xref: /freebsd/crypto/openssl/crypto/pkcs7/pk7_doit.c (revision 1d386b48)
1 /*
2  * Copyright 1995-2023 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 <openssl/rand.h>
12 #include <openssl/objects.h>
13 #include <openssl/x509.h>
14 #include <openssl/x509v3.h>
15 #include <openssl/err.h>
16 #include "internal/cryptlib.h"
17 #include "internal/sizes.h"
18 #include "pk7_local.h"
19 
20 static int add_attribute(STACK_OF(X509_ATTRIBUTE) **sk, int nid, int atrtype,
21                          void *value);
22 static ASN1_TYPE *get_attribute(const STACK_OF(X509_ATTRIBUTE) *sk, int nid);
23 
24 int PKCS7_type_is_other(PKCS7 *p7)
25 {
26     int isOther = 1;
27 
28     int nid = OBJ_obj2nid(p7->type);
29 
30     switch (nid) {
31     case NID_pkcs7_data:
32     case NID_pkcs7_signed:
33     case NID_pkcs7_enveloped:
34     case NID_pkcs7_signedAndEnveloped:
35     case NID_pkcs7_digest:
36     case NID_pkcs7_encrypted:
37         isOther = 0;
38         break;
39     default:
40         isOther = 1;
41     }
42 
43     return isOther;
44 
45 }
46 
47 ASN1_OCTET_STRING *PKCS7_get_octet_string(PKCS7 *p7)
48 {
49     if (PKCS7_type_is_data(p7))
50         return p7->d.data;
51     if (PKCS7_type_is_other(p7) && p7->d.other
52         && (p7->d.other->type == V_ASN1_OCTET_STRING))
53         return p7->d.other->value.octet_string;
54     return NULL;
55 }
56 
57 static int pkcs7_bio_add_digest(BIO **pbio, X509_ALGOR *alg,
58                                 const PKCS7_CTX *ctx)
59 {
60     BIO *btmp;
61     char name[OSSL_MAX_NAME_SIZE];
62     EVP_MD *fetched = NULL;
63     const EVP_MD *md;
64 
65     if ((btmp = BIO_new(BIO_f_md())) == NULL) {
66         ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
67         goto err;
68     }
69 
70     OBJ_obj2txt(name, sizeof(name), alg->algorithm, 0);
71 
72     (void)ERR_set_mark();
73     fetched = EVP_MD_fetch(ossl_pkcs7_ctx_get0_libctx(ctx), name,
74                            ossl_pkcs7_ctx_get0_propq(ctx));
75     if (fetched != NULL)
76         md = fetched;
77     else
78         md = EVP_get_digestbyname(name);
79 
80     if (md == NULL) {
81         (void)ERR_clear_last_mark();
82         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNKNOWN_DIGEST_TYPE);
83         goto err;
84     }
85     (void)ERR_pop_to_mark();
86 
87     if (BIO_set_md(btmp, md) <= 0) {
88         ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
89         EVP_MD_free(fetched);
90         goto err;
91     }
92     EVP_MD_free(fetched);
93     if (*pbio == NULL)
94         *pbio = btmp;
95     else if (!BIO_push(*pbio, btmp)) {
96         ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
97         goto err;
98     }
99     btmp = NULL;
100 
101     return 1;
102 
103  err:
104     BIO_free(btmp);
105     return 0;
106 }
107 
108 static int pkcs7_encode_rinfo(PKCS7_RECIP_INFO *ri,
109                               unsigned char *key, int keylen)
110 {
111     EVP_PKEY_CTX *pctx = NULL;
112     EVP_PKEY *pkey = NULL;
113     unsigned char *ek = NULL;
114     int ret = 0;
115     size_t eklen;
116     const PKCS7_CTX *ctx = ri->ctx;
117 
118     pkey = X509_get0_pubkey(ri->cert);
119     if (pkey == NULL)
120         return 0;
121 
122     pctx = EVP_PKEY_CTX_new_from_pkey(ossl_pkcs7_ctx_get0_libctx(ctx), pkey,
123                                       ossl_pkcs7_ctx_get0_propq(ctx));
124     if (pctx == NULL)
125         return 0;
126 
127     if (EVP_PKEY_encrypt_init(pctx) <= 0)
128         goto err;
129 
130     if (EVP_PKEY_encrypt(pctx, NULL, &eklen, key, keylen) <= 0)
131         goto err;
132 
133     ek = OPENSSL_malloc(eklen);
134 
135     if (ek == NULL) {
136         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
137         goto err;
138     }
139 
140     if (EVP_PKEY_encrypt(pctx, ek, &eklen, key, keylen) <= 0)
141         goto err;
142 
143     ASN1_STRING_set0(ri->enc_key, ek, eklen);
144     ek = NULL;
145 
146     ret = 1;
147 
148  err:
149     EVP_PKEY_CTX_free(pctx);
150     OPENSSL_free(ek);
151     return ret;
152 
153 }
154 
155 static int pkcs7_decrypt_rinfo(unsigned char **pek, int *peklen,
156                                PKCS7_RECIP_INFO *ri, EVP_PKEY *pkey,
157                                size_t fixlen)
158 {
159     EVP_PKEY_CTX *pctx = NULL;
160     unsigned char *ek = NULL;
161     size_t eklen;
162     int ret = -1;
163     const PKCS7_CTX *ctx = ri->ctx;
164 
165     pctx = EVP_PKEY_CTX_new_from_pkey(ossl_pkcs7_ctx_get0_libctx(ctx), pkey,
166                                       ossl_pkcs7_ctx_get0_propq(ctx));
167     if (pctx == NULL)
168         return -1;
169 
170     if (EVP_PKEY_decrypt_init(pctx) <= 0)
171         goto err;
172 
173     if (EVP_PKEY_decrypt(pctx, NULL, &eklen,
174                          ri->enc_key->data, ri->enc_key->length) <= 0)
175         goto err;
176 
177     ek = OPENSSL_malloc(eklen);
178 
179     if (ek == NULL) {
180         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
181         goto err;
182     }
183 
184     if (EVP_PKEY_decrypt(pctx, ek, &eklen,
185                          ri->enc_key->data, ri->enc_key->length) <= 0
186             || eklen == 0
