nfsd: Fix ACL null pointer deref

BugLink: http://bugs.launchpad.net/bugs/1348670
Fix regression introduced in pre-3.14 kernels by cherry-picking
aa07c713ecfc0522916f3cd57ac628ea6127c0ec
(NFSD: Call ->set_acl with a NULL ACL structure if no entries).

The affected code was removed in 3.14 by commit
4ac7249ea5a0ceef9f8269f63f33cc873c3fac61
(nfsd: use get_acl and ->set_acl).
The ->set_acl methods are already able to cope with a NULL argument.

Signed-off-by: Sergio Gelato <Sergio.Gelato@astro.su.se>
[bwh: Rewrite the subject]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Moritz Mühlenhoff <muehlenhoff@univention.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 05b0fb302717b696d695a7bbe863d22ce6757db3..635335702dc642bd60044c4c6392d718a51dfa3e 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -508,6 +508,9 @@ set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
        char *buf = NULL;
        int error = 0;
 
+       if (!pacl)
+               return vfs_setxattr(dentry, key, NULL, 0, 0);
+
        buflen = posix_acl_xattr_size(pacl->a_count);
        buf = kmalloc(buflen, GFP_KERNEL);
        error = -ENOMEM;