kernel/drivers/net/wireguard/device.c, branch linux-6.9.y

wireguard: device: remove generic .ndo_get_stats64

2024-03-19T10:22:49Z

Commit 3e2f544dd8a33 ("net: get stats64 if device if driver is configured") moved the callback to dev_get_tstats64() to net core, so, unless the driver is doing some custom stats collection, it does not need to set .ndo_get_stats64. Since this driver is now relying in NETDEV_PCPU_STAT_TSTATS, then, it doesn't need to set the dev_get_tstats64() generic .ndo_get_stats64 function pointer. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Jason A. Donenfeld Reviewed-by: Jiri Pirko Signed-off-by: Paolo Abeni

wireguard: device: leverage core stats allocator

2024-03-19T10:22:49Z

With commit 34d21de99cea9 ("net: Move {l,t,d}stats allocation to core and convert veth & vrf"), stats allocation could be done on net core instead of in this driver. With this new approach, the driver doesn't have to bother with error handling (allocation failure checking, making sure free happens in the right spot, etc). This is core responsibility now. Remove the allocation in this driver and leverage the network core allocation instead. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: Jason A. Donenfeld Reviewed-by: Jiri Pirko Signed-off-by: Paolo Abeni

wireguard: use DEV_STATS_INC()

2023-11-19T19:48:25Z

wg_xmit() can be called concurrently, KCSAN reported [1] some device stats updates can be lost. Use DEV_STATS_INC() for this unlikely case. [1] BUG: KCSAN: data-race in wg_xmit / wg_xmit read-write to 0xffff888104239160 of 8 bytes by task 1375 on cpu 0: wg_xmit+0x60f/0x680 drivers/net/wireguard/device.c:231 __netdev_start_xmit include/linux/netdevice.h:4918 [inline] netdev_start_xmit include/linux/netdevice.h:4932 [inline] xmit_one net/core/dev.c:3543 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3559 ... read-write to 0xffff888104239160 of 8 bytes by task 1378 on cpu 1: wg_xmit+0x60f/0x680 drivers/net/wireguard/device.c:231 __netdev_start_xmit include/linux/netdevice.h:4918 [inline] netdev_start_xmit include/linux/netdevice.h:4932 [inline] xmit_one net/core/dev.c:3543 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3559 ... v2: also change wg_packet_consume_data_done() (Hangbin Liu) and wg_packet_purge_staged_packets() Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Reported-by: syzbot Signed-off-by: Eric Dumazet Cc: Jason A. Donenfeld Cc: Hangbin Liu Signed-off-by: Jason A. Donenfeld Reviewed-by: Hangbin Liu Signed-off-by: David S. Miller

net: move gso declarations and functions to their own files

2023-06-10T07:11:41Z

Move declarations into include/net/gso.h and code into net/core/gso.c Signed-off-by: Eric Dumazet Cc: Stanislav Fomichev Reviewed-by: Simon Horman Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com Signed-off-by: Jakub Kicinski

pm/sleep: Add PM_USERSPACE_AUTOSLEEP Kconfig

2022-07-01T08:39:20Z

Systems that initiate frequent suspend/resume from userspace can make the kernel aware by enabling PM_USERSPACE_AUTOSLEEP config. This allows for certain sleep-sensitive code (wireguard/rng) to decide on what preparatory work should be performed (or not) in their pm_notification callbacks. This patch was prompted by the discussion at [1] which attempts to remove CONFIG_ANDROID that currently guards these code paths. [1] https://lore.kernel.org/r/20220629150102.1582425-1-hch@lst.de/ Suggested-by: Jason A. Donenfeld Acked-by: Jason A. Donenfeld Signed-off-by: Kalesh Singh Link: https://lore.kernel.org/r/20220630191230.235306-1-kaleshsingh@google.com Signed-off-by: Greg Kroah-Hartman

wireguard: device: check for metadata_dst with skb_valid_dst()

