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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2007-10-16 23:27:02 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:42:52 -0700
commit7c9e69faa28027913ee059c285a5ea8382e24b5d (patch)
tree951e6e780da734c61337eb8fef23ac3ad68b1e18 /fs/ext2/balloc.c
parent82df39738ba9e02c057fa99b7461a56117d36119 (diff)
ext2/ext3/ext4: add block bitmap validation
When a new block bitmap is read from disk in read_block_bitmap() there are a few bits that should ALWAYS be set. In particular, the blocks given by ext4_blk_bitmap, ext4_inode_bitmap and ext4_inode_table. Validate the block bitmap against these blocks. [akpm@linux-foundation.org: cleanups] Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Acked-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext2/balloc.c')
-rw-r--r--fs/ext2/balloc.c56
1 files changed, 44 insertions, 12 deletions
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 834ad4c16e2d..ffaa6d845442 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -69,6 +69,14 @@ struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
return desc + offset;
}
+static inline int
+block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
+{
+ return ext2_test_bit ((block -
+ le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
+ EXT2_BLOCKS_PER_GROUP(sb), map);
+}
+
/*
* Read the bitmap for a given block_group, reading into the specified
* slot in the superblock's bitmap cache.
@@ -78,20 +86,51 @@ struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
static struct buffer_head *
read_block_bitmap(struct super_block *sb, unsigned int block_group)
{
+ int i;
struct ext2_group_desc * desc;
struct buffer_head * bh = NULL;
-
+ unsigned int bitmap_blk;
+
desc = ext2_get_group_desc (sb, block_group, NULL);
if (!desc)
- goto error_out;
- bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
+ return NULL;
+ bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+ bh = sb_bread(sb, bitmap_blk);
if (!bh)
- ext2_error (sb, "read_block_bitmap",
+ ext2_error (sb, __FUNCTION__,
"Cannot read block bitmap - "
"block_group = %d, block_bitmap = %u",
block_group, le32_to_cpu(desc->bg_block_bitmap));
-error_out:
+
+ /* check whether block bitmap block number is set */
+ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+ /* bad block bitmap */
+ goto error_out;
+ }
+ /* check whether the inode bitmap block number is set */
+ bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
+ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+ /* bad block bitmap */
+ goto error_out;
+ }
+ /* check whether the inode table block number is set */
+ bitmap_blk = le32_to_cpu(desc->bg_inode_table);
+ for (i = 0; i < EXT2_SB(sb)->s_itb_per_group; i++, bitmap_blk++) {
+ if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
+ /* bad block bitmap */
+ goto error_out;
+ }
+ }
+
return bh;
+
+error_out:
+ brelse(bh);
+ ext2_error(sb, __FUNCTION__,
+ "Invalid block bitmap - "
+ "block_group = %d, block = %u",
+ block_group, bitmap_blk);
+ return NULL;
}
/*
@@ -583,13 +622,6 @@ unsigned long ext2_count_free_blocks (struct super_block * sb)
#endif
}
-static inline int
-block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
-{
- return ext2_test_bit ((block -
- le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
- EXT2_BLOCKS_PER_GROUP(sb), map);
-}
static inline int test_root(int a, int b)
{