From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 26 Mar 2019 01:38:58 +0000
Subject: ceph: fix use-after-free on symlink traversal
Git-commit: daf5cc27eed99afdea8d96e71b89ba41f5406ef6
Patch-mainline: v5.1-rc3
References: bsc#1134459

free the symlink body after the same RCU delay we have for freeing the
struct inode itself, so that traversal during RCU pathwalk wouldn't step
into freed memory.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/inode.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -523,6 +523,7 @@ static void ceph_i_callback(struct rcu_h
 	struct inode *inode = container_of(head, struct inode, i_rcu);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 
+	kfree(ci->i_symlink);
 	kmem_cache_free(ceph_inode_cachep, ci);
 }
 
@@ -565,7 +566,6 @@ void ceph_destroy_inode(struct inode *in
 		}
 	}
 
-	kfree(ci->i_symlink);
 	while ((n = rb_first(&ci->i_fragtree)) != NULL) {
 		frag = rb_entry(n, struct ceph_inode_frag, node);
 		rb_erase(n, &ci->i_fragtree);