ceph: fix use-after-free on symlink traversal

daf5cc27 · Al Viro <[email protected]> · 2019-03-26 01:38:58 +00:00

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 <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Ilya Dryomov <[email protected]>

Commit: daf5cc27eed99afdea8d96e71b89ba41f5406ef6
Parents: 187df763

Changes

1 files changed · +1 −1

File	Status	Add	Del	Content
fs/ceph/inode.c	modified	+1	−1	View file

fs/ceph/inode.c

View file

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index e334662..2d61ddd 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -524,6 +524,7 @@ static void ceph_i_callback(struct rcu_head *head)
 	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);
 }
 
@@ -566,7 +567,6 @@ void ceph_destroy_inode(struct inode *inode)
 		}
 	}
 
-	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);