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Commit 50c6e282 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

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: default avatarChristoph Hellwig <hch@lst.de>
Reported-by: default avatarBen Greear <greearb@candelatech.com>
Reported-by: default avatarMarco Munderloh <munderl@tnt.uni-hannover.de&gt;,>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 60942f2f

fs/posix_acl.c

+6 −0
Original line number Original line 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;

	umode_t mode = 0;

	int not_equiv = 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) {

	FOREACH_ACL_ENTRY(pa, acl, pe) {

		switch (pa->e_tag) {

		switch (pa->e_tag) {

			case ACL_USER_OBJ:

			case ACL_USER_OBJ: