kernel/linux.git/include/net/sock.h, branch v4.9.277

inet: annotate date races around sk->sk_txhash

2021-06-30T12:49:20+00:00

[ Upstream commit b71eaed8c04f72a919a9c44e83e4ee254e69e7f3 ] UDP sendmsg() path can be lockless, it is possible for another thread to re-connect an change sk->sk_txhash under us. There is no serious impact, but we can use READ_ONCE()/WRITE_ONCE() pair to document the race. BUG: KCSAN: data-race in __ip4_datagram_connect / skb_set_owner_w write to 0xffff88813397920c of 4 bytes by task 30997 on cpu 1: sk_set_txhash include/net/sock.h:1937 [inline] __ip4_datagram_connect+0x69e/0x710 net/ipv4/datagram.c:75 __ip6_datagram_connect+0x551/0x840 net/ipv6/datagram.c:189 ip6_datagram_connect+0x2a/0x40 net/ipv6/datagram.c:272 inet_dgram_connect+0xfd/0x180 net/ipv4/af_inet.c:580 __sys_connect_file net/socket.c:1837 [inline] __sys_connect+0x245/0x280 net/socket.c:1854 __do_sys_connect net/socket.c:1864 [inline] __se_sys_connect net/socket.c:1861 [inline] __x64_sys_connect+0x3d/0x50 net/socket.c:1861 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813397920c of 4 bytes by task 31039 on cpu 0: skb_set_hash_from_sk include/net/sock.h:2211 [inline] skb_set_owner_w+0x118/0x220 net/core/sock.c:2101 sock_alloc_send_pskb+0x452/0x4e0 net/core/sock.c:2359 sock_alloc_send_skb+0x2d/0x40 net/core/sock.c:2373 __ip6_append_data+0x1743/0x21a0 net/ipv6/ip6_output.c:1621 ip6_make_skb+0x258/0x420 net/ipv6/ip6_output.c:1983 udpv6_sendmsg+0x160a/0x16b0 net/ipv6/udp.c:1527 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg net/socket.c:674 [inline] ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350 ___sys_sendmsg net/socket.c:2404 [inline] __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490 __do_sys_sendmmsg net/socket.c:2519 [inline] __se_sys_sendmmsg net/socket.c:2516 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0xbca3c43d -> 0xfdb309e0 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 31039 Comm: syz-executor.2 Not tainted 5.13.0-rc3-syzkaller #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: David S. Miller Signed-off-by: Sasha Levin

net/compat: Add missing sock updates for SCM_RIGHTS

2020-08-21T09:02:08+00:00

commit d9539752d23283db4692384a634034f451261e29 upstream. Add missed sock updates to compat path via a new helper, which will be used more in coming patches. (The net/core/scm.c code is left as-is here to assist with -stable backports for the compat path.) Cc: Christoph Hellwig Cc: Sargun Dhillon Cc: Jakub Kicinski Cc: stable@vger.kernel.org Fixes: 48a87cc26c13 ("net: netprio: fd passed in SCM_RIGHTS datagram not set correctly") Fixes: d84295067fc7 ("net: net_cls: fd passed in SCM_RIGHTS datagram not set correctly") Acked-by: Christian Brauner Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman

net: Do not clear the sock TX queue in sk_set_socket()

2020-06-30T19:38:39+00:00

[ Upstream commit 41b14fb8724d5a4b382a63cb4a1a61880347ccb8 ] Clearing the sock TX queue in sk_set_socket() might cause unexpected out-of-order transmit when called from sock_orphan(), as outstanding packets can pick a different TX queue and bypass the ones already queued. This is undesired in general. More specifically, it breaks the in-order scheduling property guarantee for device-offloaded TLS sockets. Remove the call to sk_tx_queue_clear() in sk_set_socket(), and add it explicitly only where needed. Fixes: e022f0b4a03f ("net: Introduce sk_tx_queue_mapping") Signed-off-by: Tariq Toukan Reviewed-by: Boris Pismenny Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tcp/dccp: fix possible race __inet_lookup_established()

2020-01-04T12:41:12+00:00

commit 8dbd76e79a16b45b2ccb01d2f2e08dbf64e71e40 upstream. Michal Kubecek and Firo Yang did a very nice analysis of crashes happening in __inet_lookup_established(). Since a TCP socket can go from TCP_ESTABLISH to TCP_LISTEN (via a close()/socket()/listen() cycle) without a RCU grace period, I should not have changed listeners linkage in their hash table. They must use the nulls protocol (Documentation/RCU/rculist_nulls.txt), so that a lookup can detect a socket in a hash list was moved in another one. Since we added code in commit d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix"), we have to add hlist_nulls_add_tail_rcu() helper. Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood") Signed-off-by: Eric Dumazet Reported-by: Michal Kubecek Reported-by: Firo Yang Reviewed-by: Michal Kubecek Link: https://lore.kernel.org/netdev/20191120083919.GH27852@unicorn.suse.cz/ Signed-off-by: Jakub Kicinski [stable-4.9: we also need to update code in __inet_lookup_listener() and inet6_lookup_listener() which has been removed in 5.0-rc1.] Signed-off-by: Michal Kubecek Signed-off-by: Greg Kroah-Hartman

net: fix possible overflow in __sk_mem_raise_allocated()

2019-12-05T14:35:13+00:00

[ Upstream commit 5bf325a53202b8728cf7013b72688c46071e212e ] With many active TCP sockets, fat TCP sockets could fool __sk_mem_raise_allocated() thanks to an overflow. They would increase their share of the memory, instead of decreasing it. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: prevent load/store tearing on sk->sk_stamp

2019-11-12T18:16:11+00:00

[ Upstream commit f75359f3ac855940c5718af10ba089b8977bf339 ] Add a couple of READ_ONCE() and WRITE_ONCE() to prevent load-tearing and store-tearing in sock_read_timestamp() and sock_write_timestamp() This might prevent another KCSAN report. Fixes: 3a0ed3e96197 ("sock: Make sock->sk_stamp thread-safe") Signed-off-by: Eric Dumazet Cc: Deepa Dinamani Acked-by: Deepa Dinamani Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: fix sk_page_frag() recursion from memory reclaim

2019-11-10T10:23:23+00:00

[ Upstream commit 20eb4f29b60286e0d6dc01d9c260b4bd383c58fb ] sk_page_frag() optimizes skb_frag allocations by using per-task skb_frag cache when it knows it's the only user. The condition is determined by seeing whether the socket allocation mask allows blocking - if the allocation may block, it obviously owns the task's context and ergo exclusively owns current->task_frag. Unfortunately, this misses recursion through memory reclaim path. Please take a look at the following backtrace. [2] RIP: 0010:tcp_sendmsg_locked+0xccf/0xe10 ... tcp_sendmsg+0x27/0x40 sock_sendmsg+0x30/0x40 sock_xmit.isra.24+0xa1/0x170 [nbd] nbd_send_cmd+0x1d2/0x690 [nbd] nbd_queue_rq+0x1b5/0x3b0 [nbd] __blk_mq_try_issue_directly+0x108/0x1b0 blk_mq_request_issue_directly+0xbd/0xe0 blk_mq_try_issue_list_directly+0x41/0xb0 blk_mq_sched_insert_requests+0xa2/0xe0 blk_mq_flush_plug_list+0x205/0x2a0 blk_flush_plug_list+0xc3/0xf0 [1] blk_finish_plug+0x21/0x2e _xfs_buf_ioapply+0x313/0x460 __xfs_buf_submit+0x67/0x220 xfs_buf_read_map+0x113/0x1a0 xfs_trans_read_buf_map+0xbf/0x330 xfs_btree_read_buf_block.constprop.42+0x95/0xd0 xfs_btree_lookup_get_block+0x95/0x170 xfs_btree_lookup+0xcc/0x470 xfs_bmap_del_extent_real+0x254/0x9a0 __xfs_bunmapi+0x45c/0xab0 xfs_bunmapi+0x15/0x30 xfs_itruncate_extents_flags+0xca/0x250 xfs_free_eofblocks+0x181/0x1e0 xfs_fs_destroy_inode+0xa8/0x1b0 destroy_inode+0x38/0x70 dispose_list+0x35/0x50 prune_icache_sb+0x52/0x70 super_cache_scan+0x120/0x1a0 do_shrink_slab+0x120/0x290 shrink_slab+0x216/0x2b0 shrink_node+0x1b6/0x4a0 do_try_to_free_pages+0xc6/0x370 try_to_free_mem_cgroup_pages+0xe3/0x1e0 try_charge+0x29e/0x790 mem_cgroup_charge_skmem+0x6a/0x100 __sk_mem_raise_allocated+0x18e/0x390 __sk_mem_schedule+0x2a/0x40 [0] tcp_sendmsg_locked+0x8eb/0xe10 tcp_sendmsg+0x27/0x40 sock_sendmsg+0x30/0x40 ___sys_sendmsg+0x26d/0x2b0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x42/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 In [0], tcp_send_msg_locked() was using current->page_frag when it called sk_wmem_schedule(). It already calculated how many bytes can be fit into current->page_frag. Due to memory pressure, sk_wmem_schedule() called into memory reclaim path which called into xfs and then IO issue path. Because the filesystem in question is backed by nbd, the control goes back into the tcp layer - back into tcp_sendmsg_locked(). nbd sets sk_allocation to (GFP_NOIO | __GFP_MEMALLOC) which makes sense - it's in the process of freeing memory and wants to be able to, e.g., drop clean pages to make forward progress. However, this confused sk_page_frag() called from [2]. Because it only tests whether the allocation allows blocking which it does, it now thinks current->page_frag can be used again although it already was being used in [0]. After [2] used current->page_frag, the offset would be increased by the used amount. When the control returns to [0], current->page_frag's offset is increased and the previously calculated number of bytes now may overrun the end of allocated memory leading to silent memory corruptions. Fix it by adding gfpflags_normal_context() which tests sleepable && !reclaim and use it to determine whether to use current->task_frag. v2: Eric didn't like gfp flags being tested twice. Introduce a new helper gfpflags_normal_context() and combine the two tests. Signed-off-by: Tejun Heo Cc: Josef Bacik Cc: Eric Dumazet Cc: stable@vger.kernel.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

packets: Always register packet sk in the same order

2019-04-03T04:24:15+00:00

[ Upstream commit a4dc6a49156b1f8d6e17251ffda17c9e6a5db78a ] When using fanouts with AF_PACKET, the demux functions such as fanout_demux_cpu will return an index in the fanout socket array, which corresponds to the selected socket. The ordering of this array depends on the order the sockets were added to a given fanout group, so for FANOUT_CPU this means sockets are bound to cpus in the order they are configured, which is OK. However, when stopping then restarting the interface these sockets are bound to, the sockets are reassigned to the fanout group in the reverse order, due to the fact that they were inserted at the head of the interface's AF_PACKET socket list. This means that traffic that was directed to the first socket in the fanout group is now directed to the last one after an interface restart. In the case of FANOUT_CPU, traffic from CPU0 will be directed to the socket that used to receive traffic from the last CPU after an interface restart. This commit introduces a helper to add a socket at the tail of a list, then uses it to register AF_PACKET sockets. Note that this changes the order in which sockets are listed in /proc and with sock_diag. Fixes: dc99f600698d ("packet: Add fanout support") Signed-off-by: Maxime Chevallier Acked-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sock: Make sock->sk_stamp thread-safe

2019-01-09T15:16:41+00:00

[ Upstream commit 3a0ed3e9619738067214871e9cb826fa23b2ddb9 ] Al Viro mentioned (Message-ID <20170626041334.GZ10672@ZenIV.linux.org.uk>) that there is probably a race condition lurking in accesses of sk_stamp on 32-bit machines. sock->sk_stamp is of type ktime_t which is always an s64. On a 32 bit architecture, we might run into situations of unsafe access as the access to the field becomes non atomic. Use seqlocks for synchronization. This allows us to avoid using spinlocks for readers as readers do not need mutual exclusion. Another approach to solve this is to require sk_lock for all modifications of the timestamps. The current approach allows for timestamps to have their own lock: sk_stamp_lock. This allows for the patch to not compete with already existing critical sections, and side effects are limited to the paths in the patch. The addition of the new field maintains the data locality optimizations from commit 9115e8cd2a0c ("net: reorganize struct sock for better data locality") Note that all the instances of the sk_stamp accesses are either through the ioctl or the syscall recvmsg. Signed-off-by: Deepa Dinamani Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: remove hlist_nulls_add_tail_rcu()

2017-12-16T15:25:45+00:00

[ Upstream commit d7efc6c11b277d9d80b99b1334a78bfe7d7edf10 ] Alexander Potapenko reported use of uninitialized memory [1] This happens when inserting a request socket into TCP ehash, in __sk_nulls_add_node_rcu(), since sk_reuseport is not initialized. Bug was added by commit d894ba18d4e4 ("soreuseport: fix ordering for mixed v4/v6 sockets") Note that d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix") missed the opportunity to get rid of hlist_nulls_add_tail_rcu() : Both UDP sockets and TCP/DCCP listeners no longer use __sk_nulls_add_node_rcu() for their hash insertion. Since all other sockets have unique 4-tuple, the reuseport status has no special meaning, so we can always use hlist_nulls_add_head_rcu() for them and save few cycles/instructions. [1] ================================================================== BUG: KMSAN: use of uninitialized memory in inet_ehash_insert+0xd40/0x1050 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0+ #3288 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 dump_stack+0x185/0x1d0 lib/dump_stack.c:52 kmsan_report+0x13f/0x1c0 mm/kmsan/kmsan.c:1016 __msan_warning_32+0x69/0xb0 mm/kmsan/kmsan_instr.c:766 __sk_nulls_add_node_rcu ./include/net/sock.h:684 inet_ehash_insert+0xd40/0x1050 net/ipv4/inet_hashtables.c:413 reqsk_queue_hash_req net/ipv4/inet_connection_sock.c:754 inet_csk_reqsk_queue_hash_add+0x1cc/0x300 net/ipv4/inet_connection_sock.c:765 tcp_conn_request+0x31e7/0x36f0 net/ipv4/tcp_input.c:6414 tcp_v4_conn_request+0x16d/0x220 net/ipv4/tcp_ipv4.c:1314 tcp_rcv_state_process+0x42a/0x7210 net/ipv4/tcp_input.c:5917 tcp_v4_do_rcv+0xa6a/0xcd0 net/ipv4/tcp_ipv4.c:1483 tcp_v4_rcv+0x3de0/0x4ab0 net/ipv4/tcp_ipv4.c:1763 ip_local_deliver_finish+0x6bb/0xcb0 net/ipv4/ip_input.c:216 NF_HOOK ./include/linux/netfilter.h:248 ip_local_deliver+0x3fa/0x480 net/ipv4/ip_input.c:257 dst_input ./include/net/dst.h:477 ip_rcv_finish+0x6fb/0x1540 net/ipv4/ip_input.c:397 NF_HOOK ./include/linux/netfilter.h:248 ip_rcv+0x10f6/0x15c0 net/ipv4/ip_input.c:488 __netif_receive_skb_core+0x36f6/0x3f60 net/core/dev.c:4298 __netif_receive_skb net/core/dev.c:4336 netif_receive_skb_internal+0x63c/0x19c0 net/core/dev.c:4497 napi_skb_finish net/core/dev.c:4858 napi_gro_receive+0x629/0xa50 net/core/dev.c:4889 e1000_receive_skb drivers/net/ethernet/intel/e1000/e1000_main.c:4018 e1000_clean_rx_irq+0x1492/0x1d30 drivers/net/ethernet/intel/e1000/e1000_main.c:4474 e1000_clean+0x43aa/0x5970 drivers/net/ethernet/intel/e1000/e1000_main.c:3819 napi_poll net/core/dev.c:5500 net_rx_action+0x73c/0x1820 net/core/dev.c:5566 __do_softirq+0x4b4/0x8dd kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 irq_exit+0x203/0x240 kernel/softirq.c:405 exiting_irq+0xe/0x10 ./arch/x86/include/asm/apic.h:638 do_IRQ+0x15e/0x1a0 arch/x86/kernel/irq.c:263 common_interrupt+0x86/0x86 Fixes: d894ba18d4e4 ("soreuseport: fix ordering for mixed v4/v6 sockets") Fixes: d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix") Signed-off-by: Eric Dumazet Reported-by: Alexander Potapenko Acked-by: Craig Gallek Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman