1 /*
2  * Copyright 2020-2023 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 /*
11  * RSA low level APIs are deprecated for public use, but still ok for
12  * internal use.
13  */
14 #include "internal/deprecated.h"
15 
16 #include <string.h>
17 
18 #include <openssl/core_dispatch.h>
19 #include <openssl/core_names.h>
20 #include <openssl/core_object.h>
21 #include <openssl/crypto.h>
22 #include <openssl/err.h>
23 #include <openssl/params.h>
24 #include <openssl/pem.h>
25 #include <openssl/proverr.h>
26 #include "internal/nelem.h"
27 #include "prov/bio.h"
28 #include "prov/implementations.h"
29 #include "endecoder_local.h"
30 
read_pem(PROV_CTX * provctx,OSSL_CORE_BIO * cin,char ** pem_name,char ** pem_header,unsigned char ** data,long * len)31 static int read_pem(PROV_CTX *provctx, OSSL_CORE_BIO *cin,
32                     char **pem_name, char **pem_header,
33                     unsigned char **data, long *len)
34 {
35     BIO *in = ossl_bio_new_from_core_bio(provctx, cin);
36     int ok;
37 
38     if (in == NULL)
39         return 0;
40     ok = (PEM_read_bio(in, pem_name, pem_header, data, len) > 0);
41 
42     BIO_free(in);
43     return ok;
44 }
45 
46 static OSSL_FUNC_decoder_newctx_fn pem2der_newctx;
47 static OSSL_FUNC_decoder_freectx_fn pem2der_freectx;
48 static OSSL_FUNC_decoder_decode_fn pem2der_decode;
49 
50 /*
51  * Context used for PEM to DER decoding.
52  */
53 struct pem2der_ctx_st {
54     PROV_CTX *provctx;
55 };
56 
pem2der_newctx(void * provctx)57 static void *pem2der_newctx(void *provctx)
58 {
59     struct pem2der_ctx_st *ctx = OPENSSL_zalloc(sizeof(*ctx));
60 
61     if (ctx != NULL)
62         ctx->provctx = provctx;
63     return ctx;
64 }
65 
pem2der_freectx(void * vctx)66 static void pem2der_freectx(void *vctx)
67 {
68     struct pem2der_ctx_st *ctx = vctx;
69 
70     OPENSSL_free(ctx);
71 }
72 
73 /* pem_password_cb compatible function */
74 struct pem2der_pass_data_st {
75     OSSL_PASSPHRASE_CALLBACK *cb;
76     void *cbarg;
77 };
78 
pem2der_pass_helper(char * buf,int num,int w,void * data)79 static int pem2der_pass_helper(char *buf, int num, int w, void *data)
80 {
81     struct pem2der_pass_data_st *pass_data = data;
82     size_t plen;
83 
84     if (pass_data == NULL
85         || pass_data->cb == NULL
86         || !pass_data->cb(buf, num, &plen, NULL, pass_data->cbarg))
87         return -1;
88     return (int)plen;
89 }
90 
91 /*
92  * The selection parameter in pem2der_decode() is not used by this function
93  * because it's not relevant just to decode PEM to DER.
94  */
pem2der_decode(void * vctx,OSSL_CORE_BIO * cin,int selection,OSSL_CALLBACK * data_cb,void * data_cbarg,OSSL_PASSPHRASE_CALLBACK * pw_cb,void * pw_cbarg)95 static int pem2der_decode(void *vctx, OSSL_CORE_BIO *cin, int selection,
96                           OSSL_CALLBACK *data_cb, void *data_cbarg,
97                           OSSL_PASSPHRASE_CALLBACK *pw_cb, void *pw_cbarg)
98 {
99     /*
100      * PEM names we recognise.  Other PEM names should be recognised by
101      * other decoder implementations.
102      */
103     static struct pem_name_map_st {
104         const char *pem_name;
105         int object_type;
106         const char *data_type;
107         const char *data_structure;
108     } pem_name_map[] = {
109         /* PKCS#8 and SubjectPublicKeyInfo */
110         { PEM_STRING_PKCS8, OSSL_OBJECT_PKEY, NULL, "EncryptedPrivateKeyInfo" },
111         { PEM_STRING_PKCS8INF, OSSL_OBJECT_PKEY, NULL, "PrivateKeyInfo" },
112         { PEM_STRING_PUBLIC, OSSL_OBJECT_PKEY, NULL, "SubjectPublicKeyInfo" },
113 
114         /* Our set of type specific PEM types */
115         { PEM_STRING_DHPARAMS, OSSL_OBJECT_PKEY, "DH", "type-specific" },
116         { PEM_STRING_DHXPARAMS, OSSL_OBJECT_PKEY, "X9.42 DH", "type-specific" },
117         { PEM_STRING_DSA, OSSL_OBJECT_PKEY, "DSA", "type-specific" },
118         { PEM_STRING_DSA_PUBLIC, OSSL_OBJECT_PKEY, "DSA", "type-specific" },
119         { PEM_STRING_DSAPARAMS, OSSL_OBJECT_PKEY, "DSA", "type-specific" },
120         { PEM_STRING_ECPRIVATEKEY, OSSL_OBJECT_PKEY, "EC", "type-specific" },
121         { PEM_STRING_ECPARAMETERS, OSSL_OBJECT_PKEY, "EC", "type-specific" },
122         { PEM_STRING_SM2PARAMETERS, OSSL_OBJECT_PKEY, "SM2", "type-specific" },
123         { PEM_STRING_RSA, OSSL_OBJECT_PKEY, "RSA", "type-specific" },
124         { PEM_STRING_RSA_PUBLIC, OSSL_OBJECT_PKEY, "RSA", "type-specific" },
125 
126         /*
127          * A few others that there is at least have an object type for, even
128          * though there is no provider interface to handle such objects, yet.
