From b94e542582e375025c59862cee58ec45d39c9cd6 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..c45f6c3e6b 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -2228,7 +2228,13 @@ static int mov_read_stco(MOVContext *c, AVIOContext *pb, MOVAtom atom) avio_r8(pb); /* version */ avio_rb24(pb); /* flags */ + // Clamp allocation size for `chunk_offsets` -- don't throw an error for an + // invalid count since the EOF path doesn't throw either. entries = avio_rb32(pb); + entries = + FFMIN(entries, + FFMAX(0, (atom.size - 8) / + (atom.type == MKTAG('s', 't', 'c', 'o') ? 4 : 8))); if (!entries) return 0; @@ -2237,6 +2243,7 @@ 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; } + av_free(sc->chunk_offsets); sc->chunk_count = 0; sc->chunk_offsets = av_malloc_array(entries, sizeof(*sc->chunk_offsets)); -- 2.44.0.rc0.258.g7320e95886-goog