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matroskadec: validate lace_size when parsed 

Stricter validation, explicitly exit on misparsing and some error
forwarding from the ebml parsing functions used.
This commit is contained in:
Luca Barbato 2012-09-14 21:24:23 +02:00
parent c9a39cec70
commit 870e75524a
1 changed files with 16 additions and 7 deletions
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23
libavformat/matroskadec.c
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@ -1829,11 +1829,19 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
} }
total += lace_size[n]; total += lace_size[n];
} }
if (size <= total) {
res = AVERROR_INVALIDDATA;
goto end;
}
lace_size[n] = size - total; lace_size[n] = size - total;
break; break;
} }
case 0x2: /* fixed-size lacing */ case 0x2: /* fixed-size lacing */
if (size != (size / laces) * size) {
res = AVERROR_INVALIDDATA;
goto end;
}
for (n = 0; n < laces; n++) for (n = 0; n < laces; n++)
lace_size[n] = size / laces; lace_size[n] = size / laces;
break; break;
@ -1844,7 +1852,8 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
if (n < 0) { if (n < 0) {
av_log(matroska->ctx, AV_LOG_INFO, av_log(matroska->ctx, AV_LOG_INFO,
"EBML block data error\n"); "EBML block data error\n");
break; res = n;
goto end;
} }
data += n; data += n;
size -= n; size -= n;
@ -1856,13 +1865,18 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
if (r < 0) { if (r < 0) {
av_log(matroska->ctx, AV_LOG_INFO, av_log(matroska->ctx, AV_LOG_INFO,
"EBML block data error\n"); "EBML block data error\n");
break; res = r;
goto end;
} }
data += r; data += r;
size -= r; size -= r;
lace_size[n] = lace_size[n - 1] + snum; lace_size[n] = lace_size[n - 1] + snum;
total += lace_size[n]; total += lace_size[n];
} }
if (size <= total) {
res = AVERROR_INVALIDDATA;
goto end;
}
lace_size[laces - 1] = size - total; lace_size[laces - 1] = size - total;
break; break;
} }
@ -1940,11 +1954,6 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data,
uint32_t pkt_size = lace_size[n]; uint32_t pkt_size = lace_size[n];
uint8_t *pkt_data = data; uint8_t *pkt_data = data;
if (pkt_size > size) {
av_log(matroska->ctx, AV_LOG_ERROR, "Invalid packet size\n");
break;
}
if (encodings && encodings->scope & 1) { if (encodings && encodings->scope & 1) {
res = matroska_decode_buffer(&pkt_data, &pkt_size, track); res = matroska_decode_buffer(&pkt_data, &pkt_size, track);
if (res < 0) if (res < 0)