On Tue, 2012-07-31 at 22:04 +0100, Sachin Prabhu wrote:
> On Mon, 2012-07-30 at 21:54 +0000, Myklebust, Trond wrote:
> > On Tue, 2012-07-24 at 12:36 +0100, Sachin Prabhu wrote:
> > > This fixes a bug introduced by commit
> > > 5a00689930ab975fdd1b37b034475017e460cf2a
> > >
> > > Bruce Fields pointed out that the changes introduced by the patch will
> > > cause the array npages to overflow if a size requested is >=
> > > XATTR_SIZE_MAX.
> > >
> > > The patch also fixes the check for the length of the ACL returned. The
> > > flag ACL_LEN_REQUEST has been renamed to NFS4_ACL_LEN_ONLY and apart
> > > from indicating that the user is just interested in the ACL length when
> > > making a request, it is also used to indicate if the xdr pages buffer
> > > returned in response holds the complete ACL or just the length.
> > >
> > > Signed-off-by: Sachin Prabhu <sprabhu@xxxxxxxxxx>
> >
> > If this fix is going into stable, then the patch needs to be split up.
> > The rename of ACL_LEN_REQUEST to NFS4_ACL_LEN_ONLY is a cleanup and
> > should not be propagated to stable...
>
> Trond the change there was required to fix a mistake in the if
> condition.
>
> static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf,
> size_t buflen)
> {
> ..
> acl_len = res.acl_len - res.acl_data_offset;
> if (acl_len > args.acl_len)
> ..
> }
>
> At this point,
> res.acl_data_offset = size of bitmap array + size of length attribute
> res.acl_length = res.acl_data_offset + ACL length
> These 2 variables are set in decode_getacl(). The right check here would
> have been to compare res.acl_len and args.acl_len.
>
> Instead of simply replacing the if condition, I decided to clean up the
> code to use NFS4_ACL_LEN_ONLY on advice of Bruce to make the code easier
> to understand.
>
> So both parts of this patch are actually bug fixes. If you still think
> that they should be separated, I am happy to do that.
I accept that we need both fixes. The part that I want to separate out
is _only_ the rename of ACL_LEN_REQUEST, since that is not a fix.
--
Trond Myklebust
Linux NFS client maintainer
NetApp
Trond.Myklebust@xxxxxxxxxx
www.netapp.com
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