From: Al Viro Date: Tue, 26 Mar 2019 01:39:50 +0000 (+0000) Subject: jffs2: fix use-after-free on symlink traversal X-Git-Tag: v3.18.140~46 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44a476cf0bc2209c3c91ad9815cccc4a5ea2ca72;p=thirdparty%2Fkernel%2Fstable.git jffs2: fix use-after-free on symlink traversal [ Upstream commit 4fdcfab5b5537c21891e22e65996d4d0dd8ab4ca ] 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 Signed-off-by: Sasha Levin --- diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c index 386303dca382e..4f390be717234 100644 --- a/fs/jffs2/readinode.c +++ b/fs/jffs2/readinode.c @@ -1429,11 +1429,6 @@ void jffs2_do_clear_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f) jffs2_kill_fragtree(&f->fragtree, deleted?c:NULL); - if (f->target) { - kfree(f->target); - f->target = NULL; - } - fds = f->dents; while(fds) { fd = fds; diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c index 0bbc31d108570..d1be5991bb662 100644 --- a/fs/jffs2/super.c +++ b/fs/jffs2/super.c @@ -47,7 +47,10 @@ static struct inode *jffs2_alloc_inode(struct super_block *sb) static void jffs2_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); - kmem_cache_free(jffs2_inode_cachep, JFFS2_INODE_INFO(inode)); + struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); + + kfree(f->target); + kmem_cache_free(jffs2_inode_cachep, f); } static void jffs2_destroy_inode(struct inode *inode)