1/* $OpenBSD: tls_content.c,v 1.2 2022/11/11 17:15:27 jsing Exp $ */
2/*
3 * Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <stdlib.h>
19#include <string.h>
20
21#include "tls_content.h"
22
23/* Content from a TLS record. */
24struct tls_content {
25	uint8_t type;
26	uint16_t epoch;
27
28	const uint8_t *data;
29	size_t data_len;
30	CBS cbs;
31};
32
33struct tls_content *
34tls_content_new(void)
35{
36	return calloc(1, sizeof(struct tls_content));
37}
38
39void
40tls_content_clear(struct tls_content *content)
41{
42	freezero((void *)content->data, content->data_len);
43	memset(content, 0, sizeof(*content));
44}
45
46void
47tls_content_free(struct tls_content *content)
48{
49	if (content == NULL)
50		return;
51
52	tls_content_clear(content);
53
54	freezero(content, sizeof(struct tls_content));
55}
56
57CBS *
58tls_content_cbs(struct tls_content *content)
59{
60	return &content->cbs;
61}
62
63int
64tls_content_equal(struct tls_content *content, const uint8_t *buf, size_t n)
65{
66	return CBS_mem_equal(&content->cbs, buf, n);
67}
68
69size_t
70tls_content_remaining(struct tls_content *content)
71{
72	return CBS_len(&content->cbs);
73}
74
75uint8_t
76tls_content_type(struct tls_content *content)
77{
78	return content->type;
79}
80
81int
82tls_content_dup_data(struct tls_content *content, uint8_t type,
83    const uint8_t *data, size_t data_len)
84{
85	uint8_t *dup;
86
87	if ((dup = calloc(1, data_len)) == NULL)
88		return 0;
89	memcpy(dup, data, data_len);
90
91	tls_content_set_data(content, type, dup, data_len);
92
93	return 1;
94}
95
96uint16_t
97tls_content_epoch(struct tls_content *content)
98{
99	return content->epoch;
100}
101
102void
103tls_content_set_epoch(struct tls_content *content, uint16_t epoch)
104{
105	content->epoch = epoch;
106}
107
108void
109tls_content_set_data(struct tls_content *content, uint8_t type,
110    const uint8_t *data, size_t data_len)
111{
112	tls_content_clear(content);
113
114	content->type = type;
115	content->data = data;
116	content->data_len = data_len;
117
118	CBS_init(&content->cbs, content->data, content->data_len);
119}
120
121int
122tls_content_set_bounds(struct tls_content *content, size_t offset, size_t len)
123{
124	size_t content_len;
125
126	content_len = offset + len;
127	if (content_len < len)
128		return 0;
129	if (content_len > content->data_len)
130		return 0;
131
132	CBS_init(&content->cbs, content->data, content_len);
133	return CBS_skip(&content->cbs, offset);
134}
135
136static ssize_t
137tls_content_read_internal(struct tls_content *content, uint8_t *buf, size_t n,
138    int peek)
139{
140	if (n > CBS_len(&content->cbs))
141		n = CBS_len(&content->cbs);
142
143	/* XXX - CBS_memcpy? CBS_copy_bytes? */
144	memcpy(buf, CBS_data(&content->cbs), n);
145
146	if (!peek) {
147		if (!CBS_skip(&content->cbs, n))
148			return -1;
149	}
150
151	return n;
152}
153
154ssize_t
155tls_content_peek(struct tls_content *content, uint8_t *buf, size_t n)
156{
157	return tls_content_read_internal(content, buf, n, 1);
158}
159
160ssize_t
161tls_content_read(struct tls_content *content, uint8_t *buf, size_t n)
162{
163	return tls_content_read_internal(content, buf, n, 0);
164}
165