From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/net/wireguard/netlink.c | 607 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 607 insertions(+) create mode 100644 drivers/net/wireguard/netlink.c (limited to 'drivers/net/wireguard/netlink.c') diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c new file mode 100644 index 000000000..1da7e98d0 --- /dev/null +++ b/drivers/net/wireguard/netlink.c @@ -0,0 +1,607 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld . All Rights Reserved. + */ + +#include "netlink.h" +#include "device.h" +#include "peer.h" +#include "socket.h" +#include "queueing.h" +#include "messages.h" +#include "generated/netlink.h" + +#include + +#include +#include +#include +#include + +static struct genl_family genl_family; + +static struct wg_device *lookup_interface(struct nlattr **attrs, + struct sk_buff *skb) +{ + struct net_device *dev = NULL; + + if (!attrs[WGDEVICE_A_IFINDEX] == !attrs[WGDEVICE_A_IFNAME]) + return ERR_PTR(-EBADR); + if (attrs[WGDEVICE_A_IFINDEX]) + dev = dev_get_by_index(sock_net(skb->sk), + nla_get_u32(attrs[WGDEVICE_A_IFINDEX])); + else if (attrs[WGDEVICE_A_IFNAME]) + dev = dev_get_by_name(sock_net(skb->sk), + nla_data(attrs[WGDEVICE_A_IFNAME])); + if (!dev) + return ERR_PTR(-ENODEV); + if (!dev->rtnl_link_ops || !dev->rtnl_link_ops->kind || + strcmp(dev->rtnl_link_ops->kind, KBUILD_MODNAME)) { + dev_put(dev); + return ERR_PTR(-EOPNOTSUPP); + } + return netdev_priv(dev); +} + +static int get_allowedips(struct sk_buff *skb, const u8 *ip, u8 cidr, + int family) +{ + struct nlattr *allowedip_nest; + + allowedip_nest = nla_nest_start(skb, 0); + if (!allowedip_nest) + return -EMSGSIZE; + + if (nla_put_u8(skb, WGALLOWEDIP_A_CIDR_MASK, cidr) || + nla_put_u16(skb, WGALLOWEDIP_A_FAMILY, family) || + nla_put(skb, WGALLOWEDIP_A_IPADDR, family == AF_INET6 ? + sizeof(struct in6_addr) : sizeof(struct in_addr), ip)) { + nla_nest_cancel(skb, allowedip_nest); + return -EMSGSIZE; + } + + nla_nest_end(skb, allowedip_nest); + return 0; +} + +struct dump_ctx { + struct wg_device *wg; + struct wg_peer *next_peer; + u64 allowedips_seq; + struct allowedips_node *next_allowedip; +}; + +#define DUMP_CTX(cb) ((struct dump_ctx *)(cb)->args) + +static int +get_peer(struct wg_peer *peer, struct sk_buff *skb, struct dump_ctx *ctx) +{ + + struct nlattr *allowedips_nest, *peer_nest = nla_nest_start(skb, 0); + struct allowedips_node *allowedips_node = ctx->next_allowedip; + bool fail; + + if (!peer_nest) + return -EMSGSIZE; + + down_read(&peer->handshake.lock); + fail = nla_put(skb, WGPEER_A_PUBLIC_KEY, NOISE_PUBLIC_KEY_LEN, + peer->handshake.remote_static); + up_read(&peer->handshake.lock); + if (fail) + goto err; + + if (!allowedips_node) { + const struct __kernel_timespec last_handshake = { + .tv_sec = peer->walltime_last_handshake.tv_sec, + .tv_nsec = peer->walltime_last_handshake.tv_nsec + }; + + down_read(&peer->handshake.lock); + fail = nla_put(skb, WGPEER_A_PRESHARED_KEY, + NOISE_SYMMETRIC_KEY_LEN, + peer->handshake.preshared_key); + up_read(&peer->handshake.lock); + if (fail) + goto err; + + if (nla_put(skb, WGPEER_A_LAST_HANDSHAKE_TIME, + sizeof(last_handshake), &last_handshake) || + nla_put_u16(skb, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL, + peer->persistent_keepalive_interval) || + nla_put_u64_64bit(skb, WGPEER_A_TX_BYTES, peer->tx_bytes, + WGPEER_A_UNSPEC) || + nla_put_u64_64bit(skb, WGPEER_A_RX_BYTES, peer->rx_bytes, + WGPEER_A_UNSPEC) || + nla_put_u32(skb, WGPEER_A_PROTOCOL_VERSION, 1)) + goto err; + + read_lock_bh(&peer->endpoint_lock); + if (peer->endpoint.addr.sa_family == AF_INET) + fail = nla_put(skb, WGPEER_A_ENDPOINT, + sizeof(peer->endpoint.addr4), + &peer->endpoint.addr4); + else if (peer->endpoint.addr.sa_family == AF_INET6) + fail = nla_put(skb, WGPEER_A_ENDPOINT, + sizeof(peer->endpoint.addr6), + &peer->endpoint.addr6); + read_unlock_bh(&peer->endpoint_lock); + if (fail) + goto err; + allowedips_node = + list_first_entry_or_null(&peer->allowedips_list, + struct allowedips_node, peer_list); + } + if (!allowedips_node) + goto no_allowedips; + if (!ctx->allowedips_seq) + ctx->allowedips_seq = ctx->wg->peer_allowedips.seq; + else if (ctx->allowedips_seq != ctx->wg->peer_allowedips.seq) + goto no_allowedips; + + allowedips_nest = nla_nest_start(skb, WGPEER_A_ALLOWEDIPS); + if (!allowedips_nest) + goto err; + + list_for_each_entry_from(allowedips_node, &peer->allowedips_list, + peer_list) { + u8 cidr, ip[16] __aligned(__alignof(u64)); + int family; + + family = wg_allowedips_read_node(allowedips_node, ip, &cidr); + if (get_allowedips(skb, ip, cidr, family)) { + nla_nest_end(skb, allowedips_nest); + nla_nest_end(skb, peer_nest); + ctx->next_allowedip = allowedips_node; + return -EMSGSIZE; + } + } + nla_nest_end(skb, allowedips_nest); +no_allowedips: + nla_nest_end(skb, peer_nest); + ctx->next_allowedip = NULL; + ctx->allowedips_seq = 0; + return 0; +err: + nla_nest_cancel(skb, peer_nest); + return -EMSGSIZE; +} + +int wg_get_device_start(struct netlink_callback *cb) +{ + struct wg_device *wg; + + wg = lookup_interface(genl_info_dump(cb)->attrs, cb->skb); + if (IS_ERR(wg)) + return PTR_ERR(wg); + DUMP_CTX(cb)->wg = wg; + return 0; +} + +int wg_get_device_dumpit(struct sk_buff *skb, struct netlink_callback *cb) +{ + struct wg_peer *peer, *next_peer_cursor; + struct dump_ctx *ctx = DUMP_CTX(cb); + struct wg_device *wg = ctx->wg; + struct nlattr *peers_nest; + int ret = -EMSGSIZE; + bool done = true; + void *hdr; + + rtnl_lock(); + mutex_lock(&wg->device_update_lock); + cb->seq = wg->device_update_gen; + next_peer_cursor = ctx->next_peer; + + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, + &genl_family, NLM_F_MULTI, WG_CMD_GET_DEVICE); + if (!hdr) + goto out; + genl_dump_check_consistent(cb, hdr); + + if (!ctx->next_peer) { + if (nla_put_u16(skb, WGDEVICE_A_LISTEN_PORT, + wg->incoming_port) || + nla_put_u32(skb, WGDEVICE_A_FWMARK, wg->fwmark) || + nla_put_u32(skb, WGDEVICE_A_IFINDEX, wg->dev->ifindex) || + nla_put_string(skb, WGDEVICE_A_IFNAME, wg->dev->name)) + goto out; + + down_read(&wg->static_identity.lock); + if (wg->static_identity.has_identity) { + if (nla_put(skb, WGDEVICE_A_PRIVATE_KEY, + NOISE_PUBLIC_KEY_LEN, + wg->static_identity.static_private) || + nla_put(skb, WGDEVICE_A_PUBLIC_KEY, + NOISE_PUBLIC_KEY_LEN, + wg->static_identity.static_public)) { + up_read(&wg->static_identity.lock); + goto out; + } + } + up_read(&wg->static_identity.lock); + } + + peers_nest = nla_nest_start(skb, WGDEVICE_A_PEERS); + if (!peers_nest) + goto out; + ret = 0; + lockdep_assert_held(&wg->device_update_lock); + /* If the last cursor was