187             || (fixlen != 0 && eklen != fixlen)) {
188         ret = 0;
189         ERR_raise(ERR_LIB_PKCS7, ERR_R_EVP_LIB);
190         goto err;
191     }
192 
193     ret = 1;
194 
195     OPENSSL_clear_free(*pek, *peklen);
196     *pek = ek;
197     *peklen = eklen;
198 
199  err:
200     EVP_PKEY_CTX_free(pctx);
201     if (!ret)
202         OPENSSL_free(ek);
203 
204     return ret;
205 }
206 
207 BIO *PKCS7_dataInit(PKCS7 *p7, BIO *bio)
208 {
209     int i;
210     BIO *out = NULL, *btmp = NULL;
211     X509_ALGOR *xa = NULL;
212     EVP_CIPHER *fetched_cipher = NULL;
213     const EVP_CIPHER *cipher;
214     const EVP_CIPHER *evp_cipher = NULL;
215     STACK_OF(X509_ALGOR) *md_sk = NULL;
216     STACK_OF(PKCS7_RECIP_INFO) *rsk = NULL;
217     X509_ALGOR *xalg = NULL;
218     PKCS7_RECIP_INFO *ri = NULL;
219     ASN1_OCTET_STRING *os = NULL;
220     const PKCS7_CTX *p7_ctx;
221     OSSL_LIB_CTX *libctx;
222     const char *propq;
223 
224     if (p7 == NULL) {
225         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_INVALID_NULL_POINTER);
226         return NULL;
227     }
228     p7_ctx = ossl_pkcs7_get0_ctx(p7);
229     libctx = ossl_pkcs7_ctx_get0_libctx(p7_ctx);
230     propq = ossl_pkcs7_ctx_get0_propq(p7_ctx);
231 
232     /*
233      * The content field in the PKCS7 ContentInfo is optional, but that really
234      * only applies to inner content (precisely, detached signatures).
235      *
236      * When reading content, missing outer content is therefore treated as an
237      * error.
238      *
239      * When creating content, PKCS7_content_new() must be called before
240      * calling this method, so a NULL p7->d is always an error.
241      */
242     if (p7->d.ptr == NULL) {
243         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);
244         return NULL;
245     }
246 
247     i = OBJ_obj2nid(p7->type);
248     p7->state = PKCS7_S_HEADER;
249 
250     switch (i) {
251     case NID_pkcs7_signed:
252         md_sk = p7->d.sign->md_algs;
253         os = PKCS7_get_octet_string(p7->d.sign->contents);
254         break;
255     case NID_pkcs7_signedAndEnveloped:
256         rsk = p7->d.signed_and_enveloped->recipientinfo;
257         md_sk = p7->d.signed_and_enveloped->md_algs;
258         xalg = p7->d.signed_and_enveloped->enc_data->algorithm;
259         evp_cipher = p7->d.signed_and_enveloped->enc_data->cipher;
260         if (evp_cipher == NULL) {
261             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_CIPHER_NOT_INITIALIZED);
262             goto err;
263         }
264         break;
265     case NID_pkcs7_enveloped:
266         rsk = p7->d.enveloped->recipientinfo;
267         xalg = p7->d.enveloped->enc_data->algorithm;
268         evp_cipher = p7->d.enveloped->enc_data->cipher;
269         if (evp_cipher == NULL) {
270             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_CIPHER_NOT_INITIALIZED);
271             goto err;
272         }
273         break;
274     case NID_pkcs7_digest:
275         xa = p7->d.digest->md;
276         os = PKCS7_get_octet_string(p7->d.digest->contents);
277         break;
278     case NID_pkcs7_data:
279         break;
280     default:
281         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
282         goto err;
283     }
284 
285     for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++)
286         if (!pkcs7_bio_add_digest(&out, sk_X509_ALGOR_value(md_sk, i), p7_ctx))
287             goto err;
288 
289     if (xa && !pkcs7_bio_add_digest(&out, xa, p7_ctx))
290         goto err;
291 
292     if (evp_cipher != NULL) {
293         unsigned char key[EVP_MAX_KEY_LENGTH];
294         unsigned char iv[EVP_MAX_IV_LENGTH];
295         int keylen, ivlen;
296         EVP_CIPHER_CTX *ctx;
297 
298         if ((btmp = BIO_new(BIO_f_cipher())) == NULL) {
299             ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
300             goto err;
301         }
302         BIO_get_cipher_ctx(btmp, &ctx);
303         keylen = EVP_CIPHER_get_key_length(evp_cipher);
304         ivlen = EVP_CIPHER_get_iv_length(evp_cipher);
305         xalg->algorithm = OBJ_nid2obj(EVP_CIPHER_get_type(evp_cipher));
306         if (ivlen > 0)
307             if (RAND_bytes_ex(libctx, iv, ivlen, 0) <= 0)
308                 goto err;
309 
310         (void)ERR_set_mark();
311         fetched_cipher = EVP_CIPHER_fetch(libctx,
312                                           EVP_CIPHER_get0_name(evp_cipher),
313                                           propq);
314         (void)ERR_pop_to_mark();
315         if (fetched_cipher != NULL)
316             cipher = fetched_cipher;
317         else
318             cipher = evp_cipher;
319 
320         if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, 1) <= 0)
321             goto err;
322 
323         EVP_CIPHER_free(fetched_cipher);
324         fetched_cipher = NULL;
325 
326         if (EVP_CIPHER_CTX_rand_key(ctx, key) <= 0)
327             goto err;
328         if (EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, 1) <= 0)
329             goto err;
330 
331         if (ivlen > 0) {
332             if (xalg->parameter == NULL) {
333                 xalg->parameter = ASN1_TYPE_new();
