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vp3: More buffer length checks 

.5% slower to fix some crashes on invalid streams

Originally committed as revision 22893 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
David Conrad 2010-04-16 12:21:44 +00:00
parent d7097c2d88
commit 6086731299
1 changed files with 9 additions and 4 deletions
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13
libavcodec/vp3.c
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@ -379,7 +379,7 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
/* unpack the list of partially-coded superblocks */
bit = get_bits1(gb);
while (current_superblock < s->superblock_count) {
while (current_superblock < s->superblock_count && get_bits_left(gb) > 0) {
current_run = get_vlc2(gb,
s->superblock_run_length_vlc.table, 6, 2) + 1;
if (current_run == 34)
@ -409,7 +409,8 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
current_superblock = 0;
bit = get_bits1(gb);
while (superblocks_decoded < s->superblock_count - num_partial_superblocks) {
while (superblocks_decoded < s->superblock_count - num_partial_superblocks
&& get_bits_left(gb) > 0) {
current_run = get_vlc2(gb,
s->superblock_run_length_vlc.table, 6, 2) + 1;
if (current_run == 34)
@ -458,7 +459,7 @@ static int unpack_superblocks(Vp3DecodeContext *s, GetBitContext *gb)
int sb_end = sb_start + (plane ? s->c_superblock_count : s->y_superblock_count);
int num_coded_frags = 0;
for (i = sb_start; i < sb_end; i++) {
for (i = sb_start; i < sb_end && get_bits_left(gb) > 0; i++) {
/* iterate through all 16 fragments in a superblock */
for (j = 0; j < 16; j++) {
@ -542,6 +543,8 @@ static int unpack_modes(Vp3DecodeContext *s, GetBitContext *gb)
* coded fragments */
for (sb_y = 0; sb_y < s->y_superblock_height; sb_y++) {
for (sb_x = 0; sb_x < s->y_superblock_width; sb_x++) {
if (get_bits_left(gb) <= 0)
return -1;
for (j = 0; j < 4; j++) {
int mb_x = 2*sb_x + (j>>1);
@ -636,6 +639,8 @@ static int unpack_vectors(Vp3DecodeContext *s, GetBitContext *gb)
* coded fragments */
for (sb_y = 0; sb_y < s->y_superblock_height; sb_y++) {
for (sb_x = 0; sb_x < s->y_superblock_width; sb_x++) {
if (get_bits_left(gb) <= 0)
return -1;
for (j = 0; j < 4; j++) {
int mb_x = 2*sb_x + (j>>1);
@ -820,7 +825,7 @@ static int unpack_block_qpis(Vp3DecodeContext *s, GetBitContext *gb)
bit = get_bits1(gb);
else
bit ^= 1;
} while (blocks_decoded < num_blocks);
} while (blocks_decoded < num_blocks && get_bits_left(gb) > 0);
num_blocks -= num_blocks_at_qpi;
}