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2022-01-11net: udp: fix alignment problem in udp4_seq_show()yangxingwu1-1/+1
[ Upstream commit 6c25449e1a32c594d743df8e8258e8ef870b6a77 ] $ cat /pro/net/udp before: sl local_address rem_address st tx_queue rx_queue tr tm->when 26050: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000 26320: 0100007F:0143 00000000:0000 07 00000000:00000000 00:00000000 27135: 00000000:8472 00000000:0000 07 00000000:00000000 00:00000000 after: sl local_address rem_address st tx_queue rx_queue tr tm->when 26050: 0100007F:0035 00000000:0000 07 00000000:00000000 00:00000000 26320: 0100007F:0143 00000000:0000 07 00000000:00000000 00:00000000 27135: 00000000:8472 00000000:0000 07 00000000:00000000 00:00000000 Signed-off-by: yangxingwu <xingwu.yang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-01-11lwtunnel: Validate RTA_ENCAP_TYPE attribute lengthDavid Ahern1-0/+3
commit 8bda81a4d400cf8a72e554012f0d8c45e07a3904 upstream. lwtunnel_valid_encap_type_attr is used to validate encap attributes within a multipath route. Add length validation checking to the type. lwtunnel_valid_encap_type_attr is called converting attributes to fib{6,}_config struct which means it is used before fib_get_nhs, ip6_route_multipath_add, and ip6_route_multipath_del - other locations that use rtnh_ok and then nla_get_u16 on RTA_ENCAP_TYPE attribute. Fixes: 9ed59592e3e3 ("lwtunnel: fix autoload of lwt modules") Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-11ipv4: Check attribute length for RTA_FLOW in multipath routeDavid Ahern1-3/+14
commit 664b9c4b7392ce723b013201843264bf95481ce5 upstream. Make sure RTA_FLOW is at least 4B before using. Fixes: 4e902c57417c ("[IPv4]: FIB configuration using struct fib_config") Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-11ipv4: Check attribute length for RTA_GATEWAY in multipath routeDavid Ahern1-3/+26
commit 7a3429bace0e08d94c39245631ea6bc109dafa49 upstream. syzbot reported uninit-value: ============================================================ BUG: KMSAN: uninit-value in fib_get_nhs+0xac4/0x1f80 net/ipv4/fib_semantics.c:708 fib_get_nhs+0xac4/0x1f80 net/ipv4/fib_semantics.c:708 fib_create_info+0x2411/0x4870 net/ipv4/fib_semantics.c:1453 fib_table_insert+0x45c/0x3a10 net/ipv4/fib_trie.c:1224 inet_rtm_newroute+0x289/0x420 net/ipv4/fib_frontend.c:886 Add helper to validate RTA_GATEWAY length before using the attribute. Fixes: 4e902c57417c ("[IPv4]: FIB configuration using struct fib_config") Reported-by: syzbot+d4b9a2851cc3ce998741@syzkaller.appspotmail.com Signed-off-by: David Ahern <dsahern@kernel.org> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-01-05net: fix use-after-free in tw_timer_handlerMuchun Song1-6/+4
commit e22e45fc9e41bf9fcc1e92cfb78eb92786728ef0 upstream. A real world panic issue was found as follow in Linux 5.4. BUG: unable to handle page fault for address: ffffde49a863de28 PGD 7e6fe62067 P4D 7e6fe62067 PUD 7e6fe63067 PMD f51e064067 PTE 0 RIP: 0010:tw_timer_handler+0x20/0x40 Call Trace: <IRQ> call_timer_fn+0x2b/0x120 run_timer_softirq+0x1ef/0x450 __do_softirq+0x10d/0x2b8 irq_exit+0xc7/0xd0 smp_apic_timer_interrupt+0x68/0x120 apic_timer_interrupt+0xf/0x20 This issue was also reported since 2017 in the thread [1], unfortunately, the issue was still can be reproduced after fixing DCCP. The ipv4_mib_exit_net is called before tcp_sk_exit_batch when a net namespace is destroyed since tcp_sk_ops is registered befrore ipv4_mib_ops, which means tcp_sk_ops is in the front of ipv4_mib_ops in the list of pernet_list. There will be a use-after-free on net->mib.net_statistics in tw_timer_handler after ipv4_mib_exit_net if there are some inflight time-wait timers. This bug is not introduced by commit f2bf415cfed7 ("mib: add net to NET_ADD_STATS_BH") since the net_statistics is a global variable instead of dynamic allocation and freeing. Actually, commit 61a7e26028b9 ("mib: put net statistics on struct net") introduces the bug since it put net statistics on struct net and free it when net namespace is destroyed. Moving init_ipv4_mibs() to the front of tcp_init() to fix this bug and replace pr_crit() with panic() since continuing is meaningless when init_ipv4_mibs() fails. [1] https://groups.google.com/g/syzkaller/c/p1tn-_Kc6l4/m/smuL_FMAAgAJ?pli=1 Fixes: 61a7e26028b9 ("mib: put net statistics on struct net") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Cong Wang <cong.wang@bytedance.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20211228104145.9426-1-songmuchun@bytedance.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-22inet_diag: fix kernel-infoleak for UDP socketsEric Dumazet1-3/+1
[ Upstream commit 71ddeac8cd1d217744a0e060ff520e147c9328d1 ] KMSAN reported a kernel-infoleak [1], that can exploited by unpriv users. After analysis it turned out UDP was not initializing r->idiag_expires. Other users of inet_sk_diag_fill() might make the same mistake in the future, so fix this in inet_sk_diag_fill(). [1] BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline] BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:156 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x69d/0x25c0 lib/iov_iter.c:670 instrument_copy_to_user include/linux/instrumented.h:121 [inline] copyout lib/iov_iter.c:156 [inline] _copy_to_iter+0x69d/0x25c0 lib/iov_iter.c:670 copy_to_iter include/linux/uio.h:155 [inline] simple_copy_to_iter+0xf3/0x140 net/core/datagram.c:519 __skb_datagram_iter+0x2cb/0x1280 net/core/datagram.c:425 skb_copy_datagram_iter+0xdc/0x270 net/core/datagram.c:533 skb_copy_datagram_msg include/linux/skbuff.h:3657 [inline] netlink_recvmsg+0x660/0x1c60 net/netlink/af_netlink.c:1974 sock_recvmsg_nosec net/socket.c:944 [inline] sock_recvmsg net/socket.c:962 [inline] sock_read_iter+0x5a9/0x630 net/socket.c:1035 call_read_iter include/linux/fs.h:2156 [inline] new_sync_read fs/read_write.c:400 [inline] vfs_read+0x1631/0x1980 fs/read_write.c:481 ksys_read+0x28c/0x520 fs/read_write.c:619 __do_sys_read fs/read_write.c:629 [inline] __se_sys_read fs/read_write.c:627 [inline] __x64_sys_read+0xdb/0x120 fs/read_write.c:627 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Uninit was created at: slab_post_alloc_hook mm/slab.h:524 [inline] slab_alloc_node mm/slub.c:3251 [inline] __kmalloc_node_track_caller+0xe0c/0x1510 mm/slub.c:4974 kmalloc_reserve net/core/skbuff.c:354 [inline] __alloc_skb+0x545/0xf90 net/core/skbuff.c:426 alloc_skb include/linux/skbuff.h:1126 [inline] netlink_dump+0x3d5/0x16a0 net/netlink/af_netlink.c:2245 __netlink_dump_start+0xd1c/0xee0 net/netlink/af_netlink.c:2370 netlink_dump_start include/linux/netlink.h:254 [inline] inet_diag_handler_cmd+0x2e7/0x400 net/ipv4/inet_diag.c:1343 sock_diag_rcv_msg+0x24a/0x620 netlink_rcv_skb+0x447/0x800 net/netlink/af_netlink.c:2491 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x1095/0x1360 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x16f3/0x1870 net/netlink/af_netlink.c:1916 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x594/0x690 net/socket.c:1057 do_iter_readv_writev+0xa7f/0xc70 do_iter_write+0x52c/0x1500 fs/read_write.c:851 vfs_writev fs/read_write.c:924 [inline] do_writev+0x63f/0xe30 fs/read_write.c:967 __do_sys_writev fs/read_write.c:1040 [inline] __se_sys_writev fs/read_write.c:1037 [inline] __x64_sys_writev+0xe5/0x120 fs/read_write.c:1037 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x44/0xae Bytes 68-71 of 312 are uninitialized Memory access of size 312 starts at ffff88812ab54000 Data copied to user address 0000000020001440 CPU: 1 PID: 6365 Comm: syz-executor801 Not tainted 5.16.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 3c4d05c80567 ("inet_diag: Introduce the inet socket dumping routine") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20211209185058.53917-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-14udp: using datalen to cap max gso segmentsJianguo Wu1-1/+1
commit 158390e45612ef0fde160af0826f1740c36daf21 upstream. The max number of UDP gso segments is intended to cap to UDP_MAX_SEGMENTS, this is checked in udp_send_skb(): if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS) { kfree_skb(skb); return -EINVAL; } skb->len contains network and transport header len here, we should use only data len instead. Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/900742e5-81fb-30dc-6e0b-375c6cdd7982@163.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-08ipv4: convert fib_num_tclassid_users to atomic_tEric Dumazet3-5/+5
commit 213f5f8f31f10aa1e83187ae20fb7fa4e626b724 upstream. Before commit faa041a40b9f ("ipv4: Create cleanup helper for fib_nh") changes to net->ipv4.fib_num_tclassid_users were protected by RTNL. After the change, this is no longer the case, as free_fib_info_rcu() runs after rcu grace period, without rtnl being held. Fixes: faa041a40b9f ("ipv4: Create cleanup helper for fib_nh") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsahern@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-08ipv6: fix memory leak in fib6_rule_suppressmsizanoen11-0/+1