334                 if (xalg->parameter == NULL)
335                     goto err;
336             }
337             if (EVP_CIPHER_param_to_asn1(ctx, xalg->parameter) <= 0)
338                 goto err;
339         }
340 
341         /* Lets do the pub key stuff :-) */
342         for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
343             ri = sk_PKCS7_RECIP_INFO_value(rsk, i);
344             if (pkcs7_encode_rinfo(ri, key, keylen) <= 0)
345                 goto err;
346         }
347         OPENSSL_cleanse(key, keylen);
348 
349         if (out == NULL)
350             out = btmp;
351         else
352             BIO_push(out, btmp);
353         btmp = NULL;
354     }
355 
356     if (bio == NULL) {
357         if (PKCS7_is_detached(p7)) {
358             bio = BIO_new(BIO_s_null());
359         } else if (os && os->length > 0) {
360             bio = BIO_new_mem_buf(os->data, os->length);
361         } else {
362             bio = BIO_new(BIO_s_mem());
363             if (bio == NULL)
364                 goto err;
365             BIO_set_mem_eof_return(bio, 0);
366         }
367         if (bio == NULL)
368             goto err;
369     }
370     if (out)
371         BIO_push(out, bio);
372     else
373         out = bio;
374     return out;
375 
376  err:
377     EVP_CIPHER_free(fetched_cipher);
378     BIO_free_all(out);
379     BIO_free_all(btmp);
380     return NULL;
381 }
382 
383 static int pkcs7_cmp_ri(PKCS7_RECIP_INFO *ri, X509 *pcert)
384 {
385     int ret;
386     ret = X509_NAME_cmp(ri->issuer_and_serial->issuer,
387                         X509_get_issuer_name(pcert));
388     if (ret)
389         return ret;
390     return ASN1_INTEGER_cmp(X509_get0_serialNumber(pcert),
391                             ri->issuer_and_serial->serial);
392 }
393 
394 /* int */
395 BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert)
396 {
397     int i, len;
398     BIO *out = NULL, *btmp = NULL, *etmp = NULL, *bio = NULL;
399     X509_ALGOR *xa;
400     ASN1_OCTET_STRING *data_body = NULL;
401     EVP_MD *evp_md = NULL;
402     const EVP_MD *md;
403     EVP_CIPHER *evp_cipher = NULL;
404     const EVP_CIPHER *cipher = NULL;
405     EVP_CIPHER_CTX *evp_ctx = NULL;
406     X509_ALGOR *enc_alg = NULL;
407     STACK_OF(X509_ALGOR) *md_sk = NULL;
408     STACK_OF(PKCS7_RECIP_INFO) *rsk = NULL;
409     PKCS7_RECIP_INFO *ri = NULL;
410     unsigned char *ek = NULL, *tkey = NULL;
411     int eklen = 0, tkeylen = 0;
412     char name[OSSL_MAX_NAME_SIZE];
413     const PKCS7_CTX *p7_ctx;
414     OSSL_LIB_CTX *libctx;
415     const char *propq;
416 
417     if (p7 == NULL) {
418         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_INVALID_NULL_POINTER);
419         return NULL;
420     }
421 
422     p7_ctx = ossl_pkcs7_get0_ctx(p7);
423     libctx = ossl_pkcs7_ctx_get0_libctx(p7_ctx);
424     propq = ossl_pkcs7_ctx_get0_propq(p7_ctx);
425 
426     if (p7->d.ptr == NULL) {
427         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);
428         return NULL;
429     }
430 
431     i = OBJ_obj2nid(p7->type);
432     p7->state = PKCS7_S_HEADER;
433 
434     switch (i) {
435     case NID_pkcs7_signed:
436         /*
437          * p7->d.sign->contents is a PKCS7 structure consisting of a contentType
438          * field and optional content.
439          * data_body is NULL if that structure has no (=detached) content
440          * or if the contentType is wrong (i.e., not "data").
441          */
442         data_body = PKCS7_get_octet_string(p7->d.sign->contents);
443         if (!PKCS7_is_detached(p7) && data_body == NULL) {
444             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_INVALID_SIGNED_DATA_TYPE);
445             goto err;
446         }
447         md_sk = p7->d.sign->md_algs;
448         break;
449     case NID_pkcs7_signedAndEnveloped:
450         rsk = p7->d.signed_and_enveloped->recipientinfo;
451         md_sk = p7->d.signed_and_enveloped->md_algs;
452         /* data_body is NULL if the optional EncryptedContent is missing. */
453         data_body = p7->d.signed_and_enveloped->enc_data->enc_data;
454         enc_alg = p7->d.signed_and_enveloped->enc_data->algorithm;
455 
456         OBJ_obj2txt(name, sizeof(name), enc_alg->algorithm, 0);
457 
458         (void)ERR_set_mark();
459         evp_cipher = EVP_CIPHER_fetch(libctx, name, propq);
460         if (evp_cipher != NULL)
461             cipher = evp_cipher;
462         else
463             cipher = EVP_get_cipherbyname(name);
464 
465         if (cipher == NULL) {
466             (void)ERR_clear_last_mark();
467             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CIPHER_TYPE);
468             goto err;
469         }
470         (void)ERR_pop_to_mark();
471         break;
472     case NID_pkcs7_enveloped:
473         rsk = p7->d.enveloped->recipientinfo;
474         enc_alg = p7->d.enveloped->enc_data->algorithm;
475         /* data_body is NULL if the optional EncryptedContent is missing. */
476         data_body = p7->d.enveloped->enc_data->enc_data;
477         OBJ_obj2txt(name, sizeof(name), enc_alg->algorithm, 0);
478 
479         (void)ERR_set_mark();
480         evp_cipher = EVP_CIPHER_fetch(libctx, name, propq);
