diff options
author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-12-29 13:56:36 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-01-13 10:05:27 +0100 |
commit | c0e93a6d36135d5082cb3af8352f5b69c9f58d6e (patch) | |
tree | c38b9461ee9f4a58f44cf2cd2c228db4d5ea6403 /net/ax25/af_ax25.c | |
parent | 74d6170eb63f458a0ddfe75f90214d7ff03c1cc2 (diff) |
ax25: fix a use-after-free in ax25_fillin_cb()
[ Upstream commit c433570458e49bccea5c551df628d058b3526289 ]
There are multiple issues here:
1. After freeing dev->ax25_ptr, we need to set it to NULL otherwise
we may use a dangling pointer.
2. There is a race between ax25_setsockopt() and device notifier as
reported by syzbot. Close it by holding RTNL lock.
3. We need to test if dev->ax25_ptr is NULL before using it.
Reported-and-tested-by: syzbot+ae6bb869cbed29b29040@syzkaller.appspotmail.com
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ax25/af_ax25.c')
-rw-r--r-- | net/ax25/af_ax25.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c index 2fdebabbfacd..2772f6a13fcb 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -654,15 +654,22 @@ static int ax25_setsockopt(struct socket *sock, int level, int optname, break; } - dev = dev_get_by_name(&init_net, devname); + rtnl_lock(); + dev = __dev_get_by_name(&init_net, devname); if (!dev) { + rtnl_unlock(); res = -ENODEV; break; } ax25->ax25_dev = ax25_dev_ax25dev(dev); + if (!ax25->ax25_dev) { + rtnl_unlock(); + res = -ENODEV; + break; + } ax25_fillin_cb(ax25, ax25->ax25_dev); - dev_put(dev); + rtnl_unlock(); break; default: |