linux-ext4 - Re: [PATCH] ext3: Avoid underflow of in ext3_trim

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Date:	Thu, 11 Oct 2012 13:04:49 +0200
From:	Jan Kara <jack@...e.cz>
To:	Lukas Czerner <lczerner@...hat.com>
Cc:	linux-ext4@...r.kernel.org, jack@...e.cz
Subject: Re: [PATCH] ext3: Avoid underflow of in ext3_trim_fs()

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@...hat.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
> 
> --
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-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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