481         if (evp_cipher != NULL)
482             cipher = evp_cipher;
483         else
484             cipher = EVP_get_cipherbyname(name);
485 
486         if (cipher == NULL) {
487             (void)ERR_clear_last_mark();
488             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CIPHER_TYPE);
489             goto err;
490         }
491         (void)ERR_pop_to_mark();
492         break;
493     default:
494         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
495         goto err;
496     }
497 
498     /* Detached content must be supplied via in_bio instead. */
499     if (data_body == NULL && in_bio == NULL) {
500         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);
501         goto err;
502     }
503 
504     /* We will be checking the signature */
505     if (md_sk != NULL) {
506         for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++) {
507             xa = sk_X509_ALGOR_value(md_sk, i);
508             if ((btmp = BIO_new(BIO_f_md())) == NULL) {
509                 ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
510                 goto err;
511             }
512 
513             OBJ_obj2txt(name, sizeof(name), xa->algorithm, 0);
514 
515             (void)ERR_set_mark();
516             evp_md = EVP_MD_fetch(libctx, name, propq);
517             if (evp_md != NULL)
518                 md = evp_md;
519             else
520                 md = EVP_get_digestbyname(name);
521 
522             if (md == NULL) {
523                 (void)ERR_clear_last_mark();
524                 ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNKNOWN_DIGEST_TYPE);
525                 goto err;
526             }
527             (void)ERR_pop_to_mark();
528 
529             if (BIO_set_md(btmp, md) <= 0) {
530                 EVP_MD_free(evp_md);
531                 ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
532                 goto err;
533             }
534             EVP_MD_free(evp_md);
535             if (out == NULL)
536                 out = btmp;
537             else
538                 BIO_push(out, btmp);
539             btmp = NULL;
540         }
541     }
542 
543     if (cipher != NULL) {
544         if ((etmp = BIO_new(BIO_f_cipher())) == NULL) {
545             ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
546             goto err;
547         }
548 
549         /*
550          * It was encrypted, we need to decrypt the secret key with the
551          * private key
552          */
553 
554         /*
555          * Find the recipientInfo which matches the passed certificate (if
556          * any)
557          */
558 
559         if (pcert) {
560             for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
561                 ri = sk_PKCS7_RECIP_INFO_value(rsk, i);
562                 if (!pkcs7_cmp_ri(ri, pcert))
563                     break;
564                 ri = NULL;
565             }
566             if (ri == NULL) {
567                 ERR_raise(ERR_LIB_PKCS7,
568                           PKCS7_R_NO_RECIPIENT_MATCHES_CERTIFICATE);
569                 goto err;
570             }
571         }
572 
573         /* If we haven't got a certificate try each ri in turn */
574         if (pcert == NULL) {
575             /*
576              * Always attempt to decrypt all rinfo even after success as a
577              * defence against MMA timing attacks.
578              */
579             for (i = 0; i < sk_PKCS7_RECIP_INFO_num(rsk); i++) {
580                 ri = sk_PKCS7_RECIP_INFO_value(rsk, i);
581                 ri->ctx = p7_ctx;
582                 if (pkcs7_decrypt_rinfo(&ek, &eklen, ri, pkey,
583                         EVP_CIPHER_get_key_length(cipher)) < 0)
584                     goto err;
585                 ERR_clear_error();
586             }
587         } else {
588             ri->ctx = p7_ctx;
589             /* Only exit on fatal errors, not decrypt failure */
590             if (pkcs7_decrypt_rinfo(&ek, &eklen, ri, pkey, 0) < 0)
591                 goto err;
592             ERR_clear_error();
593         }
594 
595         evp_ctx = NULL;
596         BIO_get_cipher_ctx(etmp, &evp_ctx);
597         if (EVP_CipherInit_ex(evp_ctx, cipher, NULL, NULL, NULL, 0) <= 0)
598             goto err;
599         if (EVP_CIPHER_asn1_to_param(evp_ctx, enc_alg->parameter) <= 0)
600             goto err;
601         /* Generate random key as MMA defence */
602         len = EVP_CIPHER_CTX_get_key_length(evp_ctx);
603         if (len <= 0)
604             goto err;
605         tkeylen = (size_t)len;
606         tkey = OPENSSL_malloc(tkeylen);
607         if (tkey == NULL)
608             goto err;
609         if (EVP_CIPHER_CTX_rand_key(evp_ctx, tkey) <= 0)
610             goto err;
611         if (ek == NULL) {
612             ek = tkey;
613             eklen = tkeylen;
614             tkey = NULL;
615         }
616 
617         if (eklen != EVP_CIPHER_CTX_get_key_length(evp_ctx)) {
618             /*
619              * Some S/MIME clients don't use the same key and effective key
620              * length. The key length is determined by the size of the
621              * decrypted RSA key.
