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gerrit.nordix.org / fdio / vpp / 39aa7a5202a6a875bd6f5d341cb07f19ab0bf51e / . / src / vnet / ipsec / esp_decrypt.c
blob: 80b3246f925fdaaa07fd4265dfa990ea78379ce6 [file] [log] [blame]
/*
* 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/l2/l2_input.h>
#include <vnet/ipsec/ipsec.h>
#include <vnet/ipsec/esp.h>
#include <vnet/ipsec/ipsec_io.h>
#include <vnet/ipsec/ipsec_tun.h>
#include <vnet/gre/gre.h>
#define foreach_esp_decrypt_next \
_(DROP, "error-drop") \
_(IP4_INPUT, "ip4-input-no-checksum") \
_(IP6_INPUT, "ip6-input") \
_(L2_INPUT, "l2-input") \
_(HANDOFF, "handoff")
#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") \
_(DECRYPTION_FAILED, "ESP decryption failed") \
_(INTEG_ERROR, "Integrity check failed") \
_(CRYPTO_ENGINE_ERROR, "crypto engine error (packet dropped)") \
_(REPLAY, "SA replayed packet") \
_(RUNT, "undersized packet") \
_(NO_BUFFERS, "no buffers (packet dropped)") \
_(OVERSIZED_HEADER, "buffer with oversized header (dropped)") \
_(NO_TAIL_SPACE, "no enough buffer tail space (dropped)") \
_(TUN_NO_PROTO, "no tunnel protocol") \
_(UNSUP_PAYLOAD, "unsupported payload") \
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
{
u32 seq;
u32 sa_seq;
u32 sa_seq_hi;
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 pkt-seq %d sa-seq %u sa-seq-hi %u",
format_ipsec_crypto_alg, t->crypto_alg, format_ipsec_integ_alg,
t->integ_alg, t->seq, t->sa_seq, t->sa_seq_hi);
return s;
}
typedef struct
{
vlib_buffer_t *lb;
union
{
struct
{
u8 icv_sz;
u8 iv_sz;
ipsec_sa_flags_t flags;
u32 sa_index;
};
u64 sa_data;
};
u32 seq;
u32 free_buffer_index;
i16 current_data;
i16 current_length;
u16 hdr_sz;
u8 icv_removed;
u8 __unused;
} esp_decrypt_packet_data_t;
STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 4 * sizeof (u64));
#define ESP_ENCRYPT_PD_F_FD_TRANSPORT (1 << 2)
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,
int e)
{
vnet_crypto_op_t *op = ops;
u32 n_fail, n_ops = vec_len (ops);
if (n_ops == 0)
return;
n_fail = n_ops - vnet_crypto_process_ops (vm, op, n_ops);
while (n_fail)
{
ASSERT (op - ops < n_ops);
if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
{
u32 err, bi = op->user_data;
if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
err = e;
else
err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;
b[bi]->error = node->errors[err];
nexts[bi] = ESP_DECRYPT_NEXT_DROP;
n_fail--;
}
op++;
}
}
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[],
u16 * nexts, vnet_crypto_op_chunk_t * chunks, int e)
{
vnet_crypto_op_t *op = ops;
u32 n_fail, n_ops = vec_len (ops);
if (n_ops == 0)
return;
n_fail = n_ops - vnet_crypto_process_chained_ops (vm, op, chunks, n_ops);
while (n_fail)
{
ASSERT (op - ops < n_ops);
if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
{
u32 err, bi = op->user_data;
if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
err = e;
else
err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;
b[bi]->error = node->errors[err];
nexts[bi] = ESP_DECRYPT_NEXT_DROP;
n_fail--;
}
op++;
}
}
always_inline void
esp_remove_tail (vlib_main_t * vm, vlib_buffer_t * b, vlib_buffer_t * last,
u16 tail)
{
vlib_buffer_t *before_last = b;
if (last->current_length > tail)
{