commit cdef485217d30382f3bf6448c54b4401648fe3f1 upstream. The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache. After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule"). The problem with that change is that the generic `args->flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed. How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }' sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet. This patch exposes the protocol-specific flags to the protocol specific `suppress` function, and check the protocol-specific `flags` argument for RT6_LOOKUP_F_DST_NOREF instead of the generic FIB_LOOKUP_NOREF when decreasing the refcount, like this. [1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71 [2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99 Link: https://bugzilla.kernel.org/show_bug.cgi?id=215105 Fixes: ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-08net: return correct error codeliuguoqiang1-1/+1
[ Upstream commit 6def480181f15f6d9ec812bca8cbc62451ba314c ] When kmemdup called failed and register_net_sysctl return NULL, should return ENOMEM instead of ENOBUFS Signed-off-by: liuguoqiang <liuguoqiang@uniontech.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-01tcp: correctly handle increased zerocopy args struct sizeArjun Roy1-2/+2
[ Upstream commit e0fecb289ad3fd2245cdc50bf450b97fcca39884 ] A prior patch increased the size of struct tcp_zerocopy_receive but did not update do_tcp_getsockopt() handling to properly account for this. This patch simply reintroduces content erroneously cut from the referenced prior patch that handles the new struct size. Fixes: 18fb76ed5386 ("net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.") Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-01tcp_cubic: fix spurious Hystart ACK train detections for not-cwnd-limited flowsEric Dumazet1-2/+3
[ Upstream commit 4e1fddc98d2585ddd4792b5e44433dcee7ece001 ] While testing BIG TCP patch series, I was expecting that TCP_RR workloads with 80KB requests/answers would send one 80KB TSO packet, then being received as a single GRO packet. It turns out this was not happening, and the root cause was that cubic Hystart ACK train was triggering after a few (2 or 3) rounds of RPC. Hystart was wrongly setting CWND/SSTHRESH to 30, while my RPC needed a budget of ~20 segments. Ideally these TCP_RR flows should not exit slow start. Cubic Hystart should reset itself at each round, instead of assuming every TCP flow is a bulk one. Note that even after this patch, Hystart can still trigger, depending on scheduling artifacts, but at a higher CWND/SSTHRESH threshold, keeping optimal TSO packet sizes. Tested: ip link set dev eth0 gro_ipv6_max_size 131072 gso_ipv6_max_size 131072 nstat -n; netperf -H ... -t TCP_RR -l 5 -- -r 80000,80000 -K cubic; nstat|egrep "Ip6InReceives|Hystart|Ip6OutRequests" Before: 8605 Ip6InReceives 87541 0.0 Ip6OutRequests 129496 0.0 TcpExtTCPHystartTrainDetect 1 0.0 TcpExtTCPHystartTrainCwnd 30 0.0 After: 8760 Ip6InReceives 88514 0.0 Ip6OutRequests 87975 0.0 Fixes: ae27e98a5152 ("[TCP] CUBIC v2.3") Co-developed-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Link: https://lore.kernel.org/r/20211123202535.1843771-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-01net: nexthop: release IPv6 per-cpu dsts when replacing a nexthop groupNikolay Aleksandrov1-2/+23
[ Upstream commit 1005f19b9357b81aa64e1decd08d6e332caaa284 ] When replacing a nexthop group, we must release the IPv6 per-cpu dsts of the removed nexthop entries after an RCU grace period because they contain references to the nexthop's net device and to the fib6 info. With specific series of events[1] we can reach net device refcount imbalance which is unrecoverable. IPv4 is not affected because dsts don't take a refcount on the route. [1] $ ip nexthop list id 200 via 2002:db8::2 dev bridge.10 scope link onlink id 201 via 2002:db8::3 dev bridge scope link onlink id 203 group 201/200 $ ip -6 route 2001:db8::10 nhid 203 metric 1024 pref medium nexthop via 2002:db8::3 dev bridge weight 1 onlink nexthop via 2002:db8::2 dev bridge.10 weight 1 onlink Create rt6_info through one of the multipath legs, e.g.: $ taskset -a -c 1 ./pkt_inj 24 bridge.10 2001:db8::10 (pkt_inj is just a custom packet generator, nothing special) Then remove that leg from the group by replace (let's assume it is id 200 in this case): $ ip nexthop replace id 203 group 201 Now remove the IPv6 route: $ ip -6 route del 2001:db8::10/128 The route won't be really deleted due to the stale rt6_info holding 1 refcnt in nexthop id 200. At this point we have the following reference count dependency: (deleted) IPv6 route holds 1 reference over nhid 203 nh 203 holds 1 ref over id 201 nh 200 holds 1 ref over the net device and the route due to the stale rt6_info Now to create circular dependency between nh 200 and the IPv6 route, and also to get a reference over nh 200, restore nhid 200 in the group: $ ip nexthop replace id 203 group 201/200 And now we have a permanent circular dependncy because nhid 203 holds a reference over nh 200 and 201, but the route holds a ref over nh 203 and is deleted. To trigger the bug just delete the group (nhid 203): $ ip nexthop del id 203 It won't really be deleted due to the IPv6 route dependency, and now we have 2 unlinked and deleted objects that reference each other: the group and the IPv6 route. Since the group drops the reference it holds over its entries at free time (i.e. its own refcount needs to drop to 0) that will never happen and we get a permanent ref on them, since one of the entries holds a reference over the IPv6 route it will also never be released. At this point the dependencies are: (deleted, only unlinked) IPv6 route holds reference over group nh 203 (deleted, only unlinked) group nh 203 holds reference over nh 201 and 200 nh 200 holds 1 ref over the net device and the route due to the stale rt6_info This is the last point where it can be fixed by running traffic through nh 200, and specifically through the same CPU so the rt6_info (dst) will get released due to the IPv6 genid, that in turn will free the IPv6 route, which in turn will free the ref count over the group nh 203. If nh 200 is deleted at this point, it will never be released due to the ref from the unlinked group 203, it will only be unlinked: $ ip nexthop del id 200 $ ip nexthop $ Now we can never release that stale rt6_info, we have IPv6 route with ref over group nh 203, group nh 203 with ref over nh 200 and 201, nh 200 with rt6_info (dst) with ref over the net device and the IPv6 route. All of these objects are only unlinked, and cannot be released, thus they can't release their ref counts. Message from syslogd@dev at Nov 19 14:04:10 ... kernel:[73501.828730] unregister_netdevice: waiting for bridge.10 to become free. Usage count = 3 Message from syslogd@dev at Nov 19 14:04:20 ... kernel:[73512.068811] unregister_netdevice: waiting for bridge.10 to become free. Usage count = 3 Fixes: 7bf4796dd099 ("nexthops: add support for replace") Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-01net: nexthop: fix null pointer dereference when IPv6 is not enabledNikolay Aleksandrov1-3/+7
commit 1c743127cc54b112b155f434756bd4b5fa565a99 upstream. When we try to add an IPv6 nexthop and IPv6 is not enabled (!CONFIG_IPV6) we'll hit a NULL pointer dereference[1] in the error path of nh_create_ipv6() due to calling ipv6_stub->fib6_nh_release. The bug has been present since the beginning of IPv6 nexthop gateway support. Commit 1aefd3de7bc6 ("ipv6: Add fib6_nh_init and release to stubs") tells us that only fib6_nh_init has a dummy stub because fib6_nh_release should not be called if fib6_nh_init returns an error, but the commit below added a call to ipv6_stub->fib6_nh_release in its error path. To fix it return the dummy stub's -EAFNOSUPPORT error directly without calling ipv6_stub->fib6_nh_release in nh_create_ipv6()'s error path. [1] Output is a bit truncated, but it clearly shows the error. BUG: kernel NULL pointer dereference, address: 000000000000000000 #PF: supervisor instruction fetch in kernel modede #PF: error_code(0x0010) - not-present pagege PGD 0 P4D 0 Oops: 0010 [#1] PREEMPT SMP NOPTI CPU: 4 PID: 638 Comm: ip Kdump: loaded Not tainted 5.16.0-rc1+ #446 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffff888109f5b8f0 EFLAGS: 00010286^Ac RAX: 0000000000000000 RBX: ffff888109f5ba28 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881008a2860 RBP: ffff888109f5b9d8 R08: 0000000000000000 R09: 0000000000000000 R10: ffff888109f5b978 R11: ffff888109f5b948 R12: 00000000ffffff9f R13: ffff8881008a2a80 R14: ffff8881008a2860 R15: ffff8881008a2840 FS: 00007f98de70f100(0000) GS:ffff88822bf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000100efc000 CR4: 00000000000006e0 Call Trace: <TASK> nh_create_ipv6+0xed/0x10c rtm_new_nexthop+0x6d7/0x13f3 ? check_preemption_disabled+0x3d/0xf2 ? lock_is_held_type+0xbe/0xfd rtnetlink_rcv_msg+0x23f/0x26a ? check_preemption_disabled+0x3d/0xf2 ? rtnl_calcit.isra.0+0x147/0x147 netlink_rcv_skb+0x61/0xb2 netlink_unicast+0x100/0x187 netlink_sendmsg+0x37f/0x3a0 ? netlink_unicast+0x187/0x187 sock_sendmsg_nosec+0x67/0x9b ____sys_sendmsg+0x19d/0x1f9 ? copy_msghdr_from_user+0x4c/0x5e ? rcu_read_lock_any_held+0x2a/0x78 ___sys_sendmsg+0x6c/0x8c ? asm_sysvec_apic_timer_interrupt+0x12/0x20 ? lockdep_hardirqs_on+0xd9/0x102 ? sockfd_lookup_light+0x69/0x99 __sys_sendmsg+0x50/0x6e do_syscall_64+0xcb/0xf2 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f98dea28914 Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 48 8d 05 e9 5d 0c 00 8b 00 85 c0 75 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 41 89 d4 55 48 89 f5 53 RSP: 002b:00007fff859f5e68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e2e RAX: ffffffffffffffda RBX: 00000000619cb810 RCX: 00007f98dea28914 RDX: 0000000000000000 RSI: 00007fff859f5ed0 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000008 R10: fffffffffffffce6 R11: 0000000000000246 R12: 0000000000000001 R13: 000055c0097ae520 R14: 000055c0097957fd R15: 00007fff859f63a0 </TASK> Modules linked in: bridge stp llc bonding virtio_net Cc: stable@vger.kernel.org Fixes: 53010f991a9f ("nexthop: Add support for IPv6 gateways") Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26tcp: Fix uninitialized access in skb frags array for Rx 0cp.Arjun Roy1-0/+3
