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Commit f90981fe authored by Jan Kara's avatar Jan Kara
Browse files

udf: Add checks to not underflow sector_t 



Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 87bc730c

fs/udf/super.c

+13 −8
Original line number Diff line number Diff line
@@ -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);



	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;

	int last_count = 0;



	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;