/* UIxMailPartSignedViewer.m - this file is part of SOGo
 *
 * Copyright (C) 2009 Inverse inc.
 *
 * Author: Wolfgang Sourdeau <wsourdeau@inverse.ca>
 *         Ludovic Marcotte <lmarcotte@inverse.ca>
 *
 * This file 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, or (at your option)
 * any later version.
 *
 * This file 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; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/pkcs7.h>
#include <openssl/x509.h>

#import <Foundation/NSArray.h>
#import <NGMime/NGPart.h>
#import <Mailer/SOGoMailObject.h>

#import "UIxMailPartSignedViewer.h"

@implementation UIxMailPartSignedViewer : UIxMailPartMixedViewer

- (X509_STORE *) _setupVerify
{
  X509_STORE *store;
  X509_LOOKUP *lookup;
  BOOL success;

  success = NO;

  store = X509_STORE_new ();
  if (store)
    {
      lookup = X509_STORE_add_lookup (store, X509_LOOKUP_file());
      if (lookup)
        {
          X509_LOOKUP_load_file (lookup, NULL, X509_FILETYPE_DEFAULT);
          lookup = X509_STORE_add_lookup (store, X509_LOOKUP_hash_dir());
          if (lookup)
            {
              X509_LOOKUP_add_dir (lookup, NULL, X509_FILETYPE_DEFAULT);
              ERR_clear_error();
              success = YES;
            }
        }
    }

  if (!success)
    {
      if (store)
        {
          X509_STORE_free(store);
          store = NULL;
        }
    }

  return store;
}

- (void) _processMessage
{
  NSString *issuer, *subject;
  NSData *signedData;
  
  STACK_OF(X509) *certs;
  X509_STORE *x509Store;
  BIO *msgBio, *inData;
  char sslError[1024];
  PKCS7 *p7;
  int err, i;
 

  *sslError = 0;

  ERR_clear_error();

  signedData = [[self clientObject] content];
  msgBio = BIO_new_mem_buf ((void *) [signedData bytes], [signedData length]);

  inData = NULL;
  p7 = SMIME_read_PKCS7(msgBio, &inData);

  subject = nil;
  issuer = nil;
  certs = NULL;

  if (p7)
    {
      i = OBJ_obj2nid(p7->type);
      
      if (i == NID_pkcs7_signed)
	{
	  X509 *x;
	  
	  certs=p7->d.sign->cert;
	  
	  if (sk_X509_num(certs) > 0)
	    {
	      BIO *buf;
	      char p[256];
	      
	      memset(p, 0, 256);
	      x = sk_X509_value(certs,0);
	      buf = BIO_new(BIO_s_mem());
	      X509_NAME_print_ex(buf, X509_get_subject_name(x), 0, XN_FLAG_ONELINE & ~ASN1_STRFLGS_ESC_MSB);
	      BIO_gets(buf, p, 256);
	      subject = [NSString stringWithUTF8String: p];
	      
	      memset(p, 0, 256);
	      X509_NAME_print_ex(buf, X509_get_issuer_name(x), 0, XN_FLAG_ONELINE & ~ASN1_STRFLGS_ESC_MSB);
	      BIO_gets(buf, p, 256);
	      issuer = [NSString stringWithUTF8String: p];
	      
	      BIO_free(buf);
	    }
	}
      
      err = ERR_get_error();
      if (err)
	{
	  ERR_error_string_n (err, sslError, 1023);
	  validSignature = NO;
	}
      else
	{
	  x509Store = [self _setupVerify];
	  validSignature = (PKCS7_verify(p7, NULL, x509Store, inData,
					 NULL, PKCS7_DETACHED) == 1);
	  
	  err = ERR_get_error();
	  if (err)
	    ERR_error_string_n(err, sslError, 1023);
	  
	  if (x509Store)
	    X509_STORE_free (x509Store);
	}
    }
  
  BIO_free (msgBio);
  if (inData)
    BIO_free (inData);
  
  validationMessage = [NSMutableString string];

  if (!validSignature)
    [validationMessage appendString: [self labelForKey: @"Digital signature is not valid"]];
  else
    [validationMessage appendString: [self labelForKey: @"Message is signed"]];
  
  if (issuer && subject)
    [validationMessage appendFormat: @"\n%@: %@\n%@: %@",
		   [self labelForKey: @"Subject"], subject,
		     [self labelForKey: @"Issuer"], issuer];
		   
  processed = YES;
}

- (BOOL) validSignature
{
  if (!processed)
    [self _processMessage];

  return validSignature;
}

- (NSString *) validationMessage
{
  if (!processed)
    [self _processMessage];

  return validationMessage;
}

@end