1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #include <openssl/asn1.h>
58 
59 #include <string.h>
60 
61 #include <openssl/err.h>
62 #include <openssl/mem.h>
63 
64 
ASN1_INTEGER_dup(const ASN1_INTEGER * x)65 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
66 { return M_ASN1_INTEGER_dup(x);}
67 
ASN1_INTEGER_cmp(const ASN1_INTEGER * x,const ASN1_INTEGER * y)68 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const 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,const unsigned char ** pp,long len)179 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
180 	     long len)
181 	{
182 	ASN1_INTEGER *ret=NULL;
183 	const unsigned char *p, *pend;
184 	unsigned char *to,*s;
185 	int i;
186 
187 	if ((a == NULL) || ((*a) == NULL))
188 		{
189 		if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
190 		ret->type=V_ASN1_INTEGER;
191 		}
192 	else
193 		ret=(*a);
194 
195 	p= *pp;
196 	pend = p + len;
197 
198 	/* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
199 	 * signifies a missing NULL parameter. */
200 	s=(unsigned char *)OPENSSL_malloc((int)len+1);
201 	if (s == NULL)
202 		{
203 		i=ERR_R_MALLOC_FAILURE;
204 		goto err;
205 		}
206 	to=s;
207 	if(!len) {
208 		/* Strictly speaking this is an illegal INTEGER but we
209 		 * tolerate it.
210 		 */
211 		ret->type=V_ASN1_INTEGER;
212 	} else if (*p & 0x80) /* a negative number */
213 		{
214 		ret->type=V_ASN1_NEG_INTEGER;
215 		if ((*p == 0xff) && (len != 1)) {
216 			p++;
217 			len--;
218 		}
219 		i = len;
220 		p += i - 1;
221 		to += i - 1;
222 		while((!*p) && i) {
223 			*(to--) = 0;
224 			i--;
225 			p--;
226 		}
227 		/* Special case: if all zeros then the number will be of
228 		 * the form FF followed by n zero bytes: this corresponds to
229 		 * 1 followed by n zero bytes. We've already written n zeros
230 		 * so we just append an extra one and set the first byte to
231 		 * a 1. This is treated separately because it is the only case
232 		 * where the number of bytes is larger than len.
233 		 */
234 		if(!i) {
235 			*s = 1;
236 			s[len] = 0;
237 			len++;
238 		} else {
239 			*(to--) = (*(p--) ^ 0xff) + 1;
240 			i--;
241 			for(;i > 0; i--) *(to--) = *(p--) ^ 0xff;
242 		}
243 	} else {
244 		ret->type=V_ASN1_INTEGER;
245 		if ((*p == 0) && (len != 1))
246 			{
247 			p++;
248 			len--;
249 			}
250 		memcpy(s,p,(int)len);
251 	}
252 
253 	if (ret->data != NULL) OPENSSL_free(ret->data);
254 	ret->data=s;
255 	ret->length=(int)len;
256 	if (a != NULL) (*a)=ret;
257 	*pp=pend;
258 	return(ret);
259 err:
260 	OPENSSL_PUT_ERROR(ASN1, c2i_ASN1_INTEGER, i);
261 	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
262 		M_ASN1_INTEGER_free(ret);
263 	return(NULL);
264 	}
265 
266 
267 /* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
268  * ASN1 integers: some broken software can encode a positive INTEGER
269  * with its MSB set as negative (it doesn't add a padding zero).
270  */
271 
d2i_ASN1_UINTEGER(ASN1_INTEGER ** a,const unsigned char ** pp,long length)272 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
273 	     long length)
274 	{
275 	ASN1_INTEGER *ret=NULL;
276 	const unsigned char *p;
277 	unsigned char *s;
278 	long len;
279 	int inf,tag,xclass;
280 	int i;
281 
282 	if ((a == NULL) || ((*a) == NULL))
283 		{
284 		if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
285 		ret->type=V_ASN1_INTEGER;
286 		}
287 	else
288 		ret=(*a);
289 
290 	p= *pp;
291 	inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
292 	if (inf & 0x80)
293 		{
294 		i=ASN1_R_BAD_OBJECT_HEADER;
295 		goto err;
296 		}
297 
298 	if (tag != V_ASN1_INTEGER)
299 		{
300 		i=ASN1_R_EXPECTING_AN_INTEGER;
301 		goto err;
302 		}
303 
304 	/* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
305 	 * signifies a missing NULL parameter. */
306 	s=(unsigned char *)OPENSSL_malloc((int)len+1);
307 	if (s == NULL)
308 		{
309 		i=ERR_R_MALLOC_FAILURE;
310 		goto err;
311 		}
312 	ret->type=V_ASN1_INTEGER;
313 	if(len) {
314 		if ((*p == 0) && (len != 1))
315 			{
316 			p++;
317 			len--;
318 			}
319 		memcpy(s,p,(int)len);
320 		p+=len;
321 	}
322 
323 	if (ret->data != NULL) OPENSSL_free(ret->data);
324 	ret->data=s;
325 	ret->length=(int)len;
326 	if (a != NULL) (*a)=ret;
327 	*pp=p;
328 	return(ret);
329 err:
330 	OPENSSL_PUT_ERROR(ASN1, d2i_ASN1_UINTEGER, i);
331 	if ((ret != NULL) && ((a == NULL) || (*a != ret)))
332 		M_ASN1_INTEGER_free(ret);
333 	return(NULL);
334 	}
335 
ASN1_INTEGER_set(ASN1_INTEGER * a,long v)336 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
337 	{
338 	int j,k;
339 	unsigned int i;
340 	unsigned char buf[sizeof(long)+1];
341 	long d;
342 
343 	a->type=V_ASN1_INTEGER;
344 	if (a->length < (int)(sizeof(long)+1))
345 		{
346 		if (a->data != NULL)
347 			OPENSSL_free(a->data);
348 		if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL)
349 			memset((char *)a->data,0,sizeof(long)+1);
350 		}
351 	if (a->data == NULL)
352 		{
353 		OPENSSL_PUT_ERROR(ASN1, ASN1_INTEGER_set, ERR_R_MALLOC_FAILURE);
354 		return(0);
355 		}
356 	d=v;
357 	if (d < 0)
358 		{
359 		d= -d;
360 		a->type=V_ASN1_NEG_INTEGER;
361 		}
362 
363 	for (i=0; i<sizeof(long); i++)
364 		{
365 		if (d == 0) break;
366 		buf[i]=(int)d&0xff;
367 		d>>=8;
368 		}
369 	j=0;
370 	for (k=i-1; k >=0; k--)
371 		a->data[j++]=buf[k];
372 	a->length=j;
373 	return(1);
374 	}
375 
ASN1_INTEGER_get(const ASN1_INTEGER * a)376 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
377 	{
378 	int neg=0,i;
379 	long r=0;
380 
381 	if (a == NULL) return(0L);
382 	i=a->type;
383 	if (i == V_ASN1_NEG_INTEGER)
384 		neg=1;
385 	else if (i != V_ASN1_INTEGER)
386 		return -1;
387 
388 	if (a->length > (int)sizeof(long))
389 		{
390 		/* hmm... a bit ugly, return all ones */
391 		return -1;
392 		}
393 	if (a->data == NULL)
394 		return 0;
395 
396 	for (i=0; i<a->length; i++)
397 		{
398 		r<<=8;
399 		r|=(unsigned char)a->data[i];
400 		}
401 	if (neg) r= -r;
402 	return(r);
403 	}
404 
BN_to_ASN1_INTEGER(const BIGNUM * bn,ASN1_INTEGER * ai)405 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
406 	{
407 	ASN1_INTEGER *ret;
408 	int len,j;
409 
410 	if (ai == NULL)
411 		ret=M_ASN1_INTEGER_new();
412 	else
413 		ret=ai;
414 	if (ret == NULL)
415 		{
416 		OPENSSL_PUT_ERROR(ASN1, BN_to_ASN1_INTEGER, ASN1_R_NESTED_ASN1_ERROR);
417 		goto err;
418 		}
419 	if (BN_is_negative(bn) && !BN_is_zero(bn))
420 		ret->type = V_ASN1_NEG_INTEGER;
421 	else ret->type=V_ASN1_INTEGER;
422 	j=BN_num_bits(bn);
423 	len=((j == 0)?0:((j/8)+1));
424 	if (ret->length < len+4)
425 		{
426 		unsigned char *new_data=OPENSSL_realloc(ret->data, len+4);
427 		if (!new_data)
428 			{
429 			OPENSSL_PUT_ERROR(ASN1, BN_to_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
430 			goto err;
431 			}
432 		ret->data=new_data;
433 		}
434 	ret->length=BN_bn2bin(bn,ret->data);
435 	/* Correct zero case */
436 	if(!ret->length)
437 		{
438 		ret->data[0] = 0;
439 		ret->length = 1;
440 		}
441 	return(ret);
442 err:
443 	if (ret != ai) M_ASN1_INTEGER_free(ret);
444 	return(NULL);
445 	}
446 
ASN1_INTEGER_to_BN(const ASN1_INTEGER * ai,BIGNUM * bn)447 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
448 	{
449 	BIGNUM *ret;
450 
451 	if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL)
452 		OPENSSL_PUT_ERROR(ASN1, ASN1_INTEGER_to_BN, ASN1_R_BN_LIB);
453 	else if(ai->type == V_ASN1_NEG_INTEGER)
454 		BN_set_negative(ret, 1);
455 	return(ret);
456 	}
457