On Wed, 12 Mar 2025 21:54:18 +0100, Antonio Quartulli wrote: > --- a/drivers/net/ovpn/io.c > +++ b/drivers/net/ovpn/io.c > @@ -7,6 +7,7 @@ > * Antonio Quartulli <antonio@xxxxxxxxxxx> > */ > > +#include <crypto/aead.h> > #include <linux/netdevice.h> > #include <linux/skbuff.h> > #include <net/gro_cells.h> > @@ -15,6 +16,9 @@ > #include "ovpnpriv.h" > #include "peer.h" > #include "io.h" > +#include "bind.h" > +#include "crypto.h" > +#include "crypto_aead.h" > #include "netlink.h" > #include "proto.h" > #include "udp.h" > @@ -44,7 +48,7 @@ static void ovpn_netdev_write(struct ovpn_peer *peer, struct sk_buff *skb) > skb_set_queue_mapping(skb, 0); > skb_scrub_packet(skb, true); > > - skb_reset_network_header(skb); > + /* network header reset in ovpn_decrypt_post() */ > skb_reset_transport_header(skb); > skb_reset_inner_headers(skb); > > @@ -56,34 +60,147 @@ static void ovpn_netdev_write(struct ovpn_peer *peer, struct sk_buff *skb) > dev_sw_netstats_rx_add(peer->ovpn->dev, pkt_len); > } > > -static void ovpn_decrypt_post(struct sk_buff *skb, int ret) > +void ovpn_decrypt_post(void *data, int ret) > { > - struct ovpn_peer *peer = ovpn_skb_cb(skb)->peer; > + struct ovpn_crypto_key_slot *ks; > + unsigned int payload_offset = 0; > + struct sk_buff *skb = data; > + struct ovpn_peer *peer; > + __be16 proto; > + __be32 *pid; > + > + /* crypto is happening asynchronously. this function will be called > + * again later by the crypto callback with a proper return code > + */ > + if (unlikely(ret == -EINPROGRESS)) > + return; > + > + payload_offset = ovpn_skb_cb(skb)->payload_offset; > + ks = ovpn_skb_cb(skb)->ks; > + peer = ovpn_skb_cb(skb)->peer; > + > + /* crypto is done, cleanup skb CB and its members */ > + > + if (likely(ovpn_skb_cb(skb)->iv)) > + kfree(ovpn_skb_cb(skb)->iv); > + > + if (likely(ovpn_skb_cb(skb)->sg)) > + kfree(ovpn_skb_cb(skb)->sg); > + > + if (likely(ovpn_skb_cb(skb)->req)) > + aead_request_free(ovpn_skb_cb(skb)->req); > > if (unlikely(ret < 0)) > goto drop; > > + /* PID sits after the op */ > + pid = (__force __be32 *)(skb->data + OVPN_OPCODE_SIZE); > + ret = ovpn_pktid_recv(&ks->pid_recv, ntohl(*pid), 0); > + if (unlikely(ret < 0)) { > + net_err_ratelimited("%s: PKT ID RX error for peer %u: %d\n", > + netdev_name(peer->ovpn->dev), peer->id, > + ret); > + goto drop; > + } > + > + /* point to encapsulated IP packet */ > + __skb_pull(skb, payload_offset); > + > + /* check if this is a valid datapacket that has to be delivered to the > + * ovpn interface > + */ > + skb_reset_network_header(skb); > + proto = ovpn_ip_check_protocol(skb); > + if (unlikely(!proto)) { > + /* check if null packet */ > + if (unlikely(!pskb_may_pull(skb, 1))) { > + net_info_ratelimited("%s: NULL packet received from peer %u\n", > + netdev_name(peer->ovpn->dev), > + peer->id); > + goto drop; > + } > + > + net_info_ratelimited("%s: unsupported protocol received from peer %u\n", > + netdev_name(peer->ovpn->dev), peer->id); > + goto drop; > + } > + skb->protocol = proto; > + > + /* perform Reverse Path Filtering (RPF) */ > + if (unlikely(!ovpn_peer_check_by_src(peer->ovpn, skb, peer))) { > + if (skb->protocol == htons(ETH_P_IPV6)) > + net_dbg_ratelimited("%s: RPF dropped packet