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Miller" , Eric Dumazet , Paolo Abeni , Willem de Bruijn Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org X-Mailer: b4 0.13.0 Implement the PSP key derivation function (KDF) per the PSP Architecture Spec. The kdf is used to generate spi + session key pairs, and will also be used in the rx path to re-derive the tx key used by the peer. Also, remove support for psd->generation, as it is not needed for netdevsim after removing the fake authentication hack. Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Daniel Zahka --- drivers/net/Kconfig | 1 + drivers/net/netdevsim/netdevsim.h | 3 +++ drivers/net/netdevsim/psp.c | 55 ++++++++++++++++++++++++++++++++++++--- 3 files changed, 55 insertions(+), 4 deletions(-) diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index ff79c466712d..44a220c05536 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -610,6 +610,7 @@ config NETDEVSIM select NET_DEVLINK select PAGE_POOL select NET_SHAPER + select CRYPTO_LIB_AES_CBC_MACS if INET_PSP help This driver is a developer testing tool and software model that can be used to test various control path networking APIs, especially diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index dcea76429bac..112fe1ee10bc 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -38,6 +38,7 @@ #define NSIM_IPSEC_VALID BIT(31) #define NSIM_UDP_TUNNEL_N_PORTS 4 +#define NSIM_PSP_DEV_KEY_SIZE 32 #define NSIM_HDS_THRESHOLD_MAX 1024 struct nsim_sa { @@ -123,6 +124,8 @@ struct netdevsim { struct psp_dev __rcu *dev; struct dentry *rereg; struct mutex rereg_lock; + spinlock_t dev_keys_lock; + u8 dev_keys[2][NSIM_PSP_DEV_KEY_SIZE]; u32 spi; u32 assoc_cnt; } psp; diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c index e8831d4bf394..8cdb88b1e232 100644 --- a/drivers/net/netdevsim/psp.c +++ b/drivers/net/netdevsim/psp.c @@ -1,11 +1,45 @@ // SPDX-License-Identifier: GPL-2.0 +#include +#include #include +#include #include #include #include "netdevsim.h" +/* Session key derivation from device key per PSP Architecture Spec */ +static void nsim_psp_derive_key(const u8 *dev_key, __be32 spi, u32 version, + u8 *derived_key) +{ + unsigned int key_size = psp_key_size(version); + struct aes_cmac_key key; + u8 block[16]; + + aes_cmac_preparekey(&key, dev_key, NSIM_PSP_DEV_KEY_SIZE); + + block[0] = 0x00; + block[1] = 0x00; + block[2] = 0x00; + block[3] = 0x01; /* counter */ + block[4] = 0x50; /* 'P' */ + block[5] = 0x76; /* 'v' */ + block[6] = 0x30 | version; /* '0' + version */ + block[7] = 0x00; + memcpy(&block[8], &spi, sizeof(spi)); + put_unaligned_be32(key_size * 8, &block[12]); + + aes_cmac(&key, block, sizeof(block), derived_key); + + if (key_size > 16) { + block[3] = 0x02; + aes_cmac(&key, block, sizeof(block), derived_key + 16); + } + + memzero_explicit(&key, sizeof(key)); +} + enum skb_drop_reason nsim_psp_handle_tx(struct sk_buff *skb, struct netdevsim *ns) { @@ -155,7 +189,7 @@ nsim_rx_spi_alloc(struct psp_dev *psd, u32 version, struct netlink_ext_ack *extack) { struct netdevsim *ns = psd->drv_priv; - int i; + unsigned int phase; if ((ns->psp.spi ^ (ns->psp.spi + 1)) & PSP_SPI_KEY_PHASE) { NL_SET_ERR_MSG(extack, "SPI space exhausted"); @@ -163,9 +197,11 @@ nsim_rx_spi_alloc(struct psp_dev *psd, u32 version, } assoc->spi = cpu_to_be32(++ns->psp.spi); - assoc->key[0] = psd->generation; - for (i = 1; i < PSP_MAX_KEY; i++) - assoc->key[i] = ns->psp.spi + i; + phase = !!(ns->psp.spi & PSP_SPI_KEY_PHASE); + + /* dev_keys_lock not needed because of psd->lock */ + nsim_psp_derive_key(ns->psp.dev_keys[phase], assoc->spi, version, + assoc->key); return 0; } @@ -186,8 +222,15 @@ static int nsim_assoc_add(struct psp_dev *psd, struct psp_assoc *pas, static int nsim_key_rotate(struct psp_dev *psd, struct netlink_ext_ack *extack) { struct netdevsim *ns = psd->drv_priv; + unsigned int next_phase; + psd->generation = 0; ns->psp.spi = (ns->psp.spi & PSP_SPI_KEY_PHASE) ^ PSP_SPI_KEY_PHASE; + next_phase = !!(ns->psp.spi & PSP_SPI_KEY_PHASE); + + spin_lock_bh(&ns->psp.dev_keys_lock); + get_random_bytes(ns->psp.dev_keys[next_phase], NSIM_PSP_DEV_KEY_SIZE); + spin_unlock_bh(&ns->psp.dev_keys_lock); return 0; } @@ -295,6 +338,10 @@ int nsim_psp_init(struct netdevsim *ns) struct dentry *ddir = ns->nsim_dev_port->ddir; struct psp_dev *psd; + spin_lock_init(&ns->psp.dev_keys_lock); + get_random_bytes(ns->psp.dev_keys[0], NSIM_PSP_DEV_KEY_SIZE); + get_random_bytes(ns->psp.dev_keys[1], NSIM_PSP_DEV_KEY_SIZE); + psd = psp_dev_create(ns->netdev, &nsim_psp_ops, &nsim_psp_caps, ns); if (IS_ERR(psd)) return PTR_ERR(psd); -- 2.52.0