/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
* Authors: Jeffrey Stedfast <fejj@ximian.com>
*
* Copyright 2001 Ximian, Inc. (www.ximian.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "camel-smime-context.h"
#include "camel-stream-fs.h"
#include "camel-stream-mem.h"
#include <nss.h>
#include <cert.h>
#include <secpkcs7.h>
#include <gtk/gtk.h> /* for _() macro */
#define d(x)
struct _CamelSMimeContextPrivate {
CERTCertDBHandle *certdb;
};
static int smime_sign (CamelCipherContext *ctx, const char *userid, CamelCipherHash hash,
CamelStream *istream, CamelStream *ostream, CamelException *ex);
static int smime_clearsign (CamelCipherContext *context, const char *userid,
CamelCipherHash hash, CamelStream *istream,
CamelStream *ostream, CamelException *ex);
static CamelCipherValidity *smime_verify (CamelCipherContext *context, CamelStream *istream,
CamelStream *sigstream, CamelException *ex);
static int smime_encrypt (CamelCipherContext *context, gboolean sign, const char *userid,
GPtrArray *recipients, CamelStream *istream, CamelStream *ostream,
CamelException *ex);
static int smime_decrypt (CamelCipherContext *context, CamelStream *istream,
CamelStream *ostream, CamelException *ex);
static CamelCipherContextClass *parent_class;
static void
camel_smime_context_init (CamelSMimeContext *context)
{
context->priv = g_new0 (struct _CamelSMimeContextPrivate, 1);
}
static void
camel_smime_context_finalise (CamelObject *o)
{
CamelSMimeContext *context = (CamelSMimeContext *)o;
CERT_ClosePermCertDB (context->priv->certdb);
g_free (context->priv->certdb);
g_free (context->priv);
}
static void
camel_smime_context_class_init (CamelSMimeContextClass *camel_smime_context_class)
{
CamelCipherContextClass *camel_cipher_context_class =
CAMEL_CIPHER_CONTEXT_CLASS (camel_smime_context_class);
parent_class = CAMEL_CIPHER_CONTEXT_CLASS (camel_type_get_global_classfuncs (camel_cipher_context_get_type ()));
camel_cipher_context_class->sign = smime_sign;
camel_cipher_context_class->clearsign = smime_clearsign;
camel_cipher_context_class->verify = smime_verify;
camel_cipher_context_class->encrypt = smime_encrypt;
camel_cipher_context_class->decrypt = smime_decrypt;
}
CamelType
camel_smime_context_get_type (void)
{
static CamelType type = CAMEL_INVALID_TYPE;
if (type == CAMEL_INVALID_TYPE) {
type = camel_type_register (camel_cipher_context_get_type (),
"CamelSMimeContext",
sizeof (CamelSMimeContext),
sizeof (CamelSMimeContextClass),
(CamelObjectClassInitFunc) camel_smime_context_class_init,
NULL,
(CamelObjectInitFunc) camel_smime_context_init,
(CamelObjectFinalizeFunc) camel_smime_context_finalise);
}
return type;
}
/**
* camel_smime_context_new:
* @session: CamelSession
* @certdb: certificate db
*
* This creates a new CamelSMimeContext object which is used to sign,
* verify, encrypt and decrypt streams.
