Patchwork [v2] ext4: Avoid underflow of in ext4_trim_fs()

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Submitter Lukas Czerner
Date Oct. 11, 2012, 8:34 a.m.
Message ID <1349944485-13868-1-git-send-email-lczerner@redhat.com>
Download mbox | patch
Permalink /patch/190837/
State Accepted
Headers show

Comments

Lukas Czerner - Oct. 11, 2012, 8:34 a.m.
Currently if len argument in ext4_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by returning EINVAL if len is
smaller than file system block.

Also remove useless unlikely().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
---
v2: reworked, return EINVAL if len < FSB

 fs/ext4/mballoc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
Theodore Ts'o - Oct. 22, 2012, 4:37 a.m.
On Thu, Oct 11, 2012 at 10:34:45AM +0200, Lukas Czerner wrote:
> Currently if len argument in ext4_trim_fs() is smaller than one block,
> the 'end' variable underflow. Avoid that by returning EINVAL if len is
> smaller than file system block.
> 
> Also remove useless unlikely().
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>

Thanks, applied.

						- Ted
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Patch

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f8b27bf..e02ae6c 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4993,8 +4993,9 @@  int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	minlen = EXT4_NUM_B2C(EXT4_SB(sb),
 			      range->minlen >> sb->s_blocksize_bits);
 
-	if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
-	    unlikely(start >= max_blks))
+	if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+	    start >= max_blks ||
+	    range->len < sb->s_blocksize)
 		return -EINVAL;
 	if (end >= max_blks)
 		end = max_blks - 1;