This is a note to let you know that I've just added the patch titled
net: rose: fix timer races against user threads
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-rose-fix-timer-races-against-user-threads.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a8893cfbe73fda6d9eceb84d651818ef14df8e8a
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Jan 22 18:02:44 2025 +0000
net: rose: fix timer races against user threads
[ Upstream commit 5de7665e0a0746b5ad7943554b34db8f8614a196 ]
Rose timers only acquire the socket spinlock, without
checking if the socket is owned by one user thread.
Add a check and rearm the timers if needed.
BUG: KASAN: slab-use-after-free in rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174
Read of size 2 at addr ffff88802f09b82a by task swapper/0/0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
rose_timer_expiry+0x31d/0x360 net/rose/rose_timer.c:174
call_timer_fn+0x187/0x650 kernel/time/timer.c:1793
expire_timers kernel/time/timer.c:1844 [inline]
__run_timers kernel/time/timer.c:2418 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2430
run_timer_base kernel/time/timer.c:2439 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2449
handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
__do_softirq kernel/softirq.c:595 [inline]
invoke_softirq kernel/softirq.c:435 [inline]
__irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
</IRQ>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://patch.msgid.link/20250122180244.1861468-1-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/rose/rose_timer.c b/net/rose/rose_timer.c
index f06ddbed3fed6..1525773e94aa1 100644
--- a/net/rose/rose_timer.c
+++ b/net/rose/rose_timer.c
@@ -122,6 +122,10 @@ static void rose_heartbeat_expiry(struct timer_list *t)
struct rose_sock *rose = rose_sk(sk);
bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ sk_reset_timer(sk, &sk->sk_timer, jiffies + HZ/20);
+ goto out;
+ }
switch (rose->state) {
case ROSE_STATE_0:
/* Magic here: If we listen() and a new link dies before it
@@ -152,6 +156,7 @@ static void rose_heartbeat_expiry(struct timer_list *t)
}
rose_start_heartbeat(sk);
+out:
bh_unlock_sock(sk);
sock_put(sk);
}
@@ -162,6 +167,10 @@ static void rose_timer_expiry(struct timer_list *t)
struct sock *sk = &rose->sock;
bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ sk_reset_timer(sk, &rose->timer, jiffies + HZ/20);
+ goto out;
+ }
switch (rose->state) {
case ROSE_STATE_1: /* T1 */
case ROSE_STATE_4: /* T2 */
@@ -182,6 +191,7 @@ static void rose_timer_expiry(struct timer_list *t)
}
break;
}
+out:
bh_unlock_sock(sk);
sock_put(sk);
}
@@ -192,6 +202,10 @@ static void rose_idletimer_expiry(struct timer_list *t)
struct sock *sk = &rose->sock;
bh_lock_sock(sk);
+ if (sock_owned_by_user(sk)) {
+ sk_reset_timer(sk, &rose->idletimer, jiffies + HZ/20);
+ goto out;
+ }
rose_clear_queues(sk);
rose_write_internal(sk, ROSE_CLEAR_REQUEST);
@@ -207,6 +221,7 @@ static void rose_idletimer_expiry(struct timer_list *t)
sk->sk_state_change(sk);
sock_set_flag(sk, SOCK_DEAD);
}
+out:
bh_unlock_sock(sk);
sock_put(sk);
}
