tor-browser

smimemessage.c (6386B)

---

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
* SMIME message methods
*/

#include "cmslocal.h"
#include "smime.h"

#include "cert.h"
#include "keyhi.h"
#include "secasn1.h"
#include "secitem.h"
#include "secoid.h"
#include "pk11func.h"
#include "prtime.h"
#include "secerr.h"

#if 0
/*
* NSS_SMIMEMessage_CreateEncrypted - start an S/MIME encrypting context.
*
* "scert" is the cert for the sender.  It will be checked for validity.
* "rcerts" are the certs for the recipients.  They will also be checked.
*
* "certdb" is the cert database to use for verifying the certs.
* It can be NULL if a default database is available (like in the client).
*
* This function already does all of the stuff specific to S/MIME protocol
* and local policy; the return value just needs to be passed to
* SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data,
* and finally to SEC_PKCS7DestroyContentInfo().
*
* An error results in a return value of NULL and an error set.
* (Retrieve specific errors via PORT_GetError()/XP_GetError().)
*/
NSSCMSMessage *
NSS_SMIMEMessage_CreateEncrypted(CERTCertificate *scert,
                       CERTCertificate **rcerts,
                       CERTCertDBHandle *certdb,
                       PK11PasswordFunc pwfn,
                       void *pwfn_arg)
{
   NSSCMSMessage *cmsg;
   long cipher;
   SECOidTag encalg;
   int keysize;
   int mapi, rci;

   cipher = smime_choose_cipher (scert, rcerts);
   if (cipher < 0)
       return NULL;

   mapi = smime_mapi_by_cipher (cipher);
   if (mapi < 0)
       return NULL;

   /*
    * XXX This is stretching it -- CreateEnvelopedData should probably
    * take a cipher itself of some sort, because we cannot know what the
    * future will bring in terms of parameters for each type of algorithm.
    * For example, just an algorithm and keysize is *not* sufficient to
    * fully specify the usage of RC5 (which also needs to know rounds and
    * block size).  Work this out into a better API!
    */
   encalg = smime_cipher_map[mapi].algtag;
   keysize = smime_keysize_by_cipher (cipher);
   if (keysize < 0)
       return NULL;

   cinfo = SEC_PKCS7CreateEnvelopedData (scert, certUsageEmailRecipient,
                                         certdb, encalg, keysize,
                                         pwfn, pwfn_arg);
   if (cinfo == NULL)
       return NULL;

   for (rci = 0; rcerts[rci] != NULL; rci++) {
       if (rcerts[rci] == scert)
           continue;
       if (SEC_PKCS7AddRecipient (cinfo, rcerts[rci], certUsageEmailRecipient,
                                  NULL) != SECSuccess) {
           SEC_PKCS7DestroyContentInfo (cinfo);
           return NULL;
       }
   }

   return cinfo;
}


/*
* Start an S/MIME signing context.
*
* "scert" is the cert that will be used to sign the data.  It will be
* checked for validity.
*
* "ecert" is the signer's encryption cert.  If it is different from
* scert, then it will be included in the signed message so that the
* recipient can save it for future encryptions.
*
* "certdb" is the cert database to use for verifying the cert.
* It can be NULL if a default database is available (like in the client).
*
* "digestalg" names the digest algorithm (e.g. SEC_OID_SHA1).
* XXX There should be SECMIME functions for hashing, or the hashing should
* be built into this interface, which we would like because we would
* support more smartcards that way, and then this argument should go away.)
*
* "digest" is the actual digest of the data.  It must be provided in
* the case of detached data or NULL if the content will be included.
*
* This function already does all of the stuff specific to S/MIME protocol
* and local policy; the return value just needs to be passed to
* SEC_PKCS7Encode() or to SEC_PKCS7EncoderStart() to create the encoded data,
* and finally to SEC_PKCS7DestroyContentInfo().
*
* An error results in a return value of NULL and an error set.
* (Retrieve specific errors via PORT_GetError()/XP_GetError().)
*/

NSSCMSMessage *
NSS_SMIMEMessage_CreateSigned(CERTCertificate *scert,
                     CERTCertificate *ecert,
                     CERTCertDBHandle *certdb,
                     SECOidTag digestalgtag,
                     SECItem *digest,
                     PK11PasswordFunc pwfn,
                     void *pwfn_arg)
{
   NSSCMSMessage *cmsg;
   NSSCMSSignedData *sigd;
   NSSCMSSignerInfo *signerinfo = NULL;

   /* See note in header comment above about digestalg. */
   /* Doesn't explain this.  PORT_Assert (digestalgtag == SEC_OID_SHA1); */

   cmsg = NSS_CMSMessage_Create(NULL);
   if (cmsg == NULL)
       return NULL;

   sigd = NSS_CMSSignedData_Create(cmsg);
   if (sigd == NULL)
       goto loser;

   /* create just one signerinfo */
   signerinfo = NSS_CMSSignerInfo_Create(cmsg, scert, digestalgtag);
   if (signerinfo == NULL)
       goto loser;

   /* Add the signing time to the signerinfo.  */
   if (NSS_CMSSignerInfo_AddSigningTime(signerinfo, PR_Now()) != SECSuccess)
       goto loser;

   /* and add the SMIME profile */
   if (NSS_SMIMESignerInfo_AddSMIMEProfile(signerinfo, scert) != SECSuccess)
       goto loser;

   /* now add the signerinfo to the signeddata */
   if (NSS_CMSSignedData_AddSignerInfo(sigd, signerinfo) != SECSuccess)
       goto loser;
   /* sigd (and therefore cmsg) has adopted signerinfo */
   signerinfo = NULL;

   /* include the signing cert and its entire chain */
   /* note that there are no checks for duplicate certs in place, as all the */
   /* essential data structures (like set of certificate) are not there */
   if (NSS_CMSSignedData_AddCertChain(sigd, scert) != SECSuccess)
       goto loser;

   /* If the encryption cert and the signing cert differ, then include
    * the encryption cert too. */
   if ( ( ecert != NULL ) && ( ecert != scert ) ) {
       if (NSS_CMSSignedData_AddCertificate(sigd, ecert) != SECSuccess)
           goto loser;
   }

   return cmsg;
loser:
   if (cmsg)
       NSS_CMSMessage_Destroy(cmsg);
   if (signerinfo)
       NSS_CMSSignerInfo_Destroy(signerinfo);
   return NULL;
}
#endif