diff options
Diffstat (limited to 'src/vnet/ipsec')
| -rw-r--r-- | src/vnet/ipsec/esp_encrypt.c | 88 | ||||
| -rw-r--r-- | src/vnet/ipsec/ipsec_sa.h | 2 |
2 files changed, 70 insertions, 20 deletions
diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c index 8b722ef541f..c7030d313a2 100644 --- a/src/vnet/ipsec/esp_encrypt.c +++ b/src/vnet/ipsec/esp_encrypt.c @@ -234,6 +234,24 @@ 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_chained_ops (vlib_main_t * vm, vlib_node_runtime_t * node, vnet_crypto_op_t * ops, vlib_buffer_t * b[], @@ -396,10 +414,16 @@ esp_prepare_sync_op (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, vnet_crypto_op_t *op; vec_add2_aligned (crypto_ops[0], op, 1, CLIB_CACHE_LINE_BYTES); vnet_crypto_op_init (op, sa0->crypto_enc_op_id); + u8 *crypto_start = payload; + /* esp_add_footer_and_icv() in esp_encrypt_inline() makes sure we always + * have enough space for ESP header and footer which includes ICV */ + ASSERT (payload_len > icv_sz); + u16 crypto_len = payload_len - icv_sz; + + /* generate the IV in front of the payload */ + 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; op->user_data = b - bufs; if (ipsec_sa_is_set_IS_AEAD (sa0)) @@ -411,18 +435,21 @@ esp_prepare_sync_op (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, op->aad = payload - hdr_len - sizeof (esp_aead_t); op->aad_len = esp_aad_fill (op->aad, esp, sa0); - op->tag = payload + op->len; + op->tag = payload + crypto_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; } 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 */ + crypto_start -= iv_sz; + crypto_len += iv_sz; } if (lb != b[0]) @@ -431,8 +458,15 @@ esp_prepare_sync_op (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, op->flags |= VNET_CRYPTO_OP_FLAG_CHAINED_BUFFERS; op->chunk_index = vec_len (ptd->chunks); op->tag = vlib_buffer_get_tail (lb) - icv_sz; - esp_encrypt_chain_crypto (vm, ptd, sa0, b[0], lb, icv_sz, payload, - payload_len, &op->n_chunks); + esp_encrypt_chain_crypto (vm, ptd, sa0, b[0], lb, icv_sz, + crypto_start, crypto_len + icv_sz, + &op->n_chunks); + } + else + { + /* not chained */ + op->src = op->dst = crypto_start; + op->len = crypto_len; } } @@ -482,17 +516,20 @@ esp_prepare_async_frame (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, u8 *tag, *iv, *aad = 0; u8 flag = 0; u32 key_index; - i16 crypto_start_offset, integ_start_offset = 0; + i16 crypto_start_offset, integ_start_offset; u16 crypto_total_len, integ_total_len; post->next_index = next[0]; next[0] = ESP_ENCRYPT_NEXT_PENDING; /* crypto */ - crypto_start_offset = payload - b->data; + crypto_start_offset = integ_start_offset = payload - b->data; crypto_total_len = integ_total_len = payload_len - icv_sz; tag = payload + crypto_total_len; + /* generate the IV in front of the payload */ + void *pkt_iv = esp_generate_iv (sa, payload, iv_sz); + /* aead */ if (ipsec_sa_is_set_IS_AEAD (sa)) { @@ -503,7 +540,7 @@ esp_prepare_async_frame (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, esp_aad_fill (aad, esp, sa); nonce = (esp_gcm_nonce_t *) (aad - sizeof (*nonce)); nonce->salt = sa->salt; - nonce->iv = *pkt_iv = clib_host_to_net_u64 (sa->gcm_iv_counter++); + nonce->iv = *(u64 *) pkt_iv; iv = (u8 *) nonce; key_index = sa->crypto_key_index; @@ -513,25 +550,38 @@ esp_prepare_async_frame (vlib_main_t * vm, ipsec_per_thread_data_t * ptd, flag |= VNET_CRYPTO_OP_FLAG_CHAINED_BUFFERS; tag = vlib_buffer_get_tail (lb) - icv_sz; crypto_total_len = esp_encrypt_chain_crypto (vm, ptd, sa, b, lb, - icv_sz, payload, - payload_len, 0); + icv_sz, + b->data + + crypto_start_offset, + crypto_total_len + + icv_sz, 0); } goto out; } + else + { + /* construct zero iv in front of the IP header */ + iv = pkt_iv - hdr_len - iv_sz; + clib_memset_u8 (iv, 0, iv_sz); + /* include iv field in crypto */ + crypto_start_offset -= iv_sz; + crypto_total_len += iv_sz; + } /* cipher then hash */ - iv = payload - iv_sz; - integ_start_offset = crypto_start_offset - iv_sz - sizeof (esp_header_t); + integ_start_offset -= iv_sz + sizeof (esp_header_t); integ_total_len += iv_sz + sizeof (esp_header_t); - flag |= VNET_CRYPTO_OP_FLAG_INIT_IV; key_index = sa->linked_key_index; if (b != lb) { flag |= VNET_CRYPTO_OP_FLAG_CHAINED_BUFFERS; crypto_total_len = esp_encrypt_chain_crypto (vm, ptd, sa, b, lb, - icv_sz, payload, - payload_len, 0); + icv_sz, + b->data + + crypto_start_offset, + crypto_total_len + icv_sz, + 0); tag = vlib_buffer_get_tail (lb) - icv_sz; integ_total_len = esp_encrypt_chain_integ (vm, ptd, sa, b, lb, icv_sz, payload - iv_sz - diff --git a/src/vnet/ipsec/ipsec_sa.h b/src/vnet/ipsec/ipsec_sa.h index 5950d6f53b3..72636368977 100644 --- a/src/vnet/ipsec/ipsec_sa.h +++ b/src/vnet/ipsec/ipsec_sa.h @@ -182,7 +182,7 @@ typedef struct /* Salt used in GCM modes - stored in network byte order */ u32 salt; - u64 gcm_iv_counter; + u64 iv_counter; union { |