| Message ID | 20221021182223.3270269-1-cmllamas@google.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [4.9] inet: fully convert sk->sk_rx_dst to RCU rules | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Guessing tree name failed - patch did not apply, async |
On Fri, Oct 21, 2022 at 06:22:23PM +0000, Carlos Llamas wrote: > From: Eric Dumazet <edumazet@google.com> > > commit 8f905c0e7354ef261360fb7535ea079b1082c105 upstream. > > syzbot reported various issues around early demux, > one being included in this changelog [1] > > sk->sk_rx_dst is using RCU protection without clearly > documenting it. > > And following sequences in tcp_v4_do_rcv()/tcp_v6_do_rcv() > are not following standard RCU rules. > > [a] dst_release(dst); > [b] sk->sk_rx_dst = NULL; > > They look wrong because a delete operation of RCU protected > pointer is supposed to clear the pointer before > the call_rcu()/synchronize_rcu() guarding actual memory freeing. > > In some cases indeed, dst could be freed before [b] is done. > > We could cheat by clearing sk_rx_dst before calling > dst_release(), but this seems the right time to stick > to standard RCU annotations and debugging facilities. > > [1] > BUG: KASAN: use-after-free in dst_check include/net/dst.h:470 [inline] > BUG: KASAN: use-after-free in tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792 > Read of size 2 at addr ffff88807f1cb73a by task syz-executor.5/9204 > > CPU: 0 PID: 9204 Comm: syz-executor.5 Not tainted 5.16.0-rc5-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 > print_address_description.constprop.0.cold+0x8d/0x320 mm/kasan/report.c:247 > __kasan_report mm/kasan/report.c:433 [inline] > kasan_report.cold+0x83/0xdf mm/kasan/report.c:450 > dst_check include/net/dst.h:470 [inline] > tcp_v4_early_demux+0x95b/0x960 net/ipv4/tcp_ipv4.c:1792 > ip_rcv_finish_core.constprop.0+0x15de/0x1e80 net/ipv4/ip_input.c:340 > ip_list_rcv_finish.constprop.0+0x1b2/0x6e0 net/ipv4/ip_input.c:583 > ip_sublist_rcv net/ipv4/ip_input.c:609 [inline] > ip_list_rcv+0x34e/0x490 net/ipv4/ip_input.c:644 > __netif_receive_skb_list_ptype net/core/dev.c:5508 [inline] > __netif_receive_skb_list_core+0x549/0x8e0 net/core/dev.c:5556 > __netif_receive_skb_list net/core/dev.c:5608 [inline] > netif_receive_skb_list_internal+0x75e/0xd80 net/core/dev.c:5699 > gro_normal_list net/core/dev.c:5853 [inline] > gro_normal_list net/core/dev.c:5849 [inline] > napi_complete_done+0x1f1/0x880 net/core/dev.c:6590 > virtqueue_napi_complete drivers/net/virtio_net.c:339 [inline] > virtnet_poll+0xca2/0x11b0 drivers/net/virtio_net.c:1557 > __napi_poll+0xaf/0x440 net/core/dev.c:7023 > napi_poll net/core/dev.c:7090 [inline] > net_rx_action+0x801/0xb40 net/core/dev.c:7177 > __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 > invoke_softirq kernel/softirq.c:432 [inline] > __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 > irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 > common_interrupt+0x52/0xc0 arch/x86/kernel/irq.c:240 > asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:629 > RIP: 0033:0x7f5e972bfd57 > Code: 39 d1 73 14 0f 1f 80 00 00 00 00 48 8b 50 f8 48 83 e8 08 48 39 ca 77 f3 48 39 c3 73 3e 48 89 13 48 8b 50 f8 48 89 38 49 8b 0e <48> 8b 3e 48 83 c3 08 48 83 c6 08 eb bc 48 39 d1 72 9e 48 39 d0 73 > RSP: 002b:00007fff8a413210 EFLAGS: 00000283 > RAX: 00007f5e97108990 RBX: 00007f5e97108338 RCX: ffffffff81d3aa45 > RDX: ffffffff81d3aa45 RSI: 00007f5e97108340 RDI: ffffffff81d3aa45 > RBP: 00007f5e97107eb8 R08: 00007f5e97108d88 R09: 0000000093c2e8d9 > R10: 0000000000000000 R11: 0000000000000000 R12: 00007f5e97107eb0 > R13: 00007f5e97108338 R14: 00007f5e97107ea8 R15: 0000000000000019 > </TASK> > > Allocated by task 13: > kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:434 [inline] > __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:467 > kasan_slab_alloc include/linux/kasan.h:259 [inline] > slab_post_alloc_hook mm/slab.h:519 [inline] > slab_alloc_node mm/slub.c:3234 [inline] > slab_alloc mm/slub.c:3242 [inline] > kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3247 > dst_alloc+0x146/0x1f0 net/core/dst.c:92 > rt_dst_alloc+0x73/0x430 net/ipv4/route.c:1613 > ip_route_input_slow+0x1817/0x3a20 net/ipv4/route.c:2340 > ip_route_input_rcu net/ipv4/route.c:2470 [inline] > ip_route_input_noref+0x116/0x2a0 net/ipv4/route.c:2415 > ip_rcv_finish_core.constprop.0+0x288/0x1e80 net/ipv4/ip_input.c:354 > ip_list_rcv_finish.constprop.0+0x1b2/0x6e0 net/ipv4/ip_input.c:583 > ip_sublist_rcv net/ipv4/ip_input.c:609 [inline] > ip_list_rcv+0x34e/0x490 net/ipv4/ip_input.c:644 > __netif_receive_skb_list_ptype net/core/dev.c:5508 [inline] > __netif_receive_skb_list_core+0x549/0x8e0 net/core/dev.c:5556 > __netif_receive_skb_list net/core/dev.c:5608 [inline] > netif_receive_skb_list_internal+0x75e/0xd80 net/core/dev.c:5699 > gro_normal_list net/core/dev.c:5853 [inline] > gro_normal_list net/core/dev.c:5849 [inline] > napi_complete_done+0x1f1/0x880 net/core/dev.c:6590 > virtqueue_napi_complete drivers/net/virtio_net.c:339 [inline] > virtnet_poll+0xca2/0x11b0 drivers/net/virtio_net.c:1557 > __napi_poll+0xaf/0x440 net/core/dev.c:7023 > napi_poll net/core/dev.c:7090 [inline] > net_rx_action+0x801/0xb40 net/core/dev.c:7177 > __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 > > Freed by task 13: > kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 > kasan_set_track+0x21/0x30 mm/kasan/common.c:46 > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 > ____kasan_slab_free mm/kasan/common.c:366 [inline] > ____kasan_slab_free mm/kasan/common.c:328 [inline] > __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 > kasan_slab_free include/linux/kasan.h:235 [inline] > slab_free_hook mm/slub.c:1723 [inline] > slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 > slab_free mm/slub.c:3513 [inline] > kmem_cache_free+0xbd/0x5d0 mm/slub.c:3530 > dst_destroy+0x2d6/0x3f0 net/core/dst.c:127 > rcu_do_batch kernel/rcu/tree.c:2506 [inline] > rcu_core+0x7ab/0x1470 kernel/rcu/tree.c:2741 > __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 > > Last potentially related work creation: > kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 > __kasan_record_aux_stack+0xf5/0x120 mm/kasan/generic.c:348 > __call_rcu kernel/rcu/tree.c:2985 [inline] > call_rcu+0xb1/0x740 kernel/rcu/tree.c:3065 > dst_release net/core/dst.c:177 [inline] > dst_release+0x79/0xe0 net/core/dst.c:167 > tcp_v4_do_rcv+0x612/0x8d0 net/ipv4/tcp_ipv4.c:1712 > sk_backlog_rcv include/net/sock.h:1030 [inline] > __release_sock+0x134/0x3b0 net/core/sock.c:2768 > release_sock+0x54/0x1b0 net/core/sock.c:3300 > tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1441 > inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819 > sock_sendmsg_nosec net/socket.c:704 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:724 > sock_write_iter+0x289/0x3c0 net/socket.c:1057 > call_write_iter include/linux/fs.h:2162 [inline] > new_sync_write+0x429/0x660 fs/read_write.c:503 > vfs_write+0x7cd/0xae0 fs/read_write.c:590 > ksys_write+0x1ee/0x250 fs/read_write.c:643 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > > The buggy address belongs to the object at ffff88807f1cb700 > which belongs to the cache ip_dst_cache of size 176 > The buggy address is located 58 bytes inside of > 176-byte region [ffff88807f1cb700, ffff88807f1cb7b0) > The buggy address belongs to the page: > page:ffffea0001fc72c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7f1cb > flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) > raw: 00fff00000000200 dead000000000100 dead000000000122 ffff8881413bb780 > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 5, ts 108466983062, free_ts 108048976062 > prep_new_page mm/page_alloc.c:2418 [inline] > get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4149 > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5369 > alloc_pages+0x1a7/0x300 mm/mempolicy.c:2191 > alloc_slab_page mm/slub.c:1793 [inline] > allocate_slab mm/slub.c:1930 [inline] > new_slab+0x32d/0x4a0 mm/slub.c:1993 > ___slab_alloc+0x918/0xfe0 mm/slub.c:3022 > __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3109 > slab_alloc_node mm/slub.c:3200 [inline] > slab_alloc mm/slub.c:3242 [inline] > kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3247 > dst_alloc+0x146/0x1f0 net/core/dst.c:92 > rt_dst_alloc+0x73/0x430 net/ipv4/route.c:1613 > __mkroute_output net/ipv4/route.c:2564 [inline] > ip_route_output_key_hash_rcu+0x921/0x2d00 net/ipv4/route.c:2791 > ip_route_output_key_hash+0x18b/0x300 net/ipv4/route.c:2619 > __ip_route_output_key include/net/route.h:126 [inline] > ip_route_output_flow+0x23/0x150 net/ipv4/route.c:2850 > ip_route_output_key include/net/route.h:142 [inline] > geneve_get_v4_rt+0x3a6/0x830 drivers/net/geneve.c:809 > geneve_xmit_skb drivers/net/geneve.c:899 [inline] > geneve_xmit+0xc4a/0x3540 drivers/net/geneve.c:1082 > __netdev_start_xmit include/linux/netdevice.h:4994 [inline] > netdev_start_xmit include/linux/netdevice.h:5008 [inline] > xmit_one net/core/dev.c:3590 [inline] > dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3606 > __dev_queue_xmit+0x299a/0x3650 net/core/dev.c:4229 > page last free stack trace: > reset_page_owner include/linux/page_owner.h:24 [inline] > free_pages_prepare mm/page_alloc.c:1338 [inline] > free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1389 > free_unref_page_prepare mm/page_alloc.c:3309 [inline] > free_unref_page+0x19/0x690 mm/page_alloc.c:3388 > qlink_free mm/kasan/quarantine.c:146 [inline] > qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165 > kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272 > __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:444 > kasan_slab_alloc include/linux/kasan.h:259 [inline] > slab_post_alloc_hook mm/slab.h:519 [inline] > slab_alloc_node mm/slub.c:3234 [inline] > kmem_cache_alloc_node+0x255/0x3f0 mm/slub.c:3270 > __alloc_skb+0x215/0x340 net/core/skbuff.c:414 > alloc_skb include/linux/skbuff.h:1126 [inline] > alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:6078 > sock_alloc_send_pskb+0x783/0x910 net/core/sock.c:2575 > mld_newpack+0x1df/0x770 net/ipv6/mcast.c:1754 > add_grhead+0x265/0x330 net/ipv6/mcast.c:1857 > add_grec+0x1053/0x14e0 net/ipv6/mcast.c:1995 > mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2242 > mld_send_initial_cr net/ipv6/mcast.c:1232 [inline] > mld_dad_work+0x1d3/0x690 net/ipv6/mcast.c:2268 > process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 > worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 > > Memory state around the buggy address: > ffff88807f1cb600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88807f1cb680: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc > >ffff88807f1cb700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88807f1cb780: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc > ffff88807f1cb800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > Fixes: 41063e9dd119 ("ipv4: Early TCP socket demux.") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Link: https://lore.kernel.org/r/20211220143330.680945-1-eric.dumazet@gmail.com > Signed-off-by: Jakub Kicinski <kuba@kernel.org> > [cmllamas: backported to 4.9; dropped irrelevant hunks in ipv6/udp.c; > added rcu_access_pointer(sk->sk_rx_dst) in tcp_prequeue().] > Signed-off-by: Carlos Llamas <cmllamas@google.com> Now queued up, thanks. greg k-h
diff --git a/include/net/sock.h b/include/net/sock.h index 78c292f15ffc..efb7c0ff30d8 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -378,7 +378,7 @@ struct sock { #ifdef CONFIG_XFRM struct xfrm_policy __rcu *sk_policy[2]; #endif - struct dst_entry *sk_rx_dst; + struct dst_entry __rcu *sk_rx_dst; struct dst_entry __rcu *sk_dst_cache; /* Note: 32bit hole on 64bit arches */ atomic_t sk_wmem_alloc; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 970a498c1166..c897d3fd457e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -156,7 +156,7 @@ void inet_sock_destruct(struct sock *sk) kfree(rcu_dereference_protected(inet->inet_opt, 1)); dst_release(rcu_dereference_check(sk->sk_dst_cache, 1)); - dst_release(sk->sk_rx_dst); + dst_release(rcu_dereference_protected(sk->sk_rx_dst, 1)); sk_refcnt_debug_dec(sk); } EXPORT_SYMBOL(inet_sock_destruct); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 6dfb964e1ad8..7a1519be7c8f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2316,8 +2316,7 @@ int tcp_disconnect(struct sock *sk, int flags) tcp_init_send_head(sk); memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); __sk_dst_reset(sk); - dst_release(sk->sk_rx_dst); - sk->sk_rx_dst = NULL; + dst_release(xchg((__force struct dst_entry **)&sk->sk_rx_dst, NULL)); tcp_saved_syn_free(tp); tp->segs_in = 0; tp->segs_out = 0; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2029e7a36cbb..9c7f716aab44 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5481,7 +5481,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, { struct tcp_sock *tp = tcp_sk(sk); - if (unlikely(!sk->sk_rx_dst)) + if (unlikely(!rcu_access_pointer(sk->sk_rx_dst))) inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb); /* * Header prediction. diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6f895694cca1..1fd1d590fa2b 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1404,15 +1404,18 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) struct sock *rsk; if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ - struct dst_entry *dst = sk->sk_rx_dst; + struct dst_entry *dst; + + dst = rcu_dereference_protected(sk->sk_rx_dst, + lockdep_sock_is_held(sk)); sock_rps_save_rxhash(sk, skb); sk_mark_napi_id(sk, skb); if (dst) { if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || !dst->ops->check(dst, 0)) { + RCU_INIT_POINTER(sk->sk_rx_dst, NULL); dst_release(dst); - sk->sk_rx_dst = NULL; } } tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len); @@ -1489,7 +1492,7 @@ void tcp_v4_early_demux(struct sk_buff *skb) skb->sk = sk; skb->destructor = sock_edemux; if (sk_fullsock(sk)) { - struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); + struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); if (dst) dst = dst_check(dst, 0); @@ -1524,7 +1527,7 @@ bool tcp_prequeue(struct sock *sk, struct sk_buff *skb) * Instead of doing full sk_rx_dst validity here, let's perform * an optimistic check. */ - if (likely(sk->sk_rx_dst)) + if (likely(rcu_access_pointer(sk->sk_rx_dst))) skb_dst_drop(skb); else skb_dst_force_safe(skb); @@ -1818,7 +1821,7 @@ void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) struct dst_entry *dst = skb_dst(skb); if (dst && dst_hold_safe(dst)) { - sk->sk_rx_dst = dst; + rcu_assign_pointer(sk->sk_rx_dst, dst); inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; } } diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 8770966a564b..888c6eb8f0a0 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1630,7 +1630,7 @@ static void udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst) struct dst_entry *old; dst_hold(dst); - old = xchg(&sk->sk_rx_dst, dst); + old = xchg((__force struct dst_entry **)&sk->sk_rx_dst, dst); dst_release(old); } @@ -1815,7 +1815,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, struct dst_entry *dst = skb_dst(skb); int ret; - if (unlikely(sk->sk_rx_dst != dst)) + if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst)) udp_sk_rx_dst_set(sk, dst); ret = udp_unicast_rcv_skb(sk, skb, uh); @@ -1974,7 +1974,7 @@ void udp_v4_early_demux(struct sk_buff *skb) skb->sk = sk; skb->destructor = sock_efree; - dst = READ_ONCE(sk->sk_rx_dst); + dst = rcu_dereference(sk->sk_rx_dst); if (dst) dst = dst_check(dst, 0); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 6b8da8d4d1cc..d8b907910cc9 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -95,7 +95,7 @@ static void inet6_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) if (dst && dst_hold_safe(dst)) { const struct rt6_info *rt = (const struct rt6_info *)dst; - sk->sk_rx_dst = dst; + rcu_assign_pointer(sk->sk_rx_dst, dst); inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt); } @@ -1285,15 +1285,18 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb) opt_skb = skb_clone(skb, sk_gfp_mask(sk, GFP_ATOMIC)); if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ - struct dst_entry *dst = sk->sk_rx_dst; + struct dst_entry *dst; + + dst = rcu_dereference_protected(sk->sk_rx_dst, + lockdep_sock_is_held(sk)); sock_rps_save_rxhash(sk, skb); sk_mark_napi_id(sk, skb); if (dst) { if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || dst->ops->check(dst, np->rx_dst_cookie) == NULL) { + RCU_INIT_POINTER(sk->sk_rx_dst, NULL); dst_release(dst); - sk->sk_rx_dst = NULL; } } @@ -1621,7 +1624,7 @@ static void tcp_v6_early_demux(struct sk_buff *skb) skb->sk = sk; skb->destructor = sock_edemux; if (sk_fullsock(sk)) { - struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); + struct dst_entry *dst = rcu_dereference(sk->sk_rx_dst); if (dst) dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);