6.12-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Link: https://patch.msgid.link/20250122180244.1861468-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/rose/rose_timer.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
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); }