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 
63 __RCSID("$MirOS: src/lib/libssl/src/crypto/asn1/a_int.c,v 1.2 2014/06/05 13:26:36 tg Exp $");
64 
ASN1_INTEGER_dup(ASN1_INTEGER * x)65 ASN1_INTEGER *ASN1_INTEGER_dup(ASN1_INTEGER *x)
66 { return M_ASN1_INTEGER_dup(x);}
67 
ASN1_INTEGER_cmp(ASN1_INTEGER * x,ASN1_INTEGER * y)68 int ASN1_INTEGER_cmp(ASN1_INTEGER *x, ASN1_INTEGER *y)
69 	{
70 	int neg, ret;
71 	/* Compare signs */
72 	neg = x->type & V_ASN1_NEG;
73 	if (neg != (y->type & V_ASN1_NEG))
74 		{
75 		if (neg)
76 			return -1;
77 		else
78 			return 1;
79 		}
80 
81 	ret = ASN1_STRING_cmp(x, y);
82 
83 	if (neg)
84 		return -ret;
85 	else
86 		return ret;
87 	}
88 
89 
90 /*
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.
95  *
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.
98  *
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.
108  *
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.
113  */
114 
i2c_ASN1_INTEGER(ASN1_INTEGER * a,unsigned char ** pp)115 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
116 	{
117 	int pad=0,ret,i,neg;
118 	unsigned char *p,*n,pb=0;
119 
120 	if (a == NULL) return(0);
121 	neg=a->type & V_ASN1_NEG;
122 	if (a->length == 0)
123 		ret=1;
124 	else
125 		{
126 		ret=a->length;
127 		i=a->data[0];
128 		if (!neg && (i > 127)) {
129 			pad=1;
130 			pb=0;
131 		} else if(neg) {
132 			if(i>128) {
133 				pad=1;
134 				pb=0xFF;
135 			} else if(i == 128) {
136 			/*
137 			 * Special case: if any other bytes non zero we pad:
138 			 * otherwise we don't.
139 			 */
140 				for(i = 1; i < a->length; i++) if(a->data[i]) {
141 						pad=1;
142 						pb=0xFF;
143 						break;
144 				}
145 			}
146 		}
147 		ret+=pad;
148 		}
149 	if (pp == NULL) return(ret);
150 	p= *pp;
151 
152 	if (pad) *(p++)=pb;
153 	if (a->length == 0) *(p++)=0;
154 	else if (!neg) memcpy(p,a->data,(unsigned int)a->length);
155 	else {
156 		/* Begin at the end of the encoding */
157 		n=a->data + a->length - 1;
158 		p += a->length - 1;
159 		i = a->length;
160 		/* Copy zeros to destination as long as source is zero */
161 		while(!*n) {
162 			*(p--) = 0;
163 			n--;
164 			i--;
165 		}
166 		/* Complement and increment next octet */
167 		*(p--) = ((*(n--)) ^ 0xff) + 1;
168 		i--;
169 		/* Complement any octets left */
170 		for(;i > 0; i--) *(p--) = *(n--) ^ 0xff;
171 	}
172 
173 	*pp+=ret;
174 	return(ret);
175 	}
176 
177 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
178 
c2i_ASN1_INTEGER(ASN1_INTEGER ** a,unsigned char ** pp,long len)179 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, unsigned char **pp,
180 	     long len)
181 	{
182 	ASN1_INTEGER *ret=NULL;
183 	unsigned char *p,*to,*s, *pend;
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_D2I_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,unsigned char ** pp,long length)271 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, unsigned char **pp,
272 	     long length)
273 	{
274 	ASN1_INTEGER *ret=NULL;
275 	unsigned char *p,*to,*s;
276 	long len;
277 	int inf,tag,xclass;
278 	int i;
279 
280 	if ((a == NULL) || ((*a) == NULL))
281 		{
282 		if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
283 		ret->type=V_ASN1_INTEGER;
284 		}
285 	else
286 		ret=(*a);
287 
288 	p= *pp;
289 	inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
290 	if (inf & 0x80)
291 		{
292 		i=ASN1_R_BAD_OBJECT_HEADER;
293 		goto err;
294 		}
295 
296 	if (tag != V_ASN1_INTEGER)
297 		{
298 		i=ASN1_R_EXPECTING_AN_INTEGER;
299 		goto err;
300 		}
301 
302 	/* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
303 	 * signifies a missing NULL parameter. */
304 	s=(unsigned char *)OPENSSL_malloc((int)len+1);
305 	if (s == NULL)
306 		{
307 		i=ERR_R_MALLOC_FAILURE;
308 		goto err;
309 		}
310 	to=s;
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 i,j,k;
338 	unsigned char buf[sizeof(long)+1];
339 	long d;
340 
341 	a->type=V_ASN1_INTEGER;
342 	if (a->length < (sizeof(long)+1))
343 		{
344 		if (a->data != NULL)
345 			OPENSSL_free(a->data);
346 		if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL)
347 			memset((char *)a->data,0,sizeof(long)+1);
348 		}
349 	if (a->data == NULL)
350 		{
351 		ASN1err(ASN1_F_ASN1_INTEGER_SET,ERR_R_MALLOC_FAILURE);
352 		return(0);
353 		}
354 	d=v;
355 	if (d < 0)
356 		{
357 		d= -d;
358 		a->type=V_ASN1_NEG_INTEGER;
359 		}
360 
361 	for (i=0; i<sizeof(long); i++)
362 		{
363 		if (d == 0) break;
364 		buf[i]=(int)d&0xff;
365 		d>>=8;
366 		}
367 	j=0;
368 	for (k=i-1; k >=0; k--)
369 		a->data[j++]=buf[k];
370 	a->length=j;
371 	return(1);
372 	}
373 
ASN1_INTEGER_get(ASN1_INTEGER * a)374 long ASN1_INTEGER_get(ASN1_INTEGER *a)
375 	{
376 	int neg=0,i;
377 	long r=0;
378 
379 	if (a == NULL) return(0L);
380 	i=a->type;
381 	if (i == V_ASN1_NEG_INTEGER)
382 		neg=1;
383 	else if (i != V_ASN1_INTEGER)
384 		return -1;
385 
386 	if (a->length > sizeof(long))
387 		{
388 		/* hmm... a bit ugly */
389 		return(0xffffffffL);
390 		}
391 	if (a->data == NULL)
392 		return 0;
393 
394 	for (i=0; i<a->length; i++)
395 		{
396 		r<<=8;
397 		r|=(unsigned char)a->data[i];
398 		}
399 	if (neg) r= -r;
400 	return(r);
401 	}
402 
BN_to_ASN1_INTEGER(BIGNUM * bn,ASN1_INTEGER * ai)403 ASN1_INTEGER *BN_to_ASN1_INTEGER(BIGNUM *bn, ASN1_INTEGER *ai)
404 	{
405 	ASN1_INTEGER *ret;
406 	int len,j;
407 
408 	if (ai == NULL)
409 		ret=M_ASN1_INTEGER_new();
410 	else
411 		ret=ai;
412 	if (ret == NULL)
413 		{
414 		ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR);
415 		goto err;
416 		}
417 	if(bn->neg) ret->type = V_ASN1_NEG_INTEGER;
418 	else ret->type=V_ASN1_INTEGER;
419 	j=BN_num_bits(bn);
420 	len=((j == 0)?0:((j/8)+1));
421 	if (ret->length < len+4)
422 		{
423 		unsigned char *new_data=OPENSSL_realloc(ret->data, len+4);
424 		if (!new_data)
425 			{
426 			ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_MALLOC_FAILURE);
427 			goto err;
428 			}
429 		ret->data=new_data;
430 		}
431 	ret->length=BN_bn2bin(bn,ret->data);
432 	/* Correct zero case */
433 	if(!ret->length)
434 		{
435 		ret->data[0] = 0;
436 		ret->length = 1;
437 		}
438 	return(ret);
439 err:
440 	if (ret != ai) M_ASN1_INTEGER_free(ret);
441 	return(NULL);
442 	}
443 
ASN1_INTEGER_to_BN(ASN1_INTEGER * ai,BIGNUM * bn)444 BIGNUM *ASN1_INTEGER_to_BN(ASN1_INTEGER *ai, BIGNUM *bn)
445 	{
446 	BIGNUM *ret;
447 
448 	if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL)
449 		ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB);
450 	else if(ai->type == V_ASN1_NEG_INTEGER) ret->neg = 1;
451 	return(ret);
452 	}
453 
454 IMPLEMENT_STACK_OF(ASN1_INTEGER)
455 IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER)
456