diff options
| -rw-r--r-- | src/vnet/ipsec/esp_encrypt.c | 30 | ||||
| -rw-r--r-- | src/vnet/ipsec/ipsec_sa.h | 3 |
2 files changed, 28 insertions, 5 deletions
diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c index 3c2fdf4ec3c..8b3aac97a15 100644 --- a/src/vnet/ipsec/esp_encrypt.c +++ b/src/vnet/ipsec/esp_encrypt.c @@ -203,6 +203,24 @@ esp_get_ip6_hdr_len (ip6_header_t * ip6, ip6_ext_header_t ** ext_hdr) return len; } +/* IPsec IV generation: IVs requirements differ depending of the + * encryption mode: IVs must be unpredictable for AES-CBC whereas it can + * be predictable but should never be reused with the same key material + * for CTR and GCM. + * We use a packet counter as the IV for CTR and GCM, and to ensure the + * IV is unpredictable for CBC, it is then encrypted using the same key + * as the message. You can refer to NIST SP800-38a and NIST SP800-38d + * for more details. */ +static_always_inline void * +esp_generate_iv (ipsec_sa_t * sa, void *payload, int iv_sz) +{ + ASSERT (iv_sz >= sizeof (u64)); + u64 *iv = (u64 *) (payload - iv_sz); + clib_memset_u8 (iv, 0, iv_sz); + *iv = sa->iv_counter++; + return iv; +} + static_always_inline void esp_process_ops (vlib_main_t * vm, vlib_node_runtime_t * node, vnet_crypto_op_t * ops, vlib_buffer_t * b[], u16 * nexts) @@ -495,6 +513,7 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vnet_crypto_op_t *op; vec_add2_aligned (ptd->crypto_ops, op, 1, CLIB_CACHE_LINE_BYTES); vnet_crypto_op_init (op, sa0->crypto_enc_op_id); + void *pkt_iv = esp_generate_iv (sa0, payload, iv_sz); op->src = op->dst = payload; op->key_index = sa0->crypto_key_index; op->len = payload_len - icv_sz; @@ -513,16 +532,19 @@ esp_encrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node, op->tag = payload + op->len; op->tag_len = 16; - u64 *iv = (u64 *) (payload - iv_sz); nonce->salt = sa0->salt; - nonce->iv = *iv = clib_host_to_net_u64 (sa0->gcm_iv_counter++); + nonce->iv = *(u64 *) pkt_iv; op->iv = (u8 *) nonce; nonce++; } else { - op->iv = payload - iv_sz; - op->flags = VNET_CRYPTO_OP_FLAG_INIT_IV; + /* construct zero iv in front of the IP header */ + op->iv = pkt_iv - hdr_len - iv_sz; + clib_memset_u8 (op->iv, 0, iv_sz); + /* include iv field in crypto */ + op->src -= iv_sz; + op->len += iv_sz; } } diff --git a/src/vnet/ipsec/ipsec_sa.h b/src/vnet/ipsec/ipsec_sa.h index e0d74e1309e..2468ea48998 100644 --- a/src/vnet/ipsec/ipsec_sa.h +++ b/src/vnet/ipsec/ipsec_sa.h @@ -133,6 +133,8 @@ typedef struct /* data accessed by dataplane code should be above this comment */ CLIB_CACHE_LINE_ALIGN_MARK (cacheline1); + u64 iv_counter; + union { ip4_header_t ip4_hdr; @@ -163,7 +165,6 @@ typedef struct /* Salt used in GCM modes - stored in network byte order */ u32 salt; - u64 gcm_iv_counter; } ipsec_sa_t; STATIC_ASSERT_OFFSET_OF (ipsec_sa_t, cacheline1, CLIB_CACHE_LINE_BYTES); |