diff mbox series

[net,2/3] wireguard: netlink: send staged packets when setting initial private key

Message ID 20230703012723.800199-3-Jason@zx2c4.com (mailing list archive)
State Accepted
Commit f58d0a9b4c6a7a5199c3af967e43cc8b654604d4
Delegated to: Netdev Maintainers
Headers show
Series wireguard fixes for 6.4.2/6.5-rc1 | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers fail 1 blamed authors not CCed: davem@davemloft.net; 7 maintainers not CCed: kuba@kernel.org shuah@kernel.org wireguard@lists.zx2c4.com davem@davemloft.net linux-kselftest@vger.kernel.org pabeni@redhat.com edumazet@google.com
netdev/build_clang fail Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success net selftest script(s) already in Makefile
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 92 exceeds 80 columns WARNING: line length of 94 exceeds 80 columns WARNING: line length of 97 exceeds 80 columns WARNING: line length of 98 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Jason A. Donenfeld July 3, 2023, 1:27 a.m. UTC
Packets bound for peers can queue up prior to the device private key
being set. For example, if persistent keepalive is set, a packet is
queued up to be sent as soon as the device comes up. However, if the
private key hasn't been set yet, the handshake message never sends, and
no timer is armed to retry, since that would be pointless.

But, if a user later sets a private key, the expectation is that those
queued packets, such as a persistent keepalive, are actually sent. So
adjust the configuration logic to account for this edge case, and add a
test case to make sure this works.

Maxim noticed this with a wg-quick(8) config to the tune of:

    [Interface]
    PostUp = wg set %i private-key somefile

    [Peer]
    PublicKey = ...
    Endpoint = ...
    PersistentKeepalive = 25

Here, the private key gets set after the device comes up using a PostUp
script, triggering the bug.

Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Cc: stable@vger.kernel.org
Reported-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Tested-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Link: https://lore.kernel.org/wireguard/87fs7xtqrv.fsf@gmail.com/
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/net/wireguard/netlink.c            | 14 ++++++----
 tools/testing/selftests/wireguard/netns.sh | 30 +++++++++++++++++++---
 2 files changed, 35 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index 43c8c84e7ea8..6d1bd9f52d02 100644
--- a/drivers/net/wireguard/netlink.c
+++ b/drivers/net/wireguard/netlink.c
@@ -546,6 +546,7 @@  static int wg_set_device(struct sk_buff *skb, struct genl_info *info)
 		u8 *private_key = nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]);
 		u8 public_key[NOISE_PUBLIC_KEY_LEN];
 		struct wg_peer *peer, *temp;
+		bool send_staged_packets;
 
 		if (!crypto_memneq(wg->static_identity.static_private,
 				   private_key, NOISE_PUBLIC_KEY_LEN))
@@ -564,14 +565,17 @@  static int wg_set_device(struct sk_buff *skb, struct genl_info *info)
 		}
 
 		down_write(&wg->static_identity.lock);
-		wg_noise_set_static_identity_private_key(&wg->static_identity,
-							 private_key);
-		list_for_each_entry_safe(peer, temp, &wg->peer_list,
-					 peer_list) {
+		send_staged_packets = !wg->static_identity.has_identity && netif_running(wg->dev);
+		wg_noise_set_static_identity_private_key(&wg->static_identity, private_key);
+		send_staged_packets = send_staged_packets && wg->static_identity.has_identity;
+
+		wg_cookie_checker_precompute_device_keys(&wg->cookie_checker);
+		list_for_each_entry_safe(peer, temp, &wg->peer_list, peer_list) {
 			wg_noise_precompute_static_static(peer);
 			wg_noise_expire_current_peer_keypairs(peer);
+			if (send_staged_packets)
+				wg_packet_send_staged_packets(peer);
 		}
-		wg_cookie_checker_precompute_device_keys(&wg->cookie_checker);
 		up_write(&wg->static_identity.lock);
 	}
 skip_set_private_key:
diff --git a/tools/testing/selftests/wireguard/netns.sh b/tools/testing/selftests/wireguard/netns.sh
index 69c7796c7ca9..405ff262ca93 100755
--- a/tools/testing/selftests/wireguard/netns.sh
+++ b/tools/testing/selftests/wireguard/netns.sh
@@ -514,10 +514,32 @@  n2 bash -c 'printf 0 > /proc/sys/net/ipv4/conf/all/rp_filter'
 n1 ping -W 1 -c 1 192.168.241.2
 [[ $(n2 wg show wg0 endpoints) == "$pub1	10.0.0.3:1" ]]
 
-ip1 link del veth1
-ip1 link del veth3
-ip1 link del wg0
-ip2 link del wg0
+ip1 link del dev veth3
+ip1 link del dev wg0
+ip2 link del dev wg0
+
+# Make sure persistent keep alives are sent when an adapter comes up
+ip1 link add dev wg0 type wireguard
+n1 wg set wg0 private-key <(echo "$key1") peer "$pub2" endpoint 10.0.0.1:1 persistent-keepalive 1
+read _ _ tx_bytes < <(n1 wg show wg0 transfer)
+[[ $tx_bytes -eq 0 ]]
+ip1 link set dev wg0 up
+read _ _ tx_bytes < <(n1 wg show wg0 transfer)
+[[ $tx_bytes -gt 0 ]]
+ip1 link del dev wg0
+# This should also happen even if the private key is set later
+ip1 link add dev wg0 type wireguard
+n1 wg set wg0 peer "$pub2" endpoint 10.0.0.1:1 persistent-keepalive 1
+read _ _ tx_bytes < <(n1 wg show wg0 transfer)
+[[ $tx_bytes -eq 0 ]]
+ip1 link set dev wg0 up
+read _ _ tx_bytes < <(n1 wg show wg0 transfer)
+[[ $tx_bytes -eq 0 ]]
+n1 wg set wg0 private-key <(echo "$key1")
+read _ _ tx_bytes < <(n1 wg show wg0 transfer)
+[[ $tx_bytes -gt 0 ]]
+ip1 link del dev veth1
+ip1 link del dev wg0
 
 # We test that Netlink/IPC is working properly by doing things that usually cause split responses
 ip0 link add dev wg0 type wireguard