From ba3d7b93dbe3202bf8ead473d75885af773068bc Mon Sep 17 00:00:00 2001 From: Jordan Rife Date: Wed, 21 May 2025 23:27:06 +0200 Subject: wireguard: allowedips: add WGALLOWEDIP_F_REMOVE_ME flag The current netlink API for WireGuard does not directly support removal of allowed ips from a peer. A user can remove an allowed ip from a peer in one of two ways: 1. By using the WGPEER_F_REPLACE_ALLOWEDIPS flag and providing a new list of allowed ips which omits the allowed ip that is to be removed. 2. By reassigning an allowed ip to a "dummy" peer then removing that peer with WGPEER_F_REMOVE_ME. With the first approach, the driver completely rebuilds the allowed ip list for a peer. If my current configuration is such that a peer has allowed ips 192.168.0.2 and 192.168.0.3 and I want to remove 192.168.0.2 the actual transition looks like this. [192.168.0.2, 192.168.0.3] <-- Initial state [] <-- Step 1: Allowed ips removed for peer [192.168.0.3] <-- Step 2: Allowed ips added back for peer This is true even if the allowed ip list is small and the update does not need to be batched into multiple WG_CMD_SET_DEVICE requests, as the removal and subsequent addition of ips is non-atomic within a single request. Consequently, wg_allowedips_lookup_dst and wg_allowedips_lookup_src may return NULL while reconfiguring a peer even for packets bound for ips a user did not intend to remove leading to unintended interruptions in connectivity. This presents in userspace as failed calls to sendto and sendmsg for UDP sockets. In my case, I ran netperf while repeatedly reconfiguring the allowed ips for a peer with wg. /usr/local/bin/netperf -H 10.102.73.72 -l 10m -t UDP_STREAM -- -R 1 -m 1024 send_data: data send error: No route to host (errno 113) netperf: send_omni: send_data failed: No route to host While this may not be of particular concern for environments where peers and allowed ips are mostly static, systems like Cilium manage peers and allowed ips in a dynamic environment where peers (i.e. Kubernetes nodes) and allowed ips (i.e. pods running on those nodes) can frequently change making WGPEER_F_REPLACE_ALLOWEDIPS problematic. The second approach avoids any possible connectivity interruptions but is hacky and less direct, requiring the creation of a temporary peer just to dispose of an allowed ip. Introduce a new flag called WGALLOWEDIP_F_REMOVE_ME which in the same way that WGPEER_F_REMOVE_ME allows a user to remove a single peer from a WireGuard device's configuration allows a user to remove an ip from a peer's set of allowed ips. This enables incremental updates to a device's configuration without any connectivity blips or messy workarounds. A corresponding patch for wg extends the existing `wg set` interface to leverage this feature. $ wg set wg0 peer allowed-ips +192.168.88.0/24,-192.168.0.1/32 When '+' or '-' is prepended to any ip in the list, wg clears WGPEER_F_REPLACE_ALLOWEDIPS and sets the WGALLOWEDIP_F_REMOVE_ME flag on any ip prefixed with '-'. Signed-off-by: Jordan Rife [Jason: minor style nits, fixes to selftest, bump of wireguard-tools version] Signed-off-by: Jason A. Donenfeld Link: https://patch.msgid.link/20250521212707.1767879-5-Jason@zx2c4.com Signed-off-by: Paolo Abeni --- tools/testing/selftests/wireguard/netns.sh | 29 +++++++++++++++++++++++++ tools/testing/selftests/wireguard/qemu/Makefile | 2 +- 2 files changed, 30 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/testing/selftests/wireguard/netns.sh b/tools/testing/selftests/wireguard/netns.sh index 55500f901fbc..a8f550aecb35 100755 --- a/tools/testing/selftests/wireguard/netns.sh +++ b/tools/testing/selftests/wireguard/netns.sh @@ -611,6 +611,35 @@ n0 wg set wg0 peer "$pub2" allowed-ips "$allowedips" } < <(n0 wg show wg0 allowed-ips) ip0 link del wg0 +allowedips=( ) +for i in {1..197}; do + allowedips+=( 192.168.0.$i ) + allowedips+=( abcd::$i ) +done +saved_ifs="$IFS" +IFS=, +allowedips="${allowedips[*]}" +IFS="$saved_ifs" +ip0 link add wg0 type wireguard +n0 wg set wg0 peer "$pub1" allowed-ips "$allowedips" +n0 wg set wg0 peer "$pub1" allowed-ips -192.168.0.1/32,-192.168.0.20/32,-192.168.0.100/32,-abcd::1/128,-abcd::20/128,-abcd::100/128 +{ + read -r pub allowedips + [[ $pub == "$pub1" ]] + i=0 + for ip in $allowedips; do + [[ $ip != "192.168.0.1" ]] + [[ $ip != "192.168.0.20" ]] + [[ $ip != "192.168.0.100" ]] + [[ $ip != "abcd::1" ]] + [[ $ip != "abcd::20" ]] + [[ $ip != "abcd::100" ]] + ((++i)) + done + ((i == 388)) +} < <(n0 wg show wg0 allowed-ips) +ip0 link del wg0 + ! n0 wg show doesnotexist || false ip0 link add wg0 type wireguard diff --git a/tools/testing/selftests/wireguard/qemu/Makefile b/tools/testing/selftests/wireguard/qemu/Makefile index 35856b11c143..f6fbd88914ee 100644 --- a/tools/testing/selftests/wireguard/qemu/Makefile +++ b/tools/testing/selftests/wireguard/qemu/Makefile @@ -43,7 +43,7 @@ $(eval $(call tar_download,IPROUTE2,iproute2,5.17.0,.tar.gz,https://www.kernel.o $(eval $(call tar_download,IPTABLES,iptables,1.8.7,.tar.bz2,https://www.netfilter.org/projects/iptables/files/,c109c96bb04998cd44156622d36f8e04b140701ec60531a10668cfdff5e8d8f0)) $(eval $(call tar_download,NMAP,nmap,7.92,.tgz,https://nmap.org/dist/,064183ea642dc4c12b1ab3b5358ce1cef7d2e7e11ffa2849f16d339f5b717117)) $(eval $(call tar_download,IPUTILS,iputils,s20190709,.tar.gz,https://github.com/iputils/iputils/archive/s20190709.tar.gz/#,a15720dd741d7538dd2645f9f516d193636ae4300ff7dbc8bfca757bf166490a)) -$(eval $(call tar_download,WIREGUARD_TOOLS,wireguard-tools,1.0.20210914,.tar.xz,https://git.zx2c4.com/wireguard-tools/snapshot/,97ff31489217bb265b7ae850d3d0f335ab07d2652ba1feec88b734bc96bd05ac)) +$(eval $(call tar_download,WIREGUARD_TOOLS,wireguard-tools,1.0.20250521,.tar.xz,https://git.zx2c4.com/wireguard-tools/snapshot/,b6f2628b85b1b23cc06517ec9c74f82d52c4cdbd020f3dd2f00c972a1782950e)) export CFLAGS := -O3 -pipe ifeq ($(HOST_ARCH),$(ARCH)) -- cgit v1.2.3