2022-04-22T22:59:05Z

When we try to transmit an skb with md_dst attached through wireguard we hit a null pointer dereference in wg_xmit() due to the use of dst_mtu() which calls into dst_blackhole_mtu() which in turn tries to dereference dst->dev. Since wireguard doesn't use md_dsts we should use skb_valid_dst(), which checks for DST_METADATA flag, and if it's set, then falls back to wireguard's device mtu. That gives us the best chance of transmitting the packet; otherwise if the blackhole netdev is used we'd get ETH_MIN_MTU. [ 263.693506] BUG: kernel NULL pointer dereference, address: 00000000000000e0 [ 263.693908] #PF: supervisor read access in kernel mode [ 263.694174] #PF: error_code(0x0000) - not-present page [ 263.694424] PGD 0 P4D 0 [ 263.694653] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 263.694876] CPU: 5 PID: 951 Comm: mausezahn Kdump: loaded Not tainted 5.18.0-rc1+ #522 [ 263.695190] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014 [ 263.695529] RIP: 0010:dst_blackhole_mtu+0x17/0x20 [ 263.695770] Code: 00 00 00 0f 1f 44 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8b 47 10 48 83 e0 fc 8b 40 04 85 c0 75 09 48 8b 07 <8b> 80 e0 00 00 00 c3 66 90 0f 1f 44 00 00 48 89 d7 be 01 00 00 00 [ 263.696339] RSP: 0018:ffffa4a4422fbb28 EFLAGS: 00010246 [ 263.696600] RAX: 0000000000000000 RBX: ffff8ac9c3553000 RCX: 0000000000000000 [ 263.696891] RDX: 0000000000000401 RSI: 00000000fffffe01 RDI: ffffc4a43fb48900 [ 263.697178] RBP: ffffa4a4422fbb90 R08: ffffffff9622635e R09: 0000000000000002 [ 263.697469] R10: ffffffff9b69a6c0 R11: ffffa4a4422fbd0c R12: ffff8ac9d18b1a00 [ 263.697766] R13: ffff8ac9d0ce1840 R14: ffff8ac9d18b1a00 R15: ffff8ac9c3553000 [ 263.698054] FS: 00007f3704c337c0(0000) GS:ffff8acaebf40000(0000) knlGS:0000000000000000 [ 263.698470] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 263.698826] CR2: 00000000000000e0 CR3: 0000000117a5c000 CR4: 00000000000006e0 [ 263.699214] Call Trace: [ 263.699505] [ 263.699759] wg_xmit+0x411/0x450 [ 263.700059] ? bpf_skb_set_tunnel_key+0x46/0x2d0 [ 263.700382] ? dev_queue_xmit_nit+0x31/0x2b0 [ 263.700719] dev_hard_start_xmit+0xd9/0x220 [ 263.701047] __dev_queue_xmit+0x8b9/0xd30 [ 263.701344] __bpf_redirect+0x1a4/0x380 [ 263.701664] __dev_queue_xmit+0x83b/0xd30 [ 263.701961] ? packet_parse_headers+0xb4/0xf0 [ 263.702275] packet_sendmsg+0x9a8/0x16a0 [ 263.702596] ? _raw_spin_unlock_irqrestore+0x23/0x40 [ 263.702933] sock_sendmsg+0x5e/0x60 [ 263.703239] __sys_sendto+0xf0/0x160 [ 263.703549] __x64_sys_sendto+0x20/0x30 [ 263.703853] do_syscall_64+0x3b/0x90 [ 263.704162] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 263.704494] RIP: 0033:0x7f3704d50506 [ 263.704789] Code: 48 c7 c0 ff ff ff ff eb b7 66 2e 0f 1f 84 00 00 00 00 00 90 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 72 c3 90 55 48 83 ec 30 44 89 4c 24 2c 4c 89 [ 263.705652] RSP: 002b:00007ffe954b0b88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c [ 263.706141] RAX: ffffffffffffffda RBX: 0000558bb259b490 RCX: 00007f3704d50506 [ 263.706544] RDX: 000000000000004a RSI: 0000558bb259b7b2 RDI: 0000000000000003 [ 263.706952] RBP: 0000000000000000 R08: 00007ffe954b0b90 R09: 0000000000000014 [ 263.707339] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe954b0b90 [ 263.707735] R13: 000000000000004a R14: 0000558bb259b7b2 R15: 0000000000000001 [ 263.708132] [ 263.708398] Modules linked in: bridge netconsole bonding [last unloaded: bridge] [ 263.708942] CR2: 00000000000000e0 Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Link: https://github.com/cilium/cilium/issues/19428 Reported-by: Martynas Pumputis Signed-off-by: Nikolay Aleksandrov Acked-by: Daniel Borkmann Signed-off-by: Jason A. Donenfeld Signed-off-by: Jakub Kicinski

wireguard: device: clear keys on VM fork

2022-03-13T01:00:56Z

When a virtual machine forks, it's important that WireGuard clear existing sessions so that different plaintexts are not transmitted using the same key+nonce, which can result in catastrophic cryptographic failure. To accomplish this, we simply hook into the newly added vmfork notifier. As a bonus, it turns out that, like the vmfork registration function, the PM registration function is stubbed out when CONFIG_PM_SLEEP is not set, so we can actually just remove the maze of ifdefs, which makes it really quite clean to support both notifiers at once. Cc: Dominik Brodowski Cc: Greg Kroah-Hartman Cc: Theodore Ts'o Acked-by: Jakub Kicinski Signed-off-by: Jason A. Donenfeld

wireguard: receive: use ring buffer for incoming handshakes

2021-11-30T03:50:50Z

Apparently the spinlock on incoming_handshake's skb_queue is highly contended, and a torrent of handshake or cookie packets can bring the data plane to its knees, simply by virtue of enqueueing the handshake packets to be processed asynchronously. So, we try switching this to a ring buffer to hopefully have less lock contention. This alleviates the problem somewhat, though it still isn't perfect, so future patches will have to improve this further. However, it at least doesn't completely diminish the data plane. Reported-by: Streun Fabio Reported-by: Joel Wanner Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Jason A. Donenfeld Signed-off-by: Jakub Kicinski

wireguard: device: reset peer src endpoint when netns exits

2021-11-30T03:50:45Z

Each peer's endpoint contains a dst_cache entry that takes a reference to another netdev. When the containing namespace exits, we take down the socket and prevent future sockets from being created (by setting creating_net to NULL), which removes that potential reference on the netns. However, it doesn't release references to the netns that a netdev cached in dst_cache might be taking, so the netns still might fail to exit. Since the socket is gimped anyway, we can simply clear all the dst_caches (by way of clearing the endpoint src), which will release all references. However, the current dst_cache_reset function only releases those references lazily. But it turns out that all of our usages of wg_socket_clear_peer_endpoint_src are called from contexts that are not exactly high-speed or bottle-necked. For example, when there's connection difficulty, or when userspace is reconfiguring the interface. And in particular for this patch, when the netns is exiting. So for those cases, it makes more sense to call dst_release immediately. For that, we add a small helper function to dst_cache. This patch also adds a test to netns.sh from Hangbin Liu to ensure this doesn't regress. Tested-by: Hangbin Liu Reported-by: Xiumei Mu Cc: Toke Høiland-Jørgensen Cc: Paolo Abeni Fixes: 900575aa33a3 ("wireguard: device: avoid circular netns references") Signed-off-by: Jason A. Donenfeld Signed-off-by: Jakub Kicinski

wireguard: queueing: get rid of per-peer ring buffers

2021-02-23T23:59:34Z

Having two ring buffers per-peer means that every peer results in two massive ring allocations. On an 8-core x86_64 machine, this commit reduces the per-peer allocation from 18,688 bytes to 1,856 bytes, which is an 90% reduction. Ninety percent! With some single-machine deployments approaching 500,000 peers, we're talking about a reduction from 7 gigs of memory down to 700 megs of memory. In order to get rid of these per-peer allocations, this commit switches to using a list-based queueing approach. Currently GSO fragments are chained together using the skb->next pointer (the skb_list_* singly linked list approach), so we form the per-peer queue around the unused skb->prev pointer (which sort of makes sense because the links are pointing backwards). Use of skb_queue_* is not possible here, because that is based on doubly linked lists and spinlocks. Multiple cores can write into the queue at any given time, because its writes occur in the start_xmit path or in the udp_recv path. But reads happen in a single workqueue item per-peer, amounting to a multi-producer, single-consumer paradigm. The MPSC queue is implemented locklessly and never blocks. However, it is not linearizable (though it is serializable), with a very tight and unlikely race on writes, which, when hit (some tiny fraction of the 0.15% of partial adds on a fully loaded 16-core x86_64 system), causes the queue reader to terminate early. However, because every packet sent queues up the same workqueue item after it is fully added, the worker resumes again, and stopping early isn't actually a problem, since at that point the packet wouldn't have yet been added to the encryption queue. These properties allow us to avoid disabling interrupts or spinning. The design is based on Dmitry Vyukov's algorithm [1]. Performance-wise, ordinarily list-based queues aren't preferable to ringbuffers, because of cache misses when following pointers around. However, we *already* have to follow the adjacent pointers when working through fragments, so there shouldn't actually be any change there. A potential downside is that dequeueing is a bit more complicated, but the ptr_ring structure used prior had a spinlock when dequeueing, so all and all the difference appears to be a wash. Actually, from profiling, the biggest performance hit, by far, of this commit winds up being atomic_add_unless(count, 1, max) and atomic_ dec(count), which account for the majority of CPU time, according to perf. In that sense, the previous ring buffer was superior in that it could check if it was full by head==tail, which the list-based approach cannot do. But all and all, this enables us to get massive memory savings, allowing WireGuard to scale for real world deployments, without taking much of a performance hit. [1] http://www.1024cores.net/home/lock-free-algorithms/queues/intrusive-mpsc-node-based-queue Reviewed-by: Dmitry Vyukov Reviewed-by: Toke Høiland-Jørgensen Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Jason A. Donenfeld Signed-off-by: Jakub Kicinski