1/*	$OpenBSD: sshbuf-getput-basic.c,v 1.7 2017/06/01 04:51:58 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#define SSHBUF_INTERNAL
19#include "includes.h"
20
21#include <sys/types.h>
22
23#include <stdarg.h>
24#include <stdlib.h>
25#include <stdio.h>
26#include <string.h>
27
28#include "xmalloc.h"
29#include "ssherr.h"
30#include "sshbuf.h"
31
32int
33sshbuf_get(struct sshbuf *buf, void *v, size_t len)
34{
35	const u_char *p = sshbuf_ptr(buf);
36	int r;
37
38	if ((r = sshbuf_consume(buf, len)) < 0)
39		return r;
40	if (v != NULL && len != 0)
41		memcpy(v, p, len);
42	return 0;
43}
44
45int
46sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp)
47{
48	const u_char *p = sshbuf_ptr(buf);
49	int r;
50
51	if ((r = sshbuf_consume(buf, 8)) < 0)
52		return r;
53	if (valp != NULL)
54		*valp = PEEK_U64(p);
55	return 0;
56}
57
58int
59sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp)
60{
61	const u_char *p = sshbuf_ptr(buf);
62	int r;
63
64	if ((r = sshbuf_consume(buf, 4)) < 0)
65		return r;
66	if (valp != NULL)
67		*valp = PEEK_U32(p);
68	return 0;
69}
70
71int
72sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp)
73{
74	const u_char *p = sshbuf_ptr(buf);
75	int r;
76
77	if ((r = sshbuf_consume(buf, 2)) < 0)
78		return r;
79	if (valp != NULL)
80		*valp = PEEK_U16(p);
81	return 0;
82}
83
84int
85sshbuf_get_u8(struct sshbuf *buf, u_char *valp)
86{
87	const u_char *p = sshbuf_ptr(buf);
88	int r;
89
90	if ((r = sshbuf_consume(buf, 1)) < 0)
91		return r;
92	if (valp != NULL)
93		*valp = (u_int8_t)*p;
94	return 0;
95}
96
97int
98sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp)
99{
100	const u_char *val;
101	size_t len;
102	int r;
103
104	if (valp != NULL)
105		*valp = NULL;
106	if (lenp != NULL)
107		*lenp = 0;
108	if ((r = sshbuf_get_string_direct(buf, &val, &len)) < 0)
109		return r;
110	if (valp != NULL) {
111		if ((*valp = malloc(len + 1)) == NULL) {
112			SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
113			return SSH_ERR_ALLOC_FAIL;
114		}
115		if (len != 0)
116			memcpy(*valp, val, len);
117		(*valp)[len] = '\0';
118	}
119	if (lenp != NULL)
120		*lenp = len;
121	return 0;
122}
123
124int
125sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp, size_t *lenp)
126{
127	size_t len;
128	const u_char *p;
129	int r;
130
131	if (valp != NULL)
132		*valp = NULL;
133	if (lenp != NULL)
134		*lenp = 0;
135	if ((r = sshbuf_peek_string_direct(buf, &p, &len)) < 0)
136		return r;
137	if (valp != NULL)
138		*valp = p;
139	if (lenp != NULL)
140		*lenp = len;
141	if (sshbuf_consume(buf, len + 4) != 0) {
142		/* Shouldn't happen */
143		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
144		SSHBUF_ABORT();
145		return SSH_ERR_INTERNAL_ERROR;
146	}
147	return 0;
148}
149
150int
151sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
152    size_t *lenp)
153{
154	u_int32_t len;
155	const u_char *p = sshbuf_ptr(buf);
156
157	if (valp != NULL)
158		*valp = NULL;
159	if (lenp != NULL)
160		*lenp = 0;
161	if (sshbuf_len(buf) < 4) {
162		SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
163		return SSH_ERR_MESSAGE_INCOMPLETE;
164	}
165	len = PEEK_U32(p);
166	if (len > SSHBUF_SIZE_MAX - 4) {
167		SSHBUF_DBG(("SSH_ERR_STRING_TOO_LARGE"));
168		return SSH_ERR_STRING_TOO_LARGE;
169	}
170	if (sshbuf_len(buf) - 4 < len) {
171		SSHBUF_DBG(("SSH_ERR_MESSAGE_INCOMPLETE"));
172		return SSH_ERR_MESSAGE_INCOMPLETE;
173	}
174	if (valp != NULL)
175		*valp = p + 4;
176	if (lenp != NULL)
177		*lenp = len;
178	return 0;
179}
180
181int
182sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp)
183{
184	size_t len;
185	const u_char *p, *z;
186	int r;
187
188	if (valp != NULL)
189		*valp = NULL;
190	if (lenp != NULL)
191		*lenp = 0;
192	if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
193		return r;
194	/* Allow a \0 only at the end of the string */
195	if (len > 0 &&
196	    (z = memchr(p , '\0', len)) != NULL && z < p + len - 1) {
197		SSHBUF_DBG(("SSH_ERR_INVALID_FORMAT"));
198		return SSH_ERR_INVALID_FORMAT;
199	}
200	if ((r = sshbuf_skip_string(buf)) != 0)
201		return -1;
202	if (valp != NULL) {
203		if ((*valp = malloc(len + 1)) == NULL) {
204			SSHBUF_DBG(("SSH_ERR_ALLOC_FAIL"));
205			return SSH_ERR_ALLOC_FAIL;
206		}
207		if (len != 0)
208			memcpy(*valp, p, len);
209		(*valp)[len] = '\0';
210	}
211	if (lenp != NULL)
212		*lenp = (size_t)len;
213	return 0;
214}
215
216int
217sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v)
218{
219	u_int32_t len;
220	u_char *p;
221	int r;
222
223	/*
224	 * Use sshbuf_peek_string_direct() to figure out if there is
225	 * a complete string in 'buf' and copy the string directly
226	 * into 'v'.
227	 */
228	if ((r = sshbuf_peek_string_direct(buf, NULL, NULL)) != 0 ||
229	    (r = sshbuf_get_u32(buf, &len)) != 0 ||
230	    (r = sshbuf_reserve(v, len, &p)) != 0 ||
231	    (r = sshbuf_get(buf, p, len)) != 0)
232		return r;
233	return 0;
234}
235
236int
237sshbuf_put(struct sshbuf *buf, const void *v, size_t len)
238{
239	u_char *p;
240	int r;
241
242	if ((r = sshbuf_reserve(buf, len, &p)) < 0)
243		return r;
244	if (len != 0)
245		memcpy(p, v, len);
246	return 0;
247}
248
249int
250sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v)
251{
252	return sshbuf_put(buf, sshbuf_ptr(v), sshbuf_len(v));
253}
254
255int
256sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
257{
258	va_list ap;
259	int r;
260
261	va_start(ap, fmt);
262	r = sshbuf_putfv(buf, fmt, ap);
263	va_end(ap);
264	return r;
265}
266
267int
268sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
269{
270	va_list ap2;
271	int r, len;
272	u_char *p;
273
274	VA_COPY(ap2, ap);
275	if ((len = vsnprintf(NULL, 0, fmt, ap2)) < 0) {
276		r = SSH_ERR_INVALID_ARGUMENT;
277		goto out;
278	}
279	if (len == 0) {
280		r = 0;
281		goto out; /* Nothing to do */
282	}
283	va_end(ap2);
284	VA_COPY(ap2, ap);
285	if ((r = sshbuf_reserve(buf, (size_t)len + 1, &p)) < 0)
286		goto out;
287	if ((r = vsnprintf((char *)p, len + 1, fmt, ap2)) != len) {
288		r = SSH_ERR_INTERNAL_ERROR;
289		goto out; /* Shouldn't happen */
290	}
291	/* Consume terminating \0 */
292	if ((r = sshbuf_consume_end(buf, 1)) != 0)
293		goto out;
294	r = 0;
295 out:
296	va_end(ap2);
297	return r;
298}
299
300int
301sshbuf_put_u64(struct sshbuf *buf, u_int64_t val)
302{
303	u_char *p;
304	int r;
305
306	if ((r = sshbuf_reserve(buf, 8, &p)) < 0)
307		return r;
308	POKE_U64(p, val);
309	return 0;
310}
311
312int
313sshbuf_put_u32(struct sshbuf *buf, u_int32_t val)
314{
315	u_char *p;
316	int r;
317
318	if ((r = sshbuf_reserve(buf, 4, &p)) < 0)
319		return r;
320	POKE_U32(p, val);
321	return 0;
322}
323
324int
325sshbuf_put_u16(struct sshbuf *buf, u_int16_t val)
326{
327	u_char *p;
328	int r;
329
330	if ((r = sshbuf_reserve(buf, 2, &p)) < 0)
331		return r;
332	POKE_U16(p, val);
333	return 0;
334}
335
336int
337sshbuf_put_u8(struct sshbuf *buf, u_char val)
338{
339	u_char *p;
340	int r;
341
342	if ((r = sshbuf_reserve(buf, 1, &p)) < 0)
343		return r;
344	p[0] = val;
345	return 0;
346}
347
348int
349sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len)
350{
351	u_char *d;
352	int r;
353
354	if (len > SSHBUF_SIZE_MAX - 4) {
355		SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
356		return SSH_ERR_NO_BUFFER_SPACE;
357	}
358	if ((r = sshbuf_reserve(buf, len + 4, &d)) < 0)
359		return r;
360	POKE_U32(d, len);
361	if (len != 0)
362		memcpy(d + 4, v, len);
363	return 0;
364}
365
366int
367sshbuf_put_cstring(struct sshbuf *buf, const char *v)
368{
369	return sshbuf_put_string(buf, v, v == NULL ? 0 : strlen(v));
370}
371
372int
373sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v)
374{
375	return sshbuf_put_string(buf, sshbuf_ptr(v), sshbuf_len(v));
376}
377
378int
379sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp)
380{
381	const u_char *p;
382	size_t len;
383	struct sshbuf *ret;
384	int r;
385
386	if (buf == NULL || bufp == NULL)
387		return SSH_ERR_INVALID_ARGUMENT;
388	*bufp = NULL;
389	if ((r = sshbuf_peek_string_direct(buf, &p, &len)) != 0)
390		return r;
391	if ((ret = sshbuf_from(p, len)) == NULL)
392		return SSH_ERR_ALLOC_FAIL;
393	if ((r = sshbuf_consume(buf, len + 4)) != 0 ||  /* Shouldn't happen */
394	    (r = sshbuf_set_parent(ret, buf)) != 0) {
395		sshbuf_free(ret);
396		return r;
397	}
398	*bufp = ret;
399	return 0;
400}
401
402int
403sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len)
404{
405	u_char *d;
406	const u_char *s = (const u_char *)v;
407	int r, prepend;
408
409	if (len > SSHBUF_SIZE_MAX - 5) {
410		SSHBUF_DBG(("SSH_ERR_NO_BUFFER_SPACE"));
411		return SSH_ERR_NO_BUFFER_SPACE;
412	}
413	/* Skip leading zero bytes */
414	for (; len > 0 && *s == 0; len--, s++)
415		;
416	/*
417	 * If most significant bit is set then prepend a zero byte to
418	 * avoid interpretation as a negative number.
419	 */
420	prepend = len > 0 && (s[0] & 0x80) != 0;
421	if ((r = sshbuf_reserve(buf, len + 4 + prepend, &d)) < 0)
422		return r;
423	POKE_U32(d, len + prepend);
424	if (prepend)
425		d[4] = 0;
426	if (len != 0)
427		memcpy(d + 4 + prepend, s, len);
428	return 0;
429}
430
431int
432sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
433    const u_char **valp, size_t *lenp)
434{
435	const u_char *d;
436	size_t len, olen;
437	int r;
438
439	if ((r = sshbuf_peek_string_direct(buf, &d, &olen)) < 0)
440		return r;
441	len = olen;
442	/* Refuse negative (MSB set) bignums */
443	if ((len != 0 && (*d & 0x80) != 0))
444		return SSH_ERR_BIGNUM_IS_NEGATIVE;
445	/* Refuse overlong bignums, allow prepended \0 to avoid MSB set */
446	if (len > SSHBUF_MAX_BIGNUM + 1 ||
447	    (len == SSHBUF_MAX_BIGNUM + 1 && *d != 0))
448		return SSH_ERR_BIGNUM_TOO_LARGE;
449	/* Trim leading zeros */
450	while (len > 0 && *d == 0x00) {
451		d++;
452		len--;
453	}
454	if (valp != NULL)
455		*valp = d;
456	if (lenp != NULL)
457		*lenp = len;
458	if (sshbuf_consume(buf, olen + 4) != 0) {
459		/* Shouldn't happen */
460		SSHBUF_DBG(("SSH_ERR_INTERNAL_ERROR"));
461		SSHBUF_ABORT();
462		return SSH_ERR_INTERNAL_ERROR;
463	}
464	return 0;
465}
466
467/*
468 * store struct pwd
469 */
470int
471sshbuf_put_passwd(struct sshbuf *buf, const struct passwd *pwent)
472{
473	int r;
474
475	/*
476	 * We never send pointer values of struct passwd.
