Re: [PATCH] f2fs: add additional sanity check in f2fs_acl_from_disk()

[Chao Yu <chao@kernel.org>]

Hi Chengguang,

On 2018/8/30 21:33, Chengguang Xu wrote:
> Add additinal sanity check for irregular case(e.g. corruption).
> If size of extended attribution is smaller than size of acl header,
> then return -EINVAL.
> 
> Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
> ---
>  fs/f2fs/acl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
> index 111824199a88..79e9ea773070 100644
> --- a/fs/f2fs/acl.c
> +++ b/fs/f2fs/acl.c
> @@ -53,6 +53,9 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
>  	struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
>  	const char *end = value + size;
>  
> +	if (size < sizeof(f2fs_acl_header))
> +		return ERR_PTR(-EINVAL);

I guess below codes have checked that already?

	count = f2fs_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);

Thanks,

> +
>  	if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
>  		return ERR_PTR(-EINVAL);
>  
> 

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