From: Jakub Kicinski kuba@kernel.org
Provide a PSP implementation for netdevsim.
Use psp_dev_encapsulate() and psp_dev_rcv() to do actual encapsulation and decapsulation on skbs, but perform no encryption or decryption. In order to make encryption with a bad key result in a drop on the peer's rx side, we stash our psd's generation number in the first byte of each key before handing to the peer.
Signed-off-by: Jakub Kicinski kuba@kernel.org Co-developed-by: Daniel Zahka daniel.zahka@gmail.com Signed-off-by: Daniel Zahka daniel.zahka@gmail.com ---
Notes: v2: - fix compilation error when CONFIG_INET_PSP is not set
drivers/net/netdevsim/Makefile | 4 + drivers/net/netdevsim/netdev.c | 55 ++++++- drivers/net/netdevsim/netdevsim.h | 33 +++++ drivers/net/netdevsim/psp.c | 234 ++++++++++++++++++++++++++++++ net/core/skbuff.c | 1 + 5 files changed, 319 insertions(+), 8 deletions(-) create mode 100644 drivers/net/netdevsim/psp.c
diff --git a/drivers/net/netdevsim/Makefile b/drivers/net/netdevsim/Makefile index f8de93bc5f5b..14a553e000ec 100644 --- a/drivers/net/netdevsim/Makefile +++ b/drivers/net/netdevsim/Makefile @@ -18,6 +18,10 @@ ifneq ($(CONFIG_PSAMPLE),) netdevsim-objs += psample.o endif
+ifneq ($(CONFIG_INET_PSP),) +netdevsim-objs += psp.o +endif + ifneq ($(CONFIG_MACSEC),) netdevsim-objs += macsec.o endif diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 0178219f0db5..062fc55c30d7 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -103,29 +103,45 @@ static int nsim_napi_rx(struct net_device *tx_dev, struct net_device *rx_dev, static int nsim_forward_skb(struct net_device *tx_dev, struct net_device *rx_dev, struct sk_buff *skb, - struct nsim_rq *rq) + struct nsim_rq *rq, + struct skb_ext *psp_ext) { - return __dev_forward_skb(rx_dev, skb) ?: - nsim_napi_rx(tx_dev, rx_dev, rq, skb); + int ret; + + ret = __dev_forward_skb(rx_dev, skb); + if (ret) + return ret; + + nsim_psp_handle_ext(skb, psp_ext); + + return nsim_napi_rx(tx_dev, rx_dev, rq, skb); }
static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct netdevsim *ns = netdev_priv(dev); + struct skb_ext *psp_ext = NULL; struct net_device *peer_dev; unsigned int len = skb->len; struct netdevsim *peer_ns; struct netdev_config *cfg; struct nsim_rq *rq; int rxq; + int dr;
rcu_read_lock(); if (!nsim_ipsec_tx(ns, skb)) - goto out_drop_free; + goto out_drop_any;
peer_ns = rcu_dereference(ns->peer); if (!peer_ns) - goto out_drop_free; + goto out_drop_any; + + if (nsim_tx_skb_is_psp(skb)) { + dr = nsim_do_psp(skb, ns, peer_ns, &psp_ext); + if (dr) + goto out_drop_free; + }
peer_dev = peer_ns->netdev; rxq = skb_get_queue_mapping(skb); @@ -141,7 +157,8 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) skb_linearize(skb);
skb_tx_timestamp(skb); - if (unlikely(nsim_forward_skb(dev, peer_dev, skb, rq) == NET_RX_DROP)) + if (unlikely(nsim_forward_skb(dev, peer_dev, skb, rq, psp_ext) == + NET_RX_DROP)) goto out_drop_cnt;
