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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2018-12-29 13:56:36 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-30 14:07:54 -0800 |
| commit | c433570458e49bccea5c551df628d058b3526289 (patch) | |
| tree | 05427f71af7a74fb15b0eb08f138cc6004a225c1 /net/ax25/af_ax25.c | |
| parent | 7f334a7e1ae113212e39aafba51352ea9ab8c9f9 (diff) | |
| download | linux-c433570458e49bccea5c551df628d058b3526289.tar.bz2 | |
ax25: fix a use-after-free in ax25_fillin_cb()
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>
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 c603d33d5410..5d01edf8d819 100644 --- a/net/ax25/af_ax25.c +++ b/net/ax25/af_ax25.c @@ -653,15 +653,22 @@ 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: |