user/sven/linux.git/include/linux/ipv6.h, branch v4.9.5

net: tcp: check skb is non-NULL for exact match on lookups

2016-11-03T20:05:44Z

Andrey reported the following error report while running the syzkaller fuzzer: general protection fault: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 648 Comm: syz-executor Not tainted 4.9.0-rc3+ #333 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff8800398c4480 task.stack: ffff88003b468000 RIP: 0010:[] [< inline >] inet_exact_dif_match include/net/tcp.h:808 RIP: 0010:[] [] __inet_lookup_listener+0xb6/0x500 net/ipv4/inet_hashtables.c:219 RSP: 0018:ffff88003b46f270 EFLAGS: 00010202 RAX: 0000000000000004 RBX: 0000000000004242 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffc90000e3c000 RDI: 0000000000000054 RBP: ffff88003b46f2d8 R08: 0000000000004000 R09: ffffffff830910e7 R10: 0000000000000000 R11: 000000000000000a R12: ffffffff867fa0c0 R13: 0000000000004242 R14: 0000000000000003 R15: dffffc0000000000 FS: 00007fb135881700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020cc3000 CR3: 000000006d56a000 CR4: 00000000000006f0 Stack: 0000000000000000 000000000601a8c0 0000000000000000 ffffffff00004242 424200003b9083c2 ffff88003def4041 ffffffff84e7e040 0000000000000246 ffff88003a0911c0 0000000000000000 ffff88003a091298 ffff88003b9083ae Call Trace: [] tcp_v4_send_reset+0x584/0x1700 net/ipv4/tcp_ipv4.c:643 [] tcp_v4_rcv+0x198b/0x2e50 net/ipv4/tcp_ipv4.c:1718 [] ip_local_deliver_finish+0x332/0xad0 net/ipv4/ip_input.c:216 ... MD5 has a code path that calls __inet_lookup_listener with a null skb, so inet{6}_exact_dif_match needs to check skb against null before pulling the flag. Fixes: a04a480d4392 ("net: Require exact match for TCP socket lookups if dif is l3mdev") Reported-by: Andrey Konovalov Signed-off-by: David Ahern Tested-by: Andrey Konovalov Signed-off-by: David S. Miller

net: Require exact match for TCP socket lookups if dif is l3mdev

2016-10-17T14:17:05Z

Currently, socket lookups for l3mdev (vrf) use cases can match a socket that is bound to a port but not a device (ie., a global socket). If the sysctl tcp_l3mdev_accept is not set this leads to ack packets going out based on the main table even though the packet came in from an L3 domain. The end result is that the connection does not establish creating confusion for users since the service is running and a socket shows in ss output. Fix by requiring an exact dif to sk_bound_dev_if match if the skb came through an interface enslaved to an l3mdev device and the tcp_l3mdev_accept is not set. skb's through an l3mdev interface are marked by setting a flag in inet{6}_skb_parm. The IPv6 variant is already set; this patch adds the flag for IPv4. Using an skb flag avoids a device lookup on the dif. The flag is set in the VRF driver using the IP{6}CB macros. For IPv4, the inet_skb_parm struct is moved in the cb per commit 971f10eca186, so the match function in the TCP stack needs to use TCP_SKB_CB. For IPv6, the move is done after the socket lookup, so IP6CB is used. The flags field in inet_skb_parm struct needs to be increased to add another flag. There is currently a 1-byte hole following the flags, so it can be expanded to u16 without increasing the size of the struct. Fixes: 193125dbd8eb ("net: Introduce VRF device driver") Signed-off-by: David Ahern Signed-off-by: David S. Miller

ipv6 addrconf: implement RFC7559 router solicitation backoff

2016-09-30T05:54:28Z

This implements: https://tools.ietf.org/html/rfc7559 Backoff is performed according to RFC3315 section 14: https://tools.ietf.org/html/rfc3315#section-14 We allow setting /proc/sys/net/ipv6/conf/*/router_solicitations to a negative value meaning an unlimited number of retransmits, and we make this the new default (inline with the RFC). We also add a new setting: /proc/sys/net/ipv6/conf/*/router_solicitation_max_interval defaulting to 1 hour (per RFC recommendation). Signed-off-by: Maciej Żenczykowski Acked-by: Erik Kline Signed-off-by: David S. Miller

