1 /*
2 * ngtcp2
3 *
4 * Copyright (c) 2017 ngtcp2 contributors
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining
7 * a copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sublicense, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be
15 * included in all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
21 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
22 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
23 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 */
25 #include "ngtcp2_ppe.h"
26
27 #include <string.h>
28 #include <assert.h>
29
30 #include "ngtcp2_str.h"
31 #include "ngtcp2_conv.h"
32
ngtcp2_ppe_init(ngtcp2_ppe * ppe,uint8_t * out,size_t outlen,ngtcp2_crypto_cc * cc)33 void ngtcp2_ppe_init(ngtcp2_ppe *ppe, uint8_t *out, size_t outlen,
34 ngtcp2_crypto_cc *cc) {
35 ngtcp2_buf_init(&ppe->buf, out, outlen);
36
37 ppe->hdlen = 0;
38 ppe->len_offset = 0;
39 ppe->pkt_num_offset = 0;
40 ppe->pkt_numlen = 0;
41 ppe->pkt_num = 0;
42 ppe->sample_offset = 0;
43 ppe->cc = cc;
44 }
45
ngtcp2_ppe_encode_hd(ngtcp2_ppe * ppe,const ngtcp2_pkt_hd * hd)46 int ngtcp2_ppe_encode_hd(ngtcp2_ppe *ppe, const ngtcp2_pkt_hd *hd) {
47 ngtcp2_ssize rv;
48 ngtcp2_buf *buf = &ppe->buf;
49 ngtcp2_crypto_cc *cc = ppe->cc;
50
51 if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
52 return NGTCP2_ERR_NOBUF;
53 }
54
55 if (hd->flags & NGTCP2_PKT_FLAG_LONG_FORM) {
56 ppe->len_offset = 1 + 4 + 1 + hd->dcid.datalen + 1 + hd->scid.datalen;
57 if (hd->type == NGTCP2_PKT_INITIAL) {
58 ppe->len_offset += ngtcp2_put_varint_len(hd->token.len) + hd->token.len;
59 }
60 ppe->pkt_num_offset = ppe->len_offset + 2;
61 rv = ngtcp2_pkt_encode_hd_long(
62 buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
63 } else {
64 ppe->pkt_num_offset = 1 + hd->dcid.datalen;
65 rv = ngtcp2_pkt_encode_hd_short(
66 buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, hd);
67 }
68 if (rv < 0) {
69 return (int)rv;
70 }
71
72 ppe->sample_offset = ppe->pkt_num_offset + 4;
73
74 buf->last += rv;
75
76 ppe->pkt_numlen = hd->pkt_numlen;
77 ppe->hdlen = (size_t)rv;
78
79 ppe->pkt_num = hd->pkt_num;
80
81 return 0;
82 }
83
ngtcp2_ppe_encode_frame(ngtcp2_ppe * ppe,ngtcp2_frame * fr)84 int ngtcp2_ppe_encode_frame(ngtcp2_ppe *ppe, ngtcp2_frame *fr) {
85 ngtcp2_ssize rv;
86 ngtcp2_buf *buf = &ppe->buf;
87 ngtcp2_crypto_cc *cc = ppe->cc;
88
89 if (ngtcp2_buf_left(buf) < cc->aead.max_overhead) {
90 return NGTCP2_ERR_NOBUF;
91 }
92
93 rv = ngtcp2_pkt_encode_frame(
94 buf->last, ngtcp2_buf_left(buf) - cc->aead.max_overhead, fr);
95 if (rv < 0) {
96 return (int)rv;
97 }
98
99 buf->last += rv;
100
101 return 0;
102 }
103
ngtcp2_ppe_final(ngtcp2_ppe * ppe,const uint8_t ** ppkt)104 ngtcp2_ssize ngtcp2_ppe_final(ngtcp2_ppe *ppe, const uint8_t **ppkt) {
105 ngtcp2_buf *buf = &ppe->buf;
106 ngtcp2_crypto_cc *cc = ppe->cc;
107 uint8_t *payload = buf->begin + ppe->hdlen;
108 size_t payloadlen = ngtcp2_buf_len(buf) - ppe->hdlen;
109 uint8_t mask[NGTCP2_HP_SAMPLELEN];
110 uint8_t *p;
111 size_t i;
112 int rv;
113
114 assert(cc->encrypt);
115 assert(cc->hp_mask);
116
117 if (ppe->len_offset) {
118 ngtcp2_put_varint14(
119 buf->begin + ppe->len_offset,
120 (uint16_t)(payloadlen + ppe->pkt_numlen + cc->aead.max_overhead));
121 }
122
123 ngtcp2_crypto_create_nonce(ppe->nonce, cc->ckm->iv.base, cc->ckm->iv.len,
124 ppe->pkt_num);
125
126 rv = cc->encrypt(payload, &cc->aead, &cc->ckm->aead_ctx, payload, payloadlen,
127 ppe->nonce, cc->ckm->iv.len, buf->begin, ppe->hdlen);
128 if (rv != 0) {
129 return NGTCP2_ERR_CALLBACK_FAILURE;
130 }
131
132 buf->last = payload + payloadlen + cc->aead.max_overhead;
133
134 /* TODO Check that we have enough space to get sample */
135 assert(ppe->sample_offset + NGTCP2_HP_SAMPLELEN <= ngtcp2_buf_len(buf));
136
137 rv = cc->hp_mask(mask, &cc->hp, &cc->hp_ctx, buf->begin + ppe->sample_offset);
138 if (rv != 0) {
139 return NGTCP2_ERR_CALLBACK_FAILURE;
140 }
141
142 p = buf->begin;
143 if (*p & NGTCP2_HEADER_FORM_BIT) {
144 *p = (uint8_t)(*p ^ (mask[0] & 0x0f));
145 } else {
146 *p = (uint8_t)(*p ^ (mask[0] & 0x1f));
147 }
148
149 p = buf->begin + ppe->pkt_num_offset;
150 for (i = 0; i < ppe->pkt_numlen; ++i) {
151 *(p + i) ^= mask[i + 1];
152 }
153
154 if (ppkt != NULL) {
155 *ppkt = buf->begin;
156 }
157
158 return (ngtcp2_ssize)ngtcp2_buf_len(buf);
159 }
160
ngtcp2_ppe_left(ngtcp2_ppe * ppe)161 size_t ngtcp2_ppe_left(ngtcp2_ppe *ppe) {
162 ngtcp2_crypto_cc *cc = ppe->cc;
163
164 if (ngtcp2_buf_left(&ppe->buf) < cc->aead.max_overhead) {
165 return 0;
166 }
167
168 return ngtcp2_buf_left(&ppe->buf) - cc->aead.max_overhead;
169 }
170
ngtcp2_ppe_pktlen(ngtcp2_ppe * ppe)171 size_t ngtcp2_ppe_pktlen(ngtcp2_ppe *ppe) {
172 ngtcp2_crypto_cc *cc = ppe->cc;
173
174 return ngtcp2_buf_len(&ppe->buf) + cc->aead.max_overhead;
175 }
176
ngtcp2_ppe_padding(ngtcp2_ppe * ppe)177 size_t ngtcp2_ppe_padding(ngtcp2_ppe *ppe) {
178 ngtcp2_crypto_cc *cc = ppe->cc;
179 ngtcp2_buf *buf = &ppe->buf;
180 size_t len;
181
182 assert(ngtcp2_buf_left(buf) >= cc->aead.max_overhead);
183
184 len = ngtcp2_buf_left(buf) - cc->aead.max_overhead;
185 memset(buf->last, 0, len);
186 buf->last += len;
187
188 return len;
189 }
190
ngtcp2_ppe_padding_hp_sample(ngtcp2_ppe * ppe)191 size_t ngtcp2_ppe_padding_hp_sample(ngtcp2_ppe *ppe) {
192 ngtcp2_crypto_cc *cc = ppe->cc;
193 ngtcp2_buf *buf = &ppe->buf;
194 size_t max_samplelen;
195 size_t len = 0;
196
197 assert(cc->aead.max_overhead);
198
199 max_samplelen =
200 ngtcp2_buf_len(buf) + cc->aead.max_overhead - ppe->sample_offset;
201 if (max_samplelen < NGTCP2_HP_SAMPLELEN) {
202 len = NGTCP2_HP_SAMPLELEN - max_samplelen;
203 assert(ngtcp2_ppe_left(ppe) >= len);
204 memset(buf->last, 0, len);
205 buf->last += len;
206 }
207
208 return len;
209 }
210
ngtcp2_ppe_padding_size(ngtcp2_ppe * ppe,size_t n)211 size_t ngtcp2_ppe_padding_size(ngtcp2_ppe *ppe, size_t n) {
212 ngtcp2_crypto_cc *cc = ppe->cc;
213 ngtcp2_buf *buf = &ppe->buf;
214 size_t pktlen = ngtcp2_buf_len(buf) + cc->aead.max_overhead;
215 size_t len;
216
217 if (pktlen >= n) {
218 return 0;
219 }
220
221 len = n - pktlen;
222 buf->last = ngtcp2_setmem(buf->last, 0, len);
223
224 return len;
225 }
226
ngtcp2_ppe_ensure_hp_sample(ngtcp2_ppe * ppe)227 int ngtcp2_ppe_ensure_hp_sample(ngtcp2_ppe *ppe) {
228 ngtcp2_buf *buf = &ppe->buf;
229 return ngtcp2_buf_left(buf) >= (4 - ppe->pkt_numlen) + NGTCP2_HP_SAMPLELEN;
230 }
231