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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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62
fs/ext4/balloc.c
View File

@ -100,6 +100,15 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
return desc;
}
static inline int
block_in_use(ext4_fsblk_t block, struct super_block *sb, unsigned char *map)
{
ext4_grpblk_t offset;
ext4_get_group_no_and_offset(sb, block, NULL, &offset);
return ext4_test_bit (offset, map);
}
/**
* read_block_bitmap()
* @sb: super block
@ -113,21 +122,53 @@ struct ext4_group_desc * ext4_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 ext4_group_desc * desc;
struct buffer_head * bh = NULL;
ext4_fsblk_t bitmap_blk;
desc = ext4_get_group_desc (sb, block_group, NULL);
if (!desc)
goto error_out;
bh = sb_bread(sb, ext4_block_bitmap(sb, desc));
return NULL;
bitmap_blk = ext4_block_bitmap(sb, desc);
bh = sb_bread(sb, bitmap_blk);
if (!bh)
ext4_error (sb, "read_block_bitmap",
ext4_error (sb, __FUNCTION__,
"Cannot read block bitmap - "
"block_group = %d, block_bitmap = %llu",
block_group,
ext4_block_bitmap(sb, desc));
error_out:
block_group, bitmap_blk);
/* 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 = ext4_inode_bitmap(sb, desc);
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 = ext4_inode_table(sb, desc);
for (i = 0; i < EXT4_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);
ext4_error(sb, __FUNCTION__,
"Invalid block bitmap - "
"block_group = %d, block = %llu",
block_group, bitmap_blk);
return NULL;
}
/*
* The reservation window structure operations
@ -1747,15 +1788,6 @@ ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
#endif
}
static inline int
block_in_use(ext4_fsblk_t block, struct super_block *sb, unsigned char *map)
{
ext4_grpblk_t offset;
ext4_get_group_no_and_offset(sb, block, NULL, &offset);
return ext4_test_bit (offset, map);
}
static inline int test_root(int a, int b)
{
int num = b;