net: vrf: Fix crash when IPv6 is disabled at boot time

2016-06-10T06:34:42Z

Frank Kellermann reported a kernel crash with 4.5.0 when IPv6 is disabled at boot using the kernel option ipv6.disable=1. Using current net-next with the boot option: $ ip link add red type vrf table 1001 Generates: [12210.919584] BUG: unable to handle kernel NULL pointer dereference at 0000000000000748 [12210.921341] IP: [] fib6_get_table+0x2c/0x5a [12210.922537] PGD b79e3067 PUD bb32b067 PMD 0 [12210.923479] Oops: 0000 [#1] SMP [12210.924001] Modules linked in: ipvlan 8021q garp mrp stp llc [12210.925130] CPU: 3 PID: 1177 Comm: ip Not tainted 4.7.0-rc1+ #235 [12210.926168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [12210.928065] task: ffff8800b9ac4640 ti: ffff8800bacac000 task.ti: ffff8800bacac000 [12210.929328] RIP: 0010:[] [] fib6_get_table+0x2c/0x5a [12210.930697] RSP: 0018:ffff8800bacaf888 EFLAGS: 00010202 [12210.931563] RAX: 0000000000000748 RBX: ffffffff81a9e280 RCX: ffff8800b9ac4e28 [12210.932688] RDX: 00000000000000e9 RSI: 0000000000000002 RDI: 0000000000000286 [12210.933820] RBP: ffff8800bacaf898 R08: ffff8800b9ac4df0 R09: 000000000052001b [12210.934941] R10: 00000000657c0000 R11: 000000000000c649 R12: 00000000000003e9 [12210.936032] R13: 00000000000003e9 R14: ffff8800bace7800 R15: ffff8800bb3ec000 [12210.937103] FS: 00007faa1766c700(0000) GS:ffff88013ac00000(0000) knlGS:0000000000000000 [12210.938321] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [12210.939166] CR2: 0000000000000748 CR3: 00000000b79d6000 CR4: 00000000000406e0 [12210.940278] Stack: [12210.940603] ffff8800bb3ec000 ffffffff81a9e280 ffff8800bacaf8c8 ffffffff814b3135 [12210.941818] ffff8800bb3ec000 ffffffff81a9e280 ffffffff81a9e280 ffff8800bace7800 [12210.943040] ffff8800bacaf8f0 ffffffff81397c88 ffff8800bb3ec000 ffffffff81a9e280 [12210.944288] Call Trace: [12210.944688] [] fib6_new_table+0x24/0x8a [12210.945516] [] vrf_dev_init+0xd4/0x162 [12210.946328] [] register_netdevice+0x100/0x396 [12210.947209] [] vrf_newlink+0x40/0xb3 [12210.948001] [] rtnl_newlink+0x5d3/0x6d5 ... The problem above is due to the fact that the fib hash table is not allocated when IPv6 is disabled at boot. As for the VRF driver it should not do any IPv6 initializations if IPv6 is disabled, so it needs to know if IPv6 is disabled at boot. The disable parameter is private to the IPv6 module, so provide an accessor for modules to determine if IPv6 was disabled at boot time. Fixes: 35402e3136634 ("net: Add IPv6 support to VRF device") Signed-off-by: David Ahern Signed-off-by: David S. Miller

