Messages in this thread | | | From | Jeff Layton <> | Date | Tue, 26 Mar 2019 06:41:25 -0400 | Subject | Re: ceph: fix use-after-free on symlink traversal |
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On Mon, Mar 25, 2019 at 9:39 PM Al Viro <viro@zeniv.linux.org.uk> wrote: > > 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> > --- > diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c > index e3346628efe2..2d61ddda9bf5 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);
Reviewed-by: Jeff Layton <jlayton@kernel.org>
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