1/* $NetBSD: sshbuf.h,v 1.11 2019/04/20 17:16:40 christos Exp $ */
2/* $OpenBSD: sshbuf.h,v 1.13 2019/01/21 09:54:11 djm Exp $ */
3/*
4 * Copyright (c) 2011 Damien Miller
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#ifndef _SSHBUF_H
20#define _SSHBUF_H
21
22#include <sys/types.h>
23#include <stdarg.h>
24#include <stdio.h>
25#include <openssl/bn.h>
26#include <openssl/ec.h>
27
28/* move the following to a more appropriate place and name */
29#define BUFFER_MAX_LEN_HPN 0x4000000 /* 64MB */
30
31#define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */
32#define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */
33#define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */
34#define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */
35
36/*
37 * NB. do not depend on the internals of this. It will be made opaque
38 * one day.
39 */
40struct sshbuf {
41 u_char *d; /* Data */
42 const u_char *cd; /* Const data */
43 size_t off; /* First available byte is buf->d + buf->off */
44 size_t size; /* Last byte is buf->d + buf->size - 1 */
45 size_t max_size; /* Maximum size of buffer */
46 size_t alloc; /* Total bytes allocated to buf->d */
47 int readonly; /* Refers to external, const data */
48 int dont_free; /* Kludge to support sshbuf_init */
49 u_int refcount; /* Tracks self and number of child buffers */
50 struct sshbuf *parent; /* If child, pointer to parent */
51};
52
53/*
54 * Create a new sshbuf buffer.
55 * Returns pointer to buffer on success, or NULL on allocation failure.
56 */
57struct sshbuf *sshbuf_new(void);
58
59/*
60 * Create a new, read-only sshbuf buffer from existing data.
61 * Returns pointer to buffer on success, or NULL on allocation failure.
62 */
63struct sshbuf *sshbuf_from(const void *blob, size_t len);
64
65/*
66 * Create a new, read-only sshbuf buffer from the contents of an existing
67 * buffer. The contents of "buf" must not change in the lifetime of the
68 * resultant buffer.
69 * Returns pointer to buffer on success, or NULL on allocation failure.
70 */
71struct sshbuf *sshbuf_fromb(struct sshbuf *buf);
72
73/*
74 * Create a new, read-only sshbuf buffer from the contents of a string in
75 * an existing buffer (the string is consumed in the process).
76 * The contents of "buf" must not change in the lifetime of the resultant
77 * buffer.
78 * Returns pointer to buffer on success, or NULL on allocation failure.
79 */
80int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp);
81
82/*
83 * Clear and free buf
84 */
85void sshbuf_free(struct sshbuf *buf);
86
87/*
88 * Reset buf, clearing its contents. NB. max_size is preserved.
89 */
90void sshbuf_reset(struct sshbuf *buf);
91
92/*
93 * Return the maximum size of buf
94 */
95size_t sshbuf_max_size(const struct sshbuf *buf);
96
97/*
98 * Set the maximum size of buf
99 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
100 */
101int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size);
102
103/*
104 * Returns the length of data in buf
105 */
106size_t sshbuf_len(const struct sshbuf *buf);
107
108/*
109 * Returns number of bytes left in buffer before hitting max_size.
110 */
111size_t sshbuf_avail(const struct sshbuf *buf);
112
113/*
114 * Returns a read-only pointer to the start of the data in buf
115 */
116const u_char *sshbuf_ptr(const struct sshbuf *buf);
117
118/*
119 * Returns a mutable pointer to the start of the data in buf, or
120 * NULL if the buffer is read-only.
121 */
122u_char *sshbuf_mutable_ptr(const struct sshbuf *buf);
123
124/*
125 * Check whether a reservation of size len will succeed in buf
126 * Safer to use than direct comparisons again sshbuf_avail as it copes
127 * with unsigned overflows correctly.
128 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
129 */
130int sshbuf_check_reserve(const struct sshbuf *buf, size_t len);
131
132/*
133 * Preallocates len additional bytes in buf.
134 * Useful for cases where the caller knows how many bytes will ultimately be
135 * required to avoid realloc in the buffer code.
136 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
137 */
138int sshbuf_allocate(struct sshbuf *buf, size_t len);
139
140/*
141 * Reserve len bytes in buf.
142 * Returns 0 on success and a pointer to the first reserved byte via the
143 * optional dpp parameter or a negative * SSH_ERR_* error code on failure.
144 */
145int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp);
146
147/*
148 * Consume len bytes from the start of buf
149 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
150 */
151int sshbuf_consume(struct sshbuf *buf, size_t len);
152
153/*
154 * Consume len bytes from the end of buf
155 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
156 */
157int sshbuf_consume_end(struct sshbuf *buf, size_t len);
158
159/* Extract or deposit some bytes */
160int sshbuf_get(struct sshbuf *buf, void *v, size_t len);
161int sshbuf_put(struct sshbuf *buf, const void *v, size_t len);
162int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v);
163
164/* Append using a printf(3) format */
165int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
166 __attribute__((format(printf, 2, 3)));
167int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap)
168 __printflike(2, 0);
169
170/* Functions to extract or store big-endian words of various sizes */
171int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp);
172int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp);
173int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp);
174int sshbuf_get_u8(struct sshbuf *buf, u_char *valp);
175int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
176int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
177int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
178int sshbuf_put_u8(struct sshbuf *buf, u_char val);
179
180/*
181 * Functions to extract or store SSH wire encoded strings (u32 len || data)
182 * The "cstring" variants admit no \0 characters in the string contents.
183 * Caller must free *valp.
184 */
185int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp);
186int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp);
187int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v);
188int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len);
189int sshbuf_put_cstring(struct sshbuf *buf, const char *v);
190int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v);
191
192/*
193 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
194 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
195 * next sshbuf-modifying function call. Caller does not free.
196 */
197int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp,
198 size_t *lenp);
199
200/* Skip past a string */
201#define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)
202
203/* Another variant: "peeks" into the buffer without modifying it */
204int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
205 size_t *lenp);
206/* XXX peek_u8 / peek_u32 */
207
208/*
209 * Functions to extract or store SSH wire encoded bignums and elliptic
210 * curve points.
211 */
212int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM **valp);
213int sshbuf_get_bignum2_bytes_direct(struct sshbuf *buf,
214 const u_char **valp, size_t *lenp);
215int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
216int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
217int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g);
218int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v);
219int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g);
220int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v);
221
222/* Dump the contents of the buffer in a human-readable format */
223void sshbuf_dump(struct sshbuf *buf, FILE *f);
224
225/* Dump specified memory in a human-readable format */
226void sshbuf_dump_data(const void *s, size_t len, FILE *f);
227
228/* Return the hexadecimal representation of the contents of the buffer */
229char *sshbuf_dtob16(struct sshbuf *buf);
230
231/* Encode the contents of the buffer as base64 */
232char *sshbuf_dtob64(struct sshbuf *buf);
233
234/* Decode base64 data and append it to the buffer */
235int sshbuf_b64tod(struct sshbuf *buf, const char *b64);
236
237/*
238 * Duplicate the contents of a buffer to a string (caller to free).
239 * Returns NULL on buffer error, or if the buffer contains a premature
240 * nul character.
241 */
242char *sshbuf_dup_string(struct sshbuf *buf);
243
244/* Macros for decoding/encoding integers */
245#define PEEK_U64(p) \
246 (((u_int64_t)(((const u_char *)(p))[0]) << 56) | \
247 ((u_int64_t)(((const u_char *)(p))[1]) << 48) | \
248 ((u_int64_t)(((const u_char *)(p))[2]) << 40) | \
249 ((u_int64_t)(((const u_char *)(p))[3]) << 32) | \
250 ((u_int64_t)(((const u_char *)(p))[4]) << 24) | \
251 ((u_int64_t)(((const u_char *)(p))[5]) << 16) | \
252 ((u_int64_t)(((const u_char *)(p))[6]) << 8) | \
253 (u_int64_t)(((const u_char *)(p))[7]))
254#define PEEK_U32(p) \
255 (((u_int32_t)(((const u_char *)(p))[0]) << 24) | \
256 ((u_int32_t)(((const u_char *)(p))[1]) << 16) | \
257 ((u_int32_t)(((const u_char *)(p))[2]) << 8) | \
258 (u_int32_t)(((const u_char *)(p))[3]))
259#define PEEK_U16(p) \
260 (((u_int16_t)(((const u_char *)(p))[0]) << 8) | \
261 (u_int16_t)(((const u_char *)(p))[1]))
262
263#define POKE_U64(p, v) \
264 do { \
265 const u_int64_t __v = (v); \
266 ((u_char *)(p))[0] = (__v >> 56) & 0xff; \
267 ((u_char *)(p))[1] = (__v >> 48) & 0xff; \
268 ((u_char *)(p))[2] = (__v >> 40) & 0xff; \
269 ((u_char *)(p))[3] = (__v >> 32) & 0xff; \
270 ((u_char *)(p))[4] = (__v >> 24) & 0xff; \
271 ((u_char *)(p))[5] = (__v >> 16) & 0xff; \
272 ((u_char *)(p))[6] = (__v >> 8) & 0xff; \
273 ((u_char *)(p))[7] = __v & 0xff; \
274 } while (0)
275#define POKE_U32(p, v) \
276 do { \
277 const u_int32_t __v = (v); \
278 ((u_char *)(p))[0] = (__v >> 24) & 0xff; \
279 ((u_char *)(p))[1] = (__v >> 16) & 0xff; \
280 ((u_char *)(p))[2] = (__v >> 8) & 0xff; \
281 ((u_char *)(p))[3] = __v & 0xff; \
282 } while (0)
283#define POKE_U16(p, v) \
284 do { \
285 const u_int16_t __v = (v); \
286 ((u_char *)(p))[0] = (__v >> 8) & 0xff; \
287 ((u_char *)(p))[1] = __v & 0xff; \
288 } while (0)
289
290/* Internal definitions follow. Exposed for regress tests */
291#ifdef SSHBUF_INTERNAL
292
293/*
294 * Return the allocation size of buf
295 */
296size_t sshbuf_alloc(const struct sshbuf *buf);
297
298/*
299 * Increment the reference count of buf.
300 */
301int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent);
302
303/*
304 * Return the parent buffer of buf, or NULL if it has no parent.
305 */
306const struct sshbuf *sshbuf_parent(const struct sshbuf *buf);
307
308/*
309 * Return the reference count of buf
310 */
311u_int sshbuf_refcount(const struct sshbuf *buf);
312
313# define SSHBUF_SIZE_INIT 256 /* Initial allocation */
314# define SSHBUF_SIZE_INC 256 /* Preferred increment length */
315# define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */
316
317/* # define SSHBUF_ABORT abort */
318/* # define SSHBUF_DEBUG */
319
320# ifndef SSHBUF_ABORT
321# define SSHBUF_ABORT()
322# endif
323
324# ifdef SSHBUF_DEBUG
325# define SSHBUF_TELL(what) do { \
326 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
327 __FILE__, __LINE__, __func__, what, \
328 buf->size, buf->alloc, buf->off, buf->max_size); \
329 fflush(stdout); \
330 } while (0)
331# define SSHBUF_DBG(x) do { \
332 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
333 printf x; \
334 printf("\n"); \
335 fflush(stdout); \
336 } while (0)
337# else
338# define SSHBUF_TELL(what)
339# define SSHBUF_DBG(x)
340# endif
341#endif /* SSHBUF_INTERNAL */
342
343#endif /* _SSHBUF_H */
344