forked from Minki/linux
82e31755e5
There are race conditions that may lead to UAF bugs in
ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(),
ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we call
ax25_release() to deallocate ax25_dev.
One of the UAF bugs caused by ax25_release() is shown below:
(Thread 1) | (Thread 2)
ax25_dev_device_up() //(1) |
... | ax25_kill_by_device()
ax25_bind() //(2) |
ax25_connect() | ...
ax25_std_establish_data_link() |
ax25_start_t1timer() | ax25_dev_device_down() //(3)
mod_timer(&ax25->t1timer,..) |
| ax25_release()
(wait a time) | ...
| ax25_dev_put(ax25_dev) //(4)FREE
ax25_t1timer_expiry() |
ax25->ax25_dev->values[..] //USE| ...
... |
We increase the refcount of ax25_dev in position (1) and (2), and
decrease the refcount of ax25_dev in position (3) and (4).
The ax25_dev will be freed in position (4) and be used in
ax25_t1timer_expiry().
The fail log is shown below:
==============================================================
[ 106.116942] BUG: KASAN: use-after-free in ax25_t1timer_expiry+0x1c/0x60
[ 106.116942] Read of size 8 at addr ffff88800bda9028 by task swapper/0/0
[ 106.116942] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-06123-g0905eec574
[ 106.116942] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-14
[ 106.116942] Call Trace:
...
[ 106.116942] ax25_t1timer_expiry+0x1c/0x60
[ 106.116942] call_timer_fn+0x122/0x3d0
[ 106.116942] __run_timers.part.0+0x3f6/0x520
[ 106.116942] run_timer_softirq+0x4f/0xb0
[ 106.116942] __do_softirq+0x1c2/0x651
...
This patch adds del_timer_sync() in ax25_release(), which could ensure
that all timers stop before we deallocate ax25_dev.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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| .. | ||
| 6lowpan | ||
| 9p | ||
| 802 | ||
| 8021q | ||
| appletalk | ||
| atm | ||
| ax25 | ||
| batman-adv | ||
| bluetooth | ||
| bpf | ||
| bpfilter | ||
| bridge | ||
| caif | ||
| can | ||
| ceph | ||
| core | ||
| dcb | ||
| dccp | ||
| decnet | ||
| dns_resolver | ||
| dsa | ||
| ethernet | ||
| ethtool | ||
| hsr | ||
| ieee802154 | ||
| ife | ||
| ipv4 | ||
| ipv6 | ||
| iucv | ||
| kcm | ||
| key | ||
| l2tp | ||
| l3mdev | ||
| lapb | ||
| llc | ||
| mac80211 | ||
| mac802154 | ||
| mctp | ||
| mpls | ||
| mptcp | ||
| ncsi | ||
| netfilter | ||
| netlabel | ||
| netlink | ||
| netrom | ||
| nfc | ||
| nsh | ||
| openvswitch | ||
| packet | ||
| phonet | ||
| psample | ||
| qrtr | ||
| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| smc | ||
| strparser | ||
| sunrpc | ||
| switchdev | ||
| tipc | ||
| tls | ||
| unix | ||
| vmw_vsock | ||
| wireless | ||
| x25 | ||
| xdp | ||
| xfrm | ||
| compat.c | ||
| devres.c | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| socket.c | ||
| sysctl_net.c | ||