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>

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 11e1888e20e5a125c5a12fe4d75e66819e30c1cb..e2e7914aff3b4f4cba031f6cac35ae847244e602 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;