last->current_length -= tail;
return;
}
ASSERT (b->flags & VLIB_BUFFER_NEXT_PRESENT);
while (b->flags & VLIB_BUFFER_NEXT_PRESENT)
{
before_last = b;
b = vlib_get_buffer (vm, b->next_buffer);
}
before_last->current_length -= tail - last->current_length;
vlib_buffer_free_one (vm, before_last->next_buffer);
before_last->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
}
/* ICV is splitted in last two buffers so move it to the last buffer and
return pointer to it */
static_always_inline u8 *
esp_move_icv (vlib_main_t * vm, vlib_buffer_t * first,
esp_decrypt_packet_data_t * pd, u16 icv_sz, u16 * dif)
{
vlib_buffer_t *before_last, *bp;
u16 last_sz = pd->lb->current_length;
u16 first_sz = icv_sz - last_sz;
bp = before_last = first;
while (bp->flags & VLIB_BUFFER_NEXT_PRESENT)
{
before_last = bp;
bp = vlib_get_buffer (vm, bp->next_buffer);
}
u8 *lb_curr = vlib_buffer_get_current (pd->lb);
memmove (lb_curr + first_sz, lb_curr, last_sz);
clib_memcpy_fast (lb_curr, vlib_buffer_get_tail (before_last) - first_sz,
first_sz);
before_last->current_length -= first_sz;
if (dif)
dif[0] = first_sz;
pd->lb = before_last;
pd->icv_removed = 1;
pd->free_buffer_index = before_last->next_buffer;
before_last->flags &= ~VLIB_BUFFER_NEXT_PRESENT;
return lb_curr;
}
static_always_inline int
esp_insert_esn (vlib_main_t * vm, ipsec_sa_t * sa,
esp_decrypt_packet_data_t * pd, vnet_crypto_op_t * op,
u16 * len, vlib_buffer_t * b, u8 * payload)
{
if (!ipsec_sa_is_set_USE_ESN (sa))
return 1;
/* shift ICV by 4 bytes to insert ESN */
u32 seq_hi = clib_host_to_net_u32 (sa->seq_hi);
u8 tmp[ESP_MAX_ICV_SIZE], sz = sizeof (sa->seq_hi);
if (pd->icv_removed)
{
u16 space_left = vlib_buffer_space_left_at_end (vm, pd->lb);
if (space_left >= sz)
{
clib_memcpy_fast (vlib_buffer_get_tail (pd->lb), &seq_hi, sz);
op->len += sz;
}
else
return 0;
len[0] = b->current_length;
}
else
{
clib_memcpy_fast (tmp, payload + len[0], ESP_MAX_ICV_SIZE);
clib_memcpy_fast (payload + len[0], &seq_hi, sz);
clib_memcpy_fast (payload + len[0] + sz, tmp, ESP_MAX_ICV_SIZE);
op->len += sz;
op->digest += sz;
}
return 1;
}
static_always_inline u8 *
esp_move_icv_esn (vlib_main_t * vm, vlib_buffer_t * first,
esp_decrypt_packet_data_t * pd, u16 icv_sz, ipsec_sa_t * sa,
u8 * extra_esn, vnet_crypto_op_t * op)
{
u16 dif = 0;
u8 *digest = esp_move_icv (vm, first, pd, icv_sz, &dif);
if (dif)
op->len -= dif;
if (ipsec_sa_is_set_USE_ESN (sa))
{
u8 sz = sizeof (sa->seq_hi);
u32 seq_hi = clib_host_to_net_u32 (sa->seq_hi);
u16 space_left = vlib_buffer_space_left_at_end (vm, pd->lb);
if (space_left >= sz)
{
clib_memcpy_fast (vlib_buffer_get_tail (pd->lb), &seq_hi, sz);
op->len += sz;
}
else
{
/* no space for ESN at the tail, use the next buffer
* (with ICV data) */
ASSERT (pd->icv_removed);
vlib_buffer_t *tmp = vlib_get_buffer (vm, pd->free_buffer_index);
clib_memcpy_fast (vlib_buffer_get_current (tmp) - sz, &seq_hi, sz);
extra_esn[0] = 1;
}
}
return digest;
}
always_inline uword
esp_decrypt_inline (vlib_main_t * vm,
vlib_node_runtime_t * node, vlib_frame_t * from_frame,
int is_ip6, int is_tun)
{
ipsec_main_t *im = &ipsec_main;
u32 thread_index = vm->thread_index;
u16 len;
ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
u32 *from = vlib_frame_vector_args (from_frame);
u32 n_left = from_frame->n_vectors;
vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
esp_decrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
esp_decrypt_packet_data_t cpd = { };
u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
const u8 esp_sz = sizeof (esp_header_t);
ipsec_sa_t *sa0 = 0;
vnet_crypto_op_t _op, *op = &_op;
vnet_crypto_op_chunk_t *ch;
vnet_crypto_op_t **crypto_ops = &ptd->crypto_ops;
vnet_crypto_op_t **integ_ops = &ptd->integ_ops;
vlib_get_buffers (vm, from, b, n_left);
vec_reset_length (ptd->crypto_ops);
vec_reset_length (ptd->integ_ops);
vec_reset_length (ptd->chained_crypto_ops);
vec_reset_length (ptd->chained_integ_ops);
vec_reset_length (ptd->chunks);
clib_memset_u16 (nexts, -1, n_left);
while (n_left > 0)
{
u8 *payload;
if (n_left > 2)
{
u8 *p;
vlib_prefetch_buffer_header (b[2], LOAD);
p = vlib_buffer_get_current (b[1]);
CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
p -= CLIB_CACHE_LINE_BYTES;
CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
}
u32 n_bufs = vlib_buffer_chain_linearize (vm, b[0]);
if (n_bufs == 0)
{
b[0]->error = node->errors[ESP_DECRYPT_ERROR_NO_BUFFERS];
next[0] = ESP_DECRYPT_NEXT_DROP;
goto next;
}
if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
{
if (current_sa_pkts)
vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
current_sa_index,
current_sa_pkts,
current_sa_bytes);
current_sa_bytes = current_sa_pkts = 0;
current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
sa0 = pool_elt_at_index (im->sad, current_sa_index);
cpd.icv_sz = sa0->integ_icv_size;
cpd.iv_sz = sa0->crypto_iv_size;
cpd.flags = sa0->flags;
cpd.sa_index = current_sa_index;
}
if (PREDICT_FALSE (~0 == sa0->decrypt_thread_index))
{
/* this is the first packet to use this SA, claim the SA
* for this thread. this could happen simultaneously on
* another thread */
clib_atomic_cmp_and_swap (&sa0->decrypt_thread_index, ~0,
ipsec_sa_assign_thread (thread_index));
}
if (PREDICT_TRUE (thread_index != sa0->decrypt_thread_index))
{
next[0] = ESP_DECRYPT_NEXT_HANDOFF;
goto next;
}
/* store packet data for next round for easier prefetch */
pd->sa_data = cpd.sa_data;
pd->current_data = b[0]->current_data;
pd->hdr_sz = pd->current_data - vnet_buffer (b[0])->l3_hdr_offset;
payload = b[0]->data + pd->current_data;
pd->seq = clib_host_to_net_u32 (((esp_header_t *) payload)->seq);
pd->free_buffer_index = 0;
pd->icv_removed = 0;
pd->lb = b[0];
if (n_bufs > 1)
{
/* find last buffer in the chain */
while (pd->lb->flags & VLIB_BUFFER_NEXT_PRESENT)
pd->lb = vlib_get_buffer (vm, pd->lb->next_buffer);
crypto_ops = &ptd->chained_crypto_ops;
integ_ops = &ptd->chained_integ_ops;
}
pd->current_length = b[0]->current_length;
/* anti-reply check */
if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
next[0] = ESP_DECRYPT_NEXT_DROP;
goto next;
}
if (pd->current_length < cpd.icv_sz + esp_sz + cpd.iv_sz)
{
b[0]->error = node->errors[ESP_DECRYPT_ERROR_RUNT];
next[0] = ESP_DECRYPT_NEXT_DROP;
goto next;
}
len = pd->current_length - cpd.icv_sz;
current_sa_pkts += 1;
current_sa_bytes += vlib_buffer_length_in_chain (vm, b[0]);
if (PREDICT_TRUE (sa0->integ_op_id != VNET_CRYPTO_OP_NONE))
{
vnet_crypto_op_init (op, sa0->integ_op_id);
