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>
64 * This converts an ASN1 INTEGER into its DER encoding.
65 * The internal representation is an ASN1_STRING whose data is a big endian
66 * representation of the value, ignoring the sign. The sign is determined by
67 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
69 * Positive integers are no problem: they are almost the same as the DER
70 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
72 * Negative integers are a bit trickier...
73 * The DER representation of negative integers is in 2s complement form.
74 * The internal form is converted by complementing each octet and finally
75 * adding one to the result. This can be done less messily with a little trick.
76 * If the internal form has trailing zeroes then they will become FF by the
77 * complement and 0 by the add one (due to carry) so just copy as many trailing
78 * zeros to the destination as there are in the source. The carry will add one
79 * to the last none zero octet: so complement this octet and add one and finally
80 * complement any left over until you get to the start of the string.
82 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
83 * with 0xff. However if the first byte is 0x80 and one of the following bytes
84 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
85 * followed by optional zeros isn't padded.
88 int i2d_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
91 unsigned char *p,*n,pb=0;
93 if ((a == NULL) || (a->data == NULL)) return(0);
101 if ((t == V_ASN1_INTEGER) && (i > 127)) {
104 } else if(t == V_ASN1_NEG_INTEGER) {
108 } else if(i == 128) {
110 * Special case: if any other bytes non zero we pad:
111 * otherwise we don't.
113 for(i = 1; i < a->length; i++) if(a->data[i]) {
122 r=ASN1_object_size(0,ret,V_ASN1_INTEGER);
123 if (pp == NULL) return(r);
126 ASN1_put_object(&p,0,ret,V_ASN1_INTEGER,V_ASN1_UNIVERSAL);
130 else if (t == V_ASN1_INTEGER)
132 memcpy(p,a->data,(unsigned int)a->length);
136 /* Begin at the end of the encoding */
137 n=a->data + a->length - 1;
140 /* Copy zeros to destination as long as source is zero */
146 /* Complement and increment next octet */
147 *(p--) = ((*(n--)) ^ 0xff) + 1;
149 /* Complement any octets left */
150 for(;i > 0; i--) *(p--) = *(n--) ^ 0xff;
158 ASN1_INTEGER *d2i_ASN1_INTEGER(ASN1_INTEGER **a, unsigned char **pp,
161 ASN1_INTEGER *ret=NULL;
162 unsigned char *p,*to,*s;
167 if ((a == NULL) || ((*a) == NULL))
169 if ((ret=ASN1_INTEGER_new()) == NULL) return(NULL);
170 ret->type=V_ASN1_INTEGER;
176 inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
179 i=ASN1_R_BAD_OBJECT_HEADER;
183 if (tag != V_ASN1_INTEGER)
185 i=ASN1_R_EXPECTING_AN_INTEGER;
189 /* We must Malloc stuff, even for 0 bytes otherwise it
190 * signifies a missing NULL parameter. */
191 s=(unsigned char *)Malloc((int)len+1);
194 i=ERR_R_MALLOC_FAILURE;
198 if (*p & 0x80) /* a negative number */
200 ret->type=V_ASN1_NEG_INTEGER;
201 if ((*p == 0xff) && (len != 1)) {
213 /* Special case: if all zeros then the number will be of
214 * the form FF followed by n zero bytes: this corresponds to
215 * 1 followed by n zero bytes. We've already written n zeros
216 * so we just append an extra one and set the first byte to
217 * a 1. This is treated separately because it is the only case
218 * where the number of bytes is larger than len.
226 *(to--) = (*(p--) ^ 0xff) + 1;
228 for(;i > 0; i--) *(to--) = *(p--) ^ 0xff;
232 ret->type=V_ASN1_INTEGER;
233 if ((*p == 0) && (len != 1))
238 memcpy(s,p,(int)len);
242 if (ret->data != NULL) Free((char *)ret->data);
244 ret->length=(int)len;
245 if (a != NULL) (*a)=ret;
249 ASN1err(ASN1_F_D2I_ASN1_INTEGER,i);
250 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
251 ASN1_INTEGER_free(ret);
255 /* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
256 * ASN1 integers: some broken software can encode a positive INTEGER
257 * with its MSB set as negative (it doesn't add a padding zero).
260 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, unsigned char **pp,
263 ASN1_INTEGER *ret=NULL;
264 unsigned char *p,*to,*s;
269 if ((a == NULL) || ((*a) == NULL))
271 if ((ret=ASN1_INTEGER_new()) == NULL) return(NULL);
272 ret->type=V_ASN1_INTEGER;
278 inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
281 i=ASN1_R_BAD_OBJECT_HEADER;
285 if (tag != V_ASN1_INTEGER)
287 i=ASN1_R_EXPECTING_AN_INTEGER;
291 /* We must Malloc stuff, even for 0 bytes otherwise it
292 * signifies a missing NULL parameter. */
293 s=(unsigned char *)Malloc((int)len+1);
296 i=ERR_R_MALLOC_FAILURE;
300 ret->type=V_ASN1_INTEGER;
301 if ((*p == 0) && (len != 1))
306 memcpy(s,p,(int)len);
309 if (ret->data != NULL) Free((char *)ret->data);
311 ret->length=(int)len;
312 if (a != NULL) (*a)=ret;
316 ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i);
317 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
318 ASN1_INTEGER_free(ret);
322 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
325 unsigned char buf[sizeof(long)+1];
328 a->type=V_ASN1_INTEGER;
329 if (a->length < (sizeof(long)+1))
332 Free((char *)a->data);
333 if ((a->data=(unsigned char *)Malloc(sizeof(long)+1)) != NULL)
334 memset((char *)a->data,0,sizeof(long)+1);
338 ASN1err(ASN1_F_ASN1_INTEGER_SET,ERR_R_MALLOC_FAILURE);
345 a->type=V_ASN1_NEG_INTEGER;
348 for (i=0; i<sizeof(long); i++)
355 for (k=i-1; k >=0; k--)
361 long ASN1_INTEGER_get(ASN1_INTEGER *a)
366 if (a == NULL) return(0L);
368 if (i == V_ASN1_NEG_INTEGER)
370 else if (i != V_ASN1_INTEGER)
373 if (a->length > sizeof(long))
375 /* hmm... a bit ugly */
381 for (i=0; i<a->length; i++)
384 r|=(unsigned char)a->data[i];
390 ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai)
396 ret=ASN1_INTEGER_new();
401 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR);
404 if(bn->neg) ret->type = V_ASN1_NEG_INTEGER;
405 else ret->type=V_ASN1_INTEGER;
407 len=((j == 0)?0:((j/8)+1));
408 ret->data=(unsigned char *)Malloc(len+4);
409 ret->length=BN_bn2bin(bn,ret->data);
412 if (ret != ai) ASN1_INTEGER_free(ret);
416 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai, BIGNUM *bn)
420 if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL)
421 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB);
422 if(ai->type == V_ASN1_NEG_INTEGER) bn->neg = 1;