalid count since the EOF path doesn't throw either. + entries = + FFMIN(entries, FFMIN(atom.size - 8, avio_size(pb) - avio_tell(pb)) / + (atom.type == MKTAG('s', 't', 'c', 'o') ? 4 : 8)); + av_free(sc->chunk_offsets); sc->chunk_count = 0; sc->chunk_offsets = av_malloc_array(entries, sizeof(*sc->chunk_offsets)); -- 2.43.0.594.gd9cf4e227d-goog