diff options
| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2019-11-17 08:34:36 +0100 |
|---|---|---|
| committer | Mark Thompson <sw@jkqxz.net> | 2019-11-17 23:31:45 +0000 |
| commit | cda3e8ca04c0e343f5b60fda8fb467936e176f33 (patch) | |
| tree | c5982250e6354efee8023ae2776582d20d37c866 /libavcodec/cbs.c | |
| parent | 7c92eaace2b338e0b3acc18e1543b365610578fd (diff) | |
| download | ffmpeg-cda3e8ca04c0e343f5b60fda8fb467936e176f33.tar.gz | |
avcodec/cbs: Fix potential overflow
The number of bits in a PutBitContext must fit into an int, yet nothing
guaranteed the size argument cbs_write_unit_data() uses in init_put_bits()
to be in the range 0..INT_MAX / 8. This has been changed.
Furthermore, the check 8 * data_size > data_bit_start that there is
data beyond the initial padding when writing mpeg2 or H.264/5 slices
could also overflow, so divide it by 8 to get an equivalent check
without this problem.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Diffstat (limited to 'libavcodec/cbs.c')
| -rw-r--r-- | libavcodec/cbs.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c index ab3eadb534..0badb192d9 100644 --- a/libavcodec/cbs.c +++ b/libavcodec/cbs.c @@ -309,7 +309,9 @@ static int cbs_write_unit_data(CodedBitstreamContext *ctx, if (ret < 0) { if (ret == AVERROR(ENOSPC)) { // Overflow. - ctx->write_buffer_size *= 2; + if (ctx->write_buffer_size == INT_MAX / 8) + return AVERROR(ENOMEM); + ctx->write_buffer_size = FFMIN(2 * ctx->write_buffer_size, INT_MAX / 8); goto reallocate_and_try_again; } // Write failed for some other reason. |