1/*
2 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include <limits.h>
12#include "internal/cryptlib.h"
13#include <openssl/asn1.h>
14#include "asn1_local.h"
15
16static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
17                           long max);
18static void asn1_put_length(unsigned char **pp, int length);
19
20static int _asn1_check_infinite_end(const unsigned char **p, long len)
21{
22    /*
23     * If there is 0 or 1 byte left, the length check should pick things up
24     */
25    if (len <= 0) {
26        return 1;
27    } else {
28        if ((len >= 2) && ((*p)[0] == 0) && ((*p)[1] == 0)) {
29            (*p) += 2;
30            return 1;
31        }
32    }
33    return 0;
34}
35
36int ASN1_check_infinite_end(unsigned char **p, long len)
37{
38    return _asn1_check_infinite_end((const unsigned char **)p, len);
39}
40
41int ASN1_const_check_infinite_end(const unsigned char **p, long len)
42{
43    return _asn1_check_infinite_end(p, len);
44}
45
46int ASN1_get_object(const unsigned char **pp, long *plength, int *ptag,
47                    int *pclass, long omax)
48{
49    int i, ret;
50    long len;
51    const unsigned char *p = *pp;
52    int tag, xclass, inf;
53    long max = omax;
54
55    if (omax <= 0) {
56        ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_SMALL);
57        return 0x80;
58    }
59    ret = (*p & V_ASN1_CONSTRUCTED);
60    xclass = (*p & V_ASN1_PRIVATE);
61    i = *p & V_ASN1_PRIMITIVE_TAG;
62    if (i == V_ASN1_PRIMITIVE_TAG) { /* high-tag */
63        p++;
64        if (--max == 0)
65            goto err;
66        len = 0;
67        while (*p & 0x80) {
68            len <<= 7L;
69            len |= *(p++) & 0x7f;
70            if (--max == 0)
71                goto err;
72            if (len > (INT_MAX >> 7L))
73                goto err;
74        }
75        len <<= 7L;
76        len |= *(p++) & 0x7f;
77        tag = (int)len;
78        if (--max == 0)
79            goto err;
80    } else {
81        tag = i;
82        p++;
83        if (--max == 0)
84            goto err;
85    }
86    *ptag = tag;
87    *pclass = xclass;
88    if (!asn1_get_length(&p, &inf, plength, max))
89        goto err;
90
91    if (inf && !(ret & V_ASN1_CONSTRUCTED))
92        goto err;
93
94    if (*plength > (omax - (p - *pp))) {
95        ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LONG);
96        /*
97         * Set this so that even if things are not long enough the values are
98         * set correctly
99         */
100        ret |= 0x80;
101    }
102    *pp = p;
103    return ret | inf;
104 err:
105    ERR_raise(ERR_LIB_ASN1, ASN1_R_HEADER_TOO_LONG);
106    return 0x80;
107}
108
109/*
110 * Decode a length field.
111 * The short form is a single byte defining a length 0 - 127.
112 * The long form is a byte 0 - 127 with the top bit set and this indicates
113 * the number of following octets that contain the length.  These octets
114 * are stored most significant digit first.