op->key_index = sa0->integ_key_index;
op->src = payload;
op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
op->user_data = b - bufs;
op->digest = payload + len;
op->digest_len = cpd.icv_sz;
op->len = len;
if (pd->lb != b[0])
{
/* buffer is chained */
vlib_buffer_t *cb = b[0];
op->len = pd->current_length;
/* special case when ICV is splitted and needs to be reassembled
* first -> move it to the last buffer. Also take into account
* that ESN needs to be added after encrypted data and may or
* may not fit in the tail.*/
if (pd->lb->current_length < cpd.icv_sz)
{
u8 extra_esn = 0;
op->digest =
esp_move_icv_esn (vm, b[0], pd, cpd.icv_sz, sa0,
&extra_esn, op);
if (extra_esn)
{
/* esn is in the last buffer, that was unlinked from
* the chain */
op->len = b[0]->current_length;
}
else
{
if (pd->lb == b[0])
{
/* we now have a single buffer of crypto data, adjust
* the length (second buffer contains only ICV) */
integ_ops = &ptd->integ_ops;
crypto_ops = &ptd->crypto_ops;
len = b[0]->current_length;
goto out;
}
}
}
else
op->digest = vlib_buffer_get_tail (pd->lb) - cpd.icv_sz;
op->flags |= VNET_CRYPTO_OP_FLAG_CHAINED_BUFFERS;
op->chunk_index = vec_len (ptd->chunks);
vec_add2 (ptd->chunks, ch, 1);
ch->len = pd->current_length;
ch->src = payload;
cb = vlib_get_buffer (vm, cb->next_buffer);
op->n_chunks = 1;
while (1)
{
vec_add2 (ptd->chunks, ch, 1);
op->n_chunks += 1;
ch->src = vlib_buffer_get_current (cb);
if (pd->lb == cb)
{
if (pd->icv_removed)
ch->len = cb->current_length;
else
ch->len = cb->current_length - cpd.icv_sz;
if (ipsec_sa_is_set_USE_ESN (sa0))
{
u32 seq_hi = clib_host_to_net_u32 (sa0->seq_hi);
u8 tmp[ESP_MAX_ICV_SIZE], sz = sizeof (sa0->seq_hi);
u8 *esn;
vlib_buffer_t *tmp_b;
u16 space_left = vlib_buffer_space_left_at_end
(vm, pd->lb);
if (space_left < sz)
{
if (pd->icv_removed)
{
/* use pre-data area from the last bufer
that was removed from the chain */
tmp_b =
vlib_get_buffer (vm,
pd->free_buffer_index);
esn = tmp_b->data - sz;
}
else
{
/* no space, need to allocate new buffer */
u32 tmp_bi = 0;
vlib_buffer_alloc (vm, &tmp_bi, 1);
tmp_b = vlib_get_buffer (vm, tmp_bi);
esn = tmp_b->data;
pd->free_buffer_index = tmp_bi;
}
clib_memcpy_fast (esn, &seq_hi, sz);
vec_add2 (ptd->chunks, ch, 1);
op->n_chunks += 1;
ch->src = esn;
ch->len = sz;
}
else
{
if (pd->icv_removed)
{
clib_memcpy_fast (vlib_buffer_get_tail
(pd->lb), &seq_hi, sz);
}
else
{
clib_memcpy_fast (tmp, op->digest,
ESP_MAX_ICV_SIZE);
clib_memcpy_fast (op->digest, &seq_hi, sz);
clib_memcpy_fast (op->digest + sz, tmp,
ESP_MAX_ICV_SIZE);
op->digest += sz;
}
ch->len += sz;
}
}
break;
}
else
ch->len = cb->current_length;
if (!(cb->flags & VLIB_BUFFER_NEXT_PRESENT))
break;
cb = vlib_get_buffer (vm, cb->next_buffer);
}
}
else
esp_insert_esn (vm, sa0, pd, op, &len, b[0], payload);
out:
vec_add_aligned (integ_ops[0], op, 1, CLIB_CACHE_LINE_BYTES);
}
payload += esp_sz;
len -= esp_sz;
if (sa0->crypto_dec_op_id != VNET_CRYPTO_OP_NONE)
{
vnet_crypto_op_init (op, sa0->crypto_dec_op_id);
op->key_index = sa0->crypto_key_index;
op->iv = payload;
if (ipsec_sa_is_set_IS_AEAD (sa0))
{
esp_header_t *esp0;
esp_aead_t *aad;
u8 *scratch;
/*
* construct the AAD and the nonce (Salt || IV) in a scratch
* space in front of the IP header.
