Revert "capabitlies: ns_capable can use the cap helpers rather than lsm call"
authorLinus Torvalds <torvalds@linux-foundation.org>
Tue, 17 Jan 2012 18:19:41 +0000 (10:19 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 17 Jan 2012 18:19:41 +0000 (10:19 -0800)
commit951880e634a79884236a575b896abf55c39ae0bf
treeb23ec5a95cd72083227ed5b7396e2f8799f4a58c
parentc2bc3a316a7281f67e36b34dac2802cbe36a9128
Revert "capabitlies: ns_capable can use the cap helpers rather than lsm call"

This reverts commit d2a7009f0bb03fa22ad08dd25472efa0568126b9.

J. R. Okajima explains:

 "After this commit, I am afraid access(2) on NFS may not work
  correctly.  The scenario based upon my guess.
   - access(2) overrides the credentials.
   - calls inode_permission() -- ... -- generic_permission() --
      ns_capable().
   - while the old ns_capable() calls security_capable(current_cred()),
     the new ns_capable() calls has_ns_capability(current) --
     security_capable(__task_cred(t)).

  current_cred() returns current->cred which is effective (overridden)
  credentials, but __task_cred(current) returns current->real_cred (the
  NFSD's credential).  And the overridden credentials by access(2) lost."

Requested-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/capability.c