from peer %u, src: %pI6c\n", > + netdev_name(peer->ovpn->dev), > + peer->id, &ipv6_hdr(skb)->saddr); > + else > + net_dbg_ratelimited("%s: RPF dropped packet from peer %u, src: %pI4\n", > + netdev_name(peer->ovpn->dev), > + peer->id, &ip_hdr(skb)->saddr); > + goto drop; > + } > + > ovpn_netdev_write(peer, skb); > /* skb is passed to upper layer - don't free it */ > skb = NULL; > drop: > if (unlikely(skb)) > dev_core_stats_rx_dropped_inc(peer->ovpn->dev); > - ovpn_peer_put(peer); > + if (likely(peer)) > + ovpn_peer_put(peer); > + if (likely(ks)) > + ovpn_crypto_key_slot_put(ks); > kfree_skb(skb); > } > > /* RX path entry point: decrypt packet and forward it to the device */ > void ovpn_recv(struct ovpn_peer *peer, struct sk_buff *skb) > { > - ovpn_skb_cb(skb)->peer = peer; > - ovpn_decrypt_post(skb, 0); > + struct ovpn_crypto_key_slot *ks; > + u8 key_id; > + > + /* get the key slot matching the key ID in the received packet */ > + key_id = ovpn_key_id_from_skb(skb); > + ks = ovpn_crypto_key_id_to_slot(&peer->crypto, key_id); > + if (unlikely(!ks)) { > + net_info_ratelimited("%s: no available key for peer %u, key-id: %u\n", > + netdev_name(peer->ovpn->dev), peer->id, > + key_id); > + dev_core_stats_rx_dropped_inc(peer->ovpn->dev); > + kfree_skb(skb); > + ovpn_peer_put(peer); > + return; > + } > + > + memset(ovpn_skb_cb(skb), 0, sizeof(struct ovpn_cb)); > + ovpn_decrypt_post(skb, ovpn_aead_decrypt(peer, ks, skb)); > } > > -static void ovpn_encrypt_post(struct sk_buff *skb, int ret) > +void ovpn_encrypt_post(void *data, int ret) > { > - struct ovpn_peer *peer = ovpn_skb_cb(skb)->peer; > + struct ovpn_crypto_key_slot *ks; > + struct sk_buff *skb = data; > struct ovpn_socket *sock; > + struct ovpn_peer *peer; > + > + /* encryption is happening asynchronously. This function will be > + * called later by the crypto callback with a proper return value > + */ > + if (unlikely(ret == -EINPROGRESS)) > + return; > + > + ks = ovpn_skb_cb(skb)->ks; > + peer = ovpn_skb_cb(skb)->peer; > + > + /* crypto is done, cleanup skb CB and its members */ > + > + if (likely(ovpn_skb_cb(skb)->iv)) > + kfree(ovpn_skb_cb(skb)->iv); > + > + if (likely(ovpn_skb_cb(skb)->sg)) > + kfree(ovpn_skb_cb(skb)->sg); > + > + if (likely(ovpn_skb_cb(skb)->req)) > + aead_request_free(ovpn_skb_cb(skb)->req); > > if (unlikely(ret < 0)) > goto err; > @@ -110,23 +227,40 @@ static void ovpn_encrypt_post(struct sk_buff *skb, int ret) > err: > if (unlikely(skb)) > dev_core_stats_tx_dropped_inc(peer->ovpn->dev); > - ovpn_peer_put(peer); > + if (likely(peer)) > + ovpn_peer_put(peer); > + if (likely(ks)) > + ovpn_crypto_key_slot_put(ks); > kfree_skb(skb); > } > > static bool ovpn_encrypt_one(struct ovpn_peer *peer, struct sk_buff *skb) > { > - ovpn_skb_cb(skb)->peer = peer; > + struct ovpn_crypto_key_slot *ks; > + > + if (unlikely(skb->ip_summed == CHECKSUM_PARTIAL && This if statement is now not necessary as you do not advertise NETIF_F_HW_CSUM. > + skb_checksum_help(skb))) { > + net_warn_ratelimited("%s: cannot compute checksum for outgoing packet for peer %u\n", > + netdev_name(peer->ovpn->dev), peer->id); > + return false; > + } > + > + /* get primary key to be used for encrypting data */ > + ks = ovpn_crypto_key_slot_primary(&peer->crypto); > + if (unlikely(!ks)) > + return false; > > /* take a reference to the peer because the crypto code may run async. > * ovpn_encrypt_post() will release it upon completion > */ > if (unlikely(!ovpn_peer_hold(peer))) { > DEBUG_NET_WARN_ON_ONCE(1); > + ovpn_crypto_key_slot_put(ks); > return false; > } > > - ovpn_encrypt_post(skb, 0); > + memset(ovpn_skb_cb(skb), 0, sizeof(struct ovpn_cb)); > + ovpn_encrypt_post(skb, ovpn_aead_encrypt(peer, ks, skb)); > return true; > } > > diff --git a/drivers/net/ovpn/io.h b/drivers/net/ovpn/io.h > index 1cfa66873a2d4840ce57e337f8b4e8143e8b8e79..5143104b2c4b896a030ec4a8c8aea7015f40ef02 100644 > --- a/drivers/net/ovpn/io.h > +++ b/drivers/net/ovpn/io.h > @@ -23,4 +23,7 @@ netdev_tx_t ovpn_net_xmit(struct sk_buff *skb, struct net_device *dev); > > void ovpn_recv(struct ovpn_peer *peer, struct sk_buff *skb); > > +void ovpn_encrypt_post(void *data, int ret); > +void ovpn_decrypt_post(void *data, int ret); > + > #endif /* _NET_OVPN_OVPN_H_ */ > diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c > index 10eabd62ae7237162a36a333b41c748901a7d888..23eaab1b465b8b88a84cf9f1039621923b640b47 100644 > --- a/drivers/net/ovpn/peer.c > +++ b/drivers/net/ovpn/peer.c > @@ -12,6 +12,8 @@ > > #include "ovpnpriv.h" > #include "bind.h" > +#include "pktid.h" > +#include "crypto.h" > #include "io.h" > #include "main.h" > #include "netlink.h" > @@ -56,6 +58,7 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn, u32 id) > peer->vpn_addrs.ipv6 = in6addr_any; > > RCU_INIT_POINTER(peer->bind, NULL); > + ovpn_crypto_state_init(&peer->crypto); > spin_lock_init(&peer->lock); > kref_init(&peer->refcount); > > @@ -94,7 +97,10 @@ static void ovpn_peer_release_rcu(struct rcu_head *head) > */ > static void ovpn_peer_release(struct ovpn_peer *peer) > { > + ovpn_crypto_state_release(&peer->crypto); > + spin_lock_bh(&peer->lock); > ovpn_bind_reset(peer, NULL); > + spin_unlock_bh(&peer->lock); > call_rcu(&peer->rcu, ovpn_peer_release_rcu); > netdev_put(peer->ovpn->dev, &peer->dev_tracker); > } > @@ -326,6 +332,29 @@ struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_priv *ovpn, > return peer; > } > > +/** > + * ovpn_peer_check_by_src - check that skb source is routed via peer > + * @ovpn: the openvpn instance to search > + * @skb: the packet to extract source address from > + * @peer: the peer to check against the source address > + * > + * Return: true if the peer is matching or false otherwise > + */ > +bool ovpn_peer_check_by_src(struct ovpn_priv *ovpn, struct sk_buff *skb, > + struct ovpn_peer *peer) > +{ > + bool match = false; > + > + if (ovpn->mode == OVPN_MODE_P2P) { > + /* in P2P mode, no matter the destination, packets are always > + * sent to the single peer listening on the other side > + */ > + match = (peer == rcu_access_pointer(ovpn->peer)); > + } > + > + return match; > +} > + > /** > * ovpn_peer_add_p2p - add peer to related tables in a P2P instance > * @ovpn: the instance to add the peer to > diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h > index fef04311c1593db4ccfa3c417487b3d4faaae9d7..a9113a969f94d66fa17208d563d0bbd255c23fa9 100644 > --- a/drivers/net/ovpn/peer.h > +++ b/drivers/net/ovpn/peer.h > @@ -12,6 +12,7 @@ > > #include <net/dst_cache.h> > > +#include "crypto.h" > #include "socket.h" > > /** > @@ -23,6 +24,7 @@ > * @vpn_addrs.ipv4: IPv4 assigned to peer on the tunnel > * @vpn_addrs.ipv6: IPv6 assigned to peer on the tunnel > * @sock: the socket being used to talk to this peer > + * @crypto: the crypto configuration (ciphers, keys, etc..) > * @dst_cache: cache for dst_entry used to send to peer > * @bind: remote peer binding > * @delete_reason: why peer was deleted (i.e. timeout, transport error, ..) > @@ -40,6 +42,7 @@ struct ovpn_peer { > struct in6_addr ipv6; > } vpn_addrs; > struct ovpn_socket __rcu *sock; > + struct ovpn_crypto_state crypto; > struct dst_cache dst_cache; > struct ovpn_bind __rcu *bind; > enum ovpn_del_peer_reason delete_reason; > @@ -82,5 +85,7 @@ struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_priv *ovpn, > struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_priv *ovpn, u32 peer_id); > struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_priv *ovpn, > struct sk_buff *skb); > +bool ovpn_peer_check_by_src(struct ovpn_priv *ovpn, struct sk_buff *skb, > + struct ovpn_peer *peer); > > #endif /* _NET_OVPN_OVPNPEER_H_ */ > diff --git a/drivers/net/ovpn/pktid.c b/drivers/net/ovpn/pktid.c > new file mode 100644 > index 0000000000000000000000000000000000000000..2e73d1c1ec8b6c4fe2fc10ebc1a4f3008362df21 > --- /dev/null > +++ b/drivers/net/ovpn/pktid.c > @@ -0,0 +1,129 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* OpenVPN data channel offload > + * > + * Copyright (C) 2020-2025 OpenVPN, Inc. > + * > + * Author: Antonio Quartulli <antonio@xxxxxxxxxxx> > + * James Yonan <james@xxxxxxxxxxx> > + */ > + > +#include <linux/atomic.h> > +#include <linux/jiffies.h> > +#include <linux/net.h> > +#include <linux/netdevice.h> > +#include <linux/types.h> > + > +#include "ovpnpriv.h" > +#include "main.h" > +#include "pktid.h" > + > +void ovpn_pktid_xmit_init(struct ovpn_pktid_xmit *pid) > +{ > + atomic64_set(&pid->seq_num, 1); > +} > + > +void ovpn_pktid_recv_init(struct ovpn_pktid_recv *pr) > +{ > + memset(pr, 0, sizeof(*pr)); > + spin_lock_init(&pr->lock); > +} > + > +/* Packet replay detection. > + * Allows ID backtrack of up to REPLAY_WINDOW_SIZE - 1. > + */ > +int ovpn_pktid_recv(struct ovpn_pktid_recv *pr, u32 pkt_id, u32 pkt_time) > +{ > + const unsigned long now = jiffies; > + int ret; > + > + /* ID must not be zero */ > + if (unlikely(pkt_id == 0)) > + return -EINVAL; > + > + spin_lock_bh(&pr->lock); > + > + /* expire backtracks at or below pr->id after PKTID_RECV_EXPIRE time */ > + if (unlikely(time_after_eq(now, pr->expire))) > + pr->id_floor = pr->id; > + > + /* time changed? */ > + if (unlikely(pkt_time != pr->time)) { > + if (pkt_time > pr->time) { > + /* time moved forward, accept */ > + pr->base = 0; > + pr->extent = 0; > + pr->id = 0; > + pr->time = pkt_time; > + pr->id_floor = 0; > + } else { > + /* time moved backward, reject */ > + ret = -ETIME; > + goto out; > + } > + } > + > + if (likely(pkt_id == pr->id + 1)) { > + /* well-formed ID sequence (incremented by 1) */ > + pr->base = REPLAY_INDEX(pr->base, -1); > + pr->history[pr->base / 8] |= (1 << (pr->base % 8)); > + if (pr->extent < REPLAY_WINDOW_SIZE) > + ++pr->extent; > + pr->id = pkt_id; > + } else if (pkt_id > pr->id) { > + /* ID jumped forward by more than one */ > + const unsigned int delta = pkt_id - pr->id; > + > + if (delta < REPLAY_WINDOW_SIZE) { > + unsigned int i; > + > + pr->base = REPLAY_INDEX(pr->base, -delta); > + pr->history[pr->base / 8] |= (1 << (pr->base % 8)); > + pr->extent += delta; > + if (pr->extent > REPLAY_WINDOW_SIZE) > + pr->extent = REPLAY_WINDOW_SIZE; > + for (i = 1; i < delta; ++i) { > + unsigned int newb = REPLAY_INDEX(pr->base, i); > + > + pr->history[newb / 8] &= ~BIT(newb % 8); > + } > + } else { > + pr->base = 0; > + pr->extent = REPLAY_WINDOW_SIZE; > + memset(pr->history, 0, sizeof(pr->history)); > + pr->history[0] = 1; > + } > + pr->id = pkt_id; > + } else { > + /* ID backtrack */ > + const unsigned int delta = pr->id - pkt_id; > + > + if (delta > pr->max_backtrack) > + pr->max_backtrack = delta; > + if (delta < pr->extent) { > + if (pkt_id > pr->id_floor) { > + const unsigned int ri = REPLAY_INDEX(pr->base, > + delta); > + u8 *p = &pr->history[ri / 8]; > + const u8 mask = (1 << (ri % 8)); > + > + if (*p & mask) { > + ret = -EINVAL; > + goto out; > + } > + *p |= mask; > + } else { > + ret = -EINVAL; > + goto out; > + } > + } else { > + ret = -EINVAL; > + goto out; > + } > + } > + > + pr->expire = now + PKTID_RECV_EXPIRE; > + ret = 0; > +out: > + spin_unlock_bh(&pr->lock); > + return ret; > +} > diff --git a/drivers/net/ovpn/pktid.h b/drivers/net/ovpn/pktid.h > new file mode 100644 > index 0000000000000000000000000000000000000000..0e5fd91d488359f675f500a7368027f7a148f5c6 > --- /dev/null > +++ b/drivers/net/ovpn/pktid.h > @@ -0,0 +1,87 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* OpenVPN data channel offload > + * > + * Copyright (C) 2020-2025 OpenVPN, Inc. > + * > + * Author: Antonio Quartulli <antonio@xxxxxxxxxxx> > + * James Yonan <james@xxxxxxxxxxx> > + */ > + > +#ifndef _NET_OVPN_OVPNPKTID_H_ > +#define _NET_OVPN_OVPNPKTID_H_ > + > +#include "proto.h" > + > +/* If no packets received for this length of time, set a backtrack floor > + * at highest received packet ID thus far. > + */ > +#define PKTID_RECV_EXPIRE (30 * HZ) > + > +/* Packet-ID state for transmitter */ > +struct ovpn_pktid_xmit { > + atomic64_t seq_num; > +}; > + > +/* replay window sizing in bytes = 2^REPLAY_WINDOW_ORDER */ > +#define REPLAY_WINDOW_ORDER 8 > + > +#define REPLAY_WINDOW_BYTES BIT(REPLAY_WINDOW_ORDER) > +#define REPLAY_WINDOW_SIZE (REPLAY_WINDOW_BYTES * 8) > +#define REPLAY_INDEX(base, i) (((base) + (i)) & (REPLAY_WINDOW_SIZE - 1)) > + > +/* Packet-ID state for receiver. > + * Other than lock member, can be zeroed to initialize. > + */ > +struct ovpn_pktid_recv { > + /* "sliding window" bitmask of recent packet IDs received */ > + u8 history[REPLAY_WINDOW_BYTES]; > + /* bit position of deque base in history */ > + unsigned int base; > + /* extent (in bits) of deque in history */ > + unsigned int extent; > + /* expiration of history in jiffies */ > + unsigned long expire; > + /* highest sequence number received */ > + u32 id; > + /* highest time stamp received */ > + u32 time; > + /* we will only accept backtrack IDs > id_floor */ > + u32 