xref: /freebsd/crypto/openssl/crypto/asn1/asn1_lib.c (revision 4d846d26) 
1 /*
2  * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (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 
16 static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
17                            long max);
18 static void asn1_put_length(unsigned char **pp, int length);
19 
20 static 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 if ((len >= 2) && ((*p)[0] == 0) && ((*p)[1] == 0)) {
28         (*p) += 2;
29         return 1;
30     }
31     return 0;
32 }
33 
34 int ASN1_check_infinite_end(unsigned char **p, long len)
35 {
36     return _asn1_check_infinite_end((const unsigned char **)p, len);
37 }
38 
39 int ASN1_const_check_infinite_end(const unsigned char **p, long len)
40 {
41     return _asn1_check_infinite_end(p, len);
42 }
43 
44 int ASN1_get_object(const unsigned char **pp, long *plength, int *ptag,
45                     int *pclass, long omax)
46 {
47     int i, ret;
48     long l;
49     const unsigned char *p = *pp;
50     int tag, xclass, inf;
51     long max = omax;
52 
53     if (!max)
54         goto err;
55     ret = (*p & V_ASN1_CONSTRUCTED);
56     xclass = (*p & V_ASN1_PRIVATE);
57     i = *p & V_ASN1_PRIMITIVE_TAG;
58     if (i == V_ASN1_PRIMITIVE_TAG) { /* high-tag */
59         p++;
60         if (--max == 0)
61             goto err;
62         l = 0;
63         while (*p & 0x80) {
64             l <<= 7L;
65             l |= *(p++) & 0x7f;
66             if (--max == 0)
67                 goto err;
68             if (l > (INT_MAX >> 7L))
69                 goto err;
70         }
71         l <<= 7L;
72         l |= *(p++) & 0x7f;
73         tag = (int)l;
74         if (--max == 0)
75             goto err;
76     } else {
77         tag = i;
78         p++;
79         if (--max == 0)
80             goto err;
81     }
82     *ptag = tag;
83     *pclass = xclass;
84     if (!asn1_get_length(&p, &inf, plength, max))
85         goto err;
86 
87     if (inf && !(ret & V_ASN1_CONSTRUCTED))
88         goto err;
89 
90     if (*plength > (omax - (p - *pp))) {
91         ASN1err(ASN1_F_ASN1_GET_OBJECT, ASN1_R_TOO_LONG);
92         /*
93          * Set this so that even if things are not long enough the values are
94          * set correctly
95          */
96         ret |= 0x80;
97     }
98     *pp = p;
99     return ret | inf;
100  err:
101     ASN1err(ASN1_F_ASN1_GET_OBJECT, ASN1_R_HEADER_TOO_LONG);
102     return 0x80;
103 }
104 
105 /*
106  * Decode a length field.
107  * The short form is a single byte defining a length 0 - 127.
108  * The long form is a byte 0 - 127 with the top bit set and this indicates
109  * the number of following octets that contain the length.  These octets
110  * are stored most significant digit first.
111  */
112 static int asn1_get_length(const unsigned char **pp, int *inf, long *rl,
113                            long max)
114 {
115     const unsigned char *p = *pp;
116     unsigned long ret = 0;
117     int i;
118 
119     if (max-- < 1)
120         return 0;
121     if (*p == 0x80) {
122         *inf = 1;
123         p++;
124     } else {
125         *inf = 0;
126         i = *p & 0x7f;
127         if (*p++ & 0x80) {
128             if (max < i + 1)
129                 return 0;
130             /* Skip leading zeroes */
131             while (i > 0 && *p == 0) {
132                 p++;
133                 i--;
134             }
135             if (i > (int)sizeof(long))
136                 return 0;
137             while (i > 0) {
138                 ret <<= 8;
139                 ret |= *p++;
140                 i--;
141             }
142             if (ret > LONG_MAX)
143                 return 0;
144         } else
145             ret = i;
146     }
147     *pp = p;
148     *rl = (long)ret;
149     return 1;
150 }
151 
152 /*
153  * class 0 is constructed constructed == 2 for indefinite length constructed
154  */
155 void ASN1_put_object(unsigned char **pp, int constructed, int length, int tag,
156                      int xclass)
157 {
158     unsigned char *p = *pp;
159     int i, ttag;
160 
161     i = (constructed) ? V_ASN1_CONSTRUCTED : 0;
162     i |= (xclass & V_ASN1_PRIVATE);
163     if (tag < 31)
164         *(p++) = i | (tag & V_ASN1_PRIMITIVE_TAG);
165     else {
166         *(p++) = i | V_ASN1_PRIMITIVE_TAG;
167         for (i = 0, ttag = tag; ttag > 0; i++)
168             ttag >>= 7;
169         ttag = i;
170         while (i-- > 0) {
171             p[i] = tag & 0x7f;
172             if (i != (ttag - 1))
173                 p[i] |= 0x80;
174             tag >>= 7;
175         }
176         p += ttag;
177     }
178     if (constructed == 2)
179         *(p++) = 0x80;
180     else
181         asn1_put_length(&p, length);
182     *pp = p;
183 }
184 
185 int ASN1_put_eoc(unsigned char **pp)
186 {
187     unsigned char *p = *pp;
188     *p++ = 0;
189     *p++ = 0;
190     *pp = p;
191     return 2;
192 }
193 
194 static void asn1_put_length(unsigned char **pp, int length)
195 {
196     unsigned char *p = *pp;
197     int i, l;
198     if (length <= 127)
199         *(p++) = (unsigned char)length;
200     else {
201         l = length;
202         for (i = 0; l > 0; i++)
203             l >>= 8;
204         *(p++) = i | 0x80;
205         l = i;
206         while (i-- > 0) {
207             p[i] = length & 0xff;
208             length >>= 8;
209         }
210         p += l;
211     }
212     *pp = p;
213 }
214 
215 int ASN1_object_size(int constructed, int length, int tag)
216 {
217     int ret = 1;
218     if (length < 0)
219         return -1;
220     if (tag >= 31) {
221         while (tag > 0) {
222             tag >>= 7;
223             ret++;
224         }
225     }
226     if (constructed == 2) {
227         ret += 3;
228     } else {
229         ret++;
230         if (length > 127) {
231             int tmplen = length;
232             while (tmplen > 0) {
233                 tmplen >>= 8;
234                 ret++;
235             }
236         }
237     }
238     if (ret >= INT_MAX - length)
239         return -1;
240     return ret + length;
241 }
242 
243 int ASN1_STRING_copy(ASN1_STRING *dst, const ASN1_STRING *str)
244 {
245     if (str == NULL)
246         return 0;
247     dst->type = str->type;
248     if (!ASN1_STRING_set(dst, str->data, str->length))
249         return 0;
250     /* Copy flags but preserve embed value */
251     dst->flags &= ASN1_STRING_FLAG_EMBED;
252     dst->flags |= str->flags & ~ASN1_STRING_FLAG_EMBED;
253     return 1;
254 }
255 
256 ASN1_STRING *ASN1_STRING_dup(const ASN1_STRING *str)
257 {
258     ASN1_STRING *ret;
259     if (!str)
260         return NULL;
261     ret = ASN1_STRING_new();
262     if (ret == NULL)
263         return NULL;
264     if (!ASN1_STRING_copy(ret, str)) {
265         ASN1_STRING_free(ret);
266         return NULL;
267     }
268     return ret;
269 }
270 
271 int ASN1_STRING_set(ASN1_STRING *str, const void *_data, int len_in)
272 {
273     unsigned char *c;
274     const char *data = _data;
275     size_t len;
276 
277     if (len_in < 0) {
278         if (data == NULL)
279             return 0;
280         len = strlen(data);
281     } else {
282         len = (size_t)len_in;
283     }
284     /*
285      * Verify that the length fits within an integer for assignment to
286      * str->length below.  The additional 1 is subtracted to allow for the
287      * '\0' terminator even though this isn't strictly necessary.
288      */
289     if (len > INT_MAX - 1) {
290         ASN1err(0, ASN1_R_TOO_LARGE);
291         return 0;
292     }
293     if ((size_t)str->length <= len || str->data == NULL) {
294         c = str->data;
295 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
296         /* No NUL terminator in fuzzing builds */
297         str->data = OPENSSL_realloc(c, len != 0 ? len : 1);
298 #else
299         str->data = OPENSSL_realloc(c, len + 1);
300 #endif
301         if (str->data == NULL) {
302             ASN1err(ASN1_F_ASN1_STRING_SET, ERR_R_MALLOC_FAILURE);
303             str->data = c;
304             return 0;
305         }
306     }
307     str->length = len;
308     if (data != NULL) {
309         memcpy(str->data, data, len);
310 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
311         /* Set the unused byte to something non NUL and printable. */
312         if (len == 0)
313             str->data[len] = '~';
314 #else
315         /*
316          * Add a NUL terminator. This should not be necessary - but we add it as
317          * a safety precaution
318          */
319         str->data[len] = '\0';
320 #endif
321     }
322     return 1;
323 }
324 
325 void ASN1_STRING_set0(ASN1_STRING *str, void *data, int len)
326 {
327     OPENSSL_free(str->data);
328     str->data = data;
329     str->length = len;
330 }
331 
332 ASN1_STRING *ASN1_STRING_new(void)
333 {
334     return ASN1_STRING_type_new(V_ASN1_OCTET_STRING);
335 }
336 
337 ASN1_STRING *ASN1_STRING_type_new(int type)
338 {
339     ASN1_STRING *ret;
340 
341     ret = OPENSSL_zalloc(sizeof(*ret));
342     if (ret == NULL) {
343         ASN1err(ASN1_F_ASN1_STRING_TYPE_NEW, ERR_R_MALLOC_FAILURE);
344         return NULL;
345     }
346     ret->type = type;
347     return ret;
348 }
349 
350 void asn1_string_embed_free(ASN1_STRING *a, int embed)
351 {
352     if (a == NULL)
353         return;
354     if (!(a->flags & ASN1_STRING_FLAG_NDEF))
355         OPENSSL_free(a->data);
356     if (embed == 0)
357         OPENSSL_free(a);
358 }
359 
360 void ASN1_STRING_free(ASN1_STRING *a)
361 {
362     if (a == NULL)
363         return;
364     asn1_string_embed_free(a, a->flags & ASN1_STRING_FLAG_EMBED);
365 }
366 
367 void ASN1_STRING_clear_free(ASN1_STRING *a)
368 {
369     if (a == NULL)
370         return;
371     if (a->data && !(a->flags & ASN1_STRING_FLAG_NDEF))
372         OPENSSL_cleanse(a->data, a->length);
373     ASN1_STRING_free(a);
374 }
375 
376 int ASN1_STRING_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
377 {
378     int i;
379 
380     i = (a->length - b->length);
381     if (i == 0) {
382         if (a->length != 0)
383             i = memcmp(a->data, b->data, a->length);
384         if (i == 0)
385             return a->type - b->type;
386         else
387             return i;
388     } else
389         return i;
390 }
391 
392 int ASN1_STRING_length(const ASN1_STRING *x)
393 {
394     return x->length;
395 }
396 
397 void ASN1_STRING_length_set(ASN1_STRING *x, int len)
398 {
399     x->length = len;
400 }
401 
402 int ASN1_STRING_type(const ASN1_STRING *x)
403 {
404     return x->type;
405 }
406 
407 const unsigned char *ASN1_STRING_get0_data(const ASN1_STRING *x)
408 {
409     return x->data;
410 }
411 
412 # if OPENSSL_API_COMPAT < 0x10100000L
413 unsigned char *ASN1_STRING_data(ASN1_STRING *x)
414 {
415     return x->data;
416 }
417 #endif
418