From 8c7138b33e5c690c308b2a7085f6313fdcb3f616 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Fri, 27 Sep 2019 16:00:31 -0700 Subject: net: Unpublish sk from sk_reuseport_cb before call_rcu The "reuse->sock[]" array is shared by multiple sockets. The going away sk must unpublish itself from "reuse->sock[]" before making call_rcu() call. However, this unpublish-action is currently done after a grace period and it may cause use-after-free. The fix is to move reuseport_detach_sock() to sk_destruct(). Due to the above reason, any socket with sk_reuseport_cb has to go through the rcu grace period before freeing it. It is a rather old bug (~3 yrs). The Fixes tag is not necessary the right commit but it is the one that introduced the SOCK_RCU_FREE logic and this fix is depending on it. Fixes: a4298e4522d6 ("net: add SOCK_RCU_FREE socket flag") Cc: Eric Dumazet Suggested-by: Eric Dumazet Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller --- net/core/sock.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 07863edbe6fc..e23ec80a67bf 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1700,8 +1700,6 @@ static void __sk_destruct(struct rcu_head *head) sk_filter_uncharge(sk, filter); RCU_INIT_POINTER(sk->sk_filter, NULL); } - if (rcu_access_pointer(sk->sk_reuseport_cb)) - reuseport_detach_sock(sk); sock_disable_timestamp(sk, SK_FLAGS_TIMESTAMP); @@ -1728,7 +1726,14 @@ static void __sk_destruct(struct rcu_head *head) void sk_destruct(struct sock *sk) { - if (sock_flag(sk, SOCK_RCU_FREE)) + bool use_call_rcu = sock_flag(sk, SOCK_RCU_FREE); + + if (rcu_access_pointer(sk->sk_reuseport_cb)) { + reuseport_detach_sock(sk); + use_call_rcu = true; + } + + if (use_call_rcu) call_rcu(&sk->sk_rcu, __sk_destruct); else __sk_destruct(&sk->sk_rcu); -- cgit From 7a512eb865aa5fcfb396c71047bc9c3b046836b3 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 4 Oct 2019 00:44:40 +0300 Subject: net: make sock_prot_memory_pressure() return "const char *" This function returns string literals which are "const char *". Signed-off-by: Alexey Dobriyan Signed-off-by: David S. Miller --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index e23ec80a67bf..fac2b4d80de5 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3497,7 +3497,7 @@ static long sock_prot_memory_allocated(struct proto *proto) return proto->memory_allocated != NULL ? proto_memory_allocated(proto) : -1L; } -static char *sock_prot_memory_pressure(struct proto *proto) +static const char *sock_prot_memory_pressure(struct proto *proto) { return proto->memory_pressure != NULL ? proto_memory_pressure(proto) ? "yes" : "no" : "NI"; -- cgit From 503978aca46124cd714703e180b9c8292ba50ba7 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2019 12:55:53 -0700 Subject: net: avoid possible false sharing in sk_leave_memory_pressure() As mentioned in https://github.com/google/ktsan/wiki/READ_ONCE-and-WRITE_ONCE#it-may-improve-performance a C compiler can legally transform : if (memory_pressure && *memory_pressure) *memory_pressure = 0; to : if (memory_pressure) *memory_pressure = 0; Fixes: 0604475119de ("tcp: add TCPMemoryPressuresChrono counter") Fixes: 180d8cd942ce ("foundations of per-cgroup memory pressure controlling.") Fixes: 3ab224be6d69 ("[NET] CORE: Introducing new memory accounting interface.") Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- net/core/sock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index fac2b4d80de5..50647a10fdb7 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2334,8 +2334,8 @@ static void sk_leave_memory_pressure(struct sock *sk) } else { unsigned long *memory_pressure = sk->sk_prot->memory_pressure; - if (memory_pressure && *memory_pressure) - *memory_pressure = 0; + if (memory_pressure && READ_ONCE(*memory_pressure)) + WRITE_ONCE(*memory_pressure, 0); } } -- cgit From 8265792bf8871acc2d00fd03883d830e2249d395 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2019 15:21:13 -0700 Subject: net: silence KCSAN warnings around sk_add_backlog() calls sk_add_backlog() callers usually read sk->sk_rcvbuf without owning the socket lock. This means sk_rcvbuf value can be changed by other cpus, and KCSAN complains. Add READ_ONCE() annotations to document the lockless nature of these reads. Note that writes over sk_rcvbuf should also use WRITE_ONCE(), but this will be done in separate patches to ease stable backports (if we decide this is relevant for stable