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#include <limits.h>
61
62#include <openssl/err.h>
63#include <openssl/mem.h>
64
65#include "../internal.h"
66
67
68ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
69{
70    return M_ASN1_INTEGER_dup(x);
71}
72
73int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
74{
75    int neg, ret;
76    /* Compare signs */
77    neg = x->type & V_ASN1_NEG;
78    if (neg != (y->type & V_ASN1_NEG)) {
79        if (neg)
80            return -1;
81        else
82            return 1;
83    }
84
85    ret = ASN1_STRING_cmp(x, y);
86
87    if (neg)
88        return -ret;
89    else
90        return ret;
91}
92
93/*
94 * This converts an ASN1 INTEGER into its content encoding.
95 * The internal representation is an ASN1_STRING whose data is a big endian
96 * representation of the value, ignoring the sign. The sign is determined by
97 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
98 *
99 * Positive integers are no problem: they are almost the same as the DER
100 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
101 *
102 * Negative integers are a bit trickier...
103 * The DER representation of negative integers is in 2s complement form.
104 * The internal form is converted by complementing each octet and finally
105 * adding one to the result. This can be done less messily with a little trick.
106 * If the internal form has trailing zeroes then they will become FF by the
107 * complement and 0 by the add one (due to carry) so just copy as many trailing
108 * zeros to the destination as there are in the source. The carry will add one
109 * to the last none zero octet: so complement this octet and add one and finally
110 * complement any left over until you get to the start of the string.
111 *
112 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
113 * with 0xff. However if the first byte is 0x80 and one of the following bytes
114 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
115 * followed by optional zeros isn't padded.
116 */
117
118int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
119{
120    int pad = 0, ret, i, neg;
121    unsigned char *p, *n, pb = 0;
122
123    if (a == NULL)
124        return (0);
125    neg = a->type & V_ASN1_NEG;
126    if (a->length == 0)
127        ret = 1;
128    else {
129        ret = a->length;
130        i = a->data[0];
131        if (ret == 1 && i == 0)
132            neg = 0;
133        if (!neg && (i > 127)) {
134            pad = 1;
135            pb = 0;
136        } else if (neg) {
137            if (i > 128) {
138                pad = 1;
139                pb = 0xFF;
140            } else if (i == 128) {
141                /*
142                 * Special case: if any other bytes non zero we pad:
143                 * otherwise we don't.
144                 */
145                for (i = 1; i < a->length; i++)
146                    if (a->data[i]) {
147                        pad = 1;
148                        pb = 0xFF;
149                        break;
150                    }
151            }
152        }
153        ret += pad;
154    }
155    if (pp == NULL)
156        return (ret);
157    p = *pp;
158
159    if (pad)
160        *(p++) = pb;
161    if (a->length == 0)
162        *(p++) = 0;
163    else if (!neg)
164        OPENSSL_memcpy(p, a->data, (unsigned int)a->length);
165    else {
166        /* Begin at the end of the encoding */
167        n = a->data + a->length - 1;
168        p += a->length - 1;
169        i = a->length;
170        /* Copy zeros to destination as long as source is zero */
171        while (!*n && i > 1) {
172            *(p--) = 0;
173            n--;
174            i--;
175        }
176        /* Complement and increment next octet */
177        *(p--) = ((*(n--)) ^ 0xff) + 1;
178        i--;
179        /* Complement any octets left */
180        for (; i > 0; i--)
181            *(p--) = *(n--) ^ 0xff;
182    }
183
184    *pp += ret;
185    return (ret);
186}
187
188/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
189
190ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
191                               long len)
192{
193    ASN1_INTEGER *ret = NULL;
194    const unsigned char *p, *pend;
195    unsigned char *to, *s;
196    int i;
197
198    if ((a == NULL) || ((*a) == NULL)) {
199        if ((ret = M_ASN1_INTEGER_new()) == NULL)
200            return (NULL);
201        ret->type = V_ASN1_INTEGER;
202    } else
203        ret = (*a);
204
205    p = *pp;
206    pend = p + len;
207
208    /*
209     * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
210     * a missing NULL parameter.
