udf: Add checks to not underflow sector_t

Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2008-12-03 17:31:39 +01:00
parent 87bc730c07
commit f90981fed9
1 changed files with 12 additions and 7 deletions

View File

@ -731,13 +731,18 @@ static sector_t udf_scan_anchors(struct super_block *sb, sector_t lastblock)
sector_t last[6];
int i;
struct udf_sb_info *sbi = UDF_SB(sb);
int last_count = 0;
last[0] = lastblock;
last[1] = last[0] - 1;
last[2] = last[0] + 1;
last[3] = last[0] - 2;
last[4] = last[0] - 150;
last[5] = last[0] - 152;
last[last_count++] = lastblock;
if (lastblock >= 1)
last[last_count++] = lastblock - 1;
last[last_count++] = lastblock + 1;
if (lastblock >= 2)
last[last_count++] = lastblock - 2;
if (lastblock >= 150)
last[last_count++] = lastblock - 150;
if (lastblock >= 152)
last[last_count++] = lastblock - 152;
/* according to spec, anchor is in either:
* block 256
@ -745,7 +750,7 @@ static sector_t udf_scan_anchors(struct super_block *sb, sector_t lastblock)
* lastblock
* however, if the disc isn't closed, it could be 512 */
for (i = 0; i < ARRAY_SIZE(last); i++) {
for (i = 0; i < last_count; i++) {
if (last[i] >= sb->s_bdev->bd_inode->i_size >>
sb->s_blocksize_bits)
continue;