diff options
| author | Aneesh Kumar K.V | 2007-10-16 23:27:02 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2007-10-17 08:42:52 -0700 |
| commit | 7c9e69faa28027913ee059c285a5ea8382e24b5d (patch) | |
| tree | 951e6e780da734c61337eb8fef23ac3ad68b1e18 /fs/ext2/balloc.c | |
| parent | 82df39738ba9e02c057fa99b7461a56117d36119 (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.c | 56 |
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) { |