622              */
623             if (EVP_CIPHER_CTX_set_key_length(evp_ctx, eklen) <= 0) {
624                 /* Use random key as MMA defence */
625                 OPENSSL_clear_free(ek, eklen);
626                 ek = tkey;
627                 eklen = tkeylen;
628                 tkey = NULL;
629             }
630         }
631         /* Clear errors so we don't leak information useful in MMA */
632         ERR_clear_error();
633         if (EVP_CipherInit_ex(evp_ctx, NULL, NULL, ek, NULL, 0) <= 0)
634             goto err;
635 
636         OPENSSL_clear_free(ek, eklen);
637         ek = NULL;
638         OPENSSL_clear_free(tkey, tkeylen);
639         tkey = NULL;
640 
641         if (out == NULL)
642             out = etmp;
643         else
644             BIO_push(out, etmp);
645         etmp = NULL;
646     }
647     if (in_bio != NULL) {
648         bio = in_bio;
649     } else {
650         if (data_body->length > 0)
651             bio = BIO_new_mem_buf(data_body->data, data_body->length);
652         else {
653             bio = BIO_new(BIO_s_mem());
654             if (bio == NULL)
655                 goto err;
656             BIO_set_mem_eof_return(bio, 0);
657         }
658         if (bio == NULL)
659             goto err;
660     }
661     BIO_push(out, bio);
662     bio = NULL;
663     EVP_CIPHER_free(evp_cipher);
664     return out;
665 
666  err:
667     EVP_CIPHER_free(evp_cipher);
668     OPENSSL_clear_free(ek, eklen);
669     OPENSSL_clear_free(tkey, tkeylen);
670     BIO_free_all(out);
671     BIO_free_all(btmp);
672     BIO_free_all(etmp);
673     BIO_free_all(bio);
674     return NULL;
675 }
676 
677 static BIO *PKCS7_find_digest(EVP_MD_CTX **pmd, BIO *bio, int nid)
678 {
679     for (;;) {
680         bio = BIO_find_type(bio, BIO_TYPE_MD);
681         if (bio == NULL) {
682             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
683             return NULL;
684         }
685         BIO_get_md_ctx(bio, pmd);
686         if (*pmd == NULL) {
687             ERR_raise(ERR_LIB_PKCS7, ERR_R_INTERNAL_ERROR);
688             return NULL;
689         }
690         if (EVP_MD_CTX_get_type(*pmd) == nid)
691             return bio;
692         bio = BIO_next(bio);
693     }
694     return NULL;
695 }
696 
697 static int do_pkcs7_signed_attrib(PKCS7_SIGNER_INFO *si, EVP_MD_CTX *mctx)
698 {
699     unsigned char md_data[EVP_MAX_MD_SIZE];
700     unsigned int md_len;
701 
702     /* Add signing time if not already present */
703     if (!PKCS7_get_signed_attribute(si, NID_pkcs9_signingTime)) {
704         if (!PKCS7_add0_attrib_signing_time(si, NULL)) {
705             ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
706             return 0;
707         }
708     }
709 
710     /* Add digest */
711     if (!EVP_DigestFinal_ex(mctx, md_data, &md_len)) {
712         ERR_raise(ERR_LIB_PKCS7, ERR_R_EVP_LIB);
713         return 0;
714     }
715     if (!PKCS7_add1_attrib_digest(si, md_data, md_len)) {
716         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
717         return 0;
718     }
719 
720     /* Now sign the attributes */
721     if (!PKCS7_SIGNER_INFO_sign(si))
722         return 0;
723 
724     return 1;
725 }
726 
727 int PKCS7_dataFinal(PKCS7 *p7, BIO *bio)
728 {
729     int ret = 0;
730     int i, j;
731     BIO *btmp;
732     PKCS7_SIGNER_INFO *si;
733     EVP_MD_CTX *mdc, *ctx_tmp;
734     STACK_OF(X509_ATTRIBUTE) *sk;
735     STACK_OF(PKCS7_SIGNER_INFO) *si_sk = NULL;
736     ASN1_OCTET_STRING *os = NULL;
737     const PKCS7_CTX *p7_ctx;
738 
739     if (p7 == NULL) {
740         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_INVALID_NULL_POINTER);
741         return 0;
742     }
743 
744     p7_ctx = ossl_pkcs7_get0_ctx(p7);
745 
746     if (p7->d.ptr == NULL) {
747         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);
748         return 0;
749     }
750 
751     ctx_tmp = EVP_MD_CTX_new();
752     if (ctx_tmp == NULL) {
753         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
754         return 0;
755     }
756 
757     i = OBJ_obj2nid(p7->type);
758     p7->state = PKCS7_S_HEADER;
759 
760     switch (i) {
761     case NID_pkcs7_data:
762         os = p7->d.data;
763         break;
764     case NID_pkcs7_signedAndEnveloped:
765         /* XXXXXXXXXXXXXXXX */
766         si_sk = p7->d.signed_and_enveloped->signer_info;
767         os = p7->d.signed_and_enveloped->enc_data->enc_data;
768         if (os == NULL) {
769             os = ASN1_OCTET_STRING_new();
770             if (os == NULL) {
771                 ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
772                 goto err;
773             }
774             p7->d.signed_and_enveloped->enc_data->enc_data = os;
775         }
776         break;
777     case NID_pkcs7_enveloped:
778         /* XXXXXXXXXXXXXXXX */
779         os = p7->d.enveloped->enc_data->enc_data;
780         if (os == NULL) {
781             os = ASN1_OCTET_STRING_new();
782             if (os == NULL) {
783                 ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
784                 goto err;
785             }
786             p7->d.enveloped->enc_data->enc_data = os;
787         }
788         break;
789     case NID_pkcs7_signed:
790         si_sk = p7->d.sign->signer_info;
791         os = PKCS7_get_octet_string(p7->d.sign->contents);
792         /* If detached data then the content is excluded */
793         if (PKCS7_type_is_data(p7->d.sign->contents) && p7->detached) {
794             ASN1_OCTET_STRING_free(os);
795             os = NULL;
796             p7->d.sign->contents->d.data = NULL;
797         }
798         break;
799 
800     case NID_pkcs7_digest:
801         os = PKCS7_get_octet_string(p7->d.digest->contents);
802         /* If detached data then the content is excluded */
803         if (PKCS7_type_is_data(p7->d.digest->contents) && p7->detached) {
804             ASN1_OCTET_STRING_free(os);
805             os = NULL;
806             p7->d.digest->contents->d.data = NULL;
807         }
808         break;
809 
810     default:
811         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNSUPPORTED_CONTENT_TYPE);
812         goto err;
813     }
814 
815     if (si_sk != NULL) {
816         for (i = 0; i < sk_PKCS7_SIGNER_INFO_num(si_sk); i++) {
817             si = sk_PKCS7_SIGNER_INFO_value(si_sk, i);
818             if (si->pkey == NULL)
819                 continue;
820 
821             j = OBJ_obj2nid(si->digest_alg->algorithm);
822 
823             btmp = bio;
824 
825             btmp = PKCS7_find_digest(&mdc, btmp, j);
826 
827             if (btmp == NULL)
828                 goto err;
829 
830             /*
831              * We now have the EVP_MD_CTX, lets do the signing.