if (!hrtimer_active(&rq->napi_timer)) @@ -151,8 +168,10 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) dev_dstats_tx_add(dev, len); return NETDEV_TX_OK;
+out_drop_any: + dr = SKB_DROP_REASON_NOT_SPECIFIED; out_drop_free: - dev_kfree_skb(skb); + kfree_skb_reason(skb, dr); out_drop_cnt: rcu_read_unlock(); dev_dstats_tx_dropped(dev); @@ -1002,6 +1021,7 @@ static void nsim_queue_uninit(struct netdevsim *ns)
static int nsim_init_netdevsim(struct netdevsim *ns) { + struct netdevsim *peer; struct mock_phc *phc; int err;
@@ -1039,12 +1059,29 @@ static int nsim_init_netdevsim(struct netdevsim *ns) if (IS_ENABLED(CONFIG_DEBUG_NET)) { ns->nb.notifier_call = netdev_debug_event; if (register_netdevice_notifier_dev_net(ns->netdev, &ns->nb, - &ns->nn)) + &ns->nn)) { ns->nb.notifier_call = NULL; + goto err_unregister_netdev; + } }
+ err = nsim_psp_init(ns); + if (err) + goto err_unregister_notifier; + return 0;
+err_unregister_notifier: + if (ns->nb.notifier_call) + unregister_netdevice_notifier_dev_net(ns->netdev, &ns->nb, + &ns->nn); +err_unregister_netdev: + rtnl_lock(); + peer = rtnl_dereference(ns->peer); + if (peer) + RCU_INIT_POINTER(peer->peer, NULL); + RCU_INIT_POINTER(ns->peer, NULL); + unregister_netdevice(ns->netdev); err_ipsec_teardown: nsim_ipsec_teardown(ns); nsim_macsec_teardown(ns); @@ -1128,6 +1165,8 @@ void nsim_destroy(struct netdevsim *ns) debugfs_remove(ns->qr_dfs); debugfs_remove(ns->pp_dfs);
+ nsim_psp_uninit(ns); + if (ns->nb.notifier_call) unregister_netdevice_notifier_dev_net(ns->netdev, &ns->nb, &ns->nn); diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index bddd24c1389d..dd78e08fa7d6 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -108,6 +108,12 @@ struct netdevsim {
int rq_reset_mode;
+ struct { + struct psp_dev *dev; + u32 spi; + u32 assoc_cnt; + } psp; + struct nsim_bus_dev *nsim_bus_dev;
struct bpf_prog *bpf_offloaded; @@ -421,6 +427,33 @@ static inline void nsim_macsec_teardown(struct netdevsim *ns) } #endif
+#if IS_ENABLED(CONFIG_INET_PSP) +int nsim_psp_init(struct netdevsim *ns); +void nsim_psp_uninit(struct netdevsim *ns); +bool nsim_tx_skb_is_psp(struct sk_buff *skb); +void nsim_psp_handle_ext(struct sk_buff *skb, struct skb_ext *psp_ext); +enum skb_drop_reason +nsim_do_psp(struct sk_buff *skb, struct netdevsim *ns, + struct netdevsim *peer_ns, struct skb_ext **psp_ext); +#else +static inline int nsim_psp_init(struct netdevsim *ns) { return 0; } +static inline void nsim_psp_uninit(struct netdevsim *ns) {} +static inline enum skb_drop_reason +nsim_do_psp(struct sk_buff *skb, struct netdevsim *ns, + struct netdevsim *peer_ns, struct skb_ext **psp_ext) +{ + return 0; +} + +static inline bool nsim_tx_skb_is_psp(struct sk_buff *skb) +{ + return false; +} + +static inline void +nsim_psp_handle_ext(struct sk_buff *skb, struct skb_ext *psp_ext) {} +#endif + struct nsim_bus_dev { struct device dev; struct list_head list; diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c new file mode 100644 index 000000000000..5c634414237c --- /dev/null +++ b/drivers/net/netdevsim/psp.c @@ -0,0 +1,234 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/ip.h> +#include <linux/skbuff.h> +#include <net/ip6_checksum.h> +#include <net/psp.h> +#include <net/sock.h> + +#include "netdevsim.h" + +bool nsim_tx_skb_is_psp(struct sk_buff *skb) +{ + bool ret; + + rcu_read_lock(); + ret = !!psp_skb_get_assoc_rcu(skb); + rcu_read_unlock(); + return ret; +} + +void nsim_psp_handle_ext(struct sk_buff *skb, struct skb_ext *psp_ext) +{ + if (psp_ext) + __skb_ext_set(skb, SKB_EXT_PSP, psp_ext); +} + +enum skb_drop_reason +nsim_do_psp(struct sk_buff *skb, struct netdevsim *ns, + struct netdevsim *peer_ns, struct skb_ext **psp_ext) +{ + struct net *net = sock_net(skb->sk); + enum skb_drop_reason rc = 0; + struct psp_assoc *pas; + void **ptr; + + rcu_read_lock(); + pas = psp_skb_get_assoc_rcu(skb); + if (!pas) { + rc = SKB_DROP_REASON_PSP_OUTPUT; + goto out_unlock; + } + + if (!skb_transport_header_was_set(skb)) { + rc = SKB_DROP_REASON_PSP_OUTPUT; + goto out_unlock; + } + + ptr = psp_assoc_drv_data(pas); + if (*ptr != ns) { + rc = SKB_DROP_REASON_PSP_OUTPUT; + goto out_unlock; + } + + if (!psp_dev_encapsulate(net, skb, pas->tx.spi, pas->version, 0)) { + rc = SKB_DROP_REASON_PSP_OUTPUT; + goto out_unlock; + } + + /* Now pretend we just received this frame */ + if (peer_ns->psp.dev->config.versions & (1 << pas->version)) { + bool strip_icv = false; + u8 generation; + + /* We cheat a bit and put the generation in the key. + * In real life if generation was too old, then decryption would + * fail. Here, we just make it so a bad key causes a bad + * generation too, and psp_sk_rx_policy_check() will fail. + */ + generation = pas->tx.key[0]; + + skb_ext_reset(skb); + skb->mac_len = ETH_HLEN; + if (psp_dev_rcv(skb, peer_ns->psp.dev->id, generation, + strip_icv)) { + rc = SKB_DROP_REASON_PSP_OUTPUT; + goto out_unlock; + } + + *psp_ext = skb->extensions; + refcount_inc(&(*psp_ext)->refcnt); + skb->decrypted = 1; + } else { + struct ipv6hdr *ip6h; + struct iphdr *iph; + struct udphdr *uh; + __wsum csum; + + /* Do not decapsulate. Receive the skb with the udp and psp + * headers still there as if this is a normal udp packet. + * psp_dev_encapsulate() sets udp checksum to 0, so we need to + * provide a valid checksum here, so the skb isn't dropped. + */ + uh = udp_hdr(skb); + csum = skb_checksum(skb, skb_transport_offset(skb), + ntohs(uh->len), 0); + + switch (skb->protocol) { + case htons(ETH_P_IP): + iph = ip_hdr(skb); + uh->check = udp_v4_check(ntohs(uh->len), iph->saddr, + iph->daddr, csum); + break; +#if IS_ENABLED(CONFIG_IPV6) + case htons(ETH_P_IPV6): + ip6h = ipv6_hdr(skb); + uh->check = udp_v6_check(ntohs(uh->len), &ip6h->saddr, + &ip6h->daddr, csum); + break; +#endif + } + + uh->check = uh->check ?: CSUM_MANGLED_0; + skb->ip_summed = CHECKSUM_NONE; + } + +out_unlock: + rcu_read_unlock(); + return rc; +} + +static int +nsim_psp_set_config(struct psp_dev *psd, struct psp_dev_config *conf, + struct netlink_ext_ack *extack) +{ + return 0; +} + +static int +nsim_rx_spi_alloc(struct psp_dev *psd, u32 version, + struct psp_key_parsed *assoc, + struct netlink_ext_ack *extack) +{ + struct netdevsim *ns = psd->drv_priv; + unsigned int new; + int i; + + new = ++ns->psp.spi & PSP_SPI_KEY_ID; + if (psd->generation & 1) + new |= PSP_SPI_KEY_PHASE; + + assoc->spi = cpu_to_be32(new); + assoc->key[0] = psd->generation; + for (i = 1; i < PSP_MAX_KEY; i++) + assoc->key[i] = ns->psp.spi + i; + + return 0; +} + +static int nsim_assoc_add(struct psp_dev *psd, struct psp_assoc *pas, + struct netlink_ext_ack *extack) +{ + struct netdevsim *ns = psd->drv_priv; + void **ptr = psp_assoc_drv_data(pas); + + /* Copy drv_priv from psd to assoc */ + *ptr = psd->drv_priv; + ns->psp.assoc_cnt++; + + return 0; +} + +static int nsim_key_rotate(struct psp_dev *psd, struct netlink_ext_ack *extack) +{ + return 0; +} + +static void nsim_assoc_del(struct psp_dev *psd, struct psp_assoc *pas) +{ + struct netdevsim *ns = psd->drv_priv; + void **ptr = psp_assoc_drv_data(pas); + + *ptr = NULL; + ns->psp.assoc_cnt--; +} + +static struct psp_dev_ops nsim_psp_ops = { + .set_config = nsim_psp_set_config, + .rx_spi_alloc = nsim_rx_spi_alloc, + .tx_key_add = nsim_assoc_add, + .tx_key_del = nsim_assoc_del, + .key_rotate = nsim_key_rotate, +}; + +static struct psp_dev_caps nsim_psp_caps = { + .versions = 1 << PSP_VERSION_HDR0_AES_GCM_128 | + 1 << PSP_VERSION_HDR0_AES_GMAC_128 | + 1 << PSP_VERSION_HDR0_AES_GCM_256 | + 1 << PSP_VERSION_HDR0_AES_GMAC_256, + .assoc_drv_spc = sizeof(void *), +}; + +void nsim_psp_uninit(struct netdevsim *ns) +{ + if (!IS_ERR(ns->psp.dev)) + psp_dev_unregister(ns->psp.dev); + WARN_ON(ns->psp.assoc_cnt); +} + +static ssize_t +nsim_psp_rereg_write(struct file *file, const char __user *data, size_t count, + loff_t *ppos) +{ + struct netdevsim *ns = file->private_data; + int err; + + nsim_psp_uninit(ns); + + ns->psp.dev = psp_dev_create(ns->netdev, &nsim_psp_ops, + &nsim_psp_caps, ns); + err = PTR_ERR_OR_ZERO(ns->psp.dev); + return err ?: count; +} + +static const struct file_operations nsim_psp_rereg_fops = { + .open = simple_open, + .write = nsim_psp_rereg_write, + .llseek = generic_file_llseek, + .owner = THIS_MODULE, +}; + +int nsim_psp_init(struct netdevsim *ns) +{ + struct dentry *ddir = ns->nsim_dev_port->ddir; + int err; + + ns->psp.dev = psp_dev_create(ns->netdev, &nsim_psp_ops, + &nsim_psp_caps, ns); + err = PTR_ERR_OR_ZERO(ns->psp.dev); + if (err) + return err; + + debugfs_create_file("psp_rereg", 0200, ddir, ns, &nsim_psp_rereg_fops); + return 0; +} diff --git a/net/core/skbuff.c b/net/core/skbuff.c index daaf6da43cc9..618afd59afff 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -7048,6 +7048,7 @@ void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id, skb->active_extensions = 1 << id; return skb_ext_get_ptr(ext, id); } +EXPORT_SYMBOL_NS_GPL(__skb_ext_set, "NETDEV_INTERNAL");
/** * skb_ext_add - allocate space for given extension, COW if needed