From: Theodore Ts'o <tytso@mit.edu>
To: linux-ext4@vger.kernel.org
Cc: Theodore Ts'o <tytso@mit.edu>
Subject: [PATCH] ext4: Make the extent validity check more paranoid
Date: Wed, 22 Apr 2009 21:29:34 -0400 [thread overview]
Message-ID: <1240450174-25868-1-git-send-email-tytso@mit.edu> (raw)
Instead of just checking that the extent block number is greater or
equal than s_first_data_block, make sure it it is not pointing into
the block group descriptors, since that is clearly wrong. This helps
prevent filesystem from getting very badly corrupted in case an extent
block is corrupted.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/ext4/extents.c | 18 ++++++++++++------
1 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6132353..c28ffe2 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -326,11 +326,14 @@ ext4_ext_max_entries(struct inode *inode, int depth)
static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
{
- ext4_fsblk_t block = ext_pblock(ext);
+ ext4_fsblk_t block = ext_pblock(ext), valid_block;
int len = ext4_ext_get_actual_len(ext);
struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
- if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
- ((block + len) > ext4_blocks_count(es))))
+
+ valid_block = le32_to_cpu(es->s_first_data_block) +
+ EXT4_SB(inode->i_sb)->s_gdb_count;
+ if (unlikely(block <= valid_block ||
+ ((block + len) > ext4_blocks_count(es))))
return 0;
else
return 1;
@@ -339,10 +342,13 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
static int ext4_valid_extent_idx(struct inode *inode,
struct ext4_extent_idx *ext_idx)
{
- ext4_fsblk_t block = idx_pblock(ext_idx);
+ ext4_fsblk_t block = idx_pblock(ext_idx), valid_block;
struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
- if (unlikely(block < le32_to_cpu(es->s_first_data_block) ||
- (block >= ext4_blocks_count(es))))
+
+ valid_block = le32_to_cpu(es->s_first_data_block) +
+ EXT4_SB(inode->i_sb)->s_gdb_count;
+ if (unlikely(block <= valid_block ||
+ (block >= ext4_blocks_count(es))))
return 0;
else
return 1;
--
1.5.6.3
next reply other threads:[~2009-04-23 1:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-23 1:29 Theodore Ts'o [this message]
2009-04-23 2:04 ` [PATCH] ext4: Make the extent validity check more paranoid Eric Sandeen
2009-04-23 4:19 ` Theodore Tso
2009-04-23 12:52 ` Eric Sandeen
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