832              */
833             if (!EVP_MD_CTX_copy_ex(ctx_tmp, mdc))
834                 goto err;
835 
836             sk = si->auth_attr;
837 
838             /*
839              * If there are attributes, we add the digest attribute and only
840              * sign the attributes
841              */
842             if (sk_X509_ATTRIBUTE_num(sk) > 0) {
843                 if (!do_pkcs7_signed_attrib(si, ctx_tmp))
844                     goto err;
845             } else {
846                 unsigned char *abuf = NULL;
847                 unsigned int abuflen;
848                 abuflen = EVP_PKEY_get_size(si->pkey);
849                 abuf = OPENSSL_malloc(abuflen);
850                 if (abuf == NULL)
851                     goto err;
852 
853                 if (!EVP_SignFinal_ex(ctx_tmp, abuf, &abuflen, si->pkey,
854                                       ossl_pkcs7_ctx_get0_libctx(p7_ctx),
855                                       ossl_pkcs7_ctx_get0_propq(p7_ctx))) {
856                     OPENSSL_free(abuf);
857                     ERR_raise(ERR_LIB_PKCS7, ERR_R_EVP_LIB);
858                     goto err;
859                 }
860                 ASN1_STRING_set0(si->enc_digest, abuf, abuflen);
861             }
862         }
863     } else if (i == NID_pkcs7_digest) {
864         unsigned char md_data[EVP_MAX_MD_SIZE];
865         unsigned int md_len;
866         if (!PKCS7_find_digest(&mdc, bio,
867                                OBJ_obj2nid(p7->d.digest->md->algorithm)))
868             goto err;
869         if (!EVP_DigestFinal_ex(mdc, md_data, &md_len))
870             goto err;
871         if (!ASN1_OCTET_STRING_set(p7->d.digest->digest, md_data, md_len))
872             goto err;
873     }
874 
875     if (!PKCS7_is_detached(p7)) {
876         /*
877          * NOTE(emilia): I think we only reach os == NULL here because detached
878          * digested data support is broken.
879          */
880         if (os == NULL)
881             goto err;
882         if (!(os->flags & ASN1_STRING_FLAG_NDEF)) {
883             char *cont;
884             long contlen;
885             btmp = BIO_find_type(bio, BIO_TYPE_MEM);
886             if (btmp == NULL) {
887                 ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNABLE_TO_FIND_MEM_BIO);
888                 goto err;
889             }
890             contlen = BIO_get_mem_data(btmp, &cont);
891             /*
892              * Mark the BIO read only then we can use its copy of the data
893              * instead of making an extra copy.
894              */
895             BIO_set_flags(btmp, BIO_FLAGS_MEM_RDONLY);
896             BIO_set_mem_eof_return(btmp, 0);
897             ASN1_STRING_set0(os, (unsigned char *)cont, contlen);
898         }
899     }
900     ret = 1;
901  err:
902     EVP_MD_CTX_free(ctx_tmp);
903     return ret;
904 }
905 
906 int PKCS7_SIGNER_INFO_sign(PKCS7_SIGNER_INFO *si)
907 {
908     EVP_MD_CTX *mctx;
909     EVP_PKEY_CTX *pctx = NULL;
910     unsigned char *abuf = NULL;
911     int alen;
912     size_t siglen;
913     const EVP_MD *md = NULL;
914     const PKCS7_CTX *ctx = si->ctx;
915 
916     md = EVP_get_digestbyobj(si->digest_alg->algorithm);
917     if (md == NULL)
918         return 0;
919 
920     mctx = EVP_MD_CTX_new();
921     if (mctx == NULL) {
922         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
923         goto err;
924     }
925 
926     if (EVP_DigestSignInit_ex(mctx, &pctx, EVP_MD_get0_name(md),
927                               ossl_pkcs7_ctx_get0_libctx(ctx),
928                               ossl_pkcs7_ctx_get0_propq(ctx), si->pkey,
929                               NULL) <= 0)
930         goto err;
931 
932     alen = ASN1_item_i2d((ASN1_VALUE *)si->auth_attr, &abuf,
933                          ASN1_ITEM_rptr(PKCS7_ATTR_SIGN));
934     if (!abuf)
935         goto err;
936     if (EVP_DigestSignUpdate(mctx, abuf, alen) <= 0)
937         goto err;
938     OPENSSL_free(abuf);
939     abuf = NULL;
940     if (EVP_DigestSignFinal(mctx, NULL, &siglen) <= 0)
941         goto err;
942     abuf = OPENSSL_malloc(siglen);
943     if (abuf == NULL)
944         goto err;
945     if (EVP_DigestSignFinal(mctx, abuf, &siglen) <= 0)
946         goto err;
947 
948     EVP_MD_CTX_free(mctx);
949 
950     ASN1_STRING_set0(si->enc_digest, abuf, siglen);
951 
952     return 1;
953 
954  err:
955     OPENSSL_free(abuf);
956     EVP_MD_CTX_free(mctx);
957     return 0;
958 }
959 
960 int PKCS7_dataVerify(X509_STORE *cert_store, X509_STORE_CTX *ctx, BIO *bio,
961                      PKCS7 *p7, PKCS7_SIGNER_INFO *si)
962 {
963     PKCS7_ISSUER_AND_SERIAL *ias;
964     int ret = 0, i;
965     STACK_OF(X509) *cert;
966     X509 *x509;
967 
968     if (p7 == NULL) {
969         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_INVALID_NULL_POINTER);
970         return 0;
971     }
972 
973     if (p7->d.ptr == NULL) {
974         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_NO_CONTENT);
975         return 0;
976     }
977 
978     if (PKCS7_type_is_signed(p7)) {
979         cert = p7->d.sign->cert;
