On Wed, 2019-05-22 at 11:50 +0200, Jan Kara wrote:
> On Wed 22-05-19 16:28:46, Chengguang Xu wrote:
> > Actually maximum length of a valid entry value is not
> > ->s_blocksize because header, last entry and entry
> > name will also occupy some spaces. This patch
> > strengthens the value length check and return -ERANGE
> > when the length is larger than allowed maximum length.
> >
> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxx>
>
> Thanks for the patch! But what's the point of this change? We would return
> ERANGE instead of ENOSPC? I don't think that's serious enough to warrant
> changing existing behavior...
Hi Jan,
Instead of adding the check here, I propose to change value
size limit check in ext2_xattr_entry_valid().
size = le32_to_cpu(entry->e_value_size);
if (size > end_offs ||
le16_to_cpu(entry->e_value_offs) + size > end_offs)
Change to
size = EXT2_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
if (size >= end_offs - sizeof(struct ext2_xattr_header) - sizeof(__u32) ||
le16_to_cpu(entry->e_value_offs) + size > end_offs)
Will you agree this change?
Thanks,
Chengguang
