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nfsd4: don't create unnecessary mask acl

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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>
This commit is contained in:
J. Bruce Fields 2014-04-02 14:59:08 -04:00
parent 082f31a216
commit 06f9cc12ca
1 changed files with 9 additions and 4 deletions
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13
fs/nfsd/nfs4acl.c
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@ -542,7 +542,10 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
* 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 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)
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;