Happens when flushing. This triggers NULL + 0 (which is UB) in
init_get_bits_xe (which previously errored out, but the return value
has not been checked) and in copy_bits().
This fixes the wmavoice-(7|11|19)k FATE-tests with UBSan.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
libavcodec/wmavoice.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/libavcodec/wmavoice.c b/libavcodec/wmavoice.c
index 4438089e51..26744719e6 100644
--- a/libavcodec/wmavoice.c
+++ b/libavcodec/wmavoice.c
@@ -1900,6 +1900,8 @@ static int wmavoice_decode_packet(AVCodecContext *ctx,
AVFrame *frame,
{
WMAVoiceContext *s = ctx->priv_data;
GetBitContext *gb = &s->gb;
+ const uint8_t *buf = avpkt->data;
+ uint8_t dummy[1];
int size, res, pos;
/* Packets are sometimes a multiple of ctx->block_align, with a packet
@@ -1908,7 +1910,8 @@ static int wmavoice_decode_packet(AVCodecContext *ctx,
AVFrame *frame,
* in a single "muxer" packet, so we artificially emulate that by
* capping the packet size at ctx->block_align. */
for (size = avpkt->size; size > ctx->block_align; size -=
ctx->block_align);
- init_get_bits8(&s->gb, avpkt->data, size);
+ buf = size ? buf : dummy;
+ init_get_bits8(&s->gb, buf, size);
/* size == ctx->block_align is used to indicate whether we are dealing with
* a new packet or a packet of which we already read the packet header
@@ -1931,7 +1934,7 @@ static int wmavoice_decode_packet(AVCodecContext *ctx,
AVFrame *frame,
if (cnt + s->spillover_nbits > avpkt->size * 8) {
s->spillover_nbits = avpkt->size * 8 - cnt;
}
- copy_bits(&s->pb, avpkt->data, size, gb, s->spillover_nbits);
+ copy_bits(&s->pb, buf, size, gb, s->spillover_nbits);
flush_put_bits(&s->pb);
s->sframe_cache_size += s->spillover_nbits;
if ((res = synth_superframe(ctx, frame, got_frame_ptr)) == 0 &&
@@ -1968,7 +1971,7 @@ static int wmavoice_decode_packet(AVCodecContext *ctx,
AVFrame *frame,
} else if ((s->sframe_cache_size = pos) > 0) {
/* ... cache it for spillover in next packet */
init_put_bits(&s->pb, s->sframe_cache, SFRAME_CACHE_MAXSIZE);
- copy_bits(&s->pb, avpkt->data, size, gb, s->sframe_cache_size);
+ copy_bits(&s->pb, buf, size, gb, s->sframe_cache_size);
// FIXME bad - just copy bytes as whole and add use the
// skip_bits_next field
}
--
2.34.1
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