[PATCH] ext3: Avoid underflow of in ext3_trim_fs()

[PATCH] ext3: Avoid underflow of in ext3_trim_fs()

[Lukas Czerner]

Currently if len argument in ext3_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>
---
 fs/ext3/balloc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index 7320a66..22548f5 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -2101,8 +2101,9 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range)
 	end = start + (range->len >> sb->s_blocksize_bits) - 1;
 	minlen = range->minlen >> sb->s_blocksize_bits;
 
-	if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)) ||
-	    unlikely(start >= max_blks))
+	if (minlen > EXT3_BLOCKS_PER_GROUP(sb) ||
+	    start >= max_blks ||
+	    range->len < sb->s_blocksize)
 		return -EINVAL;
 	if (end >= max_blks)
 		end = max_blks - 1;
-- 
1.7.7.6

Re: [PATCH] ext3: Avoid underflow of in ext3_trim_fs()

[Jan Kara]

On Thu 11-10-12 12:28:38, Lukas Czerner wrote:
> Currently if len argument in ext3_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().
  Thanks. I've added the patch to my tree.

								Honza

> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
> ---
>  fs/ext3/balloc.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
> index 7320a66..22548f5 100644
> --- a/fs/ext3/balloc.c
> +++ b/fs/ext3/balloc.c
> @@ -2101,8 +2101,9 @@ int ext3_trim_fs(struct super_block *sb, struct fstrim_range *range)
>  	end = start + (range->len >> sb->s_blocksize_bits) - 1;
>  	minlen = range->minlen >> sb->s_blocksize_bits;
>  
> -	if (unlikely(minlen > EXT3_BLOCKS_PER_GROUP(sb)) ||
> -	    unlikely(start >= max_blks))
> +	if (minlen > EXT3_BLOCKS_PER_GROUP(sb) ||
> +	    start >= max_blks ||
> +	    range->len < sb->s_blocksize)
>  		return -EINVAL;
>  	if (end >= max_blks)
>  		end = max_blks - 1;
> -- 
> 1.7.7.6
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR