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Revert "capabitlies: ns_capable can use the cap helpers rather than l…

…sm call"

This reverts commit d2a7009.

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>
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1 parent c2bc3a3 commit 951880e634a79884236a575b896abf55c39ae0bf @torvalds torvalds committed Jan 17, 2012
Showing with 1 addition and 1 deletion.
  1. +1 −1 kernel/capability.c
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2 kernel/capability.c
@@ -384,7 +384,7 @@ bool ns_capable(struct user_namespace *ns, int cap)
BUG();
}
- if (has_ns_capability(current, ns, cap)) {
+ if (security_capable(current_cred(), ns, cap) == 0) {
current->flags |= PF_SUPERPRIV;
return true;
}

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