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avcodec/vmdav: return the amount of data that has been unpacked from lz_unpack() (as well as errors)

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and setup the bytestream buffer size accordingly

Fixes use of uninitialized memory
Fixes: msan_uninit-mem_7fdcc513cd45_229_12.vmd
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2013-12-23 18:09:58 +01:00
parent bb9f55163f
commit f07ca542e3
1 changed files with 12 additions and 8 deletions
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20
libavcodec/vmdav.c
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@ -76,7 +76,7 @@ typedef struct VmdVideoContext {
#define QUEUE_SIZE 0x1000
#define QUEUE_MASK 0x0FFF
static void lz_unpack(const unsigned char *src, int src_len,
static int lz_unpack(const unsigned char *src, int src_len,
unsigned char *dest, int dest_len)
{
unsigned char *d;
@ -97,7 +97,7 @@ static void lz_unpack(const unsigned char *src, int src_len,
dataleft = bytestream2_get_le32(&gb);
memset(queue, 0x20, QUEUE_SIZE);
if (bytestream2_get_bytes_left(&gb) < 4)
return;
return AVERROR_INVALIDDATA;
if (bytestream2_peek_le32(&gb) == 0x56781234) {
bytestream2_skipu(&gb, 4);
qpos = 0x111;
@ -111,7 +111,7 @@ static void lz_unpack(const unsigned char *src, int src_len,
tag = bytestream2_get_byteu(&gb);
if ((tag == 0xFF) && (dataleft > 8)) {
if (d_end - d < 8 || bytestream2_get_bytes_left(&gb) < 8)
return;
return AVERROR_INVALIDDATA;
for (i = 0; i < 8; i++) {
queue[qpos++] = *d++ = bytestream2_get_byteu(&gb);
qpos &= QUEUE_MASK;
@ -123,7 +123,7 @@ static void lz_unpack(const unsigned char *src, int src_len,
break;
if (tag & 0x01) {
if (d_end - d < 1 || bytestream2_get_bytes_left(&gb) < 1)
return;
return AVERROR_INVALIDDATA;
queue[qpos++] = *d++ = bytestream2_get_byteu(&gb);
qpos &= QUEUE_MASK;
dataleft--;
@ -135,7 +135,7 @@ static void lz_unpack(const unsigned char *src, int src_len,
chainlen = bytestream2_get_byte(&gb) + 0xF + 3;
}
if (d_end - d < chainlen)
return;
return AVERROR_INVALIDDATA;
for (j = 0; j < chainlen; j++) {
*d = queue[chainofs++ & QUEUE_MASK];
queue[qpos++] = *d++;
@ -147,6 +147,7 @@ static void lz_unpack(const unsigned char *src, int src_len,
}
}
}
return d - dest;
}
static int rle_unpack(const unsigned char *src, unsigned char *dest,
int src_count, int src_size, int dest_len)
@ -279,15 +280,18 @@ static int vmd_decode(VmdVideoContext *s, AVFrame *frame)
return AVERROR_INVALIDDATA;
meth = bytestream2_get_byteu(&gb);
if (meth & 0x80) {
int size;
if (!s->unpack_buffer_size) {
av_log(s->avctx, AV_LOG_ERROR,
"Trying to unpack LZ-compressed frame with no LZ buffer\n");
return AVERROR_INVALIDDATA;
}
lz_unpack(gb.buffer, bytestream2_get_bytes_left(&gb),
s->unpack_buffer, s->unpack_buffer_size);
size = lz_unpack(gb.buffer, bytestream2_get_bytes_left(&gb),
s->unpack_buffer, s->unpack_buffer_size);
if (size < 0)
return size;
meth &= 0x7F;
bytestream2_init(&gb, s->unpack_buffer, s->unpack_buffer_size);
bytestream2_init(&gb, s->unpack_buffer, size);
}
dp = &frame->data[0][frame_y * frame->linesize[0] + frame_x];