[ Upstream commit 70701b83e208767f2720d8cd3e6a62cddafb3a30 ] TCP Receive zerocopy iterates through the SKB queue via tcp_recv_skb(), acquiring a pointer to an SKB and an offset within that SKB to read from. From there, it iterates the SKB frags array to determine which offset to start remapping pages from. However, this is built on the assumption that the offset read so far within the SKB is smaller than the SKB length. If this assumption is violated, we can attempt to read an invalid frags array element, which would cause a fault. tcp_recv_skb() can cause such an SKB to be returned when the TCP FIN flag is set. Therefore, we must guard against this occurrence inside skb_advance_frag(). One way that we can reproduce this error follows: 1) In a receiver program, call getsockopt(TCP_ZEROCOPY_RECEIVE) with: char some_array[32 * 1024]; struct tcp_zerocopy_receive zc = { .copybuf_address = (__u64) &some_array[0], .copybuf_len = 32 * 1024, }; 2) In a sender program, after a TCP handshake, send the following sequence of packets: i) Seq = [X, X+4000] ii) Seq = [X+4000, X+5000] iii) Seq = [X+4000, X+5000], Flags = FIN | URG, urgptr=1000 (This can happen without URG, if we have a signal pending, but URG is a convenient way to reproduce the behaviour). In this case, the following event sequence will occur on the receiver: tcp_zerocopy_receive(): -> receive_fallback_to_copy() // copybuf_len >= inq -> tcp_recvmsg_locked() // reads 5000 bytes, then breaks due to URG -> tcp_recv_skb() // yields skb with skb->len == offset -> tcp_zerocopy_set_hint_for_skb() -> skb_advance_to_frag() // will returns a frags ptr. >= nr_frags -> find_next_mappable_frag() // will dereference this bad frags ptr. With this patch, skb_advance_to_frag() will no longer return an invalid frags pointer, and will return NULL instead, fixing the issue. Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive") Link: https://lore.kernel.org/r/20211111235215.2605384-1-arjunroy.kdev@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-26net-zerocopy: Refactor skb frag fast-forward op.Arjun Roy1-9/+26
[ Upstream commit 7fba5309efe24e4f0284ef4b8663cdf401035e72 ] Refactor skb frag fast-forwarding for tcp receive zerocopy. This is part of a patch set that introduces short-circuited hybrid copies for small receive operations, which results in roughly 33% fewer syscalls for small RPC scenarios. skb_advance_to_frag(), given a skb and an offset into the skb, iterates from the first frag for the skb until we're at the frag specified by the offset. Assuming the offset provided refers to how many bytes in the skb are already read, the returned frag points to the next frag we may read from, while offset_frag is set to the number of bytes from this frag that we have already read. If frag is not null and offset_frag is equal to 0, then we may be able to map this frag's page into the process address space with vm_insert_page(). However, if offset_frag is not equal to 0, then we cannot do so. Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-26net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.Arjun Roy1-16/+68
[ Upstream commit 18fb76ed53865c1b5d5f0157b1b825704590beb5 ] When TCP receive zerocopy does not successfully map the entire requested space, it outputs a 'hint' that the caller should recvmsg(). Augment zerocopy to accept a user buffer that it tries to copy this hint into - if it is possible to copy the entire hint, it will do so. This elides a recvmsg() call for received traffic that isn't exactly page-aligned in size. This was tested with RPC-style traffic of arbitrary sizes. Normally, each received message required at least one getsockopt() call, and one recvmsg() call for the remaining unaligned data. With this change, almost all of the recvmsg() calls are eliminated, leading to a savings of about 25%-50% in number of system calls for RPC-style workloads. Signed-off-by: Arjun Roy <arjunroy@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18bpf, sockmap: Remove unhash handler for BPF sockmap usageJohn Fastabend1-1/+0
[ Upstream commit b8b8315e39ffaca82e79d86dde26e9144addf66b ] We do not need to handle unhash from BPF side we can simply wait for the close to happen. The original concern was a socket could transition from ESTABLISHED state to a new state while the BPF hook was still attached. But, we convinced ourself this is no longer possible and we also improved BPF sockmap to handle listen sockets so this is no longer a problem. More importantly though there are cases where unhash is called when data is in the receive queue. The BPF unhash logic will flush this data which is wrong. To be correct it should keep the data in the receive queue and allow a receiving application to continue reading the data. This may happen when tcp_abort() is received for example. Instead of complicating the logic in unhash simply moving all this to tcp_close() hook solves this. Fixes: 51199405f9672 ("bpf: skb_verdict, support SK_PASS on RX BPF path") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Jussi Maki <joamaki@gmail.com> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20211103204736.248403-3-john.fastabend@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18tcp: don't free a FIN sk_buff in tcp_remove_empty_skb()Jon Maxwell1-1/+1
[ Upstream commit cf12e6f9124629b18a6182deefc0315f0a73a199 ] v1: Implement a more general statement as recommended by Eric Dumazet. The sequence number will be advanced, so this check will fix the FIN case and other cases. A customer reported sockets stuck in the CLOSING state. A Vmcore revealed that the write_queue was not empty as determined by tcp_write_queue_empty() but the sk_buff containing the FIN flag had been freed and the socket was zombied in that state. Corresponding pcaps show no FIN from the Linux kernel on the wire. Some instrumentation was added to the kernel and it was found that there is a timing window where tcp_sendmsg() can run after tcp_send_fin(). tcp_sendmsg() will hit an error, for example: 1269 ▹ if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))↩ 1270 ▹ ▹ goto do_error;↩ tcp_remove_empty_skb() will then free the FIN sk_buff as "skb->len == 0". The TCP socket is now wedged in the FIN-WAIT-1 state because the FIN is never sent. If the other side sends a FIN packet the socket will transition to CLOSING and remain that way until the system is rebooted. Fix this by checking for the FIN flag in the sk_buff and don't free it if that is the case. Testing confirmed that fixed the issue. Fixes: fdfc5c8594c2 ("tcp: remove empty skb from write queue in error cases") Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com> Reported-by: Monir Zouaoui <Monir.Zouaoui@mail.schwarz> Reported-by: Simon Stier <simon.stier@mail.schwarz> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18tcp: switch orphan_count to bare per-cpu countersEric Dumazet4-9/+37
