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1 /* crypto/asn1/a_int.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3  * All rights reserved.
4  *
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.
8  *
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).
15  *
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.
22  *
23  * Redistribution and use in source and binary forms, with or without
24  * modification, are permitted provided that the following conditions
25  * are met:
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)"
40  *
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
51  * SUCH DAMAGE.
52  *
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.]
57  */
58 
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include <openssl/asn1.h>
62 #include <openssl/bn.h>
63 
ASN1_INTEGER_dup(const ASN1_INTEGER * x)64 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
65 { return M_ASN1_INTEGER_dup(x);}
66 
ASN1_INTEGER_cmp(const ASN1_INTEGER * x,const ASN1_INTEGER * y)67 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
68 	{
69 	int neg, ret;
70 	/* Compare signs */
71 	neg = x->type & V_ASN1_NEG;
72 	if (neg != (y->type & V_ASN1_NEG))
73 		{
74 		if (neg)
75 			return -1;
76 		else
77 			return 1;
78 		}
79 
80 	ret = ASN1_STRING_cmp(x, y);
81 
82 	if (neg)
83 		return -ret;
84 	else
85 		return ret;
86 	}
87 
88 
89 /*
90  * This converts an ASN1 INTEGER into its content encoding.
91  * The internal representation is an ASN1_STRING whose data is a big endian
92  * representation of the value, ignoring the sign. The sign is determined by
93  * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
94  *
95  * Positive integers are no problem: they are almost the same as the DER
96  * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
97  *
98  * Negative integers are a bit trickier...
99  * The DER representation of negative integers is in 2s complement form.
100  * The internal form is converted by complementing each octet and finally
101  * adding one to the result. This can be done less messily with a little trick.
102  * If the internal form has trailing zeroes then they will become FF by the
103  * complement and 0 by the add one (due to carry) so just copy as many trailing
104  * zeros to the destination as there are in the source. The carry will add one
105  * to the last none zero octet: so complement this octet and add one and finally
106  * complement any left over until you get to the start of the string.
107  *
108  * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
109  * with 0xff. However if the first byte is 0x80 and one of the following bytes
110  * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
111  * followed by optional zeros isn't padded.
112  */
113 
i2c_ASN1_INTEGER(ASN1_INTEGER * a,unsigned char ** pp)114 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
115 	{
116 	int pad=0,ret,i,neg;
117 	unsigned char *p,*n,pb=0;
118 
119 	if ((a == NULL) || (a->data == NULL)) return(0);
120 	neg=a->type & V_ASN1_NEG;
121 	if (a->length == 0)
122 		ret=1;
123 	else
124 		{
125 		ret=a->length;
126 		i=a->data[0];
127 		if (!neg && (i > 127)) {
128 			pad=1;
129 			pb=0;
130 		} else if(neg) {
131 			if(i>128) {
132 				pad=1;
133 				pb=0xFF;
134 			} else if(i == 128) {
135 			/*
136 			 * Special case: if any other bytes non zero we pad:
137 			 * otherwise we don't.
138 			 */
139 				for(i = 1; i < a->length; i++) if(a->data[i]) {
140 						pad=1;
141 						pb=0xFF;
142 						break;
143 				}
144 			}
145 		}
146 		ret+=pad;
147 		}
148 	if (pp == NULL) return(ret);
149 	p= *pp;
150 
151 	if (pad) *(p++)=pb;
152 	if (a->length == 0) *(p++)=0;
153 	else if (!neg) memcpy(p,a->data,(unsigned int)a->length);
154 	else {
155 		/* Begin at the end of the encoding */
156 		n=a->data + a->length - 1;
157 		p += a->length - 1;
158 		i = a->length;
159 		/* Copy zeros to destination as long as source is zero */
160 		while(!*n) {
161 			*(p--) = 0;
162 			n--;
163 			i--;
164 		}
165 		/* Complement and increment next octet */
166 		*(p--) = ((*(n--)) ^ 0xff) + 1;
167 		i--;
168 		/* Complement any octets left */
169 		for(;i > 0; i--) *(p--) = *(n--) ^ 0xff;
170 	}
171 
172 	*pp+=ret;
173 	return(ret);
174 	}
175 
176 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
177 
c2i_ASN1_INTEGER(ASN1_INTEGER ** a,const unsigned char ** pp,long len)178 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
179 	     long len)
180 	{
181 	ASN1_INTEGER *ret=NULL;
182 	const unsigned char *p, *pend;
183 	unsigned char *to,*s;
184 	int i;
185 
186 	if ((a == NULL) || ((*a) == NULL))
187 		{
188 		if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
189 		ret->type=V_ASN1_INTEGER;
190 		}
191 	else
192 		ret=(*a);
193 
194 	p= *pp;
195 	pend = p + len;
196 
197 	/* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
198 	 * signifies a missing NULL parameter. */
199 	s=(unsigned char *)OPENSSL_malloc((int)len+1);
200 	if (s == NULL)
201 		{
202 		i=ERR_R_MALLOC_FAILURE;
203 		goto err;
204 		}
205 	to=s;
206 	if(!len) {
207 		/* Strictly speaking this is an illegal INTEGER but we
208 		 * tolerate it.
209 		 */
210 		ret->type=V_ASN1_INTEGER;
211 	} else if (*p & 0x80) /* a negative number */
212 		{
213 		ret->type=V_ASN1_NEG_INTEGER;
214 		if ((*p == 0xff) && (len != 1)) {
215 			p++;
216 			len--;
217 		}
218 		i = len;
219 		p += i - 1;
220 		to += i - 1;
221 		while((!*p) && i) {
222 			*(to--) = 0;
223 			i--;
224 			p--;
225 		}
226 		/* Special case: if all zeros then the number will be of
227 		 * the form FF followed by n zero bytes: this corresponds to
228 		 * 1 followed by n zero bytes. We've already written n zeros
229 		 * so we just append an extra one and set the first byte to
230 		 * a 1. This is treated separately because it is the only case
231 		 * where the number of bytes is larger than len.
232 		 */
233 		if(!i) {
234 			*s = 1;
235 			s[len] = 0;
236 			len++;
237 		} else {
238 			*(to--) = (*(p--) ^ 0xff) + 1;
239 			i--;
240 			for(;i > 0; i--) *(to--) = *(p--) ^ 0xff;
241 		}
242 	} else {
243 		ret->type=V_ASN1_INTEGER;
244 		if ((*p == 0) && (len != 1))
245 			{
246 			p++;
247 			len--;
248 			}
249 		memcpy(s,p,(int)len);
250 	}
251 
252 	if (ret->data != NULL) OPENSSL_free(ret->data);
253 	ret->data=s;
254 	ret->length=(int)len;
255 	if (a != NULL) (*a)=ret;
256 	*pp=pend;
257 	return(ret);
258 err:
259 	ASN1err(ASN1_F_C2I_ASN1_INTEGER,i);
260 	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
261 		M_ASN1_INTEGER_free(ret);
262 	return(NULL);
263 	}
264 
265 
266 /* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
267  * ASN1 integers: some broken software can encode a positive INTEGER
268  * with its MSB set as negative (it doesn't add a padding zero).
269  */
270 
d2i_ASN1_UINTEGER(ASN1_INTEGER ** a,const unsigned char ** pp,long length)271 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
272 	     long length)
273 	{
274 	ASN1_INTEGER *ret=NULL;
275 	const unsigned char *p;
276 	unsigned char *s;
277 	long len;
278 	int inf,tag,xclass;
279 	int i;
280 
281 	if ((a == NULL) || ((*a) == NULL))
282 		{
283 		if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
284 		ret->type=V_ASN1_INTEGER;
285 		}
286 	else
287 		ret=(*a);
288 
289 	p= *pp;
290 	inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
291 	if (inf & 0x80)
292 		{
293 		i=ASN1_R_BAD_OBJECT_HEADER;
294 		goto err;
295 		}
296 
297 	if (tag != V_ASN1_INTEGER)
298 		{
299 		i=ASN1_R_EXPECTING_AN_INTEGER;
300 		goto err;
301 		}
302 
303 	/* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
304 	 * signifies a missing NULL parameter. */
305 	s=(unsigned char *)OPENSSL_malloc((int)len+1);
306 	if (s == NULL)
307 		{
308 		i=ERR_R_MALLOC_FAILURE;
309 		goto err;
310 		}
311 	ret->type=V_ASN1_INTEGER;
312 	if(len) {
313 		if ((*p == 0) && (len != 1))
314 			{
315 			p++;
316 			len--;
317 			}
318 		memcpy(s,p,(int)len);
319 		p+=len;
320 	}
321 
322 	if (ret->data != NULL) OPENSSL_free(ret->data);
323 	ret->data=s;
324 	ret->length=(int)len;
325 	if (a != NULL) (*a)=ret;
326 	*pp=p;
327 	return(ret);
328 err:
329 	ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i);
330 	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
331 		M_ASN1_INTEGER_free(ret);
332 	return(NULL);
333 	}
334 
ASN1_INTEGER_set(ASN1_INTEGER * a,long v)335 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
336 	{
337 	int j,k;
338 	unsigned int i;
339 	unsigned char buf[sizeof(long)+1];
340 	long d;
341 
342 	a->type=V_ASN1_INTEGER;
343 	if (a->length < (int)(sizeof(long)+1))
344 		{
345 		if (a->data != NULL)
346 			OPENSSL_free(a->data);
347 		if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL)
348 			memset((char *)a->data,0,sizeof(long)+1);
349 		}
350 	if (a->data == NULL)
351 		{
352 		ASN1err(ASN1_F_ASN1_INTEGER_SET,ERR_R_MALLOC_FAILURE);
353 		return(0);
354 		}
355 	d=v;
356 	if (d < 0)
357 		{
358 		d= -d;
359 		a->type=V_ASN1_NEG_INTEGER;
360 		}
361 
362 	for (i=0; i<sizeof(long); i++)
363 		{
364 		if (d == 0) break;
365 		buf[i]=(int)d&0xff;
366 		d>>=8;
367 		}
368 	j=0;
369 	for (k=i-1; k >=0; k--)
370 		a->data[j++]=buf[k];
371 	a->length=j;
372 	return(1);
373 	}
374 
ASN1_INTEGER_get(const ASN1_INTEGER * a)375 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
376 	{
377 	int neg=0,i;
378 	long r=0;
379 
380 	if (a == NULL) return(0L);
381 	i=a->type;
382 	if (i == V_ASN1_NEG_INTEGER)
383 		neg=1;
384 	else if (i != V_ASN1_INTEGER)
385 		return -1;
386 
387 	if (a->length > (int)sizeof(long))
388 		{
389 		/* hmm... a bit ugly */
390 		return(0xffffffffL);
391 		}
392 	if (a->data == NULL)
393 		return 0;
394 
395 	for (i=0; i<a->length; i++)
396 		{
397 		r<<=8;
398 		r|=(unsigned char)a->data[i];
399 		}
400 	if (neg) r= -r;
401 	return(r);
402 	}
403 
BN_to_ASN1_INTEGER(const BIGNUM * bn,ASN1_INTEGER * ai)404 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
405 	{
406 	ASN1_INTEGER *ret;
407 	int len,j;
408 
409 	if (ai == NULL)
410 		ret=M_ASN1_INTEGER_new();
411 	else
412 		ret=ai;
413 	if (ret == NULL)
414 		{
415 		ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR);
416 		goto err;
417 		}
418 	if (BN_is_negative(bn))
419 		ret->type = V_ASN1_NEG_INTEGER;
420 	else ret->type=V_ASN1_INTEGER;
421 	j=BN_num_bits(bn);
422 	len=((j == 0)?0:((j/8)+1));
423 	if (ret->length < len+4)
424 		{
425 		unsigned char *new_data=OPENSSL_realloc(ret->data, len+4);
426 		if (!new_data)
427 			{
428 			ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_MALLOC_FAILURE);
429 			goto err;
430 			}
431 		ret->data=new_data;
432 		}
433 	ret->length=BN_bn2bin(bn,ret->data);
434 	/* Correct zero case */
435 	if(!ret->length)
436 		{
437 		ret->data[0] = 0;
438 		ret->length = 1;
439 		}
440 	return(ret);
441 err:
442 	if (ret != ai) M_ASN1_INTEGER_free(ret);
443 	return(NULL);
444 	}
445 
ASN1_INTEGER_to_BN(const ASN1_INTEGER * ai,BIGNUM * bn)446 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
447 	{
448 	BIGNUM *ret;
449 
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);
454 	return(ret);
455 	}
456 
457 IMPLEMENT_STACK_OF(ASN1_INTEGER)
458 IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER)
459