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a4980919ad
10 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Jason A. Donenfeld
|
a12d7f3cbd |
wireguard: device: use icmp_ndo_send helper
Because wireguard is calling icmp from network device context, it should use the ndo helper so that the rate limiting applies correctly. This commit adds a small test to the wireguard test suite to ensure that the new functions continue doing the right thing in the context of wireguard. It does this by setting up a condition that will definately evoke an icmp error message from the driver, but along a nat'd path. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
Jason A. Donenfeld
|
ec31c2676a |
wireguard: noise: reject peers with low order public keys
Our static-static calculation returns a failure if the public key is of
low order. We check for this when peers are added, and don't allow them
to be added if they're low order, except in the case where we haven't
yet been given a private key. In that case, we would defer the removal
of the peer until we're given a private key, since at that point we're
doing new static-static calculations which incur failures we can act on.
This meant, however, that we wound up removing peers rather late in the
configuration flow.
Syzkaller points out that peer_remove calls flush_workqueue, which in
turn might then wait for sending a handshake initiation to complete.
Since handshake initiation needs the static identity lock, holding the
static identity lock while calling peer_remove can result in a rare
deadlock. We have precisely this case in this situation of late-stage
peer removal based on an invalid public key. We can't drop the lock when
removing, because then incoming handshakes might interact with a bogus
static-static calculation.
While the band-aid patch for this would involve breaking up the peer
removal into two steps like wg_peer_remove_all does, in order to solve
the locking issue, there's actually a much more elegant way of fixing
this:
If the static-static calculation succeeds with one private key, it
*must* succeed with all others, because all 32-byte strings map to valid
private keys, thanks to clamping. That means we can get rid of this
silly dance and locking headaches of removing peers late in the
configuration flow, and instead just reject them early on, regardless of
whether the device has yet been assigned a private key. For the case
where the device doesn't yet have a private key, we safely use zeros
just for the purposes of checking for low order points by way of
checking the output of the calculation.
The following PoC will trigger the deadlock:
ip link add wg0 type wireguard
ip addr add 10.0.0.1/24 dev wg0
ip link set wg0 up
ping -f 10.0.0.2 &
while true; do
wg set wg0 private-key /dev/null peer AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA= allowed-ips 10.0.0.0/24 endpoint 10.0.0.3:1234
wg set wg0 private-key <(echo AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=)
done
[ 0.949105] ======================================================
[ 0.949550] WARNING: possible circular locking dependency detected
[ 0.950143] 5.5.0-debug+ #18 Not tainted
[ 0.950431] ------------------------------------------------------
[ 0.950959] wg/89 is trying to acquire lock:
[ 0.951252] ffff8880333e2128 ((wq_completion)wg-kex-wg0){+.+.}, at: flush_workqueue+0xe3/0x12f0
[ 0.951865]
[ 0.951865] but task is already holding lock:
[ 0.952280] ffff888032819bc0 (&wg->static_identity.lock){++++}, at: wg_set_device+0x95d/0xcc0
[ 0.953011]
[ 0.953011] which lock already depends on the new lock.
[ 0.953011]
[ 0.953651]
[ 0.953651] the existing dependency chain (in reverse order) is:
[ 0.954292]
[ 0.954292] -> #2 (&wg->static_identity.lock){++++}:
[ 0.954804] lock_acquire+0x127/0x350
[ 0.955133] down_read+0x83/0x410
[ 0.955428] wg_noise_handshake_create_initiation+0x97/0x700
[ 0.955885] wg_packet_send_handshake_initiation+0x13a/0x280
[ 0.956401] wg_packet_handshake_send_worker+0x10/0x20
[ 0.956841] process_one_work+0x806/0x1500
[ 0.957167] worker_thread+0x8c/0xcb0
[ 0.957549] kthread+0x2ee/0x3b0
[ 0.957792] ret_from_fork+0x24/0x30
[ 0.958234]
[ 0.958234] -> #1 ((work_completion)(&peer->transmit_handshake_work)){+.+.}:
[ 0.958808] lock_acquire+0x127/0x350
[ 0.959075] process_one_work+0x7ab/0x1500
[ 0.959369] worker_thread+0x8c/0xcb0
[ 0.959639] kthread+0x2ee/0x3b0
[ 0.959896] ret_from_fork+0x24/0x30
[ 0.960346]
[ 0.960346] -> #0 ((wq_completion)wg-kex-wg0){+.+.}:
[ 0.960945] check_prev_add+0x167/0x1e20
[ 0.961351] __lock_acquire+0x2012/0x3170
[ 0.961725] lock_acquire+0x127/0x350
[ 0.961990] flush_workqueue+0x106/0x12f0
[ 0.962280] peer_remove_after_dead+0x160/0x220
[ 0.962600] wg_set_device+0xa24/0xcc0
[ 0.962994] genl_rcv_msg+0x52f/0xe90
[ 0.963298] netlink_rcv_skb+0x111/0x320
[ 0.963618] genl_rcv+0x1f/0x30
[ 0.963853] netlink_unicast+0x3f6/0x610
[ 0.964245] netlink_sendmsg+0x700/0xb80
[ 0.964586] __sys_sendto+0x1dd/0x2c0
[ 0.964854] __x64_sys_sendto+0xd8/0x1b0
[ 0.965141] do_syscall_64+0x90/0xd9a
[ 0.965408] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 0.965769]
[ 0.965769] other info that might help us debug this:
[ 0.965769]
[ 0.966337] Chain exists of:
[ 0.966337] (wq_completion)wg-kex-wg0 --> (work_completion)(&peer->transmit_handshake_work) --> &wg->static_identity.lock
[ 0.966337]
[ 0.967417] Possible unsafe locking scenario:
[ 0.967417]
[ 0.967836] CPU0 CPU1
[ 0.968155] ---- ----
[ 0.968497] lock(&wg->static_identity.lock);
[ 0.968779] lock((work_completion)(&peer->transmit_handshake_work));
[ 0.969345] lock(&wg->static_identity.lock);
[ 0.969809] lock((wq_completion)wg-kex-wg0);
[ 0.970146]
[ 0.970146] *** DEADLOCK ***
[ 0.970146]
[ 0.970531] 5 locks held by wg/89:
[ 0.970908] #0: ffffffff827433c8 (cb_lock){++++}, at: genl_rcv+0x10/0x30
[ 0.971400] #1: ffffffff82743480 (genl_mutex){+.+.}, at: genl_rcv_msg+0x642/0xe90
[ 0.971924] #2: ffffffff827160c0 (rtnl_mutex){+.+.}, at: wg_set_device+0x9f/0xcc0
[ 0.972488] #3: ffff888032819de0 (&wg->device_update_lock){+.+.}, at: wg_set_device+0xb0/0xcc0
[ 0.973095] #4: ffff888032819bc0 (&wg->static_identity.lock){++++}, at: wg_set_device+0x95d/0xcc0
[ 0.973653]
[ 0.973653] stack backtrace:
[ 0.973932] CPU: 1 PID: 89 Comm: wg Not tainted 5.5.0-debug+ #18
[ 0.974476] Call Trace:
[ 0.974638] dump_stack+0x97/0xe0
[ 0.974869] check_noncircular+0x312/0x3e0
[ 0.975132] ? print_circular_bug+0x1f0/0x1f0
[ 0.975410] ? __kernel_text_address+0x9/0x30
[ 0.975727] ? unwind_get_return_address+0x51/0x90
[ 0.976024] check_prev_add+0x167/0x1e20
[ 0.976367] ? graph_lock+0x70/0x160
[ 0.976682] __lock_acquire+0x2012/0x3170
[ 0.976998] ? register_lock_class+0x1140/0x1140
[ 0.977323] lock_acquire+0x127/0x350
[ 0.977627] ? flush_workqueue+0xe3/0x12f0
[ 0.977890] flush_workqueue+0x106/0x12f0
[ 0.978147] ? flush_workqueue+0xe3/0x12f0
[ 0.978410] ? find_held_lock+0x2c/0x110
[ 0.978662] ? lock_downgrade+0x6e0/0x6e0
[ 0.978919] ? queue_rcu_work+0x60/0x60
[ 0.979166] ? netif_napi_del+0x151/0x3b0
[ 0.979501] ? peer_remove_after_dead+0x160/0x220
[ 0.979871] peer_remove_after_dead+0x160/0x220
[ 0.980232] wg_set_device+0xa24/0xcc0
[ 0.980516] ? deref_stack_reg+0x8e/0xc0
[ 0.980801] ? set_peer+0xe10/0xe10
[ 0.981040] ? __ww_mutex_check_waiters+0x150/0x150
[ 0.981430] ? __nla_validate_parse+0x163/0x270
[ 0.981719] ? genl_family_rcv_msg_attrs_parse+0x13f/0x310
[ 0.982078] genl_rcv_msg+0x52f/0xe90
[ 0.982348] ? genl_family_rcv_msg_attrs_parse+0x310/0x310
[ 0.982690] ? register_lock_class+0x1140/0x1140
[ 0.983049] netlink_rcv_skb+0x111/0x320
[ 0.983298] ? genl_family_rcv_msg_attrs_parse+0x310/0x310
[ 0.983645] ? netlink_ack+0x880/0x880
[ 0.983888] genl_rcv+0x1f/0x30
[ 0.984168] netlink_unicast+0x3f6/0x610
[ 0.984443] ? netlink_detachskb+0x60/0x60
[ 0.984729] ? find_held_lock+0x2c/0x110
[ 0.984976] netlink_sendmsg+0x700/0xb80
[ 0.985220] ? netlink_broadcast_filtered+0xa60/0xa60
[ 0.985533] __sys_sendto+0x1dd/0x2c0
[ 0.985763] ? __x64_sys_getpeername+0xb0/0xb0
[ 0.986039] ? sockfd_lookup_light+0x17/0x160
[ 0.986397] ? __sys_recvmsg+0x8c/0xf0
[ 0.986711] ? __sys_recvmsg_sock+0xd0/0xd0
[ 0.987018] __x64_sys_sendto+0xd8/0x1b0
[ 0.987283] ? lockdep_hardirqs_on+0x39b/0x5a0
[ 0.987666] do_syscall_64+0x90/0xd9a
[ 0.987903] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 0.988223] RIP: 0033:0x7fe77c12003e
[ 0.988508] Code: c3 8b 07 85 c0 75 24 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 4
[ 0.989666] RSP: 002b:00007fffada2ed58 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[ 0.990137] RAX: ffffffffffffffda RBX: 00007fe77c159d48 RCX: 00007fe77c12003e
[ 0.990583] RDX: 0000000000000040 RSI: 000055fd1d38e020 RDI: 0000000000000004
[ 0.991091] RBP: 000055fd1d38e020 R08: 000055fd1cb63358 R09: 000000000000000c
[ 0.991568] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000002c
[ 0.992014] R13: 0000000000000004 R14: 000055fd1d38e020 R15: 0000000000000001
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
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Eric Dumazet
|
9981159fc3 |
wireguard: allowedips: fix use-after-free in root_remove_peer_lists
In the unlikely case a new node could not be allocated, we need to
remove @newnode from @peer->allowedips_list before freeing it.
syzbot reported:
BUG: KASAN: use-after-free in __list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
Read of size 8 at addr ffff88809881a538 by task syz-executor.4/30133
CPU: 0 PID: 30133 Comm: syz-executor.4 Not tainted 5.5.0-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+0x197/0x210 lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:639
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
__list_del_entry_valid+0xdc/0xf5 lib/list_debug.c:54
__list_del_entry include/linux/list.h:132 [inline]
list_del include/linux/list.h:146 [inline]
root_remove_peer_lists+0x24f/0x4b0 drivers/net/wireguard/allowedips.c:65
wg_allowedips_free+0x232/0x390 drivers/net/wireguard/allowedips.c:300
wg_peer_remove_all+0xd5/0x620 drivers/net/wireguard/peer.c:187
wg_set_device+0xd01/0x1350 drivers/net/wireguard/netlink.c:542
genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:672
____sys_sendmsg+0x753/0x880 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0x105/0x1d0 net/socket.c:2430
__do_sys_sendmsg net/socket.c:2439 [inline]
__se_sys_sendmsg net/socket.c:2437 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b399
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f99a9bcdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f99a9bce6d4 RCX: 000000000045b399
RDX: 0000000000000000 RSI: 0000000020001340 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000000009ba R14: 00000000004cb2b8 R15: 0000000000000009
Allocated by task 30103:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:670 [inline]
add+0x70a/0x1970 drivers/net/wireguard/allowedips.c:236
wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320
set_allowedip drivers/net/wireguard/netlink.c:343 [inline]
set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468
wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591
genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:672
____sys_sendmsg+0x753/0x880 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0x105/0x1d0 net/socket.c:2430
__do_sys_sendmsg net/socket.c:2439 [inline]
__se_sys_sendmsg net/socket.c:2437 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 30103:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:335 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
__cache_free mm/slab.c:3426 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3757
add+0x12d2/0x1970 drivers/net/wireguard/allowedips.c:266
wg_allowedips_insert_v4+0xf6/0x160 drivers/net/wireguard/allowedips.c:320
set_allowedip drivers/net/wireguard/netlink.c:343 [inline]
set_peer+0xfb9/0x1150 drivers/net/wireguard/netlink.c:468
wg_set_device+0xbd4/0x1350 drivers/net/wireguard/netlink.c:591
genl_family_rcv_msg_doit net/netlink/genetlink.c:672 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:717 [inline]
genl_rcv_msg+0x67d/0xea0 net/netlink/genetlink.c:734
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
genl_rcv+0x29/0x40 net/netlink/genetlink.c:745
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:672
____sys_sendmsg+0x753/0x880 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0x105/0x1d0 net/socket.c:2430
__do_sys_sendmsg net/socket.c:2439 [inline]
__se_sys_sendmsg net/socket.c:2437 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff88809881a500
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 56 bytes inside of
64-byte region [ffff88809881a500, ffff88809881a540)
The buggy address belongs to the page:
page:ffffea0002620680 refcount:1 mapcount:0 mapping:ffff8880aa400380 index:0x0
raw: 00fffe0000000200 ffffea000250b748 ffffea000254bac8 ffff8880aa400380
raw: 0000000000000000 ffff88809881a000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88809881a400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88809881a480: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff88809881a500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff88809881a580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff88809881a600: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
Fixes:
|
||
|
Jason A. Donenfeld
|
dcfea72e79 |
net: introduce skb_list_walk_safe for skb segment walking
As part of the continual effort to remove direct usage of skb->next and
skb->prev, this patch adds a helper for iterating through the
singly-linked variant of skb lists, which are used for lists of GSO
packet. The name "skb_list_..." has been chosen to match the existing
function, "kfree_skb_list, which also operates on these singly-linked
lists, and the "..._walk_safe" part is the same idiom as elsewhere in
the kernel.
This patch removes the helper from wireguard and puts it into
linux/skbuff.h, while making it a bit more robust for general usage. In
particular, parenthesis are added around the macro argument usage, and it
now accounts for trying to iterate through an already-null skb pointer,
which will simply run the iteration zero times. This latter enhancement
means it can be used to replace both do { ... } while and while (...)
open-coded idioms.
This should take care of these three possible usages, which match all
current methods of iterations.
skb_list_walk_safe(segs, skb, next) { ... }
skb_list_walk_safe(skb, skb, next) { ... }
skb_list_walk_safe(segs, skb, segs) { ... }
Gcc appears to generate efficient code for each of these.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
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Jason A. Donenfeld
|
736775d06b |
wireguard: socket: mark skbs as not on list when receiving via gro
Certain drivers will pass gro skbs to udp, at which point the udp driver simply iterates through them and passes them off to encap_rcv, which is where we pick up. At the moment, we're not attempting to coalesce these into bundles, but we also don't want to wind up having cascaded lists of skbs treated separately. The right behavior here, then, is to just mark each incoming one as not on a list. This can be seen in practice, for example, with Qualcomm's rmnet_perf driver. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Tested-by: Yaroslav Furman <yaro330@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
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Jason A. Donenfeld
|
04d2ea92a1 |
wireguard: queueing: do not account for pfmemalloc when clearing skb header
Before |
||
|
Wei Yongjun
|
d89ee7d5c7 |
wireguard: allowedips: use kfree_rcu() instead of call_rcu()
The callback function of call_rcu() just calls a kfree(), so we can use kfree_rcu() instead of call_rcu() + callback function. Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
YueHaibing
|
43967b6ff9 |
wireguard: main: remove unused include <linux/version.h>
Remove <linux/version.h> from the includes for main.c, which is unused. Signed-off-by: YueHaibing <yuehaibing@huawei.com> [Jason: reworded commit message] Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Josh Soref
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a2ec8b5706 |
wireguard: global: fix spelling mistakes in comments
This fixes two spelling errors in source code comments. Signed-off-by: Josh Soref <jsoref@gmail.com> [Jason: rewrote commit message] Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Jason A. Donenfeld
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e7096c131e |
net: WireGuard secure network tunnel
WireGuard is a layer 3 secure networking tunnel made specifically for the kernel, that aims to be much simpler and easier to audit than IPsec. Extensive documentation and description of the protocol and considerations, along with formal proofs of the cryptography, are available at: * https://www.wireguard.com/ * https://www.wireguard.com/papers/wireguard.pdf This commit implements WireGuard as a simple network device driver, accessible in the usual RTNL way used by virtual network drivers. It makes use of the udp_tunnel APIs, GRO, GSO, NAPI, and the usual set of networking subsystem APIs. It has a somewhat novel multicore queueing system designed for maximum throughput and minimal latency of encryption operations, but it is implemented modestly using workqueues and NAPI. Configuration is done via generic Netlink, and following a review from the Netlink maintainer a year ago, several high profile userspace tools have already implemented the API. This commit also comes with several different tests, both in-kernel tests and out-of-kernel tests based on network namespaces, taking profit of the fact that sockets used by WireGuard intentionally stay in the namespace the WireGuard interface was originally created, exactly like the semantics of userspace tun devices. See wireguard.com/netns/ for pictures and examples. The source code is fairly short, but rather than combining everything into a single file, WireGuard is developed as cleanly separable files, making auditing and comprehension easier. Things are laid out as follows: * noise.[ch], cookie.[ch], messages.h: These implement the bulk of the cryptographic aspects of the protocol, and are mostly data-only in nature, taking in buffers of bytes and spitting out buffers of bytes. They also handle reference counting for their various shared pieces of data, like keys and key lists. * ratelimiter.[ch]: Used as an integral part of cookie.[ch] for ratelimiting certain types of cryptographic operations in accordance with particular WireGuard semantics. * allowedips.[ch], peerlookup.[ch]: The main lookup structures of WireGuard, the former being trie-like with particular semantics, an integral part of the design of the protocol, and the latter just being nice helper functions around the various hashtables we use. * device.[ch]: Implementation of functions for the netdevice and for rtnl, responsible for maintaining the life of a given interface and wiring it up to the rest of WireGuard. * peer.[ch]: Each interface has a list of peers, with helper functions available here for creation, destruction, and reference counting. * socket.[ch]: Implementation of functions related to udp_socket and the general set of kernel socket APIs, for sending and receiving ciphertext UDP packets, and taking care of WireGuard-specific sticky socket routing semantics for the automatic roaming. * netlink.[ch]: Userspace API entry point for configuring WireGuard peers and devices. The API has been implemented by several userspace tools and network management utility, and the WireGuard project distributes the basic wg(8) tool. * queueing.[ch]: Shared function on the rx and tx path for handling the various queues used in the multicore algorithms. * send.c: Handles encrypting outgoing packets in parallel on multiple cores, before sending them in order on a single core, via workqueues and ring buffers. Also handles sending handshake and cookie messages as part of the protocol, in parallel. * receive.c: Handles decrypting incoming packets in parallel on multiple cores, before passing them off in order to be ingested via the rest of the networking subsystem with GRO via the typical NAPI poll function. Also handles receiving handshake and cookie messages as part of the protocol, in parallel. * timers.[ch]: Uses the timer wheel to implement protocol particular event timeouts, and gives a set of very simple event-driven entry point functions for callers. * main.c, version.h: Initialization and deinitialization of the module. * selftest/*.h: Runtime unit tests for some of the most security sensitive functions. * tools/testing/selftests/wireguard/netns.sh: Aforementioned testing script using network namespaces. This commit aims to be as self-contained as possible, implementing WireGuard as a standalone module not needing much special handling or coordination from the network subsystem. I expect for future optimizations to the network stack to positively improve WireGuard, and vice-versa, but for the time being, this exists as intentionally standalone. We introduce a menu option for CONFIG_WIREGUARD, as well as providing a verbose debug log and self-tests via CONFIG_WIREGUARD_DEBUG. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: David Miller <davem@davemloft.net> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net> |