[FFmpeg-devel] [PATCH] mov demuxer: Check if a key is longer than the atom containing it

[Eugene Zemtsov via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

From: Eugene Zemtsov <eugene@chromium.org>

Stop reading keys and return AVERROR_INVALIDDATA if key_size
is larger than the amount of space left in the atom.

Bug: https://crbug.com/41496983
Signed-off-by: Eugene Zemtsov <eugene@chromium.org>
---
 libavformat/mov.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 662301bf67..2d92e7963b 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -5048,12 +5048,13 @@ static int mov_read_keys(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     for (i = 1; i <= count; ++i) {
         uint32_t key_size = avio_rb32(pb);
         uint32_t type = avio_rl32(pb);
-        if (key_size < 8) {
+        if (key_size < 8 || key_size > atom.size) {
             av_log(c->fc, AV_LOG_ERROR,
                    "The key# %"PRIu32" in meta has invalid size:"
                    "%"PRIu32"\n", i, key_size);
             return AVERROR_INVALIDDATA;
         }
+        atom.size -= key_size;
         key_size -= 8;
         if (type != MKTAG('m','d','t','a')) {
             avio_skip(pb, key_size);
-- 
2.44.0.478.gd926399ef9-goog

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