net: l3mdev: Add hook in ip and ipv6

2016-05-11T23:31:40Z

Currently the VRF driver uses the rx_handler to switch the skb device to the VRF device. Switching the dev prior to the ip / ipv6 layer means the VRF driver has to duplicate IP/IPv6 processing which adds overhead and makes features such as retaining the ingress device index more complicated than necessary. This patch moves the hook to the L3 layer just after the first NF_HOOK for PRE_ROUTING. This location makes exposing the original ingress device trivial (next patch) and allows adding other NF_HOOKs to the VRF driver in the future. dev_queue_xmit_nit is exported so that the VRF driver can cycle the skb with the switched device through the packet taps to maintain current behavior (tcpdump can be used on either the vrf device or the enslaved devices). Signed-off-by: David Ahern Signed-off-by: David S. Miller

net/ipv6/addrconf: simplify sysctl registration

2016-04-20T00:13:19Z

Struct ctl_table_header holds pointer to sysctl table which could be used for freeing it after unregistration. IPv4 sysctls already use that. Remove redundant NULL assignment: ndev allocated using kzalloc. This also saves some bytes: sysctl table could be shorter than DEVCONF_MAX+1 if some options are disable in config. Signed-off-by: Konstantin Khlebnikov Signed-off-by: David S. Miller

net: ipv6: Make address flushing on ifdown optional

2016-02-26T02:45:15Z

Currently, all ipv6 addresses are flushed when the interface is configured down, including global, static addresses: $ ip -6 addr show dev eth1 3: eth1: mtu 1500 state UP qlen 1000 inet6 2100:1::2/120 scope global valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link valid_lft forever preferred_lft forever $ ip link set dev eth1 down $ ip -6 addr show dev eth1 << nothing; all addresses have been flushed>> Add a new sysctl to make this behavior optional. The new setting defaults to flush all addresses to maintain backwards compatibility. When the set global addresses with no expire times are not flushed on an admin down. The sysctl is per-interface or system-wide for all interfaces $ sysctl -w net.ipv6.conf.eth1.keep_addr_on_down=1 or $ sysctl -w net.ipv6.conf.all.keep_addr_on_down=1 Will keep addresses on eth1 on an admin down. $ ip -6 addr show dev eth1 3: eth1: mtu 1500 state UP qlen 1000 inet6 2100:1::2/120 scope global valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link valid_lft forever preferred_lft forever $ ip link set dev eth1 down $ ip -6 addr show dev eth1 3: eth1: mtu 1500 state DOWN qlen 1000 inet6 2100:1::2/120 scope global tentative valid_lft forever preferred_lft forever inet6 fe80::e0:f9ff:fe79:34bd/64 scope link tentative valid_lft forever preferred_lft forever Signed-off-by: David Ahern Signed-off-by: David S. Miller

ipv6: add option to drop unsolicited neighbor advertisements

2016-02-11T09:27:36Z

In certain 802.11 wireless deployments, there will be NA proxies that use knowledge of the network to correctly answer requests. To prevent unsolicitd advertisements on the shared medium from being a problem, on such deployments wireless needs to drop them. Enable this by providing an option called "drop_unsolicited_na". Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

ipv6: add option to drop unicast encapsulated in L2 multicast

2016-02-11T09:27:36Z

In order to solve a problem with 802.11, the so-called hole-196 attack, add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if enabled, causes the stack to drop IPv6 unicast packets encapsulated in link-layer multi- or broadcast frames. Such frames can (as an attack) be created by any member of the same wireless network and transmitted as valid encrypted frames since the symmetric key for broadcast frames is shared between all stations. Reviewed-by: Julian Anastasov Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

ipv6: add complete rcu protection around np->opt

2015-12-03T04:37:16Z

This patch addresses multiple problems : UDP/RAW sendmsg() need to get a stable struct ipv6_txoptions while socket is not locked : Other threads can change np->opt concurrently. Dmitry posted a syzkaller (http://github.com/google/syzkaller) program desmonstrating use-after-free. Starting with TCP/DCCP lockless listeners, tcp_v6_syn_recv_sock() and dccp_v6_request_recv_sock() also need to use RCU protection to dereference np->opt once (before calling ipv6_dup_options()) This patch adds full RCU protection to np->opt Reported-by: Dmitry Vyukov Signed-off-by: Eric Dumazet Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller