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.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andreas Dilger <adilger@xxxxxxxxxxxxx>
---
fs/ext2/balloc.c | 56 ++++++++++++++++++++++++++++++++++++++----------
fs/ext3/balloc.c | 53 ++++++++++++++++++++++++++++++++++++---------
fs/ext4/balloc.c | 62 ++++++++++++++++++++++++++++++++++++++++-------------
3 files changed, 133 insertions(+), 38 deletions(-)
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index baf71dd..917a443 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)
{
diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index ca8aee6..b44c76f 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -79,6 +79,13 @@ struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
*bh = sbi->s_group_desc[group_desc];
return desc + offset;
}
+static inline int
+block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
+{
+ return ext3_test_bit ((block -
+ le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
+ EXT3_BLOCKS_PER_GROUP(sb), map);
+}
/**
* read_block_bitmap()
@@ -93,20 +100,51 @@ struct ext3_group_desc * ext3_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 ext3_group_desc * desc;
struct buffer_head * bh = NULL;
+ ext3_fsblk_t bitmap_blk;
desc = ext3_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)
- ext3_error (sb, "read_block_bitmap",
+ ext3_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 < EXT3_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);
+ ext3_error(sb, __FUNCTION__,
+ "Invalid block bitmap - "
+ "block_group = %d, block = %lu",
+ block_group, bitmap_blk);
+ return NULL;
}
/*
* The reservation window structure operations
@@ -1733,13 +1771,6 @@ ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
#endif
}
-static inline int
-block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
-{
- return ext3_test_bit ((block -
- le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
- EXT3_BLOCKS_PER_GROUP(sb), map);
-}
static inline int test_root(int a, int b)
{
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 3b64bb1..7d58f12 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -99,6 +99,15 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
*bh = sbi->s_group_desc[group_desc];
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()
@@ -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;
--
1.5.3.rc2.22.g69a9b-dirty
-
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