On 2/26/2024 8:27 PM, Andreas Rheinhardt wrote:
It is undefined behaviour. Fixes many failed tests with UBSan and GCC 13 like "src/libavformat/mov.c:4229:44: runtime error: store to address 0x5572abe20f80 with insufficient space for an object of type 'struct MOVIndexRange'" (The line number does not refer to the line where &entry[-1] is assigned.)Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> --- libavformat/mov.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/libavformat/mov.c b/libavformat/mov.c index 71e8f7ae8f..97caaa7723 100644 --- a/libavformat/mov.c +++ b/libavformat/mov.c @@ -4022,7 +4022,7 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) int num_discarded_begin = 0; int first_non_zero_audio_edit = -1; int packet_skip_samples = 0; - MOVIndexRange *current_index_range; + MOVIndexRange *current_index_range = NULL; int found_keyframe_after_edit = 0; int found_non_empty_edit = 0;@@ -4038,7 +4038,6 @@ static void mov_fix_index(MOVContext *mov, AVStream *st)return; } msc->current_index_range = msc->index_ranges; - current_index_range = msc->index_ranges - 1;// Clean AVStream from traces of old indexsti->index_entries = NULL; @@ -4225,8 +4224,9 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) }// Update the index ranges array- if (current_index_range < msc->index_ranges || index != current_index_range->end) { - current_index_range++; + if (!current_index_range || index != current_index_range->end) { + current_index_range = current_index_range ? current_index_range + 1 + : msc->index_ranges; current_index_range->start = index; } current_index_range->end = index + 1; @@ -4289,7 +4289,8 @@ static void mov_fix_index(MOVContext *mov, AVStream *st) av_freep(&frame_duration_buffer);// Null terminate the index ranges array- current_index_range++; + current_index_range = current_index_range ? current_index_range + 1 + : msc->index_ranges; current_index_range->start = 0; current_index_range->end = 0; msc->current_index = msc->index_ranges[0].start;
Can't test if this fixes the UB, but the changes lgtm. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