211     */
212    s = (unsigned char *)OPENSSL_malloc((int)len + 1);
213    if (s == NULL) {
214        i = ERR_R_MALLOC_FAILURE;
215        goto err;
216    }
217    to = s;
218    if (!len) {
219        /*
220         * Strictly speaking this is an illegal INTEGER but we tolerate it.
221         */
222        ret->type = V_ASN1_INTEGER;
223    } else if (*p & 0x80) {     /* a negative number */
224        ret->type = V_ASN1_NEG_INTEGER;
225        if ((*p == 0xff) && (len != 1)) {
226            p++;
227            len--;
228        }
229        i = len;
230        p += i - 1;
231        to += i - 1;
232        while ((!*p) && i) {
233            *(to--) = 0;
234            i--;
235            p--;
236        }
237        /*
238         * Special case: if all zeros then the number will be of the form FF
239         * followed by n zero bytes: this corresponds to 1 followed by n zero
240         * bytes. We've already written n zeros so we just append an extra
241         * one and set the first byte to a 1. This is treated separately
242         * because it is the only case where the number of bytes is larger
243         * than len.
244         */
245        if (!i) {
246            *s = 1;
247            s[len] = 0;
248            len++;
249        } else {
250            *(to--) = (*(p--) ^ 0xff) + 1;
251            i--;
252            for (; i > 0; i--)
253                *(to--) = *(p--) ^ 0xff;
254        }
255    } else {
256        ret->type = V_ASN1_INTEGER;
257        if ((*p == 0) && (len != 1)) {
258            p++;
259            len--;
260        }
261        OPENSSL_memcpy(s, p, (int)len);
262    }
263
264    if (ret->data != NULL)
265        OPENSSL_free(ret->data);
266    ret->data = s;
267    ret->length = (int)len;
268    if (a != NULL)
269        (*a) = ret;
270    *pp = pend;
271    return (ret);
272 err:
273    OPENSSL_PUT_ERROR(ASN1, i);
274    if ((ret != NULL) && ((a == NULL) || (*a != ret)))
275        M_ASN1_INTEGER_free(ret);
276    return (NULL);
277}
278
279/*
280 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
281 * integers: some broken software can encode a positive INTEGER with its MSB
282 * set as negative (it doesn't add a padding zero).
283 */
284
285ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
286                                long length)
287{
288    ASN1_INTEGER *ret = NULL;
289    const unsigned char *p;
290    unsigned char *s;
291    long len;
292    int inf, tag, xclass;
293    int i;
294
295    if ((a == NULL) || ((*a) == NULL)) {
296        if ((ret = M_ASN1_INTEGER_new()) == NULL)
297            return (NULL);
298        ret->type = V_ASN1_INTEGER;
299    } else
300        ret = (*a);
301
302    p = *pp;
303    inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
304    if (inf & 0x80) {
305        i = ASN1_R_BAD_OBJECT_HEADER;
306        goto err;
307    }
308
309    if (tag != V_ASN1_INTEGER) {
310        i = ASN1_R_EXPECTING_AN_INTEGER;
311        goto err;
312    }
313
314    /*
315     * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
316     * a missing NULL parameter.
317     */
318    s = (unsigned char *)OPENSSL_malloc((int)len + 1);
319    if (s == NULL) {
320        i = ERR_R_MALLOC_FAILURE;
321        goto err;
322    }
323    ret->type = V_ASN1_INTEGER;
324    if (len) {
325        if ((*p == 0) && (len != 1)) {
326            p++;
327            len--;
328        }
329        OPENSSL_memcpy(s, p, (int)len);
330        p += len;
331    }
332
333    if (ret->data != NULL)
334        OPENSSL_free(ret->data);
335    ret->data = s;
336    ret->length = (int)len;
337    if (a != NULL)
338        (*a) = ret;
339    *pp = p;
340    return (ret);
341 err:
342    OPENSSL_PUT_ERROR(ASN1, i);
343    if ((ret != NULL) && ((a == NULL) || (*a != ret)))
344        M_ASN1_INTEGER_free(ret);
345    return (NULL);
346}
347
348int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
349{
350    if (v >= 0) {
351        return ASN1_INTEGER_set_uint64(a, (uint64_t) v);
352    }
353
354    if (!ASN1_INTEGER_set_uint64(a, 0 - (uint64_t) v)) {
355        return 0;
356    }
357
358    a->type = V_ASN1_NEG_INTEGER;
359    return 1;
360}
361
362int ASN1_INTEGER_set_uint64(ASN1_INTEGER *out, uint64_t v)
363{
364    uint8_t *const newdata = OPENSSL_malloc(sizeof(uint64_t));
365    if (newdata == NULL) {
366        OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
367        return 0;
368    }
369
370    OPENSSL_free(out->data);
371    out->data = newdata;
372    v = CRYPTO_bswap8(v);
373    memcpy(out->data, &v, sizeof(v));
374
375    out->type = V_ASN1_INTEGER;
376
377    size_t leading_zeros;
378    for (leading_zeros = 0; leading_zeros < sizeof(uint64_t) - 1;
379         leading_zeros++) {
380        if (out->data[leading_zeros] != 0) {
381            break;
382        }
383    }
384
385    out->length = sizeof(uint64_t) - leading_zeros;
386    OPENSSL_memmove(out->data, out->data + leading_zeros, out->length);
387
388    return 1;
389}
390
391long ASN1_INTEGER_get(const ASN1_INTEGER *a)
392{
393    int neg = 0, i;
394
395    if (a == NULL)
396        return (0L);
397    i = a->type;
398    if (i == V_ASN1_NEG_INTEGER)
399        neg = 1;
400    else if (i != V_ASN1_INTEGER)
401        return -1;
402
403    OPENSSL_COMPILE_ASSERT(sizeof(uint64_t) >= sizeof(long),
404                           long_larger_than_uint64_t);
405
406    if (a->length > (int)sizeof(uint64_t)) {
407        /* hmm... a bit ugly, return all ones */
408        return -1;
409    }
410
411    uint64_t r64 = 0;
412    if (a->data != NULL) {
413      for (i = 0; i < a->length; i++) {
414          r64 <<= 8;
415          r64 |= (unsigned char)a->data[i];
416      }
417
418      if (r64 > LONG_MAX) {
419          return -1;
420      }
421    }
422
423    long r = (long) r64;
424    if (neg)
425        r = -r;
426
427    return r;
428}
429
430ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
431{
432    ASN1_INTEGER *ret;
433    int len, j;
434
435    if (ai == NULL)
436        ret = M_ASN1_INTEGER_new();
437    else
438        ret = ai;
439    if (ret == NULL) {
440        OPENSSL_PUT_ERROR(ASN1, ASN1_R_NESTED_ASN1_ERROR);
441        goto err;
442    }
443    if (BN_is_negative(bn) && !BN_is_zero(bn))
444        ret->type = V_ASN1_NEG_INTEGER;
445    else
446        ret->type = V_ASN1_INTEGER;
447    j = BN_num_bits(bn);
448    len = ((j == 0) ? 0 : ((j / 8) + 1));
449    if (ret->length < len + 4) {
450        unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4);
451        if (!new_data) {
452            OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
453            goto err;
454        }
455        ret->data = new_data;
456    }
457    ret->length = BN_bn2bin(bn, ret->data);
458    /* Correct zero case */
459    if (!ret->length) {
460        ret->data[0] = 0;
461        ret->length = 1;
462    }
463    return (ret);
464 err:
465    if (ret != ai)
466        M_ASN1_INTEGER_free(ret);
467    return (NULL);
468}
469
470BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
471{
472    BIGNUM *ret;
473
474    if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL)
475        OPENSSL_PUT_ERROR(ASN1, ASN1_R_BN_LIB);
476    else if (ai->type == V_ASN1_NEG_INTEGER)
477        BN_set_negative(ret, 1);
478    return (ret);
479}
480