nfsd4: don't create unnecessary mask acl
Any setattr of the ACL attribute, even if it sets just the basic 3-ACE
ACL exactly as it was returned from a file with only mode bits, creates
a mask entry, and it is only the mask, not group, entry that is changed
by subsequent modifications of the mode bits.
So, for example, it's surprising that GROUP@ is left without read or
write permissions after a chmod 0666:
touch test
chmod 0600 test
nfs4_getfacl test
A::OWNER@:rwatTcCy
A::GROUP@:tcy
A::EVERYONE@:tcy
nfs4_getfacl test | nfs4_setfacl -S - test #
chmod 0666 test
nfs4_getfacl test
A::OWNER@:rwatTcCy
A::GROUP@:tcy
D::GROUP@:rwa
A::EVERYONE@:rwatcy
So, let's stop creating the unnecessary mask ACL.
A mask will still be created on non-trivial ACLs (ACLs with actual named
user and group ACEs), so the odd posix-acl behavior of chmod modifying
only the mask will still be left in that case; but that's consistent
with local behavior.
Reported-by: Soumya Koduri <skoduri@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index d190e33..6f3f392 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -542,7 +542,10 @@
* up setting a 3-element effective posix ACL with all
* permissions zero.
*/
- nace = 4 + state->users->n + state->groups->n;
+ if (!state->users->n && !state->groups->n)
+ nace = 3;
+ else /* Note we also include a MASK ACE in this case: */
+ nace = 4 + state->users->n + state->groups->n;
pacl = posix_acl_alloc(nace, GFP_KERNEL);
if (!pacl)
return ERR_PTR(-ENOMEM);
@@ -586,9 +589,11 @@
add_to_mask(state, &state->groups->aces[i].perms);
}
- pace++;
- pace->e_tag = ACL_MASK;
- low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
+ if (!state->users->n && !state->groups->n) {
+ pace++;
+ pace->e_tag = ACL_MASK;
+ low_mode_from_nfs4(state->mask.allow, &pace->e_perm, flags);
+ }
pace++;
pace->e_tag = ACL_OTHER;