*/
scratch = payload - esp_sz;
esp0 = (esp_header_t *) (scratch);
scratch -= (sizeof (*aad) + pd->hdr_sz);
op->aad = scratch;
esp_aad_fill (op, esp0, sa0);
/*
* we don't need to refer to the ESP header anymore so we
* can overwrite it with the salt and use the IV where it is
* to form the nonce = (Salt + IV)
*/
op->iv -= sizeof (sa0->salt);
clib_memcpy_fast (op->iv, &sa0->salt, sizeof (sa0->salt));
op->tag = payload + len;
op->tag_len = 16;
}
op->src = op->dst = payload += cpd.iv_sz;
op->len = len - cpd.iv_sz;
op->user_data = b - bufs;
if (pd->lb != b[0])
{
/* buffer is chained */
vlib_buffer_t *cb = b[0];
op->flags |= VNET_CRYPTO_OP_FLAG_CHAINED_BUFFERS;
op->chunk_index = vec_len (ptd->chunks);
vec_add2 (ptd->chunks, ch, 1);
ch->len = len - cpd.iv_sz + cpd.icv_sz;
ch->src = ch->dst = payload;
cb = vlib_get_buffer (vm, cb->next_buffer);
op->n_chunks = 1;
while (1)
{
vec_add2 (ptd->chunks, ch, 1);
op->n_chunks += 1;
ch->src = ch->dst = vlib_buffer_get_current (cb);
if (pd->lb == cb)
{
if (ipsec_sa_is_set_IS_AEAD (sa0))
{
if (pd->lb->current_length < cpd.icv_sz)
{
u16 dif = 0;
op->tag =
esp_move_icv (vm, b[0], pd, cpd.icv_sz, &dif);
/* this chunk does not contain crypto data */
op->n_chunks -= 1;
/* and fix previous chunk's length as it might have
been changed */
ASSERT (op->n_chunks > 0);
if (pd->lb == b[0])
ch[-1].len -= dif;
else
ch[-1].len = pd->lb->current_length;
break;
}
else
op->tag =
vlib_buffer_get_tail (pd->lb) - cpd.icv_sz;
}
if (pd->icv_removed)
ch->len = cb->current_length;
else
ch->len = cb->current_length - cpd.icv_sz;
}
else
ch->len = cb->current_length;
if (!(cb->flags & VLIB_BUFFER_NEXT_PRESENT))
break;
cb = vlib_get_buffer (vm, cb->next_buffer);
}
}
vec_add_aligned (crypto_ops[0], op, 1, CLIB_CACHE_LINE_BYTES);
}
/* next */
next:
n_left -= 1;
next += 1;
pd += 1;
b += 1;
}
if (PREDICT_TRUE (~0 != current_sa_index))
vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
current_sa_index, current_sa_pkts,
current_sa_bytes);
esp_process_ops (vm, node, ptd->integ_ops, bufs, nexts,
ESP_DECRYPT_ERROR_INTEG_ERROR);
esp_process_chained_ops (vm, node, ptd->chained_integ_ops, bufs, nexts,
ptd->chunks, ESP_DECRYPT_ERROR_INTEG_ERROR);
esp_process_ops (vm, node, ptd->crypto_ops, bufs, nexts,
ESP_DECRYPT_ERROR_DECRYPTION_FAILED);
esp_process_chained_ops (vm, node, ptd->chained_crypto_ops, bufs, nexts,
ptd->chunks, ESP_DECRYPT_ERROR_DECRYPTION_FAILED);
/* Post decryption ronud - adjust packet data start and length and next
node */
n_left = from_frame->n_vectors;
next = nexts;
pd = pkt_data;
b = bufs;
while (n_left)
{
const u8 tun_flags = IPSEC_SA_FLAG_IS_TUNNEL |
IPSEC_SA_FLAG_IS_TUNNEL_V6;
if (n_left >= 2)
{
void *data = b[1]->data + pd[1].current_data;
/* buffer metadata */
vlib_prefetch_buffer_header (b[1], LOAD);
/* esp_footer_t */
CLIB_PREFETCH (data + pd[1].current_length - pd[1].icv_sz - 2,
CLIB_CACHE_LINE_BYTES, LOAD);
/* packet headers */
CLIB_PREFETCH (data - CLIB_CACHE_LINE_BYTES,
CLIB_CACHE_LINE_BYTES * 2, LOAD);
}
if (next[0] < ESP_DECRYPT_N_NEXT)
goto trace;
sa0 = vec_elt_at_index (im->sad, pd->sa_index);
/*
* redo the anti-reply check
* in this frame say we have sequence numbers, s, s+1, s+1, s+1
* and s and s+1 are in the window. When we did the anti-replay
* check above we did so against the state of the window (W),
* after packet s-1. So each of the packets in the sequence will be
* accepted.
* This time s will be cheked against Ws-1, s+1 chceked against Ws
* (i.e. the window state is updated/advnaced)
* so this time the successive s+! packet will be dropped.
* This is a consequence of batching the decrypts. If the
* check-dcrypt-advance process was done for each packet it would
* be fine. But we batch the decrypts because it's much more efficient
* to do so in SW and if we offload to HW and the process is async.
*
* You're probably thinking, but this means an attacker can send the
* above sequence and cause VPP to perform decrpyts that will fail,
* and that's true. But if the attacker can determine s (a valid
* sequence number in the window) which is non-trivial, it can generate
* a sequence s, s+1, s+2, s+3, ... s+n and nothing will prevent any
* implementation, sequential or batching, from decrypting these.
*/
if (ipsec_sa_anti_replay_check (sa0, pd->seq))
{
b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
next[0] = ESP_DECRYPT_NEXT_DROP;
goto trace;
}
ipsec_sa_anti_replay_advance (sa0, pd->seq);
u8 pad_length = 0, next_header = 0;
u16 icv_sz = pd->icv_removed ? 0 : pd->icv_sz;
if (pd->free_buffer_index)
vlib_buffer_free_one (vm, pd->free_buffer_index);
if (pd->lb->current_length < sizeof (esp_footer_t) + icv_sz)
{
/* esp footer is either splitted in two buffers or in the before
* last buffer */
vlib_buffer_t *before_last = b[0], *bp = b[0];
while (bp->flags & VLIB_BUFFER_NEXT_PRESENT)
{
before_last = bp;
bp = vlib_get_buffer (vm, bp->next_buffer);
}
u8 *bt = vlib_buffer_get_tail (before_last);
if (pd->lb->current_length == icv_sz)
{
esp_footer_t *f = (esp_footer_t *) (bt - sizeof (*f));
pad_length = f->pad_length;
next_header = f->next_header;
}
else
{
pad_length = (bt - 1)[0];
next_header = ((u8 *) vlib_buffer_get_current (pd->lb))[0];
}
}
else
{
esp_footer_t *f =
(esp_footer_t *) (pd->lb->data + pd->lb->current_data +
pd->lb->current_length - sizeof (esp_footer_t) -
icv_sz);
pad_length = f->pad_length;
next_header = f->next_header;
}
u16 adv = pd->iv_sz + esp_sz;
u16 tail = sizeof (esp_footer_t) + pad_length + icv_sz;
u16 tail_orig = sizeof (esp_footer_t) + pad_length + pd->icv_sz;
b[0]->flags &= ~VLIB_BUFFER_TOTAL_LENGTH_VALID;
if ((pd->flags & tun_flags) == 0 && !is_tun) /* transport mode */
{
u8 udp_sz = (is_ip6 == 0 && pd->flags & IPSEC_SA_FLAG_UDP_ENCAP) ?