trees). BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1: __sk_add_backlog include/net/sock.h:902 [inline] sk_add_backlog include/net/sock.h:933 [inline] tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x3ae/0xa50 net/core/dev.c:6418 read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0: tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Jakub Kicinski --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 50647a10fdb7..1cf06934da50 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -522,7 +522,7 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, rc = sk_backlog_rcv(sk, skb); mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_); - } else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) { + } else if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) { bh_unlock_sock(sk); atomic_inc(&sk->sk_drops); goto discard_and_relse; -- cgit From eac66402d1c342f07ff38f8d631ff95eb7ad3220 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2019 15:32:35 -0700 Subject: net: annotate sk->sk_rcvlowat lockless reads sock_rcvlowat() or int_sk_rcvlowat() might be called without the socket lock for example from tcp_poll(). Use READ_ONCE() to document the fact that other cpus might change sk->sk_rcvlowat under us and avoid KCSAN splats. Use WRITE_ONCE() on write sides too. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 1cf06934da50..b7c5c6ea51ba 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -974,7 +974,7 @@ set_rcvbuf: if (sock->ops->set_rcvlowat) ret = sock->ops->set_rcvlowat(sk, val); else - sk->sk_rcvlowat = val ? : 1; + WRITE_ONCE(sk->sk_rcvlowat, val ? : 1); break; case SO_RCVTIMEO_OLD: -- cgit From 70c2655849a25431f31b505a07fe0c861e5e41fb Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2019 15:41:03 -0700 Subject: net: silence KCSAN warnings about sk->sk_backlog.len reads sk->sk_backlog.len can be written by BH handlers, and read from process contexts in a lockless way. Note the write side should also use WRITE_ONCE() or a variant. We need some agreement about the best way to do this. syzbot reported : BUG: KCSAN: data-race in tcp_add_backlog / tcp_grow_window.isra.0 write to 0xffff88812665f32c of 4 bytes by interrupt on cpu 1: sk_add_backlog include/net/sock.h:934 [inline] tcp_add_backlog+0x4a0/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x3ae/0xa50 net/core/dev.c:6418 read to 0xffff88812665f32c of 4 bytes by task 7292 on cpu 0: tcp_space include/net/tcp.h:1373 [inline] tcp_grow_window.isra.0+0x6b/0x480 net/ipv4/tcp_input.c:413 tcp_event_data_recv+0x68f/0x990 net/ipv4/tcp_input.c:717 tcp_rcv_established+0xbfe/0xf50 net/ipv4/tcp_input.c:5618 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1542 sk_backlog_rcv include/net/sock.h:945 [inline] __release_sock+0x135/0x1e0 net/core/sock.c:2427 release_sock+0x61/0x160 net/core/sock.c:2943 tcp_recvmsg+0x63b/0x1a30 net/ipv4/tcp.c:2181 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7292 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Jakub Kicinski --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index b7c5c6ea51ba..2a053999df11 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3210,7 +3210,7 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem) mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc; mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued; mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc); - mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len; + mem[SK_MEMINFO_BACKLOG] = READ_ONCE(sk->sk_backlog.len); mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops); } -- cgit From ebb3b78db7bf842270a46fd4fe7cc45c78fa5ed6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 10 Oct 2019 20:17:44 -0700 Subject: tcp: annotate sk->sk_rcvbuf lockless reads For the sake of tcp_poll(), there are few places where we fetch sk->sk_rcvbuf while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Note that other transports probably need similar fixes. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/sock.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 2a053999df11..8c8f61e70141 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -831,7 +831,8 @@ set_rcvbuf: * returning the value we actually used in getsockopt * is the most desirable behavior. */ - sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF); + WRITE_ONCE(sk->sk_rcvbuf, + max_t(int, val * 2, SOCK_MIN_RCVBUF)); break; case SO_RCVBUFFORCE: @@ -3204,7 +3205,7 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem) memset(mem, 0, sizeof(*mem) * SK_MEMINFO_VARS); mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk); - mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf; + mem[SK_MEMINFO_RCVBUF] = READ_ONCE(sk->sk_rcvbuf); mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk); mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf; mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc; -- cgit From e292f05e0df73f9fcc93329663936e1ded97a988 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 10 Oct 2019 20:17:45 -0700 Subject: tcp: annotate sk->sk_sndbuf lockless reads For the sake of tcp_poll(), there are few places where we fetch sk->sk_sndbuf while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Note that other transports probably need similar fixes. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/sock.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index 8c8f61e70141..cd075bc86407 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -785,7 +785,8 @@ set_sndbuf: */ val = min_t(int, val, INT_MAX / 2); sk->sk_userlocks |= SOCK_SNDBUF_LOCK; - sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF); + WRITE_ONCE(sk->sk_sndbuf, + max_t(int, val * 2, SOCK_MIN_SNDBUF)); /* Wake up sending tasks if we upped the value. */ sk->sk_write_space(sk); break; @@ -2089,8 +2090,10 @@ EXPORT_SYMBOL(sock_i_ino); struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force, gfp_t priority) { - if (force || refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) { + if (force || + refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(sk->sk_sndbuf)) { struct sk_buff *skb = alloc_skb(size, priority); + if (skb) { skb_set_owner_w(skb, sk); return skb; @@ -2191,7 +2194,7 @@ static long sock_wait_for_wmem(struct sock *sk, long timeo) break; set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); - if (refcount_read(&sk->sk_wmem_alloc) < sk->sk_sndbuf) + if (refcount_read(&sk->sk_wmem_alloc) < READ_ONCE(sk->sk_sndbuf)) break; if (sk->sk_shutdown & SEND_SHUTDOWN) break; @@ -2226,7 +2229,7 @@ struct sk_buff *sock_alloc_send_pskb(struct sock *sk, unsigned long header_len, if (sk->sk_shutdown & SEND_SHUTDOWN) goto failure; - if (sk_wmem_alloc_get(sk) < sk->sk_sndbuf) + if (sk_wmem_alloc_get(sk) < READ_ONCE(sk->sk_sndbuf)) break; sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); @@ -2807,7 +2810,7 @@ static void sock_def_write_space(struct sock *sk) /* Do not wake up a writer until he can make "significant" * progress. --DaveM */ - if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf) { + if ((refcount_read(&sk->sk_wmem_alloc) << 1) <= READ_ONCE(sk->sk_sndbuf)) { wq = rcu_dereference(sk->sk_wq); if (skwq_has_sleeper(wq)) wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | @@ -3207,7 +3210,7 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem) mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk); mem[SK_MEMINFO_RCVBUF] = READ_ONCE(sk->sk_rcvbuf); mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk); - mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf; + mem[SK_MEMINFO_SNDBUF] = READ_ONCE(sk->sk_sndbuf); mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc; mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued; mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc); -- cgit From ab4e846a82d0ae00176de19f2db3c5c64f8eb5f2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 10 Oct 2019 20:17:46 -0700 Subject: tcp: annotate sk->sk_wmem_queued lockless reads For the sake of tcp_poll(), there are few places where we fetch sk->sk_wmem_queued while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. sk_wmem_queued_add() helper is added so that we can in the future convert to ADD_ONCE() or equivalent if/when available. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index cd075bc86407..a515392ba84b 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3212,7 +3212,7 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem) mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk); mem[SK_MEMINFO_SNDBUF] = READ_ONCE(sk->sk_sndbuf); mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc; - mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued; + mem[SK_MEMINFO_WMEM_QUEUED] = READ_ONCE(sk->sk_wmem_queued); mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc); mem[SK_MEMINFO_BACKLOG] = READ_ONCE(sk->sk_backlog.len); mem[SK_MEMINFO_DROPS] = atomic_read(&sk->sk_drops); -- cgit