129          * However, this is beneficial for the OSSL_STORE result handler.
130          */
131         { PEM_STRING_X509, OSSL_OBJECT_CERT, NULL, "Certificate" },
132         { PEM_STRING_X509_TRUSTED, OSSL_OBJECT_CERT, NULL, "Certificate" },
133         { PEM_STRING_X509_OLD, OSSL_OBJECT_CERT, NULL, "Certificate" },
134         { PEM_STRING_X509_CRL, OSSL_OBJECT_CRL, NULL, "CertificateList" }
135     };
136     struct pem2der_ctx_st *ctx = vctx;
137     char *pem_name = NULL, *pem_header = NULL;
138     size_t i;
139     unsigned char *der = NULL;
140     long der_len = 0;
141     int ok = 0;
142     int objtype = OSSL_OBJECT_UNKNOWN;
143 
144     ok = read_pem(ctx->provctx, cin, &pem_name, &pem_header,
145                   &der, &der_len) > 0;
146     /* We return "empty handed".  This is not an error. */
147     if (!ok)
148         return 1;
149 
150     /*
151      * 10 is the number of characters in "Proc-Type:", which
152      * PEM_get_EVP_CIPHER_INFO() requires to be present.
153      * If the PEM header has less characters than that, it's
154      * not worth spending cycles on it.
155      */
156     if (strlen(pem_header) > 10) {
157         EVP_CIPHER_INFO cipher;
158         struct pem2der_pass_data_st pass_data;
159 
160         ok = 0;                  /* Assume that we fail */
161         pass_data.cb = pw_cb;
162         pass_data.cbarg = pw_cbarg;
163         if (!PEM_get_EVP_CIPHER_INFO(pem_header, &cipher)
164             || !PEM_do_header(&cipher, der, &der_len,
165                               pem2der_pass_helper, &pass_data))
166             goto end;
167     }
168 
169     /*
170      * Indicated that we successfully decoded something, or not at all.
171      * Ending up "empty handed" is not an error.
172      */
173     ok = 1;
174 
175     /* Have a look to see if we recognise anything */
176     for (i = 0; i < OSSL_NELEM(pem_name_map); i++)
177         if (strcmp(pem_name, pem_name_map[i].pem_name) == 0)
178             break;
179 
180     if (i < OSSL_NELEM(pem_name_map)) {
181         OSSL_PARAM params[5], *p = params;
182         /* We expect these to be read only so casting away the const is ok */
183         char *data_type = (char *)pem_name_map[i].data_type;
184         char *data_structure = (char *)pem_name_map[i].data_structure;
185 
186         objtype = pem_name_map[i].object_type;
187         if (data_type != NULL)
188             *p++ =
189                 OSSL_PARAM_construct_utf8_string(OSSL_OBJECT_PARAM_DATA_TYPE,
190                                                  data_type, 0);
191 
192         /* We expect this to be read only so casting away the const is ok */
193         if (data_structure != NULL)
194             *p++ =
195                 OSSL_PARAM_construct_utf8_string(OSSL_OBJECT_PARAM_DATA_STRUCTURE,
196                                                  data_structure, 0);
197         *p++ =
198             OSSL_PARAM_construct_octet_string(OSSL_OBJECT_PARAM_DATA,
199                                               der, der_len);
200         *p++ =
201             OSSL_PARAM_construct_int(OSSL_OBJECT_PARAM_TYPE, &objtype);
202 
203         *p = OSSL_PARAM_construct_end();
204 
205         ok = data_cb(params, data_cbarg);
206     }
207 
208  end:
209     OPENSSL_free(pem_name);
210     OPENSSL_free(pem_header);
211     OPENSSL_free(der);
212     return ok;
213 }
214 
215 const OSSL_DISPATCH ossl_pem_to_der_decoder_functions[] = {
216     { OSSL_FUNC_DECODER_NEWCTX, (void (*)(void))pem2der_newctx },
217     { OSSL_FUNC_DECODER_FREECTX, (void (*)(void))pem2der_freectx },
218     { OSSL_FUNC_DECODER_DECODE, (void (*)(void))pem2der_decode },
219     OSSL_DISPATCH_END
220 };
221