linux/net/ipv4, branch v5.9

tcp: fix receive window update in tcp_add_backlog()

2020-10-06T13:11:58Z

We got reports from GKE customers flows being reset by netfilter conntrack unless nf_conntrack_tcp_be_liberal is set to 1. Traces seemed to suggest ACK packet being dropped by the packet capture, or more likely that ACK were received in the wrong order. wscale=7, SYN and SYNACK not shown here. This ACK allows the sender to send 1871*128 bytes from seq 51359321 : New right edge of the window -> 51359321+1871*128=51598809 09:17:23.389210 IP A > B: Flags [.], ack 51359321, win 1871, options [nop,nop,TS val 10 ecr 999], length 0 09:17:23.389212 IP B > A: Flags [.], seq 51422681:51424089, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 1408 09:17:23.389214 IP A > B: Flags [.], ack 51422681, win 1376, options [nop,nop,TS val 10 ecr 999], length 0 09:17:23.389253 IP B > A: Flags [.], seq 51424089:51488857, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 64768 09:17:23.389272 IP A > B: Flags [.], ack 51488857, win 859, options [nop,nop,TS val 10 ecr 999], length 0 09:17:23.389275 IP B > A: Flags [.], seq 51488857:51521241, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 32384 Receiver now allows to send 606*128=77568 from seq 51521241 : New right edge of the window -> 51521241+606*128=51598809 09:17:23.389296 IP A > B: Flags [.], ack 51521241, win 606, options [nop,nop,TS val 10 ecr 999], length 0 09:17:23.389308 IP B > A: Flags [.], seq 51521241:51553625, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 32384 It seems the sender exceeds RWIN allowance, since 51611353 > 51598809 09:17:23.389346 IP B > A: Flags [.], seq 51553625:51611353, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 57728 09:17:23.389356 IP B > A: Flags [.], seq 51611353:51618393, ack 1577, win 268, options [nop,nop,TS val 999 ecr 10], length 7040 09:17:23.389367 IP A > B: Flags [.], ack 51611353, win 0, options [nop,nop,TS val 10 ecr 999], length 0 netfilter conntrack is not happy and sends RST 09:17:23.389389 IP A > B: Flags [R], seq 92176528, win 0, length 0 09:17:23.389488 IP B > A: Flags [R], seq 174478967, win 0, length 0 Now imagine ACK were delivered out of order and tcp_add_backlog() sets window based on wrong packet. New right edge of the window -> 51521241+859*128=51631193 Normally TCP stack handles OOO packets just fine, but it turns out tcp_add_backlog() does not. It can update the window field of the aggregated packet even if the ACK sequence of the last received packet is too old. Many thanks to Alexandre Ferrieux for independently reporting the issue and suggesting a fix. Fixes: 4f693b55c3d2 ("tcp: implement coalescing on backlog queue") Signed-off-by: Eric Dumazet Reported-by: Alexandre Ferrieux Acked-by: Soheil Hassas Yeganeh Acked-by: Neal Cardwell Signed-off-by: David S. Miller

tcp: fix syn cookied MPTCP request socket leak

2020-10-02T22:34:38Z

If a syn-cookies request socket don't pass MPTCP-level validation done in syn_recv_sock(), we need to release it immediately, or it will be leaked. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/89 Fixes: 9466a1ccebbe ("mptcp: enable JOIN requests even if cookies are in use") Reported-and-tested-by: Geliang Tang Reviewed-by: Matthieu Baerts Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

tcp: use sendpage_ok() to detect misused .sendpage

2020-10-02T22:27:08Z

commit a10674bf2406 ("tcp: detecting the misuse of .sendpage for Slab objects") adds the checks for Slab pages, but the pages don't have page_count are still missing from the check. Network layer's sendpage method is not designed to send page_count 0 pages neither, therefore both PageSlab() and page_count() should be both checked for the sending page. This is exactly what sendpage_ok() does. This patch uses sendpage_ok() in do_tcp_sendpages() to detect misused .sendpage, to make the code more robust. Fixes: a10674bf2406 ("tcp: detecting the misuse of .sendpage for Slab objects") Suggested-by: Eric Dumazet Signed-off-by: Coly Li Cc: Vasily Averin Cc: David S. Miller Cc: stable@vger.kernel.org Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec

2020-09-28T19:25:42Z

Steffen Klassert says: ==================== pull request (net): ipsec 2020-09-28 1) Fix a build warning in ip_vti if CONFIG_IPV6 is not set. From YueHaibing. 2) Restore IPCB on espintcp before handing the packet to xfrm as the information there is still needed. From Sabrina Dubroca. 3) Fix pmtu updating for xfrm interfaces. From Sabrina Dubroca. 4) Some xfrm state information was not cloned with xfrm_do_migrate. Fixes to clone the full xfrm state, from Antony Antony. 5) Use the correct address family in xfrm_state_find. The struct flowi must always be interpreted along with the original address family. This got lost over the years. Fix from Herbert Xu. ==================== Signed-off-by: David S. Miller

tcp: skip DSACKs with dubious sequence ranges

2020-09-25T03:15:45Z

Currently, we use length of DSACKed range to compute number of delivered packets. And if sequence range in DSACK is corrupted, we can get bogus dsacked/acked count, and bogus cwnd. This patch put bounds on DSACKed range to skip update of data delivery and spurious retransmission information, if the DSACK is unlikely caused by sender's action: - DSACKed range shouldn't be greater than maximum advertised rwnd. - Total no. of DSACKed segments shouldn't be greater than total no. of retransmitted segs. Unlike spurious retransmits, network duplicates or corrupted DSACKs shouldn't be counted as delivery. Signed-off-by: Priyaranjan Jha Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

inet_diag: validate INET_DIAG_REQ_PROTOCOL attribute

2020-09-22T00:38:51Z

User space could send an invalid INET_DIAG_REQ_PROTOCOL attribute as caught by syzbot. BUG: KMSAN: uninit-value in inet_diag_lock_handler net/ipv4/inet_diag.c:55 [inline] BUG: KMSAN: uninit-value in __inet_diag_dump+0x58c/0x720 net/ipv4/inet_diag.c:1147 CPU: 0 PID: 8505 Comm: syz-executor174 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219 inet_diag_lock_handler net/ipv4/inet_diag.c:55 [inline] __inet_diag_dump+0x58c/0x720 net/ipv4/inet_diag.c:1147 inet_diag_dump_compat+0x2a5/0x380 net/ipv4/inet_diag.c:1254 netlink_dump+0xb73/0x1cb0 net/netlink/af_netlink.c:2246 __netlink_dump_start+0xcf2/0xea0 net/netlink/af_netlink.c:2354 netlink_dump_start include/linux/netlink.h:246 [inline] inet_diag_rcv_msg_compat+0x5da/0x6c0 net/ipv4/inet_diag.c:1288 sock_diag_rcv_msg+0x24f/0x620 net/core/sock_diag.c:256 netlink_rcv_skb+0x6d7/0x7e0 net/netlink/af_netlink.c:2470 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:275 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x11c8/0x1490 net/netlink/af_netlink.c:1330 netlink_sendmsg+0x173a/0x1840 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc82/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d1/0x820 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x441389 Code: e8 fc ab 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 1b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff3b02ce98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441389 RDX: 0000000000000000 RSI: 0000000020001500 RDI: 0000000000000003 RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402130 R13: 00000000004021c0 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:126 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80 slab_alloc_node mm/slub.c:2907 [inline] __kmalloc_node_track_caller+0x9aa/0x12f0 mm/slub.c:4511 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1094 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1176 [inline] netlink_sendmsg+0xdb9/0x1840 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg net/socket.c:671 [inline] ____sys_sendmsg+0xc82/0x1240 net/socket.c:2353 ___sys_sendmsg net/socket.c:2407 [inline] __sys_sendmsg+0x6d1/0x820 net/socket.c:2440 __do_sys_sendmsg net/socket.c:2449 [inline] __se_sys_sendmsg+0x97/0xb0 net/socket.c:2447 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2447 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 3f935c75eb52 ("inet_diag: support for wider protocol numbers") Signed-off-by: Eric Dumazet Cc: Paolo Abeni Cc: Christoph Paasch Cc: Mat Martineau Acked-by: Paolo Abeni Signed-off-by: David S. Miller