477	 * It is safe from wild pointer even if a new pointer member is added.
478	 */
479
480	if ((r = sshbuf_put_u64(buf, sizeof(*pwent)) != 0) ||
481	    (r = sshbuf_put_cstring(buf, pwent->pw_name)) != 0 ||
482	    (r = sshbuf_put_cstring(buf, "*")) != 0 ||
483	    (r = sshbuf_put_u32(buf, pwent->pw_uid)) != 0 ||
484	    (r = sshbuf_put_u32(buf, pwent->pw_gid)) != 0 ||
485#ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
486	    (r = sshbuf_put_time(buf, pwent->pw_change)) != 0 ||
487#endif
488#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
489	    (r = sshbuf_put_cstring(buf, pwent->pw_gecos)) != 0 ||
490#endif
491#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
492	    (r = sshbuf_put_cstring(buf, pwent->pw_class)) != 0 ||
493#endif
494	    (r = sshbuf_put_cstring(buf, pwent->pw_dir)) != 0 ||
495	    (r = sshbuf_put_cstring(buf, pwent->pw_shell)) != 0 ||
496#ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
497	    (r = sshbuf_put_time(buf, pwent->pw_expire)) != 0 ||
498#endif
499	    (r = sshbuf_put_u32(buf, pwent->pw_fields)) != 0) {
500		return r;
501	}
502	return 0;
503}
504
505/*
506 * extract struct pwd
507 */
508struct passwd *
509sshbuf_get_passwd(struct sshbuf *buf)
510{
511	struct passwd *pw;
512	u_int64_t len;
513	int r;
514
515	/* check if size of struct passwd is as same as sender's size */
516	r = sshbuf_get_u64(buf, &len);
517	if (r != 0 || len != sizeof(*pw))
518		return NULL;
519
520	pw = xcalloc(1, sizeof(*pw));
521	if (sshbuf_get_cstring(buf, &pw->pw_name, NULL) != 0 ||
522	    sshbuf_get_cstring(buf, &pw->pw_passwd, NULL) != 0 ||
523	    sshbuf_get_u32(buf, &pw->pw_uid) != 0 ||
524	    sshbuf_get_u32(buf, &pw->pw_gid) != 0 ||
525#ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
526	    sshbuf_get_time(buf, &pw->pw_change) != 0 ||
527#endif
528#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
529	    sshbuf_get_cstring(buf, &pw->pw_gecos, NULL) != 0 ||
530#endif
531#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
532	    sshbuf_get_cstring(buf, &pw->pw_class, NULL) != 0 ||
533#endif
534	    sshbuf_get_cstring(buf, &pw->pw_dir, NULL) != 0 ||
535	    sshbuf_get_cstring(buf, &pw->pw_shell, NULL) != 0 ||
536#ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
537	    sshbuf_get_time(buf, &pw->pw_expire) != 0 ||
538#endif
539	    sshbuf_get_u32(buf, &pw->pw_fields) != 0) {
540		sshbuf_free_passwd(pw);
541		return NULL;
542	}
543	return pw;
544}
545
546/*
547 * free struct passwd obtained from sshbuf_get_passwd.
548 */
549void
550sshbuf_free_passwd(struct passwd *pwent)
551{
552	if (pwent == NULL)
553		return;
554	free(pwent->pw_shell);
555	free(pwent->pw_dir);
556#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
557	free(pwent->pw_class);
558#endif
559#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
560	free(pwent->pw_gecos);
561#endif
562	free(pwent->pw_passwd);
563	free(pwent->pw_name);
564	free(pwent);
565}
566