1 /* crypto/asn1/a_int.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
61 #include <openssl/asn1.h>
62 #include <openssl/bn.h>
63 #include "asn1_locl.h"
65 ASN1_INTEGER
*ASN1_INTEGER_dup(const ASN1_INTEGER
*x
)
67 return ASN1_STRING_dup(x
);
70 int ASN1_INTEGER_cmp(const ASN1_INTEGER
*x
, const ASN1_INTEGER
*y
)
74 neg
= x
->type
& V_ASN1_NEG
;
75 if (neg
!= (y
->type
& V_ASN1_NEG
)) {
82 ret
= ASN1_STRING_cmp(x
, y
);
91 * This converts an ASN1 INTEGER into its content encoding.
92 * The internal representation is an ASN1_STRING whose data is a big endian
93 * representation of the value, ignoring the sign. The sign is determined by
94 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
96 * Positive integers are no problem: they are almost the same as the DER
97 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
99 * Negative integers are a bit trickier...
100 * The DER representation of negative integers is in 2s complement form.
101 * The internal form is converted by complementing each octet and finally
102 * adding one to the result. This can be done less messily with a little trick.
103 * If the internal form has trailing zeroes then they will become FF by the
104 * complement and 0 by the add one (due to carry) so just copy as many trailing
105 * zeros to the destination as there are in the source. The carry will add one
106 * to the last none zero octet: so complement this octet and add one and finally
107 * complement any left over until you get to the start of the string.
109 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
110 * with 0xff. However if the first byte is 0x80 and one of the following bytes
111 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
112 * followed by optional zeros isn't padded.
115 int i2c_ASN1_INTEGER(ASN1_INTEGER
*a
, unsigned char **pp
)
117 int pad
= 0, ret
, i
, neg
;
118 unsigned char *p
, *n
, pb
= 0;
122 neg
= a
->type
& V_ASN1_NEG
;
128 if (ret
== 1 && i
== 0)
130 if (!neg
&& (i
> 127)) {
137 } else if (i
== 128) {
139 * Special case: if any other bytes non zero we pad:
140 * otherwise we don't.
142 for (i
= 1; i
< a
->length
; i
++)
161 memcpy(p
, a
->data
, (unsigned int)a
->length
);
163 /* Begin at the end of the encoding */
164 n
= a
->data
+ a
->length
- 1;
167 /* Copy zeros to destination as long as source is zero */
168 while (!*n
&& i
> 1) {
173 /* Complement and increment next octet */
174 *(p
--) = ((*(n
--)) ^ 0xff) + 1;
176 /* Complement any octets left */
178 *(p
--) = *(n
--) ^ 0xff;
185 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
187 ASN1_INTEGER
*c2i_ASN1_INTEGER(ASN1_INTEGER
**a
, const unsigned char **pp
,
190 ASN1_INTEGER
*ret
= NULL
;
191 const unsigned char *p
, *pend
;
192 unsigned char *to
, *s
;
195 if ((a
== NULL
) || ((*a
) == NULL
)) {
196 if ((ret
= ASN1_INTEGER_new()) == NULL
)
198 ret
->type
= V_ASN1_INTEGER
;
206 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
207 * a missing NULL parameter.
209 s
= OPENSSL_malloc((int)len
+ 1);
211 i
= ERR_R_MALLOC_FAILURE
;
217 * Strictly speaking this is an illegal INTEGER but we tolerate it.
219 ret
->type
= V_ASN1_INTEGER
;
220 } else if (*p
& 0x80) { /* a negative number */
221 ret
->type
= V_ASN1_NEG_INTEGER
;
222 if ((*p
== 0xff) && (len
!= 1)) {
235 * Special case: if all zeros then the number will be of the form FF
236 * followed by n zero bytes: this corresponds to 1 followed by n zero
237 * bytes. We've already written n zeros so we just append an extra
238 * one and set the first byte to a 1. This is treated separately
239 * because it is the only case where the number of bytes is larger
247 *(to
--) = (*(p
--) ^ 0xff) + 1;
250 *(to
--) = *(p
--) ^ 0xff;
253 ret
->type
= V_ASN1_INTEGER
;
254 if ((*p
== 0) && (len
!= 1)) {
258 memcpy(s
, p
, (int)len
);
261 OPENSSL_free(ret
->data
);
263 ret
->length
= (int)len
;
269 ASN1err(ASN1_F_C2I_ASN1_INTEGER
, i
);
270 if ((a
== NULL
) || (*a
!= ret
))
271 ASN1_INTEGER_free(ret
);
276 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
277 * integers: some broken software can encode a positive INTEGER with its MSB
278 * set as negative (it doesn't add a padding zero).
281 ASN1_INTEGER
*d2i_ASN1_UINTEGER(ASN1_INTEGER
**a
, const unsigned char **pp
,
284 ASN1_INTEGER
*ret
= NULL
;
285 const unsigned char *p
;
288 int inf
, tag
, xclass
;
291 if ((a
== NULL
) || ((*a
) == NULL
)) {
292 if ((ret
= ASN1_INTEGER_new()) == NULL
)
294 ret
->type
= V_ASN1_INTEGER
;
299 inf
= ASN1_get_object(&p
, &len
, &tag
, &xclass
, length
);
301 i
= ASN1_R_BAD_OBJECT_HEADER
;
305 if (tag
!= V_ASN1_INTEGER
) {
306 i
= ASN1_R_EXPECTING_AN_INTEGER
;
311 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
312 * a missing NULL parameter.
314 s
= OPENSSL_malloc((int)len
+ 1);
316 i
= ERR_R_MALLOC_FAILURE
;
319 ret
->type
= V_ASN1_INTEGER
;
321 if ((*p
== 0) && (len
!= 1)) {
325 memcpy(s
, p
, (int)len
);
329 OPENSSL_free(ret
->data
);
331 ret
->length
= (int)len
;
337 ASN1err(ASN1_F_D2I_ASN1_UINTEGER
, i
);
338 if ((a
== NULL
) || (*a
!= ret
))
339 ASN1_INTEGER_free(ret
);
343 int ASN1_INTEGER_set(ASN1_INTEGER
*a
, long v
)
347 unsigned char buf
[sizeof(long) + 1];
349 if (a
->length
< (int)(sizeof(long) + 1)) {
350 OPENSSL_free(a
->data
);
351 if ((a
->data
= OPENSSL_malloc(sizeof(long) + 1)) != NULL
)
352 memset((char *)a
->data
, 0, sizeof(long) + 1);
354 if (a
->data
== NULL
) {
355 ASN1err(ASN1_F_ASN1_INTEGER_SET
, ERR_R_MALLOC_FAILURE
);
360 a
->type
= V_ASN1_NEG_INTEGER
;
362 a
->type
= V_ASN1_INTEGER
;
364 for (i
= 0; i
< sizeof(long); i
++) {
367 buf
[i
] = (int)v
& 0xff;
371 for (k
= i
- 1; k
>= 0; k
--)
372 a
->data
[j
++] = buf
[k
];
377 long ASN1_INTEGER_get(const ASN1_INTEGER
*a
)
385 if (i
== V_ASN1_NEG_INTEGER
)
387 else if (i
!= V_ASN1_INTEGER
)
390 if (a
->length
> (int)sizeof(long)) {
391 /* hmm... a bit ugly, return all ones */
397 for (i
= 0; i
< a
->length
; i
++) {
399 r
|= (unsigned char)a
->data
[i
];
406 ASN1_INTEGER
*BN_to_ASN1_INTEGER(const BIGNUM
*bn
, ASN1_INTEGER
*ai
)
412 ret
= ASN1_INTEGER_new();
416 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER
, ERR_R_NESTED_ASN1_ERROR
);
419 if (BN_is_negative(bn
) && !BN_is_zero(bn
))
420 ret
->type
= V_ASN1_NEG_INTEGER
;
422 ret
->type
= V_ASN1_INTEGER
;
424 len
= ((j
== 0) ? 0 : ((j
/ 8) + 1));
425 if (ret
->length
< len
+ 4) {
426 unsigned char *new_data
= OPENSSL_realloc(ret
->data
, len
+ 4);
428 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER
, ERR_R_MALLOC_FAILURE
);
431 ret
->data
= new_data
;
433 ret
->length
= BN_bn2bin(bn
, ret
->data
);
434 /* Correct zero case */
442 ASN1_INTEGER_free(ret
);
446 BIGNUM
*ASN1_INTEGER_to_BN(const ASN1_INTEGER
*ai
, BIGNUM
*bn
)
450 if ((ret
= BN_bin2bn(ai
->data
, ai
->length
, bn
)) == NULL
)
451 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN
, ASN1_R_BN_LIB
);
452 else if (ai
->type
== V_ASN1_NEG_INTEGER
)
453 BN_set_negative(ret
, 1);