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ext2/ext3/ext4: add block bitmap validation

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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>
This commit is contained in:
Aneesh Kumar K.V
2007-10-16 23:27:02 -07:00
committed by Linus Torvalds
parent 82df39738b
commit 7c9e69faa2
3 changed files with 134 additions and 38 deletions
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56
fs/ext2/balloc.c
View File

@@ -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)
{