[ Upstream commit 19757cebf0c5016a1f36f7fe9810a9f0b33c0832 ] Use of percpu_counter structure to track count of orphaned sockets is causing problems on modern hosts with 256 cpus or more. Stefan Bach reported a serious spinlock contention in real workloads, that I was able to reproduce with a netfilter rule dropping incoming FIN packets. 53.56% server [kernel.kallsyms] [k] queued_spin_lock_slowpath | ---queued_spin_lock_slowpath | --53.51%--_raw_spin_lock_irqsave | --53.51%--__percpu_counter_sum tcp_check_oom | |--39.03%--__tcp_close | tcp_close | inet_release | inet6_release | sock_close | __fput | ____fput | task_work_run | exit_to_usermode_loop | do_syscall_64 | entry_SYSCALL_64_after_hwframe | __GI___libc_close | --14.48%--tcp_out_of_resources tcp_write_timeout tcp_retransmit_timer tcp_write_timer_handler tcp_write_timer call_timer_fn expire_timers __run_timers run_timer_softirq __softirqentry_text_start As explained in commit cf86a086a180 ("net/dst: use a smaller percpu_counter batch for dst entries accounting"), default batch size is too big for the default value of tcp_max_orphans (262144). But even if we reduce batch sizes, there would still be cases where the estimated count of orphans is beyond the limit, and where tcp_too_many_orphans() has to call the expensive percpu_counter_sum_positive(). One solution is to use plain per-cpu counters, and have a timer to periodically refresh this cache. Updating this cache every 100ms seems about right, tcp pressure state is not radically changing over shorter periods. percpu_counter was nice 15 years ago while hosts had less than 16 cpus, not anymore by current standards. v2: Fix the build issue for CONFIG_CRYPTO_DEV_CHELSIO_TLS=m, reported by kernel test robot <lkp@intel.com> Remove unused socket argument from tcp_too_many_orphans() Fixes: dd24c00191d5 ("net: Use a percpu_counter for orphan_count") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Stefan Bach <sfb@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-02tcp_bpf: Fix one concurrency problem in the tcp_bpf_send_verdict functionLiu Jian1-0/+12
commit cd9733f5d75c94a32544d6ce5be47e14194cf137 upstream. With two Msgs, msgA and msgB and a user doing nonblocking sendmsg calls (or multiple cores) on a single socket 'sk' we could get the following flow. msgA, sk msgB, sk ----------- --------------- tcp_bpf_sendmsg() lock(sk) psock = sk->psock tcp_bpf_sendmsg() lock(sk) ... blocking tcp_bpf_send_verdict if (psock->eval == NONE) psock->eval = sk_psock_msg_verdict .. < handle SK_REDIRECT case > release_sock(sk) < lock dropped so grab here > ret = tcp_bpf_sendmsg_redir psock = sk->psock tcp_bpf_send_verdict lock_sock(sk) ... blocking on B if (psock->eval == NONE) <- boom. psock->eval will have msgA state The problem here is we dropped the lock on msgA and grabbed it with msgB. Now we have old state in psock and importantly psock->eval has not been cleared. So msgB will run whatever action was done on A and the verdict program may never see it. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20211012052019.184398-1-liujian56@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-27tcp: md5: Fix overlap between vrf and non-vrf keysLeonard Crestez1-3/+16
[ Upstream commit 86f1e3a8489f6a0232c1f3bc2bdb379f5ccdecec ] With net.ipv4.tcp_l3mdev_accept=1 it is possible for a listen socket to accept connection from the same client address in different VRFs. It is also possible to set different MD5 keys for these clients which differ only in the tcpm_l3index field. This appears to work when distinguishing between different VRFs but not between non-VRF and VRF connections. In particular: * tcp_md5_do_lookup_exact will match a non-vrf key against a vrf key. This means that adding a key with l3index != 0 after a key with l3index == 0 will cause the earlier key to be deleted. Both keys can be present if the non-vrf key is added later. * _tcp_md5_do_lookup can match a non-vrf key before a vrf key. This casues failures if the passwords differ. Fix this by making tcp_md5_do_lookup_exact perform an actual exact comparison on l3index and by making __tcp_md5_do_lookup perfer vrf-bound keys above other considerations like prefixlen. Fixes: dea53bb80e07 ("tcp: Add l3index to tcp_md5sig_key and md5 functions") Signed-off-by: Leonard Crestez <cdleonard@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-10-13net: prefer socket bound to interface when not in VRFMike Manning2-2/+5
[ Upstream commit 8d6c414cd2fb74aa6812e9bfec6178f8246c4f3a ] The commit 6da5b0f027a8 ("net: ensure unbound datagram socket to be chosen when not in a VRF") modified compute_score() so that a device match is always made, not just in the case of an l3mdev skb, then increments the score also for unbound sockets. This ensures that sockets bound to an l3mdev are never selected when not in a VRF. But as unbound and bound sockets are now scored equally, this results in the last opened socket being selected if there are matches in the default VRF for an unbound socket and a socket bound to a dev that is not an l3mdev. However, handling prior to this commit was to always select the bound socket in this case. Reinstate this handling by incrementing the score only for bound sockets. The required isolation due to choosing between an unbound socket and a socket bound to an l3mdev remains in place due to the device match always being made. The same approach is taken for compute_score() for stream sockets. Fixes: 6da5b0f027a8 ("net: ensure unbound datagram socket to be chosen when not in a VRF") Fixes: e78190581aff ("net: ensure unbound stream socket to be chosen when not in a VRF") Signed-off-by: Mike Manning <mmanning@vyatta.att-mail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/r/cf0a8523-b362-1edf-ee78-eef63cbbb428@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-10-06net: udp: annotate data race around udp_sk(sk)->corkflagEric Dumazet1-5/+5
commit a9f5970767d11eadc805d5283f202612c7ba1f59 upstream. up->corkflag field can be read or written without any lock. Annotate accesses to avoid possible syzbot/KCSAN reports. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-06net: ipv4: Fix rtnexthop len when RTA_FLOW is presentXiao Liang1-7/+9
[ Upstream commit 597aa16c782496bf74c5dc3b45ff472ade6cee64 ] Multipath RTA_FLOW is embedded in nexthop. Dump it in fib_add_nexthop() to get the length of rtnexthop correct. Fixes: b0f60193632e ("ipv4: Refactor nexthop attributes in fib_dump_info") Signed-off-by: Xiao Liang <shaw.leon@gmail.com> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22ip_gre: validate csum_start only on pullWillem de Bruijn1-3/+6
[ Upstream commit 8a0ed250f911da31a2aef52101bc707846a800ff ] The GRE tunnel device can pull existing outer headers in ipge_xmit. This is a rare path, apparently unique to this device. The below commit ensured that pulling does not move skb->data beyond csum_start. But it has a false positive if ip_summed is not CHECKSUM_PARTIAL and thus csum_start is irrelevant. Refine to exclude this. At the same time simplify and strengthen the test. Simplify, by moving the check next to the offending pull, making it more self documenting and removing an unnecessary branch from other code paths. Strengthen, by also ensuring that the transport header is correct and therefore the inner headers will be after skb_reset_inner_headers. The transport header is set to csum_start in skb_partial_csum_set. Link: https://lore.kernel.org/netdev/YS+h%2FtqCJJiQei+W@shredder/ Fixes: 1d011c4803c7 ("ip_gre: add validation for csum_start") Reported-by: Ido Schimmel <idosch@idosch.org> Suggested-by: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22Set fc_nlinfo in nh_create_ipv4, nh_create_ipv6Ryoga Saito1-0/+2
[ Upstream commit 9aca491e0dccf8a9d84a5b478e5eee3c6ea7803b ] This patch fixes kernel NULL pointer dereference when creating nexthop which is bound with SRv6 decapsulation. In the creation of nexthop, __seg6_end_dt_vrf_build is called. __seg6_end_dt_vrf_build expects fc_lninfo in fib6_config is set correctly, but it isn't set in nh_create_ipv6, which causes kernel crash. Here is steps to reproduce kernel crash: 1. modprobe vrf 2. ip -6 nexthop add encap seg6local action End.DT4 vrftable 1 dev eth0 We got the following message: [ 901.370336] BUG: kernel NULL pointer dereference, address: 0000000000000ba0 [ 901.371658] #PF: supervisor read access in kernel mode [ 901.372672] #PF: error_code(0x0000) - not-present page [ 901.373672] PGD 0 P4D 0 [ 901.374248] Oops: 0000 [#1] SMP PTI [ 901.374944] CPU: 0 PID: 8593 Comm: ip Not tainted 5.14-051400-generic #202108310811-Ubuntu [ 901.376404] Hardware name: Red Hat KVM, BIOS 1.11.1-4.module_el8.2.0+320+13f867d7 04/01/2014 [ 901.377907] RIP: 0010:vrf_ifindex_lookup_by_table_id+0x19/0x90 [vrf] [ 901.379182] Code: c1 e9 72 ff ff ff e8 96 49 01 c2 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 56 41 55 41 89 f5 41 54 53 8b 05 47 4c 00 00 <48> 8b 97 a0 0b 00 00 48 8b 1c c2 e8 57 27 53 c1 4c 8d a3 88 00 00 [ 901.382652] RSP: 0018:ffffbf2d02043590 EFLAGS: 00010282 [ 901.383746] RAX: 000000000000000b RBX: ffff990808255e70 RCX: ffffbf2d02043aa8 [ 901.385436] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000 [ 901.386924] RBP: ffffbf2d020435b0 R08: 00000000000000c0 R09: ffff990808255e40 [ 901.388537] R10: ffffffff83b08c90 R11: 0000000000000009 R12: 0000000000000000 [ 901.389937] R13: 0000000000000001 R14: 0000000000000000 R15: 000000000000000b [ 901.391226] FS: 00007fe49381f740(0000) GS:ffff99087dc00000(0000) knlGS:0000000000000000 [ 901.392737] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 901.393803] CR2: 0000000000000ba0 CR3: 000000000e3e8003 CR4: 0000000000770ef0 [ 901.395122] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 901.396496] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 901.397833] PKRU: 55555554 [ 901.398578] Call Trace: [ 901.399144] l3mdev_ifindex_lookup_by_table_id+0x3b/0x70 [ 901.400179] __seg6_end_dt_vrf_build+0x34/0xd0 [ 901.401067] seg6_end_dt4_build+0x16/0x20 [ 901.401904] seg6_local_build_state+0x271/0x430 [ 901.402797] lwtunnel_build_state+0x81/0x130 [ 901.403645] fib_nh_common_init+0x82/0x100 [ 901.404465] ? sock_def_readable+0x4b/0x80 [ 901.405285] fib6_nh_init+0x115/0x7c0 [ 901.406033] nh_create_ipv6.isra.0+0xe1/0x140 [ 901.406932] rtm_new_nexthop+0x3b7/0xeb0 [ 901.407828] rtnetlink_rcv_msg+0x152/0x3a0 [ 901.408663] ? rtnl_calcit.isra.0+0x130/0x130 [ 901.409535] netlink_rcv_skb+0x55/0x100 [ 901.410319] rtnetlink_rcv+0x15/0x20 [ 901.411026] netlink_unicast+0x1a8/0x250 [ 901.411813] netlink_sendmsg+0x238/0x470 [ 901.412602] ? _copy_from_user+0x2b/0x60 [ 901.413394] sock_sendmsg+0x65/0x70 [ 901.414112] ____sys_sendmsg+0x218/0x290 [ 901.414929] ? copy_msghdr_from_user+0x5c/0x90 [ 901.415814] ___sys_sendmsg+0x81/0xc0 [ 901.416559] ? fsnotify_destroy_marks+0x27/0xf0 [ 901.417447] ? call_rcu+0xa4/0x230 [ 901.418153] ? kmem_cache_free+0x23f/0x410 [ 901.418972] ? dentry_free+0x37/0x70 [ 901.419705] ? mntput_no_expire+0x4c/0x260 [ 901.420574] __sys_sendmsg+0x62/0xb0 [ 901.421297] __x64_sys_sendmsg+0x1f/0x30 [ 901.422057] do_syscall_64+0x5c/0xc0 [ 901.422756] ? syscall_exit_to_user_mode+0x27/0x50 [ 901.423675] ? __x64_sys_close+0x12/0x40 [ 901.424462] ? do_syscall_64+0x69/0xc0 [ 901.425219] ? irqentry_exit_to_user_mode+0x9/0x20 [ 901.426149] ? irqentry_exit+0x19/0x30 [ 901.426901] ? exc_page_fault+0x89/0x160 [ 901.427709] ? asm_exc_page_fault+0x8/0x30 [ 901.428536] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 901.429514] RIP: 0033:0x7fe493945747 [ 901.430248] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 [ 901.433549] RSP: 002b:00007ffe9932cf68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 901.434981] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe493945747 [ 901.436303] RDX: 0000000000000000 RSI: 00007ffe9932cfe0 RDI: 0000000000000003 [ 901.437607] RBP: 00000000613053f7 R08: 0000000000000001 R09: 00007ffe9932d07c [ 901.438990] R10: 000055f4a903a010 R11: 0000000000000246 R12: 0000000000000001 [ 901.440340] R13: 0000000000000001 R14: 000055f4a802b163 R15: 000055f4a8042020 [ 901.441630] Modules linked in: vrf nls_utf8 isofs nls_iso8859_1 dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua intel_rapl_msr intel_rapl_common isst_if_mbox_msr isst_if_common nfit rapl input_leds joydev serio_raw qemu_fw_cfg mac_hid sch_fq_codel drm virtio_rng ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel crypto_simd virtio_net net_failover cryptd psmouse virtio_blk failover i2c_piix4 pata_acpi floppy [ 901.450808] CR2: 0000000000000ba0 [ 901.451514] ---[ end trace c27b934b99ade304 ]--- [ 901.452403] RIP: 0010:vrf_ifindex_lookup_by_table_id+0x19/0x90 [vrf] [ 901.453626] Code: c1 e9 72 ff ff ff e8 96 49 01 c2 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 41 56 41 55 41 89 f5 41 54 53 8b 05 47 4c 00 00 <48> 8b 97 a0 0b 00 00 48 8b 1c c2 e8 57 27 53 c1 4c 8d a3 88 00 00 [ 901.456910] RSP: 0018:ffffbf2d02043590 EFLAGS: 00010282 [ 901.457912] RAX: 000000000000000b RBX: ffff990808255e70 RCX: ffffbf2d02043aa8 [ 901.459238] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000000 [ 901.460552] RBP: ffffbf2d020435b0 R08: 00000000000000c0 R09: ffff990808255e40 [ 901.461882] R10: ffffffff83b08c90 R11: 0000000000000009 R12: 0000000000000000 [ 901.463208] R13: 0000000000000001 R14: 0000000000000000 R15: 000000000000000b [ 901.464529] FS: 00007fe49381f740(0000) GS:ffff99087dc00000(0000) knlGS:0000000000000000 [ 901.466058] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 901.467189] CR2: 0000000000000ba0 CR3: 000000000e3e8003 CR4: 0000000000770ef0 [ 901.468515] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 901.469858] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 901.471139] PKRU: 55555554 Signed-off-by: Ryoga Saito <contact@proelbtn.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-22udp_tunnel: Fix udp_tunnel_nic work-queue typeAya Levin1-1/+1
commit e50e711351bdc656a8e6ca1022b4293cae8dcd59 upstream. Turn udp_tunnel_nic work-queue to an ordered work-queue. This queue holds the UDP-tunnel configuration commands of the different netdevs. When the netdevs are functions of the same NIC the order of execution may be crucial. Problem example: NIC with 2 PFs, both PFs declare offload quota of up to 3 UDP-ports. $ifconfig eth2 1.1.1.1/16 up $ip link add eth2_19503 type vxlan id 5049 remote 1.1.1.2 dev eth2 dstport 19053 $ip link set dev eth2_19503 up $ip link add eth2_19504 type vxlan id 5049 remote 1.1.1.3 dev eth2 dstport 19054 $ip link set dev eth2_19504 up $ip link add eth2_19505 type vxlan id 5049 remote 1.1.1.4 dev eth2 dstport 19055 $ip link set dev eth2_19505 up $ip link add eth2_19506 type vxlan id 5049 remote 1.1.1.5 dev eth2 dstport 19056 $ip link set dev eth2_19506 up NIC RX port offload infrastructure offloads the first 3 UDP-ports (on all devices which sets NETIF_F_RX_UDP_TUNNEL_PORT feature) and not UDP-port 19056. So both PFs gets this offload configuration. $ip link set dev eth2_19504 down This triggers udp-tunnel-core to remove the UDP-port 19504 from offload-ports-list and offload UDP-port 19056 instead. In this scenario it is important that the UDP-port of 19504 will be removed from both PFs before trying to add UDP-port 19056. The NIC can stop offloading a UDP-port only when all references are removed. Otherwise the NIC may report exceeding of the offload quota. Fixes: cc4e3835eff4 ("udp_tunnel: add central NIC RX port offload infrastructure") Signed-off-by: Aya Levin <ayal@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-22tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()zhenggy1-1/+1
commit 4f884f3962767877d7aabbc1ec124d2c307a4257 upstream. Commit 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") may directly retrans a multiple segments TSO/GSO packet without split, Since this commit, we can no longer assume that a retransmitted packet is a single segment. This patch fixes the tp->undo_retrans accounting in tcp_sacktag_one() that use the actual segments(pcount) of the retransmitted packet. Before that commit (10d3be569243), the assumption underlying the tp->undo_retrans-- seems correct. Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") Signed-off-by: zhenggy <zhenggy@chinatelecom.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-18tcp: enable data-less, empty-cookie SYN with TFO_SERVER_COOKIE_NOT_REQDLuke Hsiao1-2/+1
[ Upstream commit e3faa49bcecdfcc80e94dd75709d6acb1a5d89f6 ] Since the original TFO server code was implemented in commit 168a8f58059a22feb9e9a2dcc1b8053dbbbc12ef ("tcp: TCP Fast Open Server - main code path") the TFO server code has supported the sysctl bit flag TFO_SERVER_COOKIE_NOT_REQD. Currently, when the TFO_SERVER_ENABLE and TFO_SERVER_COOKIE_NOT_REQD sysctl bit flags are set, a server connection will accept a SYN with N bytes of data (N > 0) that has no TFO cookie, create a new fast open connection, process the incoming data in the SYN, and make the connection ready for accepting. After accepting, the connection is ready for read()/recvmsg() to read the N bytes of data in the SYN, ready for write()/sendmsg() calls and data transmissions to transmit data. This commit changes an edge case in this feature by changing this behavior to apply to (N >= 0) bytes of data in the SYN rather than only (N > 0) bytes of data in the SYN. Now, a server will accept a data-less SYN without a TFO cookie if TFO_SERVER_COOKIE_NOT_REQD is set. Caveat! While this enables a new kind of TFO (data-less empty-cookie SYN), some firewall rules setup may not work if they assume such packets are not legit TFOs and will filter them. Signed-off-by: Luke Hsiao <lukehsiao@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20210816205105.2533289-1-luke.w.hsiao@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-18ipv4: ip_output.c: Fix out-of-bounds warning in ip_copy_addrs()Gustavo A. R. Silva1-2/+3
[ Upstream commit 6321c7acb82872ef6576c520b0e178eaad3a25c0 ] Fix the following out-of-bounds warning: In function 'ip_copy_addrs', inlined from '__ip_queue_xmit' at net/ipv4/ip_output.c:517:2: net/ipv4/ip_output.c:449:2: warning: 'memcpy' offset [40, 43] from the object at 'fl' is out of the bounds of referenced subobject 'saddr' with type 'unsigned int' at offset 36 [-Warray-bounds] 449 | memcpy(&iph->saddr, &fl4->saddr, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 450 | sizeof(fl4->saddr) + sizeof(fl4->daddr)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The problem is that the original code is trying to copy data into a couple of struct members adjacent to each other in a single call to memcpy(). This causes a legitimate compiler warning because memcpy() overruns the length of &iph->saddr and &fl4->saddr. As these are just a couple of struct members, fix this by using direct assignments, instead of memcpy(). This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/d5ae2e65-1f18-2577-246f-bada7eee6ccd@intel.com/ Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15ipv4: fix endianness issue in inet_rtm_getroute_build_skb()Eric Dumazet1-1/+1
