>From 654f24814e7b80d3b16bec2a67c13c43cb20eb2f Mon Sep 17 00:00:00 2001
From: Jayson R. King <[email protected]>
Date: Sun, 6 Jan 2008 18:14:18 -0600
Subject: e2fsck: Fix off-by-one error in check_blocks()
e2fsck allows extra blocks to be allocated to an inode up to the next
multiple of page size iff the block size is not equal to page size. An
off-by-one error in checking for this causes e2fsck to wrongly detect
a bad i_size for such inodes and results in incorrectly adjusting the
i_size to include those blocks.
Signed-off-by: Jayson R. King <[email protected]>
---
e2fsck/pass1.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 56218ae..7bf0686 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1593,7 +1593,7 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
if ((pb.last_block >= 0) &&
/* allow allocated blocks to end of PAGE_SIZE */
(size < (__u64)pb.last_block * fs->blocksize) &&
- (pb.last_block / blkpg * blkpg != pb.last_block ||
+ ((pb.last_block+1) & (blkpg-1) != 0 ||
size < (__u64)(pb.last_block & ~(blkpg-1)) *fs->blocksize))
bad_size = 3;
else if (size > ext2_max_sizes[fs->super->s_log_block_size])
--
1.5.3.3
On Jan 06, 2008 19:30 -0600, Jayson King wrote:
> This looks to be an off-by-one bug with e2fsck in the function
> check_blocks(), and there isn't any actual filesystem corruption
> (e2fsck causes the corruption).
This is actually a problem for cases where blocksize != pagesize.
We have a similar patch in our e2fsprogs, and I thought we sent
an equivalent patch to Ted previously...
- (pb.last_block / blkpg * blkpg != pb.last_block ||
+ ((pb.last_block+1) / blkpg * blkpg != (pb.last_block+1) ||
Signed-off-by: Kalpak Shah <[email protected]>
Signed-off-by: Andreas Dilger <[email protected]>
> >From 654f24814e7b80d3b16bec2a67c13c43cb20eb2f Mon Sep 17 00:00:00 2001
> From: Jayson R. King <[email protected]>
> Date: Sun, 6 Jan 2008 18:14:18 -0600
> Subject: e2fsck: Fix off-by-one error in check_blocks()
>
> e2fsck allows extra blocks to be allocated to an inode up to the next
> multiple of page size iff the block size is not equal to page size. An
> off-by-one error in checking for this causes e2fsck to wrongly detect
> a bad i_size for such inodes and results in incorrectly adjusting the
> i_size to include those blocks.
>
> Signed-off-by: Jayson R. King <[email protected]>
> ---
> e2fsck/pass1.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
> index 56218ae..7bf0686 100644
> --- a/e2fsck/pass1.c
> +++ b/e2fsck/pass1.c
> @@ -1593,7 +1593,7 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
> if ((pb.last_block >= 0) &&
> /* allow allocated blocks to end of PAGE_SIZE */
> (size < (__u64)pb.last_block * fs->blocksize) &&
> - (pb.last_block / blkpg * blkpg != pb.last_block ||
> + ((pb.last_block+1) & (blkpg-1) != 0 ||
> size < (__u64)(pb.last_block & ~(blkpg-1)) *fs->blocksize))
> bad_size = 3;
> else if (size > ext2_max_sizes[fs->super->s_log_block_size])
> --
> 1.5.3.3
>
>
Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.