1 /* $OpenBSD: sshbuf-misc.c,v 1.16 2020/06/22 05:54:10 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
sshbuf_dump_data(const void * s,size_t len,FILE * f)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
sshbuf_dump(const struct sshbuf * buf,FILE * f)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 *
sshbuf_dtob16(struct sshbuf * buf)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
sshbuf_dtob64(const struct sshbuf * d,struct sshbuf * b64,int wrap)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 *
sshbuf_dtob64_string(const struct sshbuf * buf,int wrap)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
sshbuf_b64tod(struct sshbuf * buf,const char * b64)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 int
sshbuf_dtourlb64(const struct sshbuf * d,struct sshbuf * b64,int wrap)171 sshbuf_dtourlb64(const struct sshbuf *d, struct sshbuf *b64, int wrap)
172 {
173 int r = SSH_ERR_INTERNAL_ERROR;
174 u_char *p;
175 struct sshbuf *b = NULL;
176 size_t i, l;
177
178 if ((b = sshbuf_new()) == NULL)
179 return SSH_ERR_ALLOC_FAIL;
180 /* Encode using regular base64; we'll transform it once done */
181 if ((r = sshbuf_dtob64(d, b, wrap)) != 0)
182 goto out;
183 /* remove padding from end of encoded string*/
184 for (;;) {
185 l = sshbuf_len(b);
186 if (l <= 1 || sshbuf_ptr(b) == NULL) {
187 r = SSH_ERR_INTERNAL_ERROR;
188 goto out;
189 }
190 if (sshbuf_ptr(b)[l - 1] != '=')
191 break;
192 if ((r = sshbuf_consume_end(b, 1)) != 0)
193 goto out;
194 }
195 /* Replace characters with rfc4648 equivalents */
196 l = sshbuf_len(b);
197 if ((p = sshbuf_mutable_ptr(b)) == NULL) {
198 r = SSH_ERR_INTERNAL_ERROR;
199 goto out;
200 }
201 for (i = 0; i < l; i++) {
202 if (p[i] == '+')
203 p[i] = '-';
204 else if (p[i] == '/')
205 p[i] = '_';
206 }
207 r = sshbuf_putb(b64, b);
208 out:
209 sshbuf_free(b);
210 return r;
211 }
212
213 char *
sshbuf_dup_string(struct sshbuf * buf)214 sshbuf_dup_string(struct sshbuf *buf)
215 {
216 const u_char *p = NULL, *s = sshbuf_ptr(buf);
217 size_t l = sshbuf_len(buf);
218 char *r;
219
220 if (s == NULL || l > SIZE_MAX)
221 return NULL;
222 /* accept a nul only as the last character in the buffer */
223 if (l > 0 && (p = memchr(s, '\0', l)) != NULL) {
224 if (p != s + l - 1)
225 return NULL;
226 l--; /* the nul is put back below */
227 }
228 if ((r = malloc(l + 1)) == NULL)
229 return NULL;
230 if (l > 0)
231 memcpy(r, s, l);
232 r[l] = '\0';
233 return r;
234 }
235
236 int
sshbuf_cmp(const struct sshbuf * b,size_t offset,const void * s,size_t len)237 sshbuf_cmp(const struct sshbuf *b, size_t offset,
238 const void *s, size_t len)
239 {
240 if (sshbuf_ptr(b) == NULL)
241 return SSH_ERR_INTERNAL_ERROR;
242 if (offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
243 return SSH_ERR_INVALID_ARGUMENT;
244 if (offset + len > sshbuf_len(b))
245 return SSH_ERR_MESSAGE_INCOMPLETE;
246 if (timingsafe_bcmp(sshbuf_ptr(b) + offset, s, len) != 0)
247 return SSH_ERR_INVALID_FORMAT;
248 return 0;
249 }
250
251 int
sshbuf_find(const struct sshbuf * b,size_t start_offset,const void * s,size_t len,size_t * offsetp)252 sshbuf_find(const struct sshbuf *b, size_t start_offset,
253 const void *s, size_t len, size_t *offsetp)
254 {
255 void *p;
256
257 if (offsetp != NULL)
258 *offsetp = 0;
259 if (sshbuf_ptr(b) == NULL)
260 return SSH_ERR_INTERNAL_ERROR;
261 if (start_offset > SSHBUF_SIZE_MAX || len > SSHBUF_SIZE_MAX || len == 0)
262 return SSH_ERR_INVALID_ARGUMENT;
263 if (start_offset > sshbuf_len(b) || start_offset + len > sshbuf_len(b))
264 return SSH_ERR_MESSAGE_INCOMPLETE;
265 if ((p = memmem(sshbuf_ptr(b) + start_offset,
266 sshbuf_len(b) - start_offset, s, len)) == NULL)
267 return SSH_ERR_INVALID_FORMAT;
268 if (offsetp != NULL)
269 *offsetp = (const u_char *)p - sshbuf_ptr(b);
270 return 0;
271 }
272