[ Upstream commit 92548b0ee220e000d81c27ac9a80e0ede895a881 ] The UDP length field should be in network order. This removes the following sparse error: net/ipv4/route.c:3173:27: warning: incorrect type in assignment (different base types) net/ipv4/route.c:3173:27: expected restricted __be16 [usertype] len net/ipv4/route.c:3173:27: got unsigned long Fixes: 404eb77ea766 ("ipv4: support sport, dport and ip_proto in RTM_GETROUTE") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Roopa Prabhu <roopa@nvidia.com> Cc: David Ahern <dsahern@kernel.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15ipv4: make exception cache less predictibleEric Dumazet1-16/+30
[ Upstream commit 67d6d681e15b578c1725bad8ad079e05d1c48a8e ] Even after commit 6457378fe796 ("ipv4: use siphash instead of Jenkins in fnhe_hashfun()"), an attacker can still use brute force to learn some secrets from a victim linux host. One way to defeat these attacks is to make the max depth of the hash table bucket a random value. Before this patch, each bucket of the hash table used to store exceptions could contain 6 items under attack. After the patch, each bucket would contains a random number of items, between 6 and 10. The attacker can no longer infer secrets. This is slightly increasing memory size used by the hash table, by 50% in average, we do not expect this to be a problem. This patch is more complex than the prior one (IPv6 equivalent), because IPv4 was reusing the oldest entry. Since we need to be able to evict more than one entry per update_or_create_fnhe() call, I had to replace fnhe_oldest() with fnhe_remove_oldest(). Also note that we will queue extra kfree_rcu() calls under stress, which hopefully wont be a too big issue. Fixes: 4895c771c7f0 ("ipv4: Add FIB nexthop exceptions.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Keyu Man <kman001@ucr.edu> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net> Reviewed-by: David Ahern <dsahern@kernel.org> Tested-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15tcp: seq_file: Avoid skipping sk during tcp_seek_last_posMartin KaFai Lau1-2/+3
[ Upstream commit 525e2f9fd0229eb10cb460a9e6d978257f24804e ] st->bucket stores the current bucket number. st->offset stores the offset within this bucket that is the sk to be seq_show(). Thus, st->offset only makes sense within the same st->bucket. These two variables are an optimization for the common no-lseek case. When resuming the seq_file iteration (i.e. seq_start()), tcp_seek_last_pos() tries to continue from the st->offset at bucket st->bucket. However, it is possible that the bucket pointed by st->bucket has changed and st->offset may end up skipping the whole st->bucket without finding a sk. In this case, tcp_seek_last_pos() currently continues to satisfy the offset condition in the next (and incorrect) bucket. Instead, regardless of the offset value, the first sk of the next bucket should be returned. Thus, "bucket == st->bucket" check is added to tcp_seek_last_pos(). The chance of hitting this is small and the issue is a decade old, so targeting for the next tree. Fixes: a8b690f98baf ("tcp: Fix slowness in read /proc/net/tcp") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210701200541.1033917-1-kafai@fb.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-12igmp: Add ip_mc_list lock in ip_check_mc_rcuLiu Jian1-0/+2
commit 23d2b94043ca8835bd1e67749020e839f396a1c2 upstream. I got below panic when doing fuzz test: Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 4056 Comm: syz-executor.3 Tainted: G B 5.14.0-rc1-00195-gcff5c4254439-dirty #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl+0x7a/0x9b panic+0x2cd/0x5af end_report.cold+0x5a/0x5a kasan_report+0xec/0x110 ip_check_mc_rcu+0x556/0x5d0 __mkroute_output+0x895/0x1740 ip_route_output_key_hash_rcu+0x2d0/0x1050 ip_route_output_key_hash+0x182/0x2e0 ip_route_output_flow+0x28/0x130 udp_sendmsg+0x165d/0x2280 udpv6_sendmsg+0x121e/0x24f0 inet6_sendmsg+0xf7/0x140 sock_sendmsg+0xe9/0x180 ____sys_sendmsg+0x2b8/0x7a0 ___sys_sendmsg+0xf0/0x160 __sys_sendmmsg+0x17e/0x3c0 __x64_sys_sendmmsg+0x9e/0x100 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x462eb9 Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3df5af1c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 000000000073bf00 RCX: 0000000000462eb9 RDX: 0000000000000312 RSI: 0000000020001700 RDI: 0000000000000007 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3df5af26bc R13: 00000000004c372d R14: 0000000000700b10 R15: 00000000ffffffff It is one use-after-free in ip_check_mc_rcu. In ip_mc_del_src, the ip_sf_list of pmc has been freed under pmc->lock protection. But access to ip_sf_list in ip_check_mc_rcu is not protected by the lock. Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-03ipv4: use siphash instead of Jenkins in fnhe_hashfun()Eric Dumazet1-6/+6
[ Upstream commit 6457378fe796815c973f631a1904e147d6ee33b1 ] A group of security researchers brought to our attention the weakness of hash function used in fnhe_hashfun(). Lets use siphash instead of Jenkins Hash, to considerably reduce security risks. Also remove the inline keyword, this really is distracting. Fixes: d546c621542d ("ipv4: harden fnhe_hashfun()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Keyu Man <kman001@ucr.edu> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-03ip_gre: add validation for csum_startShreyansh Chouhan1-0/+2
[ Upstream commit 1d011c4803c72f3907eccfc1ec63caefb852fcbf ] Validate csum_start in gre_handle_offloads before we call _gre_xmit so that we do not crash later when the csum_start value is used in the lco_csum function call. This patch deals with ipv4 code. Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Reported-by: syzbot+ff8e1b9f2f36481e2efc@syzkaller.appspotmail.com Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-18net: igmp: increase size of mr_ifc_countEric Dumazet1-1/+1
[ Upstream commit b69dd5b3780a7298bd893816a09da751bc0636f7 ] Some arches support cmpxchg() on 4-byte and 8-byte only. Increase mr_ifc_count width to 32bit to fix this problem. Fixes: 4a2b285e7e10 ("net: igmp: fix data-race in igmp_ifc_timer_expire()") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20210811195715.3684218-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-18tcp_bbr: fix u32 wrap bug in round logic if bbr_init() called after 2B packetsNeal Cardwell1-1/+1
[ Upstream commit 6de035fec045f8ae5ee5f3a02373a18b939e91fb ] Currently if BBR congestion control is initialized after more than 2B packets have been delivered, depending on the phase of the tp->delivered counter the tracking of BBR round trips can get stuck. The bug arises because if tp->delivered is between 2^31 and 2^32 at the time the BBR congestion control module is initialized, then the initialization of bbr->next_rtt_delivered to 0 will cause the logic to believe that the end of the round trip is still billions of packets in the future. More specifically, the following check will fail repeatedly: !before(rs->prior_delivered, bbr->next_rtt_delivered) and thus the connection will take up to 2B packets delivered before that check will pass and the connection will set: bbr->round_start = 1; This could cause many mechanisms in BBR to fail to trigger, for example bbr_check_full_bw_reached() would likely never exit STARTUP. This bug is 5 years old and has not been observed, and as a practical matter this would likely rarely trigger, since it would require transferring at least 2B packets, or likely more than 3 terabytes of data, before switching congestion control algorithms to BBR. This patch is a stable candidate for kernels as far back as v4.9, when tcp_bbr.c was added. Fixes: 0f8782ea1497 ("tcp_bbr: add BBR congestion control") Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Reviewed-by: Kevin Yang <yyd@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20210811024056.235161-1-ncardwell@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-18net: igmp: fix data-race in igmp_ifc_timer_expire()Eric Dumazet1-7/+14