*
* Return value: the new CamelSMimeContext
**/
CamelSMimeContext *
camel_smime_context_new (CamelSession *session, const char *certdb)
{
CamelSMimeContext *context;
CERTCertDBHandle *handle;
g_return_val_if_fail (session != NULL, NULL);
context = CAMEL_SMIME_CONTEXT (camel_object_new (CAMEL_SMIME_CONTEXT_TYPE));
camel_cipher_construct (CAMEL_CIPHER_CONTEXT (context), session);
handle = g_new0 (CERTCertDBHandle, 1);
if (certdb) {
if (!CERT_OpenCertDBFilename (handle, certdb, FALSE)) {
g_free (handle);
return NULL;
}
} else {
if (!CERT_OpenVolatileCertDB (handle)) {
g_free (handle);
return NULL;
}
}
context->priv->certdb = handle;
return context;
}
/*----------------------------------------------------------------------*
* Public crypto functions
*----------------------------------------------------------------------*/
struct _GetPasswdData {
CamelSession *session;
CamelException *ex;
const char *userid;
};
static SECItem *
get_zero_len_passwd (SECKEYKeyDBHandle *handle)
{
SECItem *pwitem;
SECStatus rv;
/* hash the empty string as a password */
pwitem = SECKEY_DeriveKeyDBPassword (handle, "");
if (pwitem == NULL)
return NULL;
/* check to see if this is the right password */
rv = SECKEY_CheckKeyDBPassword (handle, pwitem);
if (rv == SECFailure)
return NULL;
return pwitem;
}
static SECItem *
get_password (void *arg, SECKEYKeyDBHandle *handle)
{
CamelSession *session = ((struct _GetPasswdData *) arg)->session;
CamelException *ex = ((struct _GetPasswdData *) arg)->ex;
const char *userid = ((struct _GetPasswdData *) arg)->userid;
char *prompt, *passwd = NULL;
SECItem *pwitem;
SECStatus rv;
/* Check to see if zero length password or not */
pwitem = get_zero_len_passwd (handle);
if (pwitem)
return pwitem;
prompt = g_strdup_printf (_("Please enter your password for %s"), userid);
passwd = camel_session_query_authenticator (session, CAMEL_AUTHENTICATOR_ASK,
prompt, TRUE, NULL, userid,
NULL);
g_free (prompt);
/* hash the password */
pwitem = SECKEY_DeriveKeyDBPassword (handle, passwd ? passwd : "");
/* clear out the password strings */
if (passwd) {
memset (passwd, 0, strlen (passwd));
g_free (passwd);
}
if (pwitem == NULL) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Error hashing password."));
return NULL;
}
/* confirm the password */
rv = SECKEY_CheckKeyDBPassword (handle, pwitem);
if (rv) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Invalid password."));
SECITEM_ZfreeItem (pwitem, PR_TRUE);
return NULL;
}
return pwitem;
}
static HASH_HashType
camel_cipher_hash_to_nss (CamelCipherHash hash)
{
switch (hash) {
case CAMEL_CIPHER_HASH_DEFAULT:
return HASH_AlgSHA1;
case CAMEL_CIPHER_HASH_MD2:
return HASH_AlgMD2;
case CAMEL_CIPHER_HASH_MD5:
return HASH_AlgMD5;
case CAMEL_CIPHER_HASH_SHA1:
return HASH_AlgSHA1;
}
return HASH_AlgNULL;
}
static SECOidTag
nss_hash_to_sec_oid (HASH_HashType hash)
{
switch (hash) {
case HASH_AlgMD2:
return SEC_OID_MD2;
case HASH_AlgMD5:
return SEC_OID_MD5;
case Hash_AlgSHA1:
return SEC_OID_SHA1;
default:
g_assert_not_reached ();
return 0;
}
}
static int
smime_digest (SECItem *data, char *digestdata, unsigned int *len, unsigned int maxlen, HASH_HashType hash)
{
SECHashObject *hashObj;
void *hashcx;
hashObj = &SECHashObjects[hash];
hashcx = (* hashObj->create)();
if (hashcx == NULL)
return -1;
(* hashObj->begin)(hashcx);
(* hashObj->update)(hashcx, data->data, data->len);
(* hashObj->end)(hashcx, (unsigned char *)digestdata, len, maxlen);
(* hashObj->destroy)(hashcx, PR_TRUE);
return 0;
}
static void
smime_output_cb (void *arg, const char *buf, unsigned long len)
{
CamelStream *stream;
stream = CAMEL_STREAM (arg);
camel_stream_write (stream, buf, len);
}
static int
smime_sign (CamelCipherContext *ctx, const char *userid, CamelCipherHash hash,
CamelStream *istream, CamelStream *ostream, CamelException *ex)
{
CamelSMimeContext *context = CAMEL_SMIME_CONTEXT (ctx);
SEC_PKCS7EncoderContext *ecx = NULL;
struct _GetPasswdData *data = NULL;
SEC_PKCS7ContentInfo *cinfo = NULL;
SECItem data2sign, digest;
HASH_HashType hash_type;
CERTCertificate *cert;
guchar digestdata[32];
