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-rw-r--r--fs/udf/balloc.c31
1 files changed, 27 insertions, 4 deletions
diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c
index cdf90928b7f2..14b9db4c80f0 100644
--- a/fs/udf/balloc.c
+++ b/fs/udf/balloc.c
@@ -36,18 +36,41 @@ static int read_block_bitmap(struct super_block *sb,
unsigned long bitmap_nr)
{
struct buffer_head *bh = NULL;
- int retval = 0;
+ int i;
+ int max_bits, off, count;
struct kernel_lb_addr loc;
loc.logicalBlockNum = bitmap->s_extPosition;
loc.partitionReferenceNum = UDF_SB(sb)->s_partition;
bh = sb_bread(sb, udf_get_lb_pblock(sb, &loc, block));
+ bitmap->s_block_bitmap[bitmap_nr] = bh;
if (!bh)
- retval = -EIO;
+ return -EIO;
- bitmap->s_block_bitmap[bitmap_nr] = bh;
- return retval;
+ /* Check consistency of Space Bitmap buffer. */
+ max_bits = sb->s_blocksize * 8;
+ if (!bitmap_nr) {
+ off = sizeof(struct spaceBitmapDesc) << 3;
+ count = min(max_bits - off, bitmap->s_nr_groups);
+ } else {
+ /*
+ * Rough check if bitmap number is too big to have any bitmap
+ * blocks reserved.
+ */
+ if (bitmap_nr >
+ (bitmap->s_nr_groups >> (sb->s_blocksize_bits + 3)) + 2)
+ return 0;
+ off = 0;
+ count = bitmap->s_nr_groups - bitmap_nr * max_bits +
+ (sizeof(struct spaceBitmapDesc) << 3);
+ count = min(count, max_bits);
+ }
+
+ for (i = 0; i < count; i++)
+ if (udf_test_bit(i + off, bh->b_data))
+ return -EFSCORRUPTED;
+ return 0;
}
static int __load_block_bitmap(struct super_block *sb,