vfs: Check attribute names in posix acl xattr handers

The get and set operations of the POSIX ACL xattr handlers failed to check
the attribute names, so all names with "system.posix_acl_access" or
"system.posix_acl_default" as a prefix were accepted.  Reject invalid names
from now on.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 4fb17ded7d47..b1a66e844d35 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -768,6 +768,8 @@ posix_acl_xattr_get(struct dentry *dentry, const char *name,
         struct posix_acl *acl;
         int error;
 
+        if (strcmp(name, "") != 0)
+                return -EINVAL;
         if (!IS_POSIXACL(d_backing_inode(dentry)))
                 return -EOPNOTSUPP;
         if (d_is_symlink(dentry))
@@ -793,6 +795,8 @@ posix_acl_xattr_set(struct dentry *dentry, const char *name,
         struct posix_acl *acl = NULL;
         int ret;
 
+        if (strcmp(name, "") != 0)
+                return -EINVAL;
         if (!IS_POSIXACL(inode))
                 return -EOPNOTSUPP;
         if (!inode->i_op->set_acl)