980     } else if (PKCS7_type_is_signedAndEnveloped(p7)) {
981         cert = p7->d.signed_and_enveloped->cert;
982     } else {
983         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_PKCS7_TYPE);
984         goto err;
985     }
986     /* XXXXXXXXXXXXXXXXXXXXXXX */
987     ias = si->issuer_and_serial;
988 
989     x509 = X509_find_by_issuer_and_serial(cert, ias->issuer, ias->serial);
990 
991     /* were we able to find the cert in passed to us */
992     if (x509 == NULL) {
993         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNABLE_TO_FIND_CERTIFICATE);
994         goto err;
995     }
996 
997     /* Lets verify */
998     if (!X509_STORE_CTX_init(ctx, cert_store, x509, cert)) {
999         ERR_raise(ERR_LIB_PKCS7, ERR_R_X509_LIB);
1000         goto err;
1001     }
1002     X509_STORE_CTX_set_purpose(ctx, X509_PURPOSE_SMIME_SIGN);
1003     i = X509_verify_cert(ctx);
1004     if (i <= 0) {
1005         ERR_raise(ERR_LIB_PKCS7, ERR_R_X509_LIB);
1006         goto err;
1007     }
1008 
1009     return PKCS7_signatureVerify(bio, p7, si, x509);
1010  err:
1011     return ret;
1012 }
1013 
1014 int PKCS7_signatureVerify(BIO *bio, PKCS7 *p7, PKCS7_SIGNER_INFO *si,
1015                           X509 *x509)
1016 {
1017     ASN1_OCTET_STRING *os;
1018     EVP_MD_CTX *mdc_tmp, *mdc;
1019     const EVP_MD *md;
1020     EVP_MD *fetched_md = NULL;
1021     int ret = 0, i;
1022     int md_type;
1023     STACK_OF(X509_ATTRIBUTE) *sk;
1024     BIO *btmp;
1025     EVP_PKEY *pkey;
1026     const PKCS7_CTX *ctx = ossl_pkcs7_get0_ctx(p7);
1027     OSSL_LIB_CTX *libctx = ossl_pkcs7_ctx_get0_libctx(ctx);
1028     const char *propq = ossl_pkcs7_ctx_get0_propq(ctx);
1029 
1030     mdc_tmp = EVP_MD_CTX_new();
1031     if (mdc_tmp == NULL) {
1032         ERR_raise(ERR_LIB_PKCS7, ERR_R_MALLOC_FAILURE);
1033         goto err;
1034     }
1035 
1036     if (!PKCS7_type_is_signed(p7) && !PKCS7_type_is_signedAndEnveloped(p7)) {
1037         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_WRONG_PKCS7_TYPE);
1038         goto err;
1039     }
1040 
1041     md_type = OBJ_obj2nid(si->digest_alg->algorithm);
1042 
1043     btmp = bio;
1044     for (;;) {
1045         if ((btmp == NULL) ||
1046             ((btmp = BIO_find_type(btmp, BIO_TYPE_MD)) == NULL)) {
1047             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
1048             goto err;
1049         }
1050         BIO_get_md_ctx(btmp, &mdc);
1051         if (mdc == NULL) {
1052             ERR_raise(ERR_LIB_PKCS7, ERR_R_INTERNAL_ERROR);
1053             goto err;
1054         }
1055         if (EVP_MD_CTX_get_type(mdc) == md_type)
1056             break;
1057         /*
1058          * Workaround for some broken clients that put the signature OID
1059          * instead of the digest OID in digest_alg->algorithm
1060          */
1061         if (EVP_MD_get_pkey_type(EVP_MD_CTX_get0_md(mdc)) == md_type)
1062             break;
1063         btmp = BIO_next(btmp);
1064     }
1065 
1066     /*
1067      * mdc is the digest ctx that we want, unless there are attributes, in
1068      * which case the digest is the signed attributes
1069      */
1070     if (!EVP_MD_CTX_copy_ex(mdc_tmp, mdc))
1071         goto err;
1072 
1073     sk = si->auth_attr;
1074     if ((sk != NULL) && (sk_X509_ATTRIBUTE_num(sk) != 0)) {
1075         unsigned char md_dat[EVP_MAX_MD_SIZE], *abuf = NULL;
1076         unsigned int md_len;
1077         int alen;
1078         ASN1_OCTET_STRING *message_digest;
1079 
1080         if (!EVP_DigestFinal_ex(mdc_tmp, md_dat, &md_len))
1081             goto err;
1082         message_digest = PKCS7_digest_from_attributes(sk);
1083         if (!message_digest) {
1084             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_UNABLE_TO_FIND_MESSAGE_DIGEST);
1085             goto err;
1086         }
1087         if ((message_digest->length != (int)md_len) ||
1088             (memcmp(message_digest->data, md_dat, md_len))) {
1089             ERR_raise(ERR_LIB_PKCS7, PKCS7_R_DIGEST_FAILURE);
1090             ret = -1;
1091             goto err;
1092         }
1093 
1094         (void)ERR_set_mark();
1095         fetched_md = EVP_MD_fetch(libctx, OBJ_nid2sn(md_type), propq);
1096 
1097         if (fetched_md != NULL)
1098             md = fetched_md;
1099         else
1100             md = EVP_get_digestbynid(md_type);
1101 
1102         if (md == NULL || !EVP_VerifyInit_ex(mdc_tmp, md, NULL)) {
1103             (void)ERR_clear_last_mark();
1104             goto err;
1105         }
1106         (void)ERR_pop_to_mark();
1107 
1108         alen = ASN1_item_i2d((ASN1_VALUE *)sk, &abuf,
1109                              ASN1_ITEM_rptr(PKCS7_ATTR_VERIFY));
1110         if (alen <= 0) {
1111             ERR_raise(ERR_LIB_PKCS7, ERR_R_ASN1_LIB);
1112             ret = -1;
1113             goto err;
1114         }
1115         if (!EVP_VerifyUpdate(mdc_tmp, abuf, alen))
1116             goto err;
1117 
1118         OPENSSL_free(abuf);
1119     }
1120 
1121     os = si->enc_digest;
1122     pkey = X509_get0_pubkey(x509);
1123     if (pkey == NULL) {
1124         ret = -1;
1125         goto err;
1126     }
1127 
1128     i = EVP_VerifyFinal_ex(mdc_tmp, os->data, os->length, pkey, libctx, propq);
1129     if (i <= 0) {
1130         ERR_raise(ERR_LIB_PKCS7, PKCS7_R_SIGNATURE_FAILURE);
1131         ret = -1;
1132         goto err;
1133     }
1134     ret = 1;
1135  err:
1136     EVP_MD_CTX_free(mdc_tmp);
1137     EVP_MD_free(fetched_md);
1138     return ret;
1139 }
1140 
1141 PKCS7_ISSUER_AND_SERIAL *PKCS7_get_issuer_and_serial(PKCS7 *p7, int idx)
1142 {
1143     STACK_OF(PKCS7_RECIP_INFO) *rsk;
1144     PKCS7_RECIP_INFO *ri;
1145     int i;
1146 
1147     i = OBJ_obj2nid(p7->type);
1148     if (i != NID_pkcs7_signedAndEnveloped)
1149         return NULL;
1150     if (p7->d.signed_and_enveloped == NULL)
1151         return NULL;
1152     rsk = p7->d.signed_and_enveloped->recipientinfo;
1153     if (rsk == NULL)
1154         return NULL;
1155     if (sk_PKCS7_RECIP_INFO_num(rsk) <= idx)
1156         return NULL;
1157     ri = sk_PKCS7_RECIP_INFO_value(rsk, idx);
1158     return ri->issuer_and_serial;
1159 }
1160 
1161 ASN1_TYPE *PKCS7_get_signed_attribute(const PKCS7_SIGNER_INFO *si, int nid)
1162 {
1163     return get_attribute(si->auth_attr, nid);
1164 }
1165 
1166 ASN1_TYPE *PKCS7_get_attribute(const PKCS7_SIGNER_INFO *si, int nid)
1167 {
1168     return get_attribute(si->unauth_attr, nid);
1169 }
1170 
1171 static ASN1_TYPE *get_attribute(const STACK_OF(X509_ATTRIBUTE) *sk, int nid)
1172 {
1173     int idx;
1174     X509_ATTRIBUTE *xa;
1175     idx = X509at_get_attr_by_NID(sk, nid, -1);
1176     xa = X509at_get_attr(sk, idx);
1177     return X509_ATTRIBUTE_get0_type(xa, 0);
1178 }
1179 
1180 ASN1_OCTET_STRING *PKCS7_digest_from_attributes(STACK_OF(X509_ATTRIBUTE) *sk)
1181 {
1182     ASN1_TYPE *astype;
1183     if ((astype = get_attribute(sk, NID_pkcs9_messageDigest)) == NULL)
1184         return NULL;
1185     return astype->value.octet_string;
1186 }
1187 
1188 int PKCS7_set_signed_attributes(PKCS7_SIGNER_INFO *p7si,
1189                                 STACK_OF(X509_ATTRIBUTE) *sk)
1190 {
1191     int i;
1192 
1193     sk_X509_ATTRIBUTE_pop_free(p7si->auth_attr, X509_ATTRIBUTE_free);
1194     p7si->auth_attr = sk_X509_ATTRIBUTE_dup(sk);
1195     if (p7si->auth_attr == NULL)
1196         return 0;
1197     for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
1198         if ((sk_X509_ATTRIBUTE_set(p7si->auth_attr, i,
1199                                    X509_ATTRIBUTE_dup(sk_X509_ATTRIBUTE_value
1200                                                       (sk, i))))
1201             == NULL)
1202             return 0;
1203     }
1204     return 1;
1205 }
1206 
1207 int PKCS7_set_attributes(PKCS7_SIGNER_INFO *p7si,
1208                          STACK_OF(X509_ATTRIBUTE) *sk)
1209 {
1210     int i;
1211 
1212     sk_X509_ATTRIBUTE_pop_free(p7si->unauth_attr, X509_ATTRIBUTE_free);
1213     p7si->unauth_attr = sk_X509_ATTRIBUTE_dup(sk);
1214     if (p7si->unauth_attr == NULL)
1215         return 0;
1216     for (i = 0; i < sk_X509_ATTRIBUTE_num(sk); i++) {
1217         if ((sk_X509_ATTRIBUTE_set(p7si->unauth_attr, i,
1218                                    X509_ATTRIBUTE_dup(sk_X509_ATTRIBUTE_value
1219                                                       (sk, i))))
1220             == NULL)
1221             return 0;
1222     }
1223     return 1;
1224 }
1225 
1226 int PKCS7_add_signed_attribute(PKCS7_SIGNER_INFO *p7si, int nid, int atrtype,
1227                                void *value)
1228 {
1229     return add_attribute(&(p7si->auth_attr), nid, atrtype, value);
1230 }
1231 
1232 int PKCS7_add_attribute(PKCS7_SIGNER_INFO *p7si, int nid, int atrtype,
1233                         void *value)
1234 {
1235     return add_attribute(&(p7si->unauth_attr), nid, atrtype, value);
1236 }
1237 
1238 static int add_attribute(STACK_OF(X509_ATTRIBUTE) **sk, int nid, int atrtype,
1239                          void *value)
1240 {
1241     X509_ATTRIBUTE *attr = NULL;
1242 
1243     if (*sk == NULL) {
1244         if ((*sk = sk_X509_ATTRIBUTE_new_null()) == NULL)
1245             return 0;
1246  new_attrib:
1247         if ((attr = X509_ATTRIBUTE_create(nid, atrtype, value)) == NULL)
1248             return 0;
1249         if (!sk_X509_ATTRIBUTE_push(*sk, attr)) {
1250             X509_ATTRIBUTE_free(attr);
1251             return 0;
1252         }
1253     } else {
1254         int i;
1255 
1256         for (i = 0; i < sk_X509_ATTRIBUTE_num(*sk); i++) {
1257             attr = sk_X509_ATTRIBUTE_value(*sk, i);
1258             if (OBJ_obj2nid(X509_ATTRIBUTE_get0_object(attr)) == nid) {
1259                 X509_ATTRIBUTE_free(attr);
1260                 attr = X509_ATTRIBUTE_create(nid, atrtype, value);
1261                 if (attr == NULL)
1262                     return 0;
1263                 if (!sk_X509_ATTRIBUTE_set(*sk, i, attr)) {
1264                     X509_ATTRIBUTE_free(attr);
1265                     return 0;
1266                 }
1267                 goto end;
1268             }
1269         }
1270         goto new_attrib;
1271     }
1272  end:
1273     return 1;
1274 }
1275