115 */
116static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
117                           long max)
118{
119    const unsigned char *p = *pp;
120    unsigned long ret = 0;
121    int i;
122
123    if (max-- < 1)
124        return 0;
125    if (*p == 0x80) {
126        *inf = 1;
127        p++;
128    } else {
129        *inf = 0;
130        i = *p & 0x7f;
131        if (*p++ & 0x80) {
132            if (max < i + 1)
133                return 0;
134            /* Skip leading zeroes */
135            while (i > 0 && *p == 0) {
136                p++;
137                i--;
138            }
139            if (i > (int)sizeof(long))
140                return 0;
141            while (i > 0) {
142                ret <<= 8;
143                ret |= *p++;
144                i--;
145            }
146            if (ret > LONG_MAX)
147                return 0;
148        } else {
149            ret = i;
150        }
151    }
152    *pp = p;
153    *rl = (long)ret;
154    return 1;
155}
156
157/*
158 * constructed == 2 for indefinite length constructed
159 */
160void ASN1_put_object(unsigned char **pp, int constructed, int length, int tag,
161                     int xclass)
162{
163    unsigned char *p = *pp;
164    int i, ttag;
165
166    i = (constructed) ? V_ASN1_CONSTRUCTED : 0;
167    i |= (xclass & V_ASN1_PRIVATE);
168    if (tag < 31) {
169        *(p++) = i | (tag & V_ASN1_PRIMITIVE_TAG);
170    } else {
171        *(p++) = i | V_ASN1_PRIMITIVE_TAG;
172        for (i = 0, ttag = tag; ttag > 0; i++)
173            ttag >>= 7;
174        ttag = i;
175        while (i-- > 0) {
176            p[i] = tag & 0x7f;
177            if (i != (ttag - 1))
178                p[i] |= 0x80;
179            tag >>= 7;
180        }
181        p += ttag;
182    }
183    if (constructed == 2)
184        *(p++) = 0x80;
185    else
186        asn1_put_length(&p, length);
187    *pp = p;
188}
189
190int ASN1_put_eoc(unsigned char **pp)
191{
192    unsigned char *p = *pp;
193
194    *p++ = 0;
195    *p++ = 0;
196    *pp = p;
197    return 2;
198}
199
200static void asn1_put_length(unsigned char **pp, int length)
201{
202    unsigned char *p = *pp;
203    int i, len;
204
205    if (length <= 127) {
206        *(p++) = (unsigned char)length;
207    } else {
208        len = length;
209        for (i = 0; len > 0; i++)
210            len >>= 8;
211        *(p++) = i | 0x80;
212        len = i;
213        while (i-- > 0) {
214            p[i] = length & 0xff;
215            length >>= 8;
216        }
217        p += len;
218    }
219    *pp = p;
220}
221
222int ASN1_object_size(int constructed, int length, int tag)
223{
224    int ret = 1;
225
226    if (length < 0)
227        return -1;
228    if (tag >= 31) {
229        while (tag > 0) {
230            tag >>= 7;
231            ret++;
232        }
233    }
234    if (constructed == 2) {
235        ret += 3;
236    } else {
237        ret++;
238        if (length > 127) {
239            int tmplen = length;
240            while (tmplen > 0) {
241                tmplen >>= 8;
242                ret++;
243            }
244        }
245    }
246    if (ret >= INT_MAX - length)
247        return -1;
248    return ret + length;
249}
250
251int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str)
252{
253    if (str == NULL)
254        return 0;
255    dst->type = str->type;
256    if (!ASN1_STRING_set(dst, str->data, str->length))
257        return 0;
258    /* Copy flags but preserve embed value */
259    dst->flags &= ASN1_STRING_FLAG_EMBED;
260    dst->flags |= str->flags & ~ASN1_STRING_FLAG_EMBED;
261    return 1;
262}
263
264ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *str)
265{
266    ASN1_STRING *ret;
267
268    if (!str)
269        return NULL;
270    ret = ASN1_STRING_new();
271    if (ret == NULL)
272        return NULL;
273    if (!ASN1_STRING_copy(ret, str)) {
274        ASN1_STRING_free(ret);
275        return NULL;
276    }
277    return ret;
278}
279
280int ASN1_STRING_set(ASN1_STRING *str, const void *_data, int len_in)
281{
282    unsigned char *c;
283    const char *data = _data;
284    size_t len;
285
286    if (len_in < 0) {
287        if (data == NULL)
288            return 0;
289        len = strlen(data);
290    } else {
291        len = (size_t)len_in;
292    }
293    /*
294     * Verify that the length fits within an integer for assignment to
295     * str->length below.  The additional 1 is subtracted to allow for the
296     * '\0' terminator even though this isn't strictly necessary.
297     */
298    if (len > INT_MAX - 1) {
299        ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
300        return 0;
301    }
302    if ((size_t)str->length <= len || str->data == NULL) {
303        c = str->data;
304#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
305        /* No NUL terminator in fuzzing builds */
306        str->data = OPENSSL_realloc(c, len != 0 ? len : 1);
307#else
308        str->data = OPENSSL_realloc(c, len + 1);
309#endif
310        if (str->data == NULL) {
311            ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
312            str->data = c;
313            return 0;
314        }
315    }
316    str->length = len;
317    if (data != NULL) {
318        memcpy(str->data, data, len);
319#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
320        /* Set the unused byte to something non NUL and printable. */
321        if (len == 0)
322            str->data[len] = '~';
323#else
324        /*
325         * Add a NUL terminator. This should not be necessary - but we add it as
326         * a safety precaution
327         */
328        str->data[len] = '\0';
329#endif
330    }
331    return 1;
332}
333
334void ASN1_STRING_set0(ASN1_STRING *str, void *data, int len)
335{
336    OPENSSL_free(str->data);
337    str->data = data;
338    str->length = len;
339}
340
341ASN1_STRING *ASN1_STRING_new(void)
342{
343    return ASN1_STRING_type_new(V_ASN1_OCTET_STRING);
344}
345
346ASN1_STRING *ASN1_STRING_type_new(int type)
347{
348    ASN1_STRING *ret;
349
350    ret = OPENSSL_zalloc(sizeof(*ret));
351    if (ret == NULL) {
352        ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
353        return NULL;
354    }
355    ret->type = type;
356    return ret;
357}
358
359void ossl_asn1_string_embed_free(ASN1_STRING *a, int embed)
360{
361    if (a == NULL)
362        return;
363    if (!(a->flags & ASN1_STRING_FLAG_NDEF))
364        OPENSSL_free(a->data);
365    if (embed == 0)
366        OPENSSL_free(a);
367}
368
369void ASN1_STRING_free(ASN1_STRING *a)
370{
371    if (a == NULL)
372        return;
373    ossl_asn1_string_embed_free(a, a->flags & ASN1_STRING_FLAG_EMBED);
374}
375
376void ASN1_STRING_clear_free(ASN1_STRING *a)
377{
378    if (a == NULL)
379        return;
380    if (a->data && !(a->flags & ASN1_STRING_FLAG_NDEF))
381        OPENSSL_cleanse(a->data, a->length);
382    ASN1_STRING_free(a);
383}
384
385int ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
386{
387    int i;
388
389    i = (a->length - b->length);
390    if (i == 0) {
391        if (a->length != 0)
392            i = memcmp(a->data, b->data, a->length);
393        if (i == 0)
394            return a->type - b->type;
395        else
396            return i;
397    } else {
398        return i;
399    }
400}
401
402int ASN1_STRING_length(const ASN1_STRING *x)
403{
404    return x->length;
405}
406
407#ifndef OPENSSL_NO_DEPRECATED_3_0
408void ASN1_STRING_length_set(ASN1_STRING *x, int len)
409{
410    x->length = len;
411}
412#endif
413
414int ASN1_STRING_type(const ASN1_STRING *x)
415{
416    return x->type;
417}
418
419const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x)
420{
421    return x->data;
422}
423
424#ifndef OPENSSL_NO_DEPRECATED_1_1_0
425unsigned char *ASN1_STRING_data(ASN1_STRING *x)
426{
427    return x->data;
428}
429#endif
430
431/* |max_len| excludes NUL terminator and may be 0 to indicate no restriction */
432char *ossl_sk_ASN1_UTF8STRING2text(STACK_OF(ASN1_UTF8STRING) *text,
433                                   const char *sep, size_t max_len)
434{
435    int i;
436    ASN1_UTF8STRING *current;
437    size_t length = 0, sep_len;
438    char *result = NULL;
439    char *p;
440
441    if (sep == NULL)
442        sep = "";
443    sep_len = strlen(sep);
444
445    for (i = 0; i < sk_ASN1_UTF8STRING_num(text); i++) {
446        current = sk_ASN1_UTF8STRING_value(text, i);
447        if (i > 0)
448            length += sep_len;
449        length += ASN1_STRING_length(current);
450        if (max_len != 0 && length > max_len)
451            return NULL;
452    }
453    if ((result = OPENSSL_malloc(length + 1)) == NULL)
454        return NULL;
455
456    p = result;
457    for (i = 0; i < sk_ASN1_UTF8STRING_num(text); i++) {
458        current = sk_ASN1_UTF8STRING_value(text, i);
459        length = ASN1_STRING_length(current);
460        if (i > 0 && sep_len > 0) {
461            strncpy(p, sep, sep_len + 1); /* using + 1 to silence gcc warning */
462            p += sep_len;
463        }
464        strncpy(p, (const char *)ASN1_STRING_get0_data(current), length);
465        p += length;
466    }
467    *p = '\0';
468
469    return result;
470}
471