linux-ext4 - Re: [PATCH] ext2: add additinal sanity check for ext2_acl_from

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Message-ID: <20180903115848.GG10027@quack2.suse.cz>
Date:   Mon, 3 Sep 2018 13:58:48 +0200
From:   Jan Kara <jack@...e.cz>
To:     Chengguang Xu <cgxu519@....com>
Cc:     jack@...e.com, linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext2: add additinal sanity check for ext2_acl_from_disk()

On Sun 02-09-18 23:31:00, Chengguang Xu wrote:
> In the case ACL_USER and ACL_GROUP we check if value has exceeded end,
> add same check in the case ACL_OTHER as well.
> 
> Signed-off-by: Chengguang Xu <cgxu519@....com>
> ---
>  fs/ext2/acl.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
> index 224c04abb2e5..3082d93f1cb1 100644
> --- a/fs/ext2/acl.c
> +++ b/fs/ext2/acl.c
> @@ -53,6 +53,8 @@ ext2_acl_from_disk(const void *value, size_t size)
>  			case ACL_OTHER:
>  				value = (char *)value +
>  					sizeof(ext2_acl_entry_short);
> +				if ((char *)value > end)
> +					goto fail;

This is not needed. This condition is already checked 10 lines above...

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR