This is a follow up to 2d4fa2a6e7.
Upstream commit 2c64605b590edadb3fb46d1ec6badb49e940b479 has been backported
to 5.4.29 and 5.5.14.
Signed-off-by: Christian Hesse <mail@eworm.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This backports upstream commit 2c64605b590edadb3fb46d1ec6badb49e940b479.
It makes no difference for us, but it's nice to keep this code in sync
with upstream as much as possible.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
We precompute the static-static ECDH during configuration time, in order
to save an expensive computation later when receiving network packets.
However, not all ECDH computations yield a contributory result. Prior,
we were just not letting those peers be added to the interface. However,
this creates a strange inconsistency, since it was still possible to add
other weird points, like a valid public key plus a low-order point, and,
like points that result in zeros, a handshake would not complete. In
order to make the behavior more uniform and less surprising, simply
allow all peers to be added. Then, we'll error out later when doing the
crypto if there's an issue. This also adds more separation between the
crypto layer and the configuration layer.
Discussed-with: Mathias Hall-Andersen <mathias@hall-andersen.dk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The situation in which we wind up hitting the default case here
indicates a major bug in earlier parsing code. It is not a usual thing
that should ever happen, which means a "friendly" message for it doesn't
make sense. Rather, replace this with a WARN_ON, just like we do earlier
in the file for a similar situation, so that somebody sends us a bug
report and we can fix it.
Reported-by: Fabian Freyer <fabianfreyer@radicallyopensecurity.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
We carry out checks to the effect of:
if (skb->protocol != wg_examine_packet_protocol(skb))
goto err;
By having wg_skb_examine_untrusted_ip_hdr return 0 on failure, this
means that the check above still passes in the case where skb->protocol
is zero, which is possible to hit with AF_PACKET:
struct sockaddr_pkt saddr = { .spkt_device = "wg0" };
unsigned char buffer[5] = { 0 };
sendto(socket(AF_PACKET, SOCK_PACKET, /* skb->protocol = */ 0),
buffer, sizeof(buffer), 0, (const struct sockaddr *)&saddr, sizeof(saddr));
Additional checks mean that this isn't actually a problem in the code
base, but I could imagine it becoming a problem later if the function is
used more liberally.
I would prefer to fix this by having wg_examine_packet_protocol return a
32-bit ~0 value on failure, which will never match any value of
skb->protocol, which would simply change the generated code from a mov
to a movzx. However, sparse complains, and adding __force casts doesn't
seem like a good idea, so instead we just add a simple helper function
to check for the zero return value. Since wg_examine_packet_protocol
itself gets inlined, this winds up not adding an additional branch to
the generated code, since the 0 return value already happens in a
mergable branch.
Reported-by: Fabian Freyer <fabianfreyer@radicallyopensecurity.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This causes problems with RAP and KERNEXEC for PaX, as r12 is a
reserved register.
It also leads to a more compact instruction encoding, saving about 100
cycles.
Suggested-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Utter non-sense from way back when.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Fixes: 8906775b ("socket: synchronize net on socket tear down")
It turns out there's an easy way to get packets queued up while still
having an MTU of zero, and that's via persistent keep alive. This commit
makes sure that in whatever condition, we don't wind up dividing by
zero. Note that an MTU of zero for a wireguard interface is something
quasi-valid, so I don't think the correct fix is to limit it via
min_mtu. This can be reproduced easily with:
ip link add wg0 type wireguard
ip link add wg1 type wireguard
ip link set wg0 up mtu 0
ip link set wg1 up
wg set wg0 private-key <(wg genkey)
wg set wg1 listen-port 1 private-key <(wg genkey) peer $(wg show wg0 public-key)
wg set wg0 peer $(wg show wg1 public-key) persistent-keepalive 1 endpoint 127.0.0.1:1
However, while min_mtu=0 seems fine, it makes sense to restrict the
max_mtu. This commit also restricts the maximum MTU to the greatest
number for which rounding up to the padding multiple won't overflow a
signed integer. Packets this large were always rejected anyway
eventually, due to checks deeper in, but it seems more sound not to even
let the administrator configure something that won't work anyway.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This is a small optimization that prevents more expensive comparisons
from happening when they are no longer necessary, by clearing the
last_under_load variable whenever we wind up in a state where we were
under load but we no longer are.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Suggested-by: Matt Dunwoodie <ncon@noconroy.net>
This is a small test to ensure that icmp_ndo_send is actually doing the
right with with regards to the source address. It tests this by
ensuring that the error comes back along the right path.
Also, backport the new ndo function for this.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Ensure that peers with low order points are ignored, both in the case
where we already have a device private key and in the case where we do
not. This adds points that naturally give a zero output.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Without this, we wind up proceeding too early sometimes when the
previous process has just used the same listening port. So, we tie the
listening socket query to the specific pid we're interested in.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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>
RedHat backported some more changes, now released as kernel 4.18.0-168.el8.
To maintain compatibility with kernel -147, a new macro is introduced: ISRHEL82.
Compile-tested with the -168 and -147 kernels.
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
[zx2c4: we normally only support the latest RHEL, but having some beta
support for the time being sounds like a good plan, given that there
may be interest from RedHat in actually merging this into their
kernels.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This comes from INRIA's HACL*/Vale. It implements the same algorithm and
implementation strategy as the code it replaces, only this code has been
formally verified, sans the base point multiplication, which uses code
similar to prior, only it uses the formally verified field arithmetic
alongside reproducable ladder generation steps. This doesn't have a
pure-bmi2 version, which means haswell no longer benefits, but the
increased (doubled) code complexity is not worth it for a single
generation of chips that's already old.
Performance-wise, this is around 1% slower on older microarchitectures,
and slightly faster on newer microarchitectures, mainly 10nm ones or
backports of 10nm to 14nm. This implementation is "everest" below:
Xeon E5-2680 v4 (Broadwell)
armfazh: 133340 cycles per call
everest: 133436 cycles per call
Xeon Gold 5120 (Sky Lake Server)
armfazh: 112636 cycles per call
everest: 113906 cycles per call
Core i5-6300U (Sky Lake Client)
armfazh: 116810 cycles per call
everest: 117916 cycles per call
Core i7-7600U (Kaby Lake)
armfazh: 119523 cycles per call
everest: 119040 cycles per call
Core i7-8750H (Coffee Lake)
armfazh: 113914 cycles per call
everest: 113650 cycles per call
Core i9-9880H (Coffee Lake Refresh)
armfazh: 112616 cycles per call
everest: 114082 cycles per call
Core i3-8121U (Cannon Lake)
armfazh: 113202 cycles per call
everest: 111382 cycles per call
Core i7-8265U (Whiskey Lake)
armfazh: 127307 cycles per call
everest: 127697 cycles per call
Core i7-8550U (Kaby Lake Refresh)
armfazh: 127522 cycles per call
everest: 127083 cycles per call
Xeon Platinum 8275CL (Cascade Lake)
armfazh: 114380 cycles per call
everest: 114656 cycles per call
Achieving these kind of results with formally verified code is quite
remarkable, especialy considering that performance is favorable for
newer chips.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
We also no longer do anything dynamic with dkms.conf, and we don't
rewrite any files at all, but rather pass this through as a cflag to the
compiler optionally.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: Egbert Verhage <egbert@eggiecode.org>
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>
