/* * esp_decrypt.c : IPSec ESP decrypt node * * Copyright (c) 2015 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vnet/vnet.h> #include <vnet/api_errno.h> #include <vnet/ip/ip.h> #include <vnet/ipsec/ipsec.h> #include <vnet/ipsec/esp.h> #define foreach_esp_decrypt_next \ _(DROP, "error-drop") \ _(IP4_INPUT, "ip4-input") \ _(IP6_INPUT, "ip6-input") \ _(IPSEC_GRE_INPUT, "ipsec-gre-input") #define _(v, s) ESP_DECRYPT_NEXT_##v, typedef enum { foreach_esp_decrypt_next #undef _ ESP_DECRYPT_N_NEXT, } esp_decrypt_next_t; #define foreach_esp_decrypt_error \ _(RX_PKTS, "ESP pkts received") \ _(NO_BUFFER, "No buffer (packed dropped)") \ _(DECRYPTION_FAILED, "ESP decryption failed") \ _(INTEG_ERROR, "Integrity check failed") \ _(REPLAY, "SA replayed packet") \ _(NOT_IP, "Not IP packet (dropped)") typedef enum { #define _(sym,str) ESP_DECRYPT_ERROR_##sym, foreach_esp_decrypt_error #undef _ ESP_DECRYPT_N_ERROR, } esp_decrypt_error_t; static char *esp_decrypt_error_strings[] = { #define _(sym,string) string, foreach_esp_decrypt_error #undef _ }; typedef struct { ipsec_crypto_alg_t crypto_alg; ipsec_integ_alg_t integ_alg; } esp_decrypt_trace_t; /* packet trace format function */ static u8 * format_esp_decrypt_trace (u8 * s, va_list * args) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *); esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *); s = format (s, "esp: crypto %U integrity %U", format_ipsec_crypto_alg, t->crypto_alg, format_ipsec_integ_alg, t->integ_alg); return s; } always_inline void esp_decrypt_aes_cbc (ipsec_crypto_alg_t alg, u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv) { esp_main_t *em = &esp_main; u32 thread_index = vlib_get_thread_index (); EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].decrypt_ctx); const EVP_CIPHER *cipher = NULL; int out_len; ASSERT (alg < IPSEC_CRYPTO_N_ALG); if (PREDICT_FALSE (em->esp_crypto_algs[alg].type == 0)) return; if (PREDICT_FALSE (alg != em->per_thread_data[thread_index].last_decrypt_alg)) { cipher = em->esp_crypto_algs[alg].type; em->per_thread_data[thread_index].last_decrypt_alg = alg; } EVP_DecryptInit_ex (ctx, cipher, NULL, key, iv); EVP_DecryptUpdate (ctx, out, &out_len, in, in_len); EVP_DecryptFinal_ex (ctx, out + out_len, &out_len); } static uword esp_decrypt_node_fn (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { u32 n_left_from, *from, next_index, *to_next; ipsec_main_t *im = &ipsec_main; esp_main_t *em = &esp_main; u32 *recycle = 0; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; u32 thread_index = vlib_get_thread_index (); ipsec_alloc_empty_buffers (vm, im); u32 *empty_buffers = im->empty_buffers[thread_index]; if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from)) { vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from); goto free_buffers_and_exit; } next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 i_bi0, o_bi0 = (u32) ~ 0, next0; vlib_buffer_t *i_b0; vlib_buffer_t *o_b0 = 0; esp_header_t *esp0; ipsec_sa_t *sa0; u32 sa_index0 = ~0; u32 seq; ip4_header_t *ih4 = 0, *oh4 = 0; ip6_header_t *ih6 = 0, *oh6 = 0; u8 tunnel_mode = 1; u8 transport_ip6 = 0; i_bi0 = from[0]; from += 1; n_left_from -= 1; n_left_to_next -= 1; next0 = ESP_DECRYPT_NEXT_DROP; i_b0 = vlib_get_buffer (vm, i_bi0); esp0 = vlib_buffer_get_current (i_b0); sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index; sa0 = pool_elt_at_index (im->sad, sa_index0); seq = clib_host_to_net_u32 (esp0->seq); /* anti-replay check */ if (sa0->use_anti_replay) { int rv = 0; if (PREDICT_TRUE (sa0->use_esn)) rv = esp_replay_check_esn (sa0, seq); else rv = esp_replay_check (sa0, seq); if (PREDICT_FALSE (rv)) { clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq); vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_REPLAY, 1); o_bi0 = i_bi0; to_next[0] = o_bi0; to_next += 1; goto trace; } } sa0->total_data_size += i_b0->current_length; if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE)) { u8 sig[64]; int icv_size = em->esp_integ_algs[sa0->integ_alg].trunc_size; memset (sig, 0, sizeof (sig)); u8 *icv = vlib_buffer_get_current (i_b0) + i_b0->current_length - icv_size; i_b0->current_length -= icv_size; hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len, (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn, sa0->seq_hi); if (PREDICT_FALSE (memcmp (icv, sig, icv_size))) { vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_INTEG_ERROR, 1); o_bi0 = i_bi0; to_next[0] = o_bi0; to_next += 1; goto trace; } } if (PREDICT_TRUE (sa0->use_anti_replay)) { if (PREDICT_TRUE (sa0->use_esn)) esp_replay_advance_esn (sa0, seq); else esp_replay_advance (sa0, seq); } /* grab free buffer */ uword last_empty_buffer = vec_len (empty_buffers) - 1; o_bi0 = empty_buffers[last_empty_buffer]; to_next[0] = o_bi0; to_next += 1; o_b0 = vlib_get_buffer (vm, o_bi0); vlib_prefetch_buffer_with_index (vm, empty_buffers[last_empty_buffer - 1], STORE); _vec_len (empty_buffers) = last_empty_buffer; /* add old buffer to the recycle list */ vec_add1 (recycle, i_bi0); if (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 && sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) { const int BLOCK_SIZE = 16; const int IV_SIZE = 16; esp_footer_t *f0; u8 ip_hdr_size = 0; int blocks = (i_b0->current_length - sizeof (esp_header_t) - IV_SIZE) / BLOCK_SIZE; o_b0->current_data = sizeof (ethernet_header_t); /* transport mode */ if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6)) { tunnel_mode = 0; ih4 = (ip4_header_t *) (i_b0->data + sizeof (ethernet_header_t)); if (PREDICT_TRUE ((ih4->ip_version_and_header_length & 0xF0) != 0x40)) { if (PREDICT_TRUE ((ih4->ip_version_and_header_length & 0xF0) == 0x60)) { transport_ip6 = 1; ip_hdr_size = sizeof (ip6_header_t); ih6 = (ip6_header_t *) (i_b0->data + sizeof (ethernet_header_t)); oh6 = vlib_buffer_get_current (o_b0); } else { vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_NOT_IP, 1); o_b0 = 0; goto trace; } } else { oh4 = vlib_buffer_get_current (o_b0); ip_hdr_size = sizeof (ip4_header_t); } } esp_decrypt_aes_cbc (sa0->crypto_alg, esp0->data + IV_SIZE, (u8 *) vlib_buffer_get_current (o_b0) + ip_hdr_size, BLOCK_SIZE * blocks, sa0->crypto_key, esp0->data); o_b0->current_length = (blocks * 16) - 2 + ip_hdr_size; o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID; f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) + o_b0->current_length); o_b0->current_length -= f0->pad_length; /* tunnel mode */ if (PREDICT_TRUE (tunnel_mode)) { if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP)) { next0 = ESP_DECRYPT_NEXT_IP4_INPUT; oh4 = vlib_buffer_get_current (o_b0); } else if (f0->next_header == IP_PROTOCOL_IPV6) next0 = ESP_DECRYPT_NEXT_IP6_INPUT; else { clib_warning ("next header: 0x%x", f0->next_header); vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_DECRYPTION_FAILED, 1); o_b0 = 0; goto trace; } } /* transport mode */ else { if (PREDICT_FALSE (transport_ip6)) { next0 = ESP_DECRYPT_NEXT_IP6_INPUT; oh6->ip_version_traffic_class_and_flow_label = ih6->ip_version_traffic_class_and_flow_label; oh6->protocol = f0->next_header; oh6->hop_limit = ih6->hop_limit; oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0]; oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1]; oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0]; oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1]; oh6->payload_length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0) - sizeof (ip6_header_t)); } else { next0 = ESP_DECRYPT_NEXT_IP4_INPUT; oh4->ip_version_and_header_length = 0x45; oh4->tos = ih4->tos; oh4->fragment_id = 0; oh4->flags_and_fragment_offset = 0; oh4->ttl = ih4->ttl; oh4->protocol = f0->next_header; oh4->src_address.as_u32 = ih4->src_address.as_u32; oh4->dst_address.as_u32 = ih4->dst_address.as_u32; oh4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, o_b0)); oh4->checksum = ip4_header_checksum (oh4); } } /* for IPSec-GRE tunnel next node is ipsec-gre-input */ if (PREDICT_FALSE ((vnet_buffer (i_b0)->ipsec.flags) & IPSEC_FLAG_IPSEC_GRE_TUNNEL)) next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT; vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0; vnet_buffer (o_b0)->sw_if_index[VLIB_RX] = vnet_buffer (i_b0)->sw_if_index[VLIB_RX]; } trace: if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED)) { if (o_b0) { o_b0->flags |= VLIB_BUFFER_IS_TRACED; o_b0->trace_index = i_b0->trace_index; esp_decrypt_trace_t *tr = vlib_add_trace (vm, node, o_b0, sizeof (*tr)); tr->crypto_alg = sa0->crypto_alg; tr->integ_alg = sa0->integ_alg; } } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, o_bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } vlib_node_increment_counter (vm, esp_decrypt_node.index, ESP_DECRYPT_ERROR_RX_PKTS, from_frame->n_vectors); free_buffers_and_exit: if (recycle) vlib_buffer_free (vm, recycle, vec_len (recycle)); vec_free (recycle); return from_frame->n_vectors; } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (esp_decrypt_node) = { .function = esp_decrypt_node_fn, .name = "esp-decrypt", .vector_size = sizeof (u32), .format_trace = format_esp_decrypt_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = ARRAY_LEN(esp_decrypt_error_strings), .error_strings = esp_decrypt_error_strings, .n_next_nodes = ESP_DECRYPT_N_NEXT, .next_nodes = { #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n, foreach_esp_decrypt_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (esp_decrypt_node, esp_decrypt_node_fn) /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */