1 /* This Source Code Form is subject to the terms of the Mozilla Public
2  * License, v. 2.0. If a copy of the MPL was not distributed with this
3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
4 
5 /*
6  * SMIME message methods
7  */
8 
9 #include "cmslocal.h"
10 #include "smime.h"
11 
12 #include "cert.h"
13 #include "keyhi.h"
14 #include "secasn1.h"
15 #include "secitem.h"
16 #include "secoid.h"
17 #include "pk11func.h"
18 #include "prtime.h"
19 #include "secerr.h"
20 
21 #if 0
22 /*
23  * NSS_SMIMEMessage_CreateEncrypted - start an S/MIME encrypting context.
24  *
25  * "scert" is the cert for the sender.  It will be checked for validity.
26  * "rcerts" are the certs for the recipients.  They will also be checked.
27  *
28  * "certdb" is the cert database to use for verifying the certs.
29  * It can be NULL if a default database is available (like in the client).
30  *
31  * This function already does all of the stuff specific to S/MIME protocol
32  * and local policy; the return value just needs to be passed to
33  * SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data,
34  * and finally to SEC_PKCS7DestroyContentInfo().
35  *
36  * An error results in a return value of NULL and an error set.
37  * (Retrieve specific errors via PORT_GetError()/XP_GetError().)
38  */
39 NSSCMSMessage *
40 NSS_SMIMEMessage_CreateEncrypted(CERTCertificate *scert,
41                         CERTCertificate **rcerts,
42                         CERTCertDBHandle *certdb,
43                         PK11PasswordFunc pwfn,
44                         void *pwfn_arg)
45 {
46     NSSCMSMessage *cmsg;
47     long cipher;
48     SECOidTag encalg;
49     int keysize;
50     int mapi, rci;
51 
52     cipher = smime_choose_cipher (scert, rcerts);
53     if (cipher < 0)
54         return NULL;
55 
56     mapi = smime_mapi_by_cipher (cipher);
57     if (mapi < 0)
58         return NULL;
59 
60     /*
61      * XXX This is stretching it -- CreateEnvelopedData should probably
62      * take a cipher itself of some sort, because we cannot know what the
63      * future will bring in terms of parameters for each type of algorithm.
64      * For example, just an algorithm and keysize is *not* sufficient to
65      * fully specify the usage of RC5 (which also needs to know rounds and
66      * block size).  Work this out into a better API!
67      */
68     encalg = smime_cipher_map[mapi].algtag;
69     keysize = smime_keysize_by_cipher (cipher);
70     if (keysize < 0)
71         return NULL;
72 
73     cinfo = SEC_PKCS7CreateEnvelopedData (scert, certUsageEmailRecipient,
74                                           certdb, encalg, keysize,
75                                           pwfn, pwfn_arg);
76     if (cinfo == NULL)
77         return NULL;
78 
79     for (rci = 0; rcerts[rci] != NULL; rci++) {
80         if (rcerts[rci] == scert)
81             continue;
82         if (SEC_PKCS7AddRecipient (cinfo, rcerts[rci], certUsageEmailRecipient,
83                                    NULL) != SECSuccess) {
84             SEC_PKCS7DestroyContentInfo (cinfo);
85             return NULL;
86         }
87     }
88 
89     return cinfo;
90 }
91 
92 
93 /*
94  * Start an S/MIME signing context.
95  *
96  * "scert" is the cert that will be used to sign the data.  It will be
97  * checked for validity.
98  *
99  * "ecert" is the signer's encryption cert.  If it is different from
100  * scert, then it will be included in the signed message so that the
101  * recipient can save it for future encryptions.
102  *
103  * "certdb" is the cert database to use for verifying the cert.
104  * It can be NULL if a default database is available (like in the client).
105  *
106  * "digestalg" names the digest algorithm (e.g. SEC_OID_SHA1).
107  * XXX There should be SECMIME functions for hashing, or the hashing should
108  * be built into this interface, which we would like because we would
109  * support more smartcards that way, and then this argument should go away.)
110  *
111  * "digest" is the actual digest of the data.  It must be provided in
112  * the case of detached data or NULL if the content will be included.
113  *
114  * This function already does all of the stuff specific to S/MIME protocol
115  * and local policy; the return value just needs to be passed to
116  * SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data,
117  * and finally to SEC_PKCS7DestroyContentInfo().
118  *
119  * An error results in a return value of NULL and an error set.
120  * (Retrieve specific errors via PORT_GetError()/XP_GetError().)
121  */
122 
123 NSSCMSMessage *
124 NSS_SMIMEMessage_CreateSigned(CERTCertificate *scert,
125                       CERTCertificate *ecert,
126                       CERTCertDBHandle *certdb,
127                       SECOidTag digestalgtag,
128                       SECItem *digest,
129                       PK11PasswordFunc pwfn,
130                       void *pwfn_arg)
131 {
132     NSSCMSMessage *cmsg;
133     NSSCMSSignedData *sigd;
134     NSSCMSSignerInfo *signerinfo;
135 
136     /* See note in header comment above about digestalg. */
137     /* Doesn't explain this.  PORT_Assert (digestalgtag == SEC_OID_SHA1); */
138 
139     cmsg = NSS_CMSMessage_Create(NULL);
140     if (cmsg == NULL)
141         return NULL;
142 
143     sigd = NSS_CMSSignedData_Create(cmsg);
144     if (sigd == NULL)
145         goto loser;
146 
147     /* create just one signerinfo */
148     signerinfo = NSS_CMSSignerInfo_Create(cmsg, scert, digestalgtag);
149     if (signerinfo == NULL)
150         goto loser;
151 
152     /* Add the signing time to the signerinfo.  */
153     if (NSS_CMSSignerInfo_AddSigningTime(signerinfo, PR_Now()) != SECSuccess)
154         goto loser;
155 
156     /* and add the SMIME profile */
157     if (NSS_SMIMESignerInfo_AddSMIMEProfile(signerinfo, scert) != SECSuccess)
158         goto loser;
159 
160     /* now add the signerinfo to the signeddata */
161     if (NSS_CMSSignedData_AddSignerInfo(sigd, signerinfo) != SECSuccess)
162         goto loser;
163 
164     /* include the signing cert and its entire chain */
165     /* note that there are no checks for duplicate certs in place, as all the */
166     /* essential data structures (like set of certificate) are not there */
167     if (NSS_CMSSignedData_AddCertChain(sigd, scert) != SECSuccess)
168         goto loser;
169 
170     /* If the encryption cert and the signing cert differ, then include
171      * the encryption cert too. */
172     if ( ( ecert != NULL ) && ( ecert != scert ) ) {
173         if (NSS_CMSSignedData_AddCertificate(sigd, ecert) != SECSuccess)
174             goto loser;
175     }
176 
177     return cmsg;
178 loser:
179     if (cmsg)
180         NSS_CMSMessage_Destroy(cmsg);
181     return NULL;
182 }
183 #endif
184