sizeof (udp_header_t) : 0;
u16 ip_hdr_sz = pd->hdr_sz - udp_sz;
u8 *old_ip = b[0]->data + pd->current_data - ip_hdr_sz - udp_sz;
u8 *ip = old_ip + adv + udp_sz;
if (is_ip6 && ip_hdr_sz > 64)
memmove (ip, old_ip, ip_hdr_sz);
else
clib_memcpy_le64 (ip, old_ip, ip_hdr_sz);
b[0]->current_data = pd->current_data + adv - ip_hdr_sz;
b[0]->current_length += ip_hdr_sz - adv;
esp_remove_tail (vm, b[0], pd->lb, tail);
if (is_ip6)
{
ip6_header_t *ip6 = (ip6_header_t *) ip;
u16 len = clib_net_to_host_u16 (ip6->payload_length);
len -= adv + tail_orig;
ip6->payload_length = clib_host_to_net_u16 (len);
ip6->protocol = next_header;
next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
}
else
{
ip4_header_t *ip4 = (ip4_header_t *) ip;
ip_csum_t sum = ip4->checksum;
u16 len = clib_net_to_host_u16 (ip4->length);
len = clib_host_to_net_u16 (len - adv - tail_orig - udp_sz);
sum = ip_csum_update (sum, ip4->protocol, next_header,
ip4_header_t, protocol);
sum = ip_csum_update (sum, ip4->length, len,
ip4_header_t, length);
ip4->checksum = ip_csum_fold (sum);
ip4->protocol = next_header;
ip4->length = len;
next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
}
}
else
{
if (PREDICT_TRUE (next_header == IP_PROTOCOL_IP_IN_IP))
{
next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
b[0]->current_data = pd->current_data + adv;
b[0]->current_length = pd->current_length - adv;
esp_remove_tail (vm, b[0], pd->lb, tail);
}
else if (next_header == IP_PROTOCOL_IPV6)
{
next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
b[0]->current_data = pd->current_data + adv;
b[0]->current_length = pd->current_length - adv;
esp_remove_tail (vm, b[0], pd->lb, tail);
}
else
{
if (is_tun && next_header == IP_PROTOCOL_GRE)
{
gre_header_t *gre;
b[0]->current_data = pd->current_data + adv;
b[0]->current_length = pd->current_length - adv - tail;
gre = vlib_buffer_get_current (b[0]);
vlib_buffer_advance (b[0], sizeof (*gre));
switch (clib_net_to_host_u16 (gre->protocol))
{
case GRE_PROTOCOL_teb:
vnet_update_l2_len (b[0]);
next[0] = ESP_DECRYPT_NEXT_L2_INPUT;
break;
case GRE_PROTOCOL_ip4:
next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
break;
case GRE_PROTOCOL_ip6:
next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
break;
default:
b[0]->error =
node->errors[ESP_DECRYPT_ERROR_UNSUP_PAYLOAD];
next[0] = ESP_DECRYPT_NEXT_DROP;
break;
}
}
else
{
next[0] = ESP_DECRYPT_NEXT_DROP;
b[0]->error = node->errors[ESP_DECRYPT_ERROR_UNSUP_PAYLOAD];
goto trace;
}
}
if (is_tun)
{
if (ipsec_sa_is_set_IS_PROTECT (sa0))
{
/*
* There are two encap possibilities
* 1) the tunnel and ths SA are prodiving encap, i.e. it's
* MAC | SA-IP | TUN-IP | ESP | PAYLOAD
* implying the SA is in tunnel mode (on a tunnel interface)
* 2) only the tunnel provides encap
* MAC | TUN-IP | ESP | PAYLOAD
* implying the SA is in transport mode.
*
* For 2) we need only strip the tunnel encap and we're good.
* since the tunnel and crypto ecnap (int the tun=protect
* object) are the same and we verified above that these match
* for 1) we need to strip the SA-IP outer headers, to
* reveal the tunnel IP and then check that this matches
* the configured tunnel.
*/
const ipsec_tun_protect_t *itp;
itp = ipsec_tun_protect_get
(vnet_buffer (b[0])->ipsec.protect_index);
if (PREDICT_TRUE (next_header == IP_PROTOCOL_IP_IN_IP))
{
const ip4_header_t *ip4;
ip4 = vlib_buffer_get_current (b[0]);
if (!ip46_address_is_equal_v4 (&itp->itp_tun.src,
&ip4->dst_address) ||
!ip46_address_is_equal_v4 (&itp->itp_tun.dst,
&ip4->src_address))
{
next[0] = ESP_DECRYPT_NEXT_DROP;
b[0]->error =
node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
}
}
else if (next_header == IP_PROTOCOL_IPV6)
{
const ip6_header_t *ip6;
ip6 = vlib_buffer_get_current (b[0]);
if (!ip46_address_is_equal_v6 (&itp->itp_tun.src,
&ip6->dst_address) ||
!ip46_address_is_equal_v6 (&itp->itp_tun.dst,
&ip6->src_address))
{
next[0] = ESP_DECRYPT_NEXT_DROP;
b[0]->error =
node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
}
}
}
}
}
trace:
if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
{
esp_decrypt_trace_t *tr;
tr = vlib_add_trace (vm, node, b[0], sizeof (*tr));
sa0 = pool_elt_at_index (im->sad,
vnet_buffer (b[0])->ipsec.sad_index);
tr->crypto_alg = sa0->crypto_alg;
tr->integ_alg = sa0->integ_alg;
tr->seq = pd->seq;
tr->sa_seq = sa0->last_seq;
tr->sa_seq_hi = sa0->seq_hi;
}
/* next */
n_left -= 1;
next += 1;
pd += 1;
b += 1;
}
n_left = from_frame->n_vectors;
vlib_node_increment_counter (vm, node->node_index,
ESP_DECRYPT_ERROR_RX_PKTS, n_left);
vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);
return n_left;
}
VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 0, 0);
}
VLIB_NODE_FN (esp4_decrypt_tun_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 0, 1);
}
VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 1, 0);
}
VLIB_NODE_FN (esp6_decrypt_tun_node) (vlib_main_t * vm,
vlib_node_runtime_t * node,
vlib_frame_t * from_frame)
{
return esp_decrypt_inline (vm, node, from_frame, 1, 1);
}
/* *INDENT-OFF* */
VLIB_REGISTER_NODE (esp4_decrypt_node) = {
.name = "esp4-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 = {
[ESP_DECRYPT_NEXT_DROP] = "ip4-drop",
[ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[ESP_DECRYPT_NEXT_L2_INPUT] = "l2-input",
[ESP_DECRYPT_NEXT_HANDOFF] = "esp4-decrypt-handoff",
},
};
VLIB_REGISTER_NODE (esp6_decrypt_node) = {
.name = "esp6-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 = {
[ESP_DECRYPT_NEXT_DROP] = "ip6-drop",
[ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[ESP_DECRYPT_NEXT_L2_INPUT] = "l2-input",
[ESP_DECRYPT_NEXT_HANDOFF]= "esp6-decrypt-handoff",
},
};
VLIB_REGISTER_NODE (esp4_decrypt_tun_node) = {
.name = "esp4-decrypt-tun",
.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 = {
[ESP_DECRYPT_NEXT_DROP] = "ip4-drop",
[ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[ESP_DECRYPT_NEXT_L2_INPUT] = "l2-input",
[ESP_DECRYPT_NEXT_HANDOFF] = "esp4-decrypt-tun-handoff",
},
};
VLIB_REGISTER_NODE (esp6_decrypt_tun_node) = {
.name = "esp6-decrypt-tun",
.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 = {
[ESP_DECRYPT_NEXT_DROP] = "ip6-drop",
[ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
[ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
[ESP_DECRYPT_NEXT_L2_INPUT] = "l2-input",
[ESP_DECRYPT_NEXT_HANDOFF]= "esp6-decrypt-tun-handoff",
},
};
/* *INDENT-ON* */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/