[FFmpeg-devel] [PATCH 04/37] avformat/matroskadec: Don't zero unnecessarily
James Almer
jamrial at gmail.com
Tue Jun 25 03:04:36 EEST 2019
On 5/16/2019 7:29 PM, Andreas Rheinhardt wrote:
> It is only necessary to zero the initial allocated memory used to store
> the size of laced frames if the block used Xiph lacing. Otherwise no
> unintialized data was ever used, so use av_malloc instead of av_mallocz.
>
> Also use the correct type for the allocations.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> I checked this via the --enable-memory-poisoning compile option. It
> yielded identical output to patched version without this option as well
> as to current git head; I used Alexander Noe's AVI-Mux GUI
> (http://www.alexander-noe.com/video/amg/) to create files using Xiph
> lacing to test this on.
> I unfortunately couldn't make Clang's MemorySanitizer or its
> AddressSanitizer run under MinGW64.
> libavformat/matroskadec.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
> index 3b8ddc5ecb..4dd933ef74 100644
> --- a/libavformat/matroskadec.c
> +++ b/libavformat/matroskadec.c
> @@ -2814,7 +2814,7 @@ static int matroska_parse_laces(MatroskaDemuxContext *matroska, uint8_t **buf,
>
> if (!type) {
> *laces = 1;
> - *lace_buf = av_mallocz(sizeof(int));
> + *lace_buf = av_malloc(sizeof(**lace_buf));
> if (!*lace_buf)
> return AVERROR(ENOMEM);
>
> @@ -2826,7 +2826,7 @@ static int matroska_parse_laces(MatroskaDemuxContext *matroska, uint8_t **buf,
> *laces = *data + 1;
> data += 1;
> size -= 1;
> - lace_size = av_mallocz(*laces * sizeof(int));
> + lace_size = av_malloc(*laces * sizeof(*lace_size));
Changed this to av_malloc_array() while at it, and applied.
Thanks.
> if (!lace_size)
> return AVERROR(ENOMEM);
>
> @@ -2836,6 +2836,8 @@ static int matroska_parse_laces(MatroskaDemuxContext *matroska, uint8_t **buf,
> uint8_t temp;
> uint32_t total = 0;
> for (n = 0; res == 0 && n < *laces - 1; n++) {
> + lace_size[n] = 0;
> +
> while (1) {
> if (size <= total) {
> res = AVERROR_INVALIDDATA;
>
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