diff options
author | Schspa Shi <schspa@gmail.com> | 2022-11-16 14:45:11 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2022-11-18 15:14:55 +0300 |
commit | ab0377803dafc58f1e22296708c1c28e309414d6 (patch) | |
tree | 5601c8970cfa5eae40892611a133acb88a5655f9 /net/802 | |
parent | 8cf4f8c7d99addb6c2c2273fac7c20ca7c50db45 (diff) | |
download | linux-ab0377803dafc58f1e22296708c1c28e309414d6.tar.xz |
mrp: introduce active flags to prevent UAF when applicant uninit
The caller of del_timer_sync must prevent restarting of the timer, If
we have no this synchronization, there is a small probability that the
cancellation will not be successful.
And syzbot report the fellowing crash:
==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:929 [inline]
BUG: KASAN: use-after-free in enqueue_timer+0x18/0xa4 kernel/time/timer.c:605
Write at addr f9ff000024df6058 by task syz-fuzzer/2256
Pointer tag: [f9], memory tag: [fe]
CPU: 1 PID: 2256 Comm: syz-fuzzer Not tainted 6.1.0-rc5-syzkaller-00008-
ge01d50cbd6ee #0
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace.part.0+0xe0/0xf0 arch/arm64/kernel/stacktrace.c:156
dump_backtrace arch/arm64/kernel/stacktrace.c:162 [inline]
show_stack+0x18/0x40 arch/arm64/kernel/stacktrace.c:163
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x68/0x84 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:284 [inline]
print_report+0x1a8/0x4a0 mm/kasan/report.c:395
kasan_report+0x94/0xb4 mm/kasan/report.c:495
__do_kernel_fault+0x164/0x1e0 arch/arm64/mm/fault.c:320
do_bad_area arch/arm64/mm/fault.c:473 [inline]
do_tag_check_fault+0x78/0x8c arch/arm64/mm/fault.c:749
do_mem_abort+0x44/0x94 arch/arm64/mm/fault.c:825
el1_abort+0x40/0x60 arch/arm64/kernel/entry-common.c:367
el1h_64_sync_handler+0xd8/0xe4 arch/arm64/kernel/entry-common.c:427
el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:576
hlist_add_head include/linux/list.h:929 [inline]
enqueue_timer+0x18/0xa4 kernel/time/timer.c:605
mod_timer+0x14/0x20 kernel/time/timer.c:1161
mrp_periodic_timer_arm net/802/mrp.c:614 [inline]
mrp_periodic_timer+0xa0/0xc0 net/802/mrp.c:627
call_timer_fn.constprop.0+0x24/0x80 kernel/time/timer.c:1474
expire_timers+0x98/0xc4 kernel/time/timer.c:1519
To fix it, we can introduce a new active flags to make sure the timer will
not restart.
Reported-by: syzbot+6fd64001c20aa99e34a4@syzkaller.appspotmail.com
Signed-off-by: Schspa Shi <schspa@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/802')
-rw-r--r-- | net/802/mrp.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/net/802/mrp.c b/net/802/mrp.c index 155f74d8b14f..6c927d4b35f0 100644 --- a/net/802/mrp.c +++ b/net/802/mrp.c @@ -606,7 +606,10 @@ static void mrp_join_timer(struct timer_list *t) spin_unlock(&app->lock); mrp_queue_xmit(app); - mrp_join_timer_arm(app); + spin_lock(&app->lock); + if (likely(app->active)) + mrp_join_timer_arm(app); + spin_unlock(&app->lock); } static void mrp_periodic_timer_arm(struct mrp_applicant *app) @@ -620,11 +623,12 @@ static void mrp_periodic_timer(struct timer_list *t) struct mrp_applicant *app = from_timer(app, t, periodic_timer); spin_lock(&app->lock); - mrp_mad_event(app, MRP_EVENT_PERIODIC); - mrp_pdu_queue(app); + if (likely(app->active)) { + mrp_mad_event(app, MRP_EVENT_PERIODIC); + mrp_pdu_queue(app); + mrp_periodic_timer_arm(app); + } spin_unlock(&app->lock); - - mrp_periodic_timer_arm(app); } static int mrp_pdu_parse_end_mark(struct sk_buff *skb, int *offset) @@ -872,6 +876,7 @@ int mrp_init_applicant(struct net_device *dev, struct mrp_application *appl) app->dev = dev; app->app = appl; app->mad = RB_ROOT; + app->active = true; spin_lock_init(&app->lock); skb_queue_head_init(&app->queue); rcu_assign_pointer(dev->mrp_port->applicants[appl->type], app); @@ -900,6 +905,9 @@ void mrp_uninit_applicant(struct net_device *dev, struct mrp_application *appl) RCU_INIT_POINTER(port->applicants[appl->type], NULL); + spin_lock_bh(&app->lock); + app->active = false; + spin_unlock_bh(&app->lock); /* Delete timer and generate a final TX event to flush out * all pending messages before the applicant is gone. */ |