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Damien Miller05e82c32014-05-15 14:33:43 +10001/* $OpenBSD: sshbuf.h,v 1.1 2014/04/30 05:29:56 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#ifndef _SSHBUF_H
19#define _SSHBUF_H
20
21#include <sys/types.h>
22#include <stdarg.h>
23#include <stdio.h>
24#include <openssl/bn.h>
25#include <openssl/ec.h>
26
27#define SSHBUF_SIZE_MAX 0x8000000 /* Hard maximum size */
28#define SSHBUF_REFS_MAX 0x100000 /* Max child buffers */
29#define SSHBUF_MAX_BIGNUM (16384 / 8) /* Max bignum *bytes* */
30#define SSHBUF_MAX_ECPOINT ((528 * 2 / 8) + 1) /* Max EC point *bytes* */
31
32/*
33 * NB. do not depend on the internals of this. It will be made opaque
34 * one day.
35 */
36struct sshbuf {
37 u_char *d; /* Data */
38 const u_char *cd; /* Const data */
39 size_t off; /* First available byte is buf->d + buf->off */
40 size_t size; /* Last byte is buf->d + buf->size - 1 */
41 size_t max_size; /* Maximum size of buffer */
42 size_t alloc; /* Total bytes allocated to buf->d */
43 int readonly; /* Refers to external, const data */
44 int dont_free; /* Kludge to support sshbuf_init */
45 u_int refcount; /* Tracks self and number of child buffers */
46 struct sshbuf *parent; /* If child, pointer to parent */
47};
48
49#ifndef SSHBUF_NO_DEPREACTED
50/*
51 * NB. Please do not use sshbuf_init() in new code. Please use sshbuf_new()
52 * instead. sshbuf_init() is deprectated and will go away soon (it is
53 * only included to allow compat with buffer_* in OpenSSH)
54 */
55void sshbuf_init(struct sshbuf *buf);
56#endif
57
58/*
59 * Create a new sshbuf buffer.
60 * Returns pointer to buffer on success, or NULL on allocation failure.
61 */
62struct sshbuf *sshbuf_new(void);
63
64/*
65 * Create a new, read-only sshbuf buffer from existing data.
66 * Returns pointer to buffer on success, or NULL on allocation failure.
67 */
68struct sshbuf *sshbuf_from(const void *blob, size_t len);
69
70/*
71 * Create a new, read-only sshbuf buffer from the contents of an existing
72 * buffer. The contents of "buf" must not change in the lifetime of the
73 * resultant buffer.
74 * Returns pointer to buffer on success, or NULL on allocation failure.
75 */
76struct sshbuf *sshbuf_fromb(struct sshbuf *buf);
77
78/*
79 * Create a new, read-only sshbuf buffer from the contents of a string in
80 * an existing buffer (the string is consumed in the process).
81 * The contents of "buf" must not change in the lifetime of the resultant
82 * buffer.
83 * Returns pointer to buffer on success, or NULL on allocation failure.
84 */
85int sshbuf_froms(struct sshbuf *buf, struct sshbuf **bufp);
86
87/*
88 * Clear and free buf
89 */
90void sshbuf_free(struct sshbuf *buf);
91
92/*
93 * Reset buf, clearing its contents. NB. max_size is preserved.
94 */
95void sshbuf_reset(struct sshbuf *buf);
96
97/*
98 * Return the maximum size of buf
99 */
100size_t sshbuf_max_size(const struct sshbuf *buf);
101
102/*
103 * Set the maximum size of buf
104 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
105 */
106int sshbuf_set_max_size(struct sshbuf *buf, size_t max_size);
107
108/*
109 * Returns the length of data in buf
110 */
111size_t sshbuf_len(const struct sshbuf *buf);
112
113/*
114 * Returns number of bytes left in buffer before hitting max_size.
115 */
116size_t sshbuf_avail(const struct sshbuf *buf);
117
118/*
119 * Returns a read-only pointer to the start of the the data in buf
120 */
121const u_char *sshbuf_ptr(const struct sshbuf *buf);
122
123/*
124 * Returns a mutable pointer to the start of the the data in buf, or
125 * NULL if the buffer is read-only.
126 */
127u_char *sshbuf_mutable_ptr(const struct sshbuf *buf);
128
129/*
130 * Check whether a reservation of size len will succeed in buf
131 * Safer to use than direct comparisons again sshbuf_avail as it copes
132 * with unsigned overflows correctly.
133 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
134 */
135int sshbuf_check_reserve(const struct sshbuf *buf, size_t len);
136
137/*
138 * Reserve len bytes in buf.
139 * Returns 0 on success and a pointer to the first reserved byte via the
140 * optional dpp parameter or a negative * SSH_ERR_* error code on failure.
