| Message ID | 20180518114755.56152-1-edumazet@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] sock_diag: fix use-after-free read in __sk_free | expand |
From: Eric Dumazet <edumazet@google.com> Date: Fri, 18 May 2018 04:47:55 -0700 > We must not call sock_diag_has_destroy_listeners(sk) on a socket > that has no reference on net structure. ... > Fixes: b922622ec6ef ("sock_diag: don't broadcast kernel sockets") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Craig Gallek <kraig@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> Applied and queued up for -stable, thanks Eric.
diff --git a/net/core/sock.c b/net/core/sock.c index 6444525f610cf8039516744ad26aec58485b9b8a..3b6d02854e57736254975963c45369515f369ddc 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1606,7 +1606,7 @@ static void __sk_free(struct sock *sk) if (likely(sk->sk_net_refcnt)) sock_inuse_add(sock_net(sk), -1); - if (unlikely(sock_diag_has_destroy_listeners(sk) && sk->sk_net_refcnt)) + if (unlikely(sk->sk_net_refcnt && sock_diag_has_destroy_listeners(sk))) sock_diag_broadcast_destroy(sk); else sk_destruct(sk);
We must not call sock_diag_has_destroy_listeners(sk) on a socket that has no reference on net structure. BUG: KASAN: use-after-free in sock_diag_has_destroy_listeners include/linux/sock_diag.h:75 [inline] BUG: KASAN: use-after-free in __sk_free+0x329/0x340 net/core/sock.c:1609 Read of size 8 at addr ffff88018a02e3a0 by task swapper/1/0 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.17.0-rc5+ #54 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 sock_diag_has_destroy_listeners include/linux/sock_diag.h:75 [inline] __sk_free+0x329/0x340 net/core/sock.c:1609 sk_free+0x42/0x50 net/core/sock.c:1623 sock_put include/net/sock.h:1664 [inline] reqsk_free include/net/request_sock.h:116 [inline] reqsk_put include/net/request_sock.h:124 [inline] inet_csk_reqsk_queue_drop_and_put net/ipv4/inet_connection_sock.c:672 [inline] reqsk_timer_handler+0xe27/0x10e0 net/ipv4/inet_connection_sock.c:739 call_timer_fn+0x230/0x940 kernel/time/timer.c:1326 expire_timers kernel/time/timer.c:1363 [inline] __run_timers+0x79e/0xc50 kernel/time/timer.c:1666 run_timer_softirq+0x4c/0x70 kernel/time/timer.c:1692 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285 invoke_softirq kernel/softirq.c:365 [inline] irq_exit+0x1d1/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:525 [inline] smp_apic_timer_interrupt+0x17e/0x710 arch/x86/kernel/apic/apic.c:1052 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 </IRQ> RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801d9ae7c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 1ffff1003b35cf8a RCX: 0000000000000000 RDX: 1ffffffff11a30d0 RSI: 0000000000000001 RDI: ffffffff88d18680 RBP: ffff8801d9ae7c38 R08: ffffed003b5e46c3 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801d9ae7cf0 R14: ffffffff897bef20 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0xc2/0x440 arch/x86/kernel/process.c:354 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:345 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x395/0x560 kernel/sched/idle.c:262 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:368 start_secondary+0x426/0x5b0 arch/x86/kernel/smpboot.c:269 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:242 Allocated by task 4557: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 kmem_cache_zalloc include/linux/slab.h:691 [inline] net_alloc net/core/net_namespace.c:383 [inline] copy_net_ns+0x159/0x4c0 net/core/net_namespace.c:423 create_new_namespaces+0x69d/0x8f0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:206 ksys_unshare+0x708/0xf90 kernel/fork.c:2408 __do_sys_unshare kernel/fork.c:2476 [inline] __se_sys_unshare kernel/fork.c:2474 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2474 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 69: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 net_free net/core/net_namespace.c:399 [inline] net_drop_ns.part.14+0x11a/0x130 net/core/net_namespace.c:406 net_drop_ns net/core/net_namespace.c:405 [inline] cleanup_net+0x6a1/0xb20 net/core/net_namespace.c:541 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 kthread+0x345/0x410 kernel/kthread.c:240 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 The buggy address belongs to the object at ffff88018a02c140 which belongs to the cache net_namespace of size 8832 The buggy address is located 8800 bytes inside of 8832-byte region [ffff88018a02c140, ffff88018a02e3c0) The buggy address belongs to the page: page:ffffea0006280b00 count:1 mapcount:0 mapping:ffff88018a02c140 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff88018a02c140 0000000000000000 0000000100000001 raw: ffffea00062a1320 ffffea0006268020 ffff8801d9bdde40 0000000000000000 page dumped because: kasan: bad access detected Fixes: b922622ec6ef ("sock_diag: don't broadcast kernel sockets") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Craig Gallek <kraig@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)