ipv4: Update exception handling for multipath routes via same device

2020-09-15T22:44:09Z

Kfir reported that pmtu exceptions are not created properly for deployments where multipath routes use the same device. After some digging I see 2 compounding problems: 1. ip_route_output_key_hash_rcu is updating the flowi4_oif *after* the route lookup. This is the second use case where this has been a problem (the first is related to use of vti devices with VRF). I can not find any reason for the oif to be changed after the lookup; the code goes back to the start of git. It does not seem logical so remove it. 2. fib_lookups for exceptions do not call fib_select_path to handle multipath route selection based on the hash. The end result is that the fib_lookup used to add the exception always creates it based using the first leg of the route. An example topology showing the problem: | host1 +------+ | eth0 | .209 +------+ | +------+ switch | br0 | +------+ | +---------+---------+ | host2 | host3 +------+ +------+ | eth0 | .250 | eth0 | 192.168.252.252 +------+ +------+ +-----+ +-----+ | vti | .2 | vti | 192.168.247.3 +-----+ +-----+ \ / ================================= tunnels 192.168.247.1/24 for h in host1 host2 host3; do ip netns add ${h} ip -netns ${h} link set lo up ip netns exec ${h} sysctl -wq net.ipv4.ip_forward=1 done ip netns add switch ip -netns switch li set lo up ip -netns switch link add br0 type bridge stp 0 ip -netns switch link set br0 up for n in 1 2 3; do ip -netns switch link add eth-sw type veth peer name eth-h${n} ip -netns switch li set eth-h${n} master br0 up ip -netns switch li set eth-sw netns host${n} name eth0 done ip -netns host1 addr add 192.168.252.209/24 dev eth0 ip -netns host1 link set dev eth0 up ip -netns host1 route add 192.168.247.0/24 \ nexthop via 192.168.252.250 dev eth0 nexthop via 192.168.252.252 dev eth0 ip -netns host2 addr add 192.168.252.250/24 dev eth0 ip -netns host2 link set dev eth0 up ip -netns host2 addr add 192.168.252.252/24 dev eth0 ip -netns host3 link set dev eth0 up ip netns add tunnel ip -netns tunnel li set lo up ip -netns tunnel li add br0 type bridge ip -netns tunnel li set br0 up for n in $(seq 11 20); do ip -netns tunnel addr add dev br0 192.168.247.${n}/24 done for n in 2 3 do ip -netns tunnel link add vti${n} type veth peer name eth${n} ip -netns tunnel link set eth${n} mtu 1360 master br0 up ip -netns tunnel link set vti${n} netns host${n} mtu 1360 up ip -netns host${n} addr add dev vti${n} 192.168.247.${n}/24 done ip -netns tunnel ro add default nexthop via 192.168.247.2 nexthop via 192.168.247.3 ip netns exec host1 ping -M do -s 1400 -c3 -I 192.168.252.209 192.168.247.11 ip netns exec host1 ping -M do -s 1400 -c3 -I 192.168.252.209 192.168.247.15 ip -netns host1 ro ls cache Before this patch the cache always shows exceptions against the first leg in the multipath route; 192.168.252.250 per this example. Since the hash has an initial random seed, you may need to vary the final octet more than what is listed. In my tests, using addresses between 11 and 19 usually found 1 that used both legs. With this patch, the cache will have exceptions for both legs. Fixes: 4895c771c7f0 ("ipv4: Add FIB nexthop exceptions") Reported-by: Kfir Itzhak Signed-off-by: David Ahern Signed-off-by: David S. Miller

lwtunnel: only keep the available bits when setting vxlan md->gbp

2020-09-14T23:49:39Z

As we can see from vxlan_build/parse_gbp_hdr(), when processing metadata on vxlan rx/tx path, only dont_learn/policy_applied/policy_id fields can be set to or parse from the packet for vxlan gbp option. So do the mask when set it in lwtunnel, as it does in act_tunnel_key and cls_flower. Signed-off-by: Xin Long Signed-off-by: David S. Miller

ipv4: Initialize flowi4_multipath_hash in data path

2020-09-14T21:54:56Z

flowi4_multipath_hash was added by the commit referenced below for tunnels. Unfortunately, the patch did not initialize the new field for several fast path lookups that do not initialize the entire flow struct to 0. Fix those locations. Currently, flowi4_multipath_hash is random garbage and affects the hash value computed by fib_multipath_hash for multipath selection. Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash") Signed-off-by: David Ahern Cc: wenxu Signed-off-by: David S. Miller

ip: fix tos reflection in ack and reset packets

2020-09-09T03:19:08Z

Currently, in tcp_v4_reqsk_send_ack() and tcp_v4_send_reset(), we echo the TOS value of the received packets in the response. However, we do not want to echo the lower 2 ECN bits in accordance with RFC 3168 6.1.5 robustness principles. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller