From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: syzbot <syzbot+7a8ba368b47fdefca61e@syzkaller.appspotmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: jffs2: fix use-after-free on symlink traversal
Date: Tue, 26 Mar 2019 01:39:50 +0000 [thread overview]
Message-ID: <20190326013950.GV2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190326013858.GU2217@ZenIV.linux.org.uk>
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/jffs2/readinode.c b/fs/jffs2/readinode.c
index 389ea53ea487..bccfc40b3a74 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -1414,11 +1414,6 @@ 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 bb6ae387469f..05d892c79339 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)
next prev parent reply other threads:[~2019-03-26 1:39 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 17:40 KASAN: use-after-free Read in path_lookupat syzbot
2019-03-25 0:44 ` syzbot
2019-03-25 1:25 ` Linus Torvalds
2019-03-25 1:23 ` Linus Torvalds
2019-03-25 4:57 ` Al Viro
2019-03-25 9:15 ` Daniel Borkmann
2019-03-25 11:11 ` Al Viro
2019-03-25 11:17 ` Al Viro
2019-03-25 11:21 ` Daniel Borkmann
2019-03-25 18:36 ` Linus Torvalds
2019-03-25 19:18 ` Linus Torvalds
2019-03-25 21:14 ` Al Viro
2019-03-25 21:45 ` Linus Torvalds
2019-03-25 22:04 ` Daniel Borkmann
2019-03-25 22:13 ` Linus Torvalds
2019-03-25 22:41 ` Daniel Borkmann
2019-03-25 22:49 ` Al Viro
2019-03-25 23:37 ` Al Viro
2019-03-25 23:44 ` Alexei Starovoitov
2019-03-26 0:21 ` Al Viro
2019-03-26 1:38 ` ceph: fix use-after-free on symlink traversal Al Viro
2019-03-26 1:39 ` Al Viro [this message]
2019-03-26 1:40 ` ubifs: " Al Viro
2019-03-26 1:43 ` debugfs: " Al Viro
2019-03-26 10:41 ` ceph: " Jeff Layton
2019-03-26 11:38 ` Ilya Dryomov
2019-03-26 1:45 ` KASAN: use-after-free Read in path_lookupat Al Viro
2019-04-10 18:11 ` Al Viro
2019-04-10 19:44 ` Linus Torvalds
2019-03-25 19:43 ` Al Viro
2019-03-25 22:48 ` Dave Chinner
2019-03-25 23:02 ` Al Viro
[not found] ` <CAGe7X7mb=gK7zhSwmT_6mmmkcbjhZAOb=wj31BdUcHkNUPsm2Q@mail.gmail.com>
2019-03-26 4:15 ` Al Viro
2019-03-27 16:58 ` Jan Kara
2019-03-27 18:59 ` Al Viro
2019-03-28 9:00 ` Jan Kara
2019-03-27 17:22 ` Jan Kara
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