[ Upstream commit 4a2b285e7e103d4d6c6ed3e5052a0ff74a5d7f15 ] Fix the data-race reported by syzbot [1] Issue here is that igmp_ifc_timer_expire() can update in_dev->mr_ifc_count while another change just occured from another context. in_dev->mr_ifc_count is only 8bit wide, so the race had little consequences. [1] BUG: KCSAN: data-race in igmp_ifc_event / igmp_ifc_timer_expire write to 0xffff8881051e3062 of 1 bytes by task 12547 on cpu 0: igmp_ifc_event+0x1d5/0x290 net/ipv4/igmp.c:821 igmp_group_added+0x462/0x490 net/ipv4/igmp.c:1356 ____ip_mc_inc_group+0x3ff/0x500 net/ipv4/igmp.c:1461 __ip_mc_join_group+0x24d/0x2c0 net/ipv4/igmp.c:2199 ip_mc_join_group_ssm+0x20/0x30 net/ipv4/igmp.c:2218 do_ip_setsockopt net/ipv4/ip_sockglue.c:1285 [inline] ip_setsockopt+0x1827/0x2a80 net/ipv4/ip_sockglue.c:1423 tcp_setsockopt+0x8c/0xa0 net/ipv4/tcp.c:3657 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3362 __sys_setsockopt+0x18f/0x200 net/socket.c:2159 __do_sys_setsockopt net/socket.c:2170 [inline] __se_sys_setsockopt net/socket.c:2167 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2167 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881051e3062 of 1 bytes by interrupt on cpu 1: igmp_ifc_timer_expire+0x706/0xa30 net/ipv4/igmp.c:808 call_timer_fn+0x2e/0x1d0 kernel/time/timer.c:1419 expire_timers+0x135/0x250 kernel/time/timer.c:1464 __run_timers+0x358/0x420 kernel/time/timer.c:1732 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1745 __do_softirq+0x12c/0x26e kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x9a/0xb0 kernel/softirq.c:636 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 console_unlock+0x8e8/0xb30 kernel/printk/printk.c:2646 vprintk_emit+0x125/0x3d0 kernel/printk/printk.c:2174 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392 printk+0x62/0x87 kernel/printk/printk.c:2216 selinux_netlink_send+0x399/0x400 security/selinux/hooks.c:6041 security_netlink_send+0x42/0x90 security/security.c:2070 netlink_sendmsg+0x59e/0x7c0 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:703 [inline] sock_sendmsg net/socket.c:723 [inline] ____sys_sendmsg+0x360/0x4d0 net/socket.c:2392 ___sys_sendmsg net/socket.c:2446 [inline] __sys_sendmsg+0x1ed/0x270 net/socket.c:2475 __do_sys_sendmsg net/socket.c:2484 [inline] __se_sys_sendmsg net/socket.c:2482 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2482 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x01 -> 0x02 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 12539 Comm: syz-executor.1 Not tainted 5.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-12net, gro: Set inner transport header offset in tcp/udp GRO hookJakub Sitnicki2-0/+7
[ Upstream commit d51c5907e9809a803b276883d203f45849abd4d6 ] GSO expects inner transport header offset to be valid when skb->encapsulation flag is set. GSO uses this value to calculate the length of an individual segment of a GSO packet in skb_gso_transport_seglen(). However, tcp/udp gro_complete callbacks don't update the skb->inner_transport_header when processing an encapsulated TCP/UDP segment. As a result a GRO skb has ->inner_transport_header set to a value carried over from earlier skb processing. This can have mild to tragic consequences. From miscalculating the GSO segment length to triggering a page fault [1], when trying to read TCP/UDP header at an address past the skb->data page. The latter scenario leads to an oops report like so: BUG: unable to handle page fault for address: ffff9fa7ec00d008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 123f201067 P4D 123f201067 PUD 123f209067 PMD 0 Oops: 0000 [#1] SMP NOPTI CPU: 44 PID: 0 Comm: swapper/44 Not tainted 5.4.53-cloudflare-2020.7.21 #1 Hardware name: HYVE EDGE-METAL-GEN10/HS-1811DLite1, BIOS V2.15 02/21/2020 RIP: 0010:skb_gso_transport_seglen+0x44/0xa0 Code: c0 41 83 e0 11 f6 87 81 00 00 00 20 74 30 0f b7 87 aa 00 00 00 0f [...] RSP: 0018:ffffad8640bacbb8 EFLAGS: 00010202 RAX: 000000000000feda RBX: ffff9fcc8d31bc00 RCX: ffff9fa7ec00cffc RDX: ffff9fa7ebffdec0 RSI: 000000000000feda RDI: 0000000000000122 RBP: 00000000000005c4 R08: 0000000000000001 R09: 0000000000000000 R10: ffff9fe588ae3800 R11: ffff9fe011fc92f0 R12: ffff9fcc8d31bc00 R13: ffff9fe0119d4300 R14: 00000000000005c4 R15: ffff9fba57d70900 FS: 0000000000000000(0000) GS:ffff9fe68df00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff9fa7ec00d008 CR3: 0000003e99b1c000 CR4: 0000000000340ee0 Call Trace: <IRQ> skb_gso_validate_network_len+0x11/0x70 __ip_finish_output+0x109/0x1c0 ip_sublist_rcv_finish+0x57/0x70 ip_sublist_rcv+0x2aa/0x2d0 ? ip_rcv_finish_core.constprop.0+0x390/0x390 ip_list_rcv+0x12b/0x14f __netif_receive_skb_list_core+0x2a9/0x2d0 netif_receive_skb_list_internal+0x1b5/0x2e0 napi_complete_done+0x93/0x140 veth_poll+0xc0/0x19f [veth] ? mlx5e_napi_poll+0x221/0x610 [mlx5_core] net_rx_action+0x1f8/0x790 __do_softirq+0xe1/0x2bf irq_exit+0x8e/0xc0 do_IRQ+0x58/0xe0 common_interrupt+0xf/0xf </IRQ> The bug can be observed in a simple setup where we send IP/GRE/IP/TCP packets into a netns over a veth pair. Inside the netns, packets are forwarded to dummy device: trafgen -> [veth A]--[veth B] -forward-> [dummy] For veth B to GRO aggregate packets on receive, it needs to have an XDP program attached (for example, a trivial XDP_PASS). Additionally, for UDP, we need to enable GSO_UDP_L4 feature on the device: ip netns exec A ethtool -K AB rx-udp-gro-forwarding on The last component is an artificial delay to increase the chances of GRO batching happening: ip netns exec A tc qdisc add dev AB root \ netem delay 200us slot 5ms 10ms packets 2 bytes 64k With such a setup in place, the bug can be observed by tracing the skb outer and inner offsets when GSO skb is transmitted from the dummy device: tcp: FUNC DEV SKB_LEN NH TH ENC INH ITH GSO_SIZE GSO_TYPE ip_finish_output dumB 2830 270 290 1 294 254 1383 (tcpv4,gre,) ^^^ udp: FUNC DEV SKB_LEN NH TH ENC INH ITH GSO_SIZE GSO_TYPE ip_finish_output dumB 2818 270 290 1 294 254 1383 (gre,udp_l4,) ^^^ Fix it by updating the inner transport header offset in tcp/udp gro_complete callbacks, similar to how {inet,ipv6}_gro_complete callbacks update the inner network header offset, when skb->encapsulation flag is set. [1] https://lore.kernel.org/netdev/CAKxSbF01cLpZem2GFaUaifh0S-5WYViZemTicAg7FCHOnh6kug@mail.gmail.com/ Fixes: bf296b125b21 ("tcp: Add GRO support") Fixes: f993bc25e519 ("net: core: handle encapsulation offloads when computing segment lengths") Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") Reported-by: Alex Forster <aforster@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-04net: Set true network header for ECN decapsulationGilad Naaman1-1/+1
[ Upstream commit 227adfb2b1dfbc53dfc53b9dd7a93a6298ff7c56 ] In cases where the header straight after the tunnel header was another ethernet header (TEB), instead of the network header, the ECN decapsulation code would treat the ethernet header as if it was an IP header, resulting in mishandling and possible wrong drops or corruption of the IP header. In this case, ECT(1) is sent, so IP_ECN_decapsulate tries to copy it to the inner IPv4 header, and correct its checksum. The offset of the ECT bits in an IPv4 header corresponds to the lower 2 bits of the second octet of the destination MAC address in the ethernet header. The IPv4 checksum corresponds to end of the source address. In order to reproduce: $ ip netns add A $ ip netns add B $ ip -n A link add _v0 type veth peer name _v1 netns B $ ip -n A link set _v0 up $ ip -n A addr add dev _v0 10.254.3.1/24 $ ip -n A route add default dev _v0 scope global $ ip -n B link set _v1 up $ ip -n B addr add dev _v1 10.254.1.6/24 $ ip -n B route add default dev _v1 scope global $ ip -n B link add gre1 type gretap local 10.254.1.6 remote 10.254.3.1 key 0x49000000 $ ip -n B link set gre1 up # Now send an IPv4/GRE/Eth/IPv4 frame where the outer header has ECT(1), # and the inner header has no ECT bits set: $ cat send_pkt.py #!/usr/bin/env python3 from scapy.all import * pkt = IP(b'E\x01\x00\xa7\x00\x00\x00\x00@/`%\n\xfe\x03\x01\n\xfe\x01\x06 \x00eXI\x00' b'\x00\x00\x18\xbe\x92\xa0\xee&\x18\xb0\x92\xa0l&\x08\x00E\x00\x00}\x8b\x85' b'@\x00\x01\x01\xe4\xf2\x82\x82\x82\x01\x82\x82\x82\x02\x08\x00d\x11\xa6\xeb' b'3\x1e\x1e\\xf3\\xf7`\x00\x00\x00\x00ZN\x00\x00\x00\x00\x00\x00\x10\x11\x12' b'\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234' b'56789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ') send(pkt) $ sudo ip netns exec B tcpdump -neqlllvi gre1 icmp & ; sleep 1 $ sudo ip netns exec A python3 send_pkt.py In the original packet, the source/destinatio MAC addresses are dst=18:be:92:a0:ee:26 src=18:b0:92:a0:6c:26 In the received packet, they are dst=18:bd:92:a0:ee:26 src=18:b0:92:a0:6c:27 Thanks to Lahav Schlesinger <lschlesinger@drivenets.com> and Isaac Garzon <isaac@speed.io> for helping me pinpoint the origin. Fixes: b723748750ec ("tunnel: Propagate ECT(1) when decapsulating as recommended by RFC6040") Cc: David S. Miller <davem@davemloft.net> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: David Ahern <dsahern@kernel.org> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Gilad Naaman <gnaaman@drivenets.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28tcp: disable TFO blackhole logic by defaultWei Wang2-2/+9
[ Upstream commit 213ad73d06073b197a02476db3a4998e219ddb06 ] Multiple complaints have been raised from the TFO users on the internet stating that the TFO blackhole logic is too aggressive and gets falsely triggered too often. (e.g. https://blog.apnic.net/2021/07/05/tcp-fast-open-not-so-fast/) Considering that most middleboxes no longer drop TFO packets, we decide to disable the blackhole logic by setting /proc/sys/net/ipv4/tcp_fastopen_blackhole_timeout_set to 0 by default. Fixes: cf1ef3f0719b4 ("net/tcp_fastopen: Disable active side TFO in certain scenarios") Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28net/tcp_fastopen: fix data races around tfo_active_disable_stampEric Dumazet1-3/+16