141 */
142int sshbuf_reserve(struct sshbuf *buf, size_t len, u_char **dpp);
143
144/*
145 * Consume len bytes from the start of buf
146 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
147 */
148int sshbuf_consume(struct sshbuf *buf, size_t len);
149
150/*
151 * Consume len bytes from the end of buf
152 * Returns 0 on success, or a negative SSH_ERR_* error code on failure.
153 */
154int sshbuf_consume_end(struct sshbuf *buf, size_t len);
155
156/* Extract or deposit some bytes */
157int sshbuf_get(struct sshbuf *buf, void *v, size_t len);
158int sshbuf_put(struct sshbuf *buf, const void *v, size_t len);
159int sshbuf_putb(struct sshbuf *buf, const struct sshbuf *v);
160
161/* Append using a printf(3) format */
162int sshbuf_putf(struct sshbuf *buf, const char *fmt, ...)
163 __attribute__((format(printf, 2, 3)));
164int sshbuf_putfv(struct sshbuf *buf, const char *fmt, va_list ap);
165
166/* Functions to extract or store big-endian words of various sizes */
167int sshbuf_get_u64(struct sshbuf *buf, u_int64_t *valp);
168int sshbuf_get_u32(struct sshbuf *buf, u_int32_t *valp);
169int sshbuf_get_u16(struct sshbuf *buf, u_int16_t *valp);
170int sshbuf_get_u8(struct sshbuf *buf, u_char *valp);
171int sshbuf_put_u64(struct sshbuf *buf, u_int64_t val);
172int sshbuf_put_u32(struct sshbuf *buf, u_int32_t val);
173int sshbuf_put_u16(struct sshbuf *buf, u_int16_t val);
174int sshbuf_put_u8(struct sshbuf *buf, u_char val);
175
176/*
177 * Functions to extract or store SSH wire encoded strings (u32 len || data)
178 * The "cstring" variants admit no \0 characters in the string contents.
179 * Caller must free *valp.
180 */
181int sshbuf_get_string(struct sshbuf *buf, u_char **valp, size_t *lenp);
182int sshbuf_get_cstring(struct sshbuf *buf, char **valp, size_t *lenp);
183int sshbuf_get_stringb(struct sshbuf *buf, struct sshbuf *v);
184int sshbuf_put_string(struct sshbuf *buf, const void *v, size_t len);
185int sshbuf_put_cstring(struct sshbuf *buf, const char *v);
186int sshbuf_put_stringb(struct sshbuf *buf, const struct sshbuf *v);
187
188/*
189 * "Direct" variant of sshbuf_get_string, returns pointer into the sshbuf to
190 * avoid an malloc+memcpy. The pointer is guaranteed to be valid until the
191 * next sshbuf-modifying function call. Caller does not free.
192 */
193int sshbuf_get_string_direct(struct sshbuf *buf, const u_char **valp,
194 size_t *lenp);
195
196/* Skip past a string */
197#define sshbuf_skip_string(buf) sshbuf_get_string_direct(buf, NULL, NULL)
198
199/* Another variant: "peeks" into the buffer without modifying it */
200int sshbuf_peek_string_direct(const struct sshbuf *buf, const u_char **valp,
201 size_t *lenp);
202
203/*
204 * Functions to extract or store SSH wire encoded bignums and elliptic
205 * curve points.
206 */
207int sshbuf_get_bignum2(struct sshbuf *buf, BIGNUM *v);
208int sshbuf_get_bignum1(struct sshbuf *buf, BIGNUM *v);
209int sshbuf_get_ec(struct sshbuf *buf, EC_POINT *v, const EC_GROUP *g);
210int sshbuf_get_eckey(struct sshbuf *buf, EC_KEY *v);
211int sshbuf_put_bignum2(struct sshbuf *buf, const BIGNUM *v);
212int sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v);
213int sshbuf_put_ec(struct sshbuf *buf, const EC_POINT *v, const EC_GROUP *g);
214int sshbuf_put_eckey(struct sshbuf *buf, const EC_KEY *v);
215int sshbuf_put_bignum2_bytes(struct sshbuf *buf, const void *v, size_t len);
216
217/* Dump the contents of the buffer to stderr in a human-readable format */
218void sshbuf_dump(struct sshbuf *buf, FILE *f);
219
220/* Return the hexadecimal representation of the contents of the buffer */
221char *sshbuf_dtob16(struct sshbuf *buf);
222
223/* Encode the contents of the buffer as base64 */
224char *sshbuf_dtob64(struct sshbuf *buf);
225
226/* Decode base64 data and append it to the buffer */
227int sshbuf_b64tod(struct sshbuf *buf, const char *b64);
228
229/* Macros for decoding/encoding integers */
230#define PEEK_U64(p) \
231 (((u_int64_t)(((u_char *)(p))[0]) << 56) | \
232 ((u_int64_t)(((u_char *)(p))[1]) << 48) | \
233 ((u_int64_t)(((u_char *)(p))[2]) << 40) | \
234 ((u_int64_t)(((u_char *)(p))[3]) << 32) | \
235 ((u_int64_t)(((u_char *)(p))[4]) << 24) | \
236 ((u_int64_t)(((u_char *)(p))[5]) << 16) | \
237 ((u_int64_t)(((u_char *)(p))[6]) << 8) | \
238 (u_int64_t)(((u_char *)(p))[7]))
239#define PEEK_U32(p) \
240 (((u_int32_t)(((u_char *)(p))[0]) << 24) | \
241 ((u_int32_t)(((u_char *)(p))[1]) << 16) | \
242 ((u_int32_t)(((u_char *)(p))[2]) << 8) | \
243 (u_int32_t)(((u_char *)(p))[3]))
244#define PEEK_U16(p) \
245 (((u_int16_t)(((u_char *)(p))[0]) << 8) | \
246 (u_int16_t)(((u_char *)(p))[1]))
247
248#define POKE_U64(p, v) \
249 do { \
250 ((u_char *)(p))[0] = (((u_int64_t)(v)) >> 56) & 0xff; \
251 ((u_char *)(p))[1] = (((u_int64_t)(v)) >> 48) & 0xff; \
252 ((u_char *)(p))[2] = (((u_int64_t)(v)) >> 40) & 0xff; \
253 ((u_char *)(p))[3] = (((u_int64_t)(v)) >> 32) & 0xff; \
254 ((u_char *)(p))[4] = (((u_int64_t)(v)) >> 24) & 0xff; \
255 ((u_char *)(p))[5] = (((u_int64_t)(v)) >> 16) & 0xff; \
256 ((u_char *)(p))[6] = (((u_int64_t)(v)) >> 8) & 0xff; \
257 ((u_char *)(p))[7] = ((u_int64_t)(v)) & 0xff; \
258 } while (0)
259#define POKE_U32(p, v) \
260 do { \
261 ((u_char *)(p))[0] = (((u_int64_t)(v)) >> 24) & 0xff; \
262 ((u_char *)(p))[1] = (((u_int64_t)(v)) >> 16) & 0xff; \
263 ((u_char *)(p))[2] = (((u_int64_t)(v)) >> 8) & 0xff; \
264 ((u_char *)(p))[3] = ((u_int64_t)(v)) & 0xff; \
265 } while (0)
266#define POKE_U16(p, v) \
267 do { \
268 ((u_char *)(p))[0] = (((u_int64_t)(v)) >> 8) & 0xff; \
269 ((u_char *)(p))[1] = ((u_int64_t)(v)) & 0xff; \
270 } while (0)
271
272/* Internal definitions follow. Exposed for regress tests */
273#ifdef SSHBUF_INTERNAL
274
275/*
276 * Return the allocation size of buf
277 */
278size_t sshbuf_alloc(const struct sshbuf *buf);
279
280/*
281 * Increment the reference count of buf.
282 */
283int sshbuf_set_parent(struct sshbuf *child, struct sshbuf *parent);
284
285/*
286 * Return the parent buffer of buf, or NULL if it has no parent.
287 */
288const struct sshbuf *sshbuf_parent(const struct sshbuf *buf);
289
290/*
291 * Return the reference count of buf
292 */
293u_int sshbuf_refcount(const struct sshbuf *buf);
294
295# define SSHBUF_SIZE_INIT 256 /* Initial allocation */
296# define SSHBUF_SIZE_INC 256 /* Preferred increment length */
297# define SSHBUF_PACK_MIN 8192 /* Minimim packable offset */
298
299/* # define SSHBUF_ABORT abort */
300/* # define SSHBUF_DEBUG */
301
302# ifndef SSHBUF_ABORT
303# define SSHBUF_ABORT()
304# endif
305
306# ifdef SSHBUF_DEBUG
307# define SSHBUF_TELL(what) do { \
308 printf("%s:%d %s: %s size %zu alloc %zu off %zu max %zu\n", \
309 __FILE__, __LINE__, __func__, what, \
310 buf->size, buf->alloc, buf->off, buf->max_size); \
311 fflush(stdout); \
312 } while (0)
313# define SSHBUF_DBG(x) do { \
314 printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
315 printf x; \
316 printf("\n"); \
317 fflush(stdout); \
318 } while (0)
319# else
320# define SSHBUF_TELL(what)
321# define SSHBUF_DBG(x)
322# endif
323#endif /* SSHBUF_INTERNAL */
324
325#endif /* _SSHBUF_H */