xref: /openssh-portable/sshbuf-misc.c (revision 69796297)
1 /*	$OpenBSD: sshbuf-misc.c,v 1.15 2020/06/05 03:24:36 djm Exp $	*/
2 /*
3  * Copyright (c) 2011 Damien Miller
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 "includes.h"
19 
20 #include <sys/types.h>
21 #include <sys/socket.h>
22 #include <netinet/in.h>
23 #include <errno.h>
24 #include <stdlib.h>
25 #ifdef HAVE_STDINT_H
26 # include <stdint.h>
27 #endif
28 #include <stdio.h>
29 #include <limits.h>
30 #include <string.h>
31 #include <resolv.h>
32 #include <ctype.h>
33 
34 #include "ssherr.h"
35 #define SSHBUF_INTERNAL
36 #include "sshbuf.h"
37 
38 void
39 sshbuf_dump_data(const void *s, size_t len, FILE *f)
40 {
41 	size_t i, j;
42 	const u_char *p = (const u_char *)s;
43 
44 	for (i = 0; i < len; i += 16) {
45 		fprintf(f, "%.4zu: ", i);
46 		for (j = i; j < i + 16; j++) {
47 			if (j < len)
48 				fprintf(f, "%02x ", p[j]);
49 			else
50 				fprintf(f, "   ");
51 		}
52 		fprintf(f, " ");
53 		for (j = i; j < i + 16; j++) {
54 			if (j < len) {
55 				if  (isascii(p[j]) && isprint(p[j]))
56 					fprintf(f, "%c", p[j]);
57 				else
58 					fprintf(f, ".");
59 			}
60 		}
61 		fprintf(f, "\n");
62 	}
63 }
64 
65 void
66 sshbuf_dump(const struct sshbuf *buf, FILE *f)
67 {
68 	fprintf(f, "buffer %p len = %zu\n", buf, sshbuf_len(buf));
69 	sshbuf_dump_data(sshbuf_ptr(buf), sshbuf_len(buf), f);
70 }
71 
72 char *
73 sshbuf_dtob16(struct sshbuf *buf)
74 {
75 	size_t i, j, len = sshbuf_len(buf);
76 	const u_char *p = sshbuf_ptr(buf);
77 	char *ret;
78 	const char hex[] = "0123456789abcdef";
79 
80 	if (len == 0)
81 		return strdup("");
82 	if (SIZE_MAX / 2 <= len || (ret = malloc(len * 2 + 1)) == NULL)
83 		return NULL;
84 	for (i = j = 0; i < len; i++) {
85 		ret[j++] = hex[(p[i] >> 4) & 0xf];
86 		ret[j++] = hex[p[i] & 0xf];
87 	}
88 	ret[j] = '\0';
89 	return ret;
90 }
91 
92 int
93 sshbuf_dtob64(const struct sshbuf *d, struct sshbuf *b64, int wrap)
94 {
95 	size_t i, slen = 0;
96 	char *s = NULL;
97 	int r;
98 
99 	if (d == NULL || b64 == NULL || sshbuf_len(d) >= SIZE_MAX / 2)
100 		return SSH_ERR_INVALID_ARGUMENT;
101 	if (sshbuf_len(d) == 0)
102 		return 0;
103 	slen = ((sshbuf_len(d) + 2) / 3) * 4 + 1;
104 	if ((s = malloc(slen)) == NULL)
105 		return SSH_ERR_ALLOC_FAIL;
106 	if (b64_ntop(sshbuf_ptr(d), sshbuf_len(d), s, slen) == -1) {
107 		r = SSH_ERR_INTERNAL_ERROR;
108 		goto fail;
109 	}
110 	if (wrap) {
111 		for (i = 0; s[i] != '\0'; i++) {
112 			if ((r = sshbuf_put_u8(b64, s[i])) != 0)
113 				goto fail;
114 			if (i % 70 == 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)
115 				goto fail;
116 		}
117 		if ((i - 1) % 70 != 69 && (r = sshbuf_put_u8(b64, '\n')) != 0)
118 			goto fail;
119 	} else {
120 		if ((r = sshbuf_put(b64, s, strlen(s))) != 0)
121 			goto fail;
122 	}
123 	/* Success */
124 	r = 0;
125  fail:
126 	freezero(s, slen);
127 	return r;
128 }
129 
130 char *
131 sshbuf_dtob64_string(const struct sshbuf *buf, int wrap)
132 {
133 	struct sshbuf *tmp;
134 	char *ret;
135 
136 	if ((tmp = sshbuf_new()) == NULL)
137 		return NULL;
138 	if (sshbuf_dtob64(buf, tmp, wrap) != 0) {
139 		sshbuf_free(tmp);
140 		return NULL;
141 	}
142 	ret = sshbuf_dup_string(tmp);
143 	sshbuf_free(tmp);
144 	return ret;
145 }
146 
147 int
148 sshbuf_b64tod(struct sshbuf *buf, const char *b64)
149 {
150 	size_t plen = strlen(b64);
151 	int nlen, r;
152 	u_char *p;
153 
154 	if (plen == 0)
155 		return 0;
156 	if ((p = malloc(plen)) == NULL)
157 		return SSH_ERR_ALLOC_FAIL;
158 	if ((nlen = b64_pton(b64, p, plen)) < 0) {
159 		freezero(p, plen);
160 		return SSH_ERR_INVALID_FORMAT;
161 	}
162 	if ((r = sshbuf_put(buf, p, nlen)) < 0) {
163 		freezero(p, plen);
164 		return r;
165 	}
166 	freezero(p, plen);
167 	return 0;
168 }
169 
170 char *
171 sshbuf_dup_string(struct sshbuf *buf)
172 {
173 	const u_char *p = NULL, *s = sshbuf_ptr(buf);
174 	size_t l = sshbuf_len(buf);
175 	char *r;
176 
177 	if (s == NULL || l > SIZE_MAX)
178 		return NULL;
179 	/* accept a nul only as the last character in the buffer */
180 	if (l > 0 && (p = memchr(s, '\0', l)) != NULL) {
181 		if (p != s + l - 1)
182 			return NULL;
183 		l--; /* the nul is put back below */
184 	}
185 	if ((r = malloc(l + 1)) == NULL)
186 		return NULL;
187 	if (l > 0)
188 		memcpy(r, s, l);
189 	r[l] = '\0';
190 	return r;
191 }
192 
193 int
194 sshbuf_cmp(const struct sshbuf *b, size_t offset,
195     const void *s, size_t len)
196 {
197 	if (sshbuf_ptr(b) == NULL)
198 		return SSH_ERR_INTERNAL_ERROR;
199 	if (offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
200 		return SSH_ERR_INVALID_ARGUMENT;
201 	if (offset + len > sshbuf_len(b))
202 		return SSH_ERR_MESSAGE_INCOMPLETE;
203 	if (timingsafe_bcmp(sshbuf_ptr(b) + offset, s, len) != 0)
204 		return SSH_ERR_INVALID_FORMAT;
205 	return 0;
206 }
207 
208 int
209 sshbuf_find(const struct sshbuf *b, size_t start_offset,
210     const void *s, size_t len, size_t *offsetp)
211 {
212 	void *p;
213 
214 	if (offsetp != NULL)
215 		*offsetp = 0;
216 	if (sshbuf_ptr(b) == NULL)
217 		return SSH_ERR_INTERNAL_ERROR;
218 	if (start_offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
219 		return SSH_ERR_INVALID_ARGUMENT;
220 	if (start_offset > sshbuf_len(b) || start_offset + len > sshbuf_len(b))
221 		return SSH_ERR_MESSAGE_INCOMPLETE;
222 	if ((p = memmem(sshbuf_ptr(b) + start_offset,
223 	    sshbuf_len(b) - start_offset, s, len)) == NULL)
224 		return SSH_ERR_INVALID_FORMAT;
225 	if (offsetp != NULL)
226 		*offsetp = (const u_char *)p - sshbuf_ptr(b);
227 	return 0;
228 }
229