removed in peer_remove or peer_remove_all, then + * we just treat this the same as there being no more peers left. The + * reason is that seq_nr should indicate to userspace that this isn't a + * coherent dump anyway, so they'll try again. + */ + if (list_empty(&wg->peer_list) || + (ctx->next_peer && ctx->next_peer->is_dead)) { + nla_nest_cancel(skb, peers_nest); + goto out; + } + peer = list_prepare_entry(ctx->next_peer, &wg->peer_list, peer_list); + list_for_each_entry_continue(peer, &wg->peer_list, peer_list) { + if (get_peer(peer, skb, ctx)) { + done = false; + break; + } + next_peer_cursor = peer; + } + nla_nest_end(skb, peers_nest); + +out: + if (!ret && !done && next_peer_cursor) + wg_peer_get(next_peer_cursor); + wg_peer_put(ctx->next_peer); + mutex_unlock(&wg->device_update_lock); + rtnl_unlock(); + + if (ret) { + genlmsg_cancel(skb, hdr); + return ret; + } + genlmsg_end(skb, hdr); + if (done) { + ctx->next_peer = NULL; + return 0; + } + ctx->next_peer = next_peer_cursor; + return skb->len; + + /* At this point, we can't really deal ourselves with safely zeroing out + * the private key material after usage. This will need an additional API + * in the kernel for marking skbs as zero_on_free. + */ +} + +int wg_get_device_done(struct netlink_callback *cb) +{ + struct dump_ctx *ctx = DUMP_CTX(cb); + + if (ctx->wg) + dev_put(ctx->wg->dev); + wg_peer_put(ctx->next_peer); + return 0; +} + +static int set_port(struct wg_device *wg, u16 port) +{ + struct wg_peer *peer; + + if (wg->incoming_port == port) + return 0; + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_socket_clear_peer_endpoint_src(peer); + if (!netif_running(wg->dev)) { + wg->incoming_port = port; + return 0; + } + return wg_socket_init(wg, port); +} + +static int set_allowedip(struct wg_peer *peer, struct nlattr **attrs) +{ + int ret = -EINVAL; + u32 flags = 0; + u16 family; + u8 cidr; + + if (!attrs[WGALLOWEDIP_A_FAMILY] || !attrs[WGALLOWEDIP_A_IPADDR] || + !attrs[WGALLOWEDIP_A_CIDR_MASK]) + return ret; + family = nla_get_u16(attrs[WGALLOWEDIP_A_FAMILY]); + cidr = nla_get_u8(attrs[WGALLOWEDIP_A_CIDR_MASK]); + if (attrs[WGALLOWEDIP_A_FLAGS]) + flags = nla_get_u32(attrs[WGALLOWEDIP_A_FLAGS]); + + if (family == AF_INET && cidr <= 32 && + nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in_addr)) { + if (flags & WGALLOWEDIP_F_REMOVE_ME) + ret = wg_allowedips_remove_v4(&peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, + peer, &peer->device->device_update_lock); + else + ret = wg_allowedips_insert_v4(&peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, + peer, &peer->device->device_update_lock); + } else if (family == AF_INET6 && cidr <= 128 && + nla_len(attrs[WGALLOWEDIP_A_IPADDR]) == sizeof(struct in6_addr)) { + if (flags & WGALLOWEDIP_F_REMOVE_ME) + ret = wg_allowedips_remove_v6(&peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, + peer, &peer->device->device_update_lock); + else + ret = wg_allowedips_insert_v6(&peer->device->peer_allowedips, + nla_data(attrs[WGALLOWEDIP_A_IPADDR]), cidr, + peer, &peer->device->device_update_lock); + } + + return ret; +} + +static int set_peer(struct wg_device *wg, struct nlattr **attrs) +{ + u8 *public_key = NULL, *preshared_key = NULL; + struct wg_peer *peer = NULL; + u32 flags = 0; + int ret; + + ret = -EINVAL; + if (attrs[WGPEER_A_PUBLIC_KEY] && + nla_len(attrs[WGPEER_A_PUBLIC_KEY]) == NOISE_PUBLIC_KEY_LEN) + public_key = nla_data(attrs[WGPEER_A_PUBLIC_KEY]); + else + goto out; + if (attrs[WGPEER_A_PRESHARED_KEY] && + nla_len(attrs[WGPEER_A_PRESHARED_KEY]) == NOISE_SYMMETRIC_KEY_LEN) + preshared_key = nla_data(attrs[WGPEER_A_PRESHARED_KEY]); + + if (attrs[WGPEER_A_FLAGS]) + flags = nla_get_u32(attrs[WGPEER_A_FLAGS]); + + ret = -EPFNOSUPPORT; + if (attrs[WGPEER_A_PROTOCOL_VERSION]) { + if (nla_get_u32(attrs[WGPEER_A_PROTOCOL_VERSION]) != 1) + goto out; + } + + peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, + nla_data(attrs[WGPEER_A_PUBLIC_KEY])); + ret = 0; + if (!peer) { /* Peer doesn't exist yet. Add a new one. */ + if (flags & (WGPEER_F_REMOVE_ME | WGPEER_F_UPDATE_ONLY)) + goto out; + + /* The peer is new, so there aren't allowed IPs to remove. */ + flags &= ~WGPEER_F_REPLACE_ALLOWEDIPS; + + down_read(&wg->static_identity.lock); + if (wg->static_identity.has_identity && + !memcmp(nla_data(attrs[WGPEER_A_PUBLIC_KEY]), + wg->static_identity.static_public, + NOISE_PUBLIC_KEY_LEN)) { + /* We silently ignore peers that have the same public + * key as the device. The reason we do it silently is + * that we'd like for people to be able to reuse the + * same set of API calls across peers. + */ + up_read(&wg->static_identity.lock); + ret = 0; + goto out; + } + up_read(&wg->static_identity.lock); + + peer = wg_peer_create(wg, public_key, preshared_key); + if (IS_ERR(peer)) { + ret = PTR_ERR(peer); + peer = NULL; + goto out; + } + /* Take additional reference, as though we've just been + * looked up. + */ + wg_peer_get(peer); + } + + if (flags & WGPEER_F_REMOVE_ME) { + wg_peer_remove(peer); + goto out; + } + + if (preshared_key) { + down_write(&peer->handshake.lock); + memcpy(&peer->handshake.preshared_key, preshared_key, + NOISE_SYMMETRIC_KEY_LEN); + up_write(&peer->handshake.lock); + } + + if (attrs[WGPEER_A_ENDPOINT]) { + struct sockaddr *addr = nla_data(attrs[WGPEER_A_ENDPOINT]); + size_t len = nla_len(attrs[WGPEER_A_ENDPOINT]); + struct endpoint endpoint = { { { 0 } } }; + + if (len == sizeof(struct sockaddr_in) && addr->sa_family == AF_INET) { + endpoint.addr4 = *(struct sockaddr_in *)addr; + wg_socket_set_peer_endpoint(peer, &endpoint); + } else if (len == sizeof(struct sockaddr_in6) && addr->sa_family == AF_INET6) { + endpoint.addr6 = *(struct sockaddr_in6 *)addr; + wg_socket_set_peer_endpoint(peer, &endpoint); + } + } + + if (flags & WGPEER_F_REPLACE_ALLOWEDIPS) + wg_allowedips_remove_by_peer(&wg->peer_allowedips, peer, + &wg->device_update_lock); + + if (attrs[WGPEER_A_ALLOWEDIPS]) { + struct nlattr *attr, *allowedip[WGALLOWEDIP_A_MAX + 1]; + int rem; + + nla_for_each_nested(attr, attrs[WGPEER_A_ALLOWEDIPS], rem) { + ret = nla_parse_nested(allowedip, WGALLOWEDIP_A_MAX, + attr, NULL, NULL); + if (ret < 0) + goto out; + ret = set_allowedip(peer, allowedip); + if (ret < 0) + goto out; + } + } + + if (attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]) { + const u16 persistent_keepalive_interval = nla_get_u16( + attrs[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]); + const bool send_keepalive = + !peer->persistent_keepalive_interval && + persistent_keepalive_interval && + netif_running(wg->dev); + + peer->persistent_keepalive_interval = persistent_keepalive_interval; + if (send_keepalive) + wg_packet_send_keepalive(peer); + } + + if (netif_running(wg->dev)) + wg_packet_send_staged_packets(peer); + +out: + wg_peer_put(peer); + if (attrs[WGPEER_A_PRESHARED_KEY]) + memzero_explicit(nla_data(attrs[WGPEER_A_PRESHARED_KEY]), + nla_len(attrs[WGPEER_A_PRESHARED_KEY])); + return ret; +} + +int wg_set_device_doit(struct sk_buff *skb, struct genl_info *info) +{ + struct wg_device *wg = lookup_interface(info->attrs, skb); + u32 flags = 0; + int ret; + + if (IS_ERR(wg)) { + ret = PTR_ERR(wg); + goto out_nodev; + } + + rtnl_lock(); + mutex_lock(&wg->device_update_lock); + + if (info->attrs[WGDEVICE_A_FLAGS]) + flags = nla_get_u32(info->attrs[WGDEVICE_A_FLAGS]); + + if (info->attrs[WGDEVICE_A_LISTEN_PORT] || info->attrs[WGDEVICE_A_FWMARK]) { + struct net *net; + rcu_read_lock(); + net = rcu_dereference(wg->creating_net); + ret = !net || !ns_capable(net->user_ns, CAP_NET_ADMIN) ? -EPERM : 0; + rcu_read_unlock(); + if (ret) + goto out; + } + + ++wg->device_update_gen; + + if (info->attrs[WGDEVICE_A_FWMARK]) { + struct wg_peer *peer; + + wg->fwmark = nla_get_u32(info->attrs[WGDEVICE_A_FWMARK]); + list_for_each_entry(peer, &wg->peer_list, peer_list) + wg_socket_clear_peer_endpoint_src(peer); + } + + if (info->attrs[WGDEVICE_A_LISTEN_PORT]) { + ret = set_port(wg, + nla_get_u16(info->attrs[WGDEVICE_A_LISTEN_PORT])); + if (ret) + goto out; + } + + if (flags & WGDEVICE_F_REPLACE_PEERS) + wg_peer_remove_all(wg); + + if (info->attrs[WGDEVICE_A_PRIVATE_KEY] && + nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY]) == + NOISE_PUBLIC_KEY_LEN) { + 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)) + goto skip_set_private_key; + + /* We remove before setting, to prevent race, which means doing + * two 25519-genpub ops. + */ + if (curve25519_generate_public(public_key, private_key)) { + peer = wg_pubkey_hashtable_lookup(wg->peer_hashtable, + public_key); + if (peer) { + wg_peer_put(peer); + wg_peer_remove(peer); + } + } + + down_write(&wg->static_identity.lock); + 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); + } + up_write(&wg->static_identity.lock); + } +skip_set_private_key: + + if (info->attrs[WGDEVICE_A_PEERS]) { + struct nlattr *attr, *peer[WGPEER_A_MAX + 1]; + int rem; + + nla_for_each_nested(attr, info->attrs[WGDEVICE_A_PEERS], rem) { + ret = nla_parse_nested(peer, WGPEER_A_MAX, attr, + NULL, NULL); + if (ret < 0) + goto out; + ret = set_peer(wg, peer); + if (ret < 0) + goto out; + } + } + ret = 0; + +out: + mutex_unlock(&wg->device_update_lock); + rtnl_unlock(); + dev_put(wg->dev); +out_nodev: + if (info->attrs[WGDEVICE_A_PRIVATE_KEY]) + memzero_explicit(nla_data(info->attrs[WGDEVICE_A_PRIVATE_KEY]), + nla_len(info->attrs[WGDEVICE_A_PRIVATE_KEY])); + return ret; +} + +static struct genl_family genl_family __ro_after_init = { + .split_ops = wireguard_nl_ops, + .n_split_ops = ARRAY_SIZE(wireguard_nl_ops), + .name = WG_GENL_NAME, + .version = WG_GENL_VERSION, + .module = THIS_MODULE, + .netnsok = true +}; + +int __init wg_genetlink_init(void) +{ + BUILD_BUG_ON(WG_KEY_LEN != NOISE_PUBLIC_KEY_LEN); + BUILD_BUG_ON(WG_KEY_LEN != NOISE_SYMMETRIC_KEY_LEN); + + return genl_register_family(&genl_family); +} + +void __exit wg_genetlink_uninit(void) +{ + genl_unregister_family(&genl_family); +} -- cgit v1.3.1