id_floor; > + unsigned int max_backtrack; > + /* protects entire pktd ID state */ > + spinlock_t lock; > +}; > + > +/* Get the next packet ID for xmit */ > +static inline int ovpn_pktid_xmit_next(struct ovpn_pktid_xmit *pid, u32 *pktid) > +{ > + const s64 seq_num = atomic64_fetch_add_unless(&pid->seq_num, 1, > + 0x100000000LL); > + /* when the 32bit space is over, we return an error because the packet > + * ID is used to create the cipher IV and we do not want to reuse the > + * same value more than once > + */ > + if (unlikely(seq_num == 0x100000000LL)) > + return -ERANGE; > + > + *pktid = (u32)seq_num; > + > + return 0; > +} > + > +/* Write 12-byte AEAD IV to dest */ > +static inline void ovpn_pktid_aead_write(const u32 pktid, > + const u8 nt[], > + unsigned char *dest) > +{ > + *(__force __be32 *)(dest) = htonl(pktid); > + BUILD_BUG_ON(4 + OVPN_NONCE_TAIL_SIZE != OVPN_NONCE_SIZE); > + memcpy(dest + 4, nt, OVPN_NONCE_TAIL_SIZE); > +} > + > +void ovpn_pktid_xmit_init(struct ovpn_pktid_xmit *pid); > +void ovpn_pktid_recv_init(struct ovpn_pktid_recv *pr); > + > +int ovpn_pktid_recv(struct ovpn_pktid_recv *pr, u32 pkt_id, u32 pkt_time); > + > +#endif /* _NET_OVPN_OVPNPKTID_H_ */ > diff --git a/drivers/net/ovpn/proto.h b/drivers/net/ovpn/proto.h > index 591b97a9925fd9b91f996d6d591fac41b1aa6148..b7322c7c515e5c0744719e11ca81fece3ca28569 100644 > --- a/drivers/net/ovpn/proto.h > +++ b/drivers/net/ovpn/proto.h > @@ -83,4 +83,36 @@ static inline u32 ovpn_peer_id_from_skb(const struct sk_buff *skb, u16 offset) > return FIELD_GET(OVPN_OPCODE_PEERID_MASK, opcode); > } > > +/** > + * ovpn_key_id_from_skb - extract key ID from the skb head > + * @skb: the packet to extract the key ID code from > + * > + * Note: this function assumes that the skb head was pulled enough > + * to access the first byte. > + * > + * Return: the key ID > + */ > +static inline u8 ovpn_key_id_from_skb(const struct sk_buff *skb) > +{ > + u32 opcode = be32_to_cpu(*(__be32 *)skb->data); > + > + return FIELD_GET(OVPN_OPCODE_KEYID_MASK, opcode); > +} > + > +/** > + * ovpn_opcode_compose - combine OP code, key ID and peer ID to wire format > + * @opcode: the OP code > + * @key_id: the key ID > + * @peer_id: the peer ID > + * > + * Return: a 4 bytes integer obtained combining all input values following the > + * OpenVPN wire format. This integer can then be written to the packet header. > + */ > +static inline u32 ovpn_opcode_compose(u8 opcode, u8 key_id, u32 peer_id) > +{ > + return FIELD_PREP(OVPN_OPCODE_PKTTYPE_MASK, opcode) | > + FIELD_PREP(OVPN_OPCODE_KEYID_MASK, key_id) | > + FIELD_PREP(OVPN_OPCODE_PEERID_MASK, peer_id); > +} > + > #endif /* _NET_OVPN_OVPNPROTO_H_ */ > diff --git a/drivers/net/ovpn/skb.h b/drivers/net/ovpn/skb.h > index 9db7a9adebdb4cc493f162f89fb2e9c6301fa213..bd3cbcfc770d2c28d234fcdd081b4d02e6496ea0 100644 > --- a/drivers/net/ovpn/skb.h > +++ b/drivers/net/ovpn/skb.h > @@ -20,6 +20,11 @@ > > struct ovpn_cb { > struct ovpn_peer *peer; > + struct ovpn_crypto_key_slot *ks; > + struct aead_request *req; > + struct scatterlist *sg; > + u8 *iv; > + unsigned int payload_offset; > }; > > static inline struct ovpn_cb *ovpn_skb_cb(struct sk_buff *skb) > > -- > 2.48.1 > > -- Qingfang