CamelStream *stream;
GByteArray *buf;
guint len;
g_return_val_if_fail (userid != NULL, -1);
g_return_val_if_fail (istream != NULL, -1);
g_return_val_if_fail (ostream != NULL, -1);
stream = camel_stream_mem_new ();
camel_stream_write_to_stream (istream, stream);
buf = CAMEL_STREAM_MEM (stream)->buffer;
data2sign.data = buf->data;
data2sign.len = buf->len;
hash_type = camel_cipher_hash_to_nss (hash);
smime_digest (&data2sign, digestdata, &len, 32, hash_type);
digest.data = (unsigned char *)digestdata;
digest.len = len;
camel_object_unref (CAMEL_OBJECT (stream));
cert = CERT_FindCertByNickname (context->priv->certdb, userid);
if (!cert) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not sign: certificate not found for \"%s\"."),
userid);
return -1;
}
data = g_new (struct _GetPasswdData, 1);
data->session = ctx->session;
data->userid = userid;
data->ex = ex;
cinfo = SECMIME_CreateSigned (cert, cert, context->priv->certdb,
nss_hash_to_sec_oid (hash_type),
&digest, get_password, data);
if (cinfo == NULL) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not sign: failed to create content info."));
goto exception;
}
ecx = SEC_PKCS7EncoderStart (cinfo, smime_output_cb, ostream, NULL);
if (ecx == NULL) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not sign: failed to create signing context."));
goto exception;
}
if (SEC_PKCS7EncoderFinish (ecx, NULL, NULL) != SECSuccess) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not sign: failed to create signature."));
goto exception;
}
g_free (data);
SEC_PKCS7DestroyContentInfo (cinfo);
return 0;
exception:
if (cinfo)
SEC_PKCS7DestroyContentInfo (cinfo);
if (data)
g_free (data);
return -1;
}
static int
smime_clearsign (CamelCipherContext *ctx, const char *userid, CamelCipherHash hash,
CamelStream *istream, CamelStream *ostream, CamelException *ex)
{
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("'clearsign' is not supported by S/MIME."));
return -1;
}
#if 0
/* this is just meant as a reference so I can see what the valid enums are */
typedef enum {
certUsageSSLClient,
certUsageSSLServer,
certUsageSSLServerWithStepUp,
certUsageSSLCA,
certUsageEmailSigner,
certUsageEmailRecipient,
certUsageObjectSigner,
certUsageUserCertImport,
certUsageVerifyCA,
certUsageProtectedObjectSigner,
certUsageStatusResponder,
certUsageAnyCA
} SECCertUsage;
#endif
/* FIXME: god knows if this code works, NSS "docs" are so not helpful at all */
static CamelCipherValidity *
smime_verify (CamelCipherContext *ctx, CamelCipherHash hash, CamelStream *istream,
CamelStream *sigstream, CamelException *ex)
{
CamelSMimeContext *context = CAMEL_SMIME_CONTEXT (ctx);
CamelCipherValidity *valid = NULL;
SEC_PKCS7ContentInfo *cinfo;
SECCertUsage usage;
GByteArray *plaintext;
CamelStream *stream;
/* create our ContentInfo object */
stream = camel_stream_mem_new ();
camel_stream_write_to_stream (istream, stream);
plaintext = CAMEL_STREAM_MEM (stream)->buffer;
cinfo = SEC_PKCS7CreateData ();
SEC_PKCS7SetContent (cinfo, plaintext->data, plaintext->len);
camel_object_unref (CAMEL_OBJECT (stream));
usage = certUsageEmailSigner; /* just a guess. or maybe certUsageVerifyCA?? */
valid = camel_cipher_validity_new ();
if (sigstream) {
HASH_HashType digest_type;
GByteArray *signature;
SECItem digest;
/* create our digest object */
stream = camel_stream_mem_new ();
camel_stream_write_to_stream (sigstream, stream);
signature = CAMEL_STREAM_MEM (stream)->buffer;
digest.data = signature->data;
digest.len = signature->len;
switch (hash) {
default:
case CAMEL_CIPHER_HASH_DEFAULT:
digest_type = HASH_AlgNULL;
break;
case CAMEL_CIPHER_HASH_MD2:
digest_type = HASH_AlgMD2;
break;
case CAMEL_CIPHER_HASH_MD5:
digest_type = HASH_AlgMD5;
break;
case CAMEL_CIPHER_HASH_SHA1:
digest_type = HASH_AlgSHA1;
break;
}
valid->valid = SEC_PKCS7VerifyDetachedSignature (cinfo, usage, &digest,
digest_type, PR_FALSE);
camel_object_unref (CAMEL_OBJECT (stream));
} else {
valid->valid = SEC_PKCS7VerifySignature (cinfo, usage, PR_FALSE);
}
SEC_PKCS7DestroyContentInfo (cinfo);
/* FIXME: set a meaningful description...in UTF8 */
camel_cipher_validity_set_description (valid, "");
return valid;
}
static int
smime_encrypt (CamelCipherContext *ctx, gboolean sign, const char *userid, GPtrArray *recipients,
CamelStream *istream, CamelStream *ostream, CamelException *ex)
{
CamelSMimeContext *context = CAMEL_SMIME_CONTEXT (ctx);
const char *invalid_userkey = NULL;
SEC_PKCS7ContentInfo *cinfo = NULL;
GPtrArray *certificates = NULL;
SEC_PKCS7EncoderContext *ecx;
struct _GetPasswdData *data;
CamelStream *stream = NULL;
CERTCertificate *scert;
SECItem secdata;
GByteArray *buf;
int i = 0;
g_return_val_if_fail (userid != NULL, -1);
g_return_val_if_fail (recipients != NULL, -1);
g_return_val_if_fail (recipients->len != 0, -1);
g_return_val_if_fail (istream != NULL, -1);
g_return_val_if_fail (ostream != NULL, -1);
scert = CERT_FindCertByNickname (context->priv->certdb, userid);
if (!scert) {
invalid_userkey = recipients->pdata[i];
goto exception;
}
certificates = g_ptr_array_new ();
for (i = 0; i < recipients->len; i++) {
CERTCertificate *cert;
cert = CERT_FindCertByNickname (context->priv->certdb, recipients->pdata[i]);
if (!cert) {
invalid_userkey = recipients->pdata[i];
goto exception;
}
g_ptr_array_add (certificates, cert);
}
g_ptr_array_add (certificates, NULL);
data = g_new (struct _GetPasswdData, 1);
data->session = session;
data->userid = userid;
data->ex = ex;
cinfo = SECMIME_CreateEncrypted (scert, (CERTCertificate **) certificates->pdata,
context->priv->certdb, get_password, data);
g_free (data);
if (!cinfo) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not encrypt: failed to create enveloped data."));
goto exception;
}
ecx = SEC_PKCS7EncoderStart (cinfo, smime_output_cb, ostream, NULL);
if (ecx == NULL) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not encrypt: failed to create encryption context."));
goto exception;
}
stream = camel_stream_mem_new ();
camel_stream_write_to_stream (istream, stream);
buf = CAMEL_STREAM_MEM (stream)->buffer;
if (SEC_PKCS7EncoderUpdate (ecx, buf->data, buf->len) != SECSuccess)
goto exception;
camel_object_unref (CAMEL_OBJECT (stream));
stream = NULL;
if (SEC_PKCS7EncoderFinish (ecx, NULL, NULL) != SECSuccess)
goto exception;
g_ptr_array_free (certificates, TRUE);
SEC_PKCS7DestroyContentInfo (cinfo);
return 0;
exception:
if (certificates)
g_ptr_array_free (certificates, TRUE);
if (stream)
camel_object_unref (CAMEL_OBJECT (stream));
if (cinfo)
SEC_PKCS7DestroyContentInfo (cinfo);
if (invalid_userkey) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not encrypt data: invalid user key: \"%s\"."),
invalid_userkey);
}
if (!camel_exception_is_set (ex)) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Could not encrypt: encoding failed."));
}
return -1;
}
static PRBool
decryption_allowed (SECAlgorithmID *algid, PK11SymKey *key)
{
return PR_TRUE;
}
static int
smime_decrypt (CamelCipherContext *ctx, CamelStream *istream,
CamelStream *ostream, CamelException *ex)
{
CamelSMimeContext *context = CAMEL_SMIME_CONTEXT (ctx);
struct _GetPasswdData *data;
SEC_PKCS7DecoderContext *dcx;
SEC_PKCS7ContentInfo *cinfo;
CamelStream *stream = NULL;
SECItem secdata;
GByteArray *buf;
g_return_val_if_fail (istream != NULL, -1);
g_return_val_if_fail (ostream != NULL, -1);
stream = camel_stream_mem_new ();
camel_stream_write_to_stream (istream, stream);
buf = CAMEL_STREAM_MEM (stream)->buffer;
secdata.data = buf->data;
secdata.len = buf->len;
data = g_new (struct _GetPasswdData, 1);
data->session = ctx->session;
data->userid = NULL;
data->ex = ex;
dcx = SEC_PKCS7DecoderStart (smime_output_cb, ostream, get_password, data,
NULL, NULL, decryption_allowed);
if (dcx == NULL)
goto exception;
SEC_PKCS7DecoderUpdate (dcx, secdata.data, secdata.len);
cinfo = SEC_PKCS7DecoderFinish (dcx);
camel_object_unref (CAMEL_OBJECT (stream));
g_free (data);
if (cinfo == NULL) {
camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
_("Failed to decrypt: Unknown"));
return -1;
}
SEC_PKCS7DestroyContentInfo (cinfo);
return 0;
exception:
if (stream)
camel_object_unref (CAMEL_OBJECT (stream));
return -1;
}
