Commit 50c6e282 authored May 04, 2014 by Christoph Hellwig Committed by Al Viro May 06, 2014

posix_acl: handle NULL ACL in posix_acl_equiv_mode



Various filesystems don't bother checking for a NULL ACL in
posix_acl_equiv_mode, and thus can dereference a NULL pointer when it
gets passed one. This usually happens from the NFS server, as the ACL tools
never pass a NULL ACL, but instead of one representing the mode bits.

Instead of adding boilerplat to all filesystems put this check into one place,
which will allow us to remove the check from other filesystems as well later
on.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Ben Greear <greearb@candelatech.com>
Reported-by: Marco Munderloh <munderl@tnt.uni-hannover.de&gt;,>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent 60942f2f

fs/posix_acl.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -246,6 +246,12 @@ posix_acl_equiv_mode(const struct posix_acl acl, umode_t mode_p)
		umode_t mode = 0;
		int not_equiv = 0;

		/*
		* A null ACL can always be presented as mode bits.
		*/
		if (!acl)
		return 0;

		FOREACH_ACL_ENTRY(pa, acl, pe) {
		switch (pa->e_tag) {
		case ACL_USER_OBJ:

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