[ Upstream commit 6f20c8adb1813467ea52c1296d52c4e95978cb2f ] tfo_active_disable_stamp is read and written locklessly. We need to annotate these accesses appropriately. Then, we need to perform the atomic_inc(tfo_active_disable_times) after the timestamp has been updated, and thus add barriers to make sure tcp_fastopen_active_should_disable() wont read a stale timestamp. Fixes: cf1ef3f0719b ("net/tcp_fastopen: Disable active side TFO in certain scenarios") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Wei Wang <weiwan@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Wei Wang <weiwan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28bpf, sockmap, udp: sk_prot needs inuse_idx set for proc statsJakub Sitnicki1-1/+1
[ Upstream commit 54ea2f49fd9400dd698c25450be3352b5613b3b4 ] The proc socket stats use sk_prot->inuse_idx value to record inuse sock stats. We currently do not set this correctly from sockmap side. The result is reading sock stats '/proc/net/sockstat' gives incorrect values. The socket counter is incremented correctly, but because we don't set the counter correctly when we replace sk_prot we may omit the decrement. To get the correct inuse_idx value move the core_initcall that initializes the UDP proto handlers to late_initcall. This way it is initialized after UDP has the chance to assign the inuse_idx value from the register protocol handler. Fixes: edc6741cc660 ("bpf: Add sockmap hooks for UDP sockets") Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Cong Wang <cong.wang@bytedance.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20210714154750.528206-1-jakub@cloudflare.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28bpf, sockmap, tcp: sk_prot needs inuse_idx set for proc statsJohn Fastabend1-1/+1
[ Upstream commit 228a4a7ba8e99bb9ef980b62f71e3be33f4aae69 ] The proc socket stats use sk_prot->inuse_idx value to record inuse sock stats. We currently do not set this correctly from sockmap side. The result is reading sock stats '/proc/net/sockstat' gives incorrect values. The socket counter is incremented correctly, but because we don't set the counter correctly when we replace sk_prot we may omit the decrement. To get the correct inuse_idx value move the core_initcall that initializes the TCP proto handlers to late_initcall. This way it is initialized after TCP has the chance to assign the inuse_idx value from the register protocol handler. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Suggested-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Cong Wang <cong.wang@bytedance.com> Link: https://lore.kernel.org/bpf/20210712195546.423990-3-john.fastabend@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-25udp: annotate data races around unix_sk(sk)->gso_sizeEric Dumazet1-3/+3
commit 18a419bad63b7f68a1979e28459782518e7b6bbe upstream. Accesses to unix_sk(sk)->gso_size are lockless. Add READ_ONCE()/WRITE_ONCE() around them. BUG: KCSAN: data-race in udp_lib_setsockopt / udpv6_sendmsg write to 0xffff88812d78f47c of 2 bytes by task 10849 on cpu 1: udp_lib_setsockopt+0x3b3/0x710 net/ipv4/udp.c:2696 udpv6_setsockopt+0x63/0x90 net/ipv6/udp.c:1630 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3265 __sys_setsockopt+0x18f/0x200 net/socket.c:2104 __do_sys_setsockopt net/socket.c:2115 [inline] __se_sys_setsockopt net/socket.c:2112 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2112 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88812d78f47c of 2 bytes by task 10852 on cpu 0: udpv6_sendmsg+0x161/0x16b0 net/ipv6/udp.c:1299 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:2337 ___sys_sendmsg net/socket.c:2391 [inline] __sys_sendmmsg+0x315/0x4b0 net/socket.c:2477 __do_sys_sendmmsg net/socket.c:2506 [inline] __se_sys_sendmmsg net/socket.c:2503 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2503 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000 -> 0x0005 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 10852 Comm: syz-executor.0 Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25tcp: call sk_wmem_schedule before sk_mem_charge in zerocopy pathTalal Ahmad1-0/+3
commit 358ed624207012f03318235017ac6fb41f8af592 upstream. sk_wmem_schedule makes sure that sk_forward_alloc has enough bytes for charging that is going to be done by sk_mem_charge. In the transmit zerocopy path, there is sk_mem_charge but there was no call to sk_wmem_schedule. This change adds that call. Without this call to sk_wmem_schedule, sk_forward_alloc can go negetive which is a bug because sk_forward_alloc is a per-socket space that has been forward charged so this can't be negative. Fixes: f214f915e7db ("tcp: enable MSG_ZEROCOPY") Signed-off-by: Talal Ahmad <talalahmad@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Wei Wang <weiwan@google.com> Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25ipv6: tcp: drop silly ICMPv6 packet too big messagesEric Dumazet1-0/+1
commit c7bb4b89033b764eb07db4e060548a6311d801ee upstream. While TCP stack scales reasonably well, there is still one part that can be used to DDOS it. IPv6 Packet too big messages have to lookup/insert a new route, and if abused by attackers, can easily put hosts under high stress, with many cpus contending on a spinlock while one is stuck in fib6_run_gc() ip6_protocol_deliver_rcu() icmpv6_rcv() icmpv6_notify() tcp_v6_err() tcp_v6_mtu_reduced() inet6_csk_update_pmtu() ip6_rt_update_pmtu() __ip6_rt_update_pmtu() ip6_rt_cache_alloc() ip6_dst_alloc() dst_alloc() ip6_dst_gc() fib6_run_gc() spin_lock_bh() ... Some of our servers have been hit by malicious ICMPv6 packets trying to _increase_ the MTU/MSS of TCP flows. We believe these ICMPv6 packets are a result of a bug in one ISP stack, since they were blindly sent back for _every_ (small) packet sent to them. These packets are for one TCP flow: 09:24:36.266491 IP6 Addr1 > Victim ICMP6, packet too big, mtu 1460, length 1240 09:24:36.266509 IP6 Addr1 > Victim ICMP6, packet too big, mtu 1460, length 1240 09:24:36.316688 IP6 Addr1 > Victim ICMP6, packet too big, mtu 1460, length 1240 09:24:36.316704 IP6 Addr1 > Victim ICMP6, packet too big, mtu 1460, length 1240 09:24:36.608151 IP6 Addr1 > Victim ICMP6, packet too big, mtu 1460, length 1240 TCP stack can filter some silly requests : 1) MTU below IPV6_MIN_MTU can be filtered early in tcp_v6_err() 2) tcp_v6_mtu_reduced() can drop requests trying to increase current MSS. This tests happen before the IPv6 routing stack is entered, thus removing the potential contention and route exhaustion. Note that IPv6 stack was performing these checks, but too late (ie : after the route has been added, and after the potential garbage collect war) v2: fix typo caught by Martin, thanks ! v3: exports tcp_mtu_to_mss(), caught by David, thanks ! Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Cc: Martin KaFai Lau <kafai@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25tcp: fix tcp_init_transfer() to not reset icsk_ca_initializedNguyen Dinh Phi1-1/+1
commit be5d1b61a2ad28c7e57fe8bfa277373e8ecffcdc upstream. This commit fixes a bug (found by syzkaller) that could cause spurious double-initializations for congestion control modules, which could cause memory leaks or other problems for congestion control modules (like CDG) that allocate memory in their init functions. The buggy scenario constructed by syzkaller was something like: (1) create a TCP socket (2) initiate a TFO connect via sendto() (3) while socket is in TCP_SYN_SENT, call setsockopt(TCP_CONGESTION), which calls: tcp_set_congestion_control() -> tcp_reinit_congestion_control() -> tcp_init_congestion_control() (4) receive ACK, connection is established, call tcp_init_transfer(), set icsk_ca_initialized=0 (without first calling cc->release()), call tcp_init_congestion_control() again. Note that in this sequence tcp_init_congestion_control() is called twice without a cc->release() call in between. Thus, for CC modules that allocate memory in their init() function, e.g, CDG, a memory leak may occur. The syzkaller tool managed to find a reproducer that triggered such a leak in CDG. The bug was introduced when that commit 8919a9b31eb4 ("tcp: Only init congestion control if not initialized already") introduced icsk_ca_initialized and set icsk_ca_initialized to 0 in tcp_init_transfer(), missing the possibility for a sequence like the one above, where a process could call setsockopt(TCP_CONGESTION) in state TCP_SYN_SENT (i.e. after the connect() or TFO open sendmsg()), which would call tcp_init_congestion_control(). It did not intend to reset any initialization that the user had already explicitly made; it just missed the possibility of that particular sequence (which syzkaller managed to find). Fixes: 8919a9b31eb4 ("tcp: Only init congestion control if not initialized already") Reported-by: syzbot+f1e24a0594d4e3a895d3@syzkaller.appspotmail.com Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>