Encrypting against a SHA1 hash and with a different secret per number

This commit is contained in:
Pierre Pronchery 2010-08-01 16:57:22 +00:00
parent aa1cd2ced4
commit 65f998b8d4

View File

@ -25,6 +25,7 @@
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <openssl/sha.h>
#include <System.h>
#include "Phone.h"
@ -34,8 +35,8 @@
/* types */
typedef struct _SMSCrypt
{
char * secret;
size_t secret_len;
unsigned char buf[20];
size_t len;
} SMSCrypt;
@ -43,6 +44,7 @@ typedef struct _SMSCrypt
static int _smscrypt_init(PhonePlugin * plugin);
static int _smscrypt_destroy(PhonePlugin * plugin);
static int _smscrypt_event(PhonePlugin * plugin, PhoneEvent event, ...);
static int _smscrypt_secret(PhonePlugin * plugin, char const * number);
static void _smscrypt_settings(PhonePlugin * plugin);
@ -67,24 +69,14 @@ PhonePlugin plugin =
static int _smscrypt_init(PhonePlugin * plugin)
{
SMSCrypt * smscrypt;
char const * secret;
if((secret = plugin->helper->config_get(plugin->helper->phone,
"smscrypt", "secret")) == NULL)
return 1;
#ifdef DEBUG
fprintf(stderr, "DEBUG: %s() secret=\"%s\"\n", __func__, secret);
#endif
if((smscrypt = malloc(sizeof(*smscrypt))) == NULL)
return error_set_code(1, "%s", strerror(errno));
plugin->priv = smscrypt;
smscrypt->secret = strdup(secret);
smscrypt->secret_len = strlen(secret);
if(smscrypt->secret == NULL || smscrypt->secret_len == 0)
{
_smscrypt_destroy(plugin);
return error_set_code(1, "%s", strerror(errno));
}
smscrypt->len = sizeof(smscrypt->buf);
return 0;
}
@ -94,26 +86,22 @@ static int _smscrypt_destroy(PhonePlugin * plugin)
{
SMSCrypt * smscrypt = plugin->priv;
if(smscrypt->secret != NULL)
memset(smscrypt->secret, 0, smscrypt->secret_len);
free(smscrypt->secret);
free(smscrypt);
return 0;
}
/* smscrypt_event */
static int _smscrypt_event_sms_receiving(SMSCrypt * smscrypt,
static int _smscrypt_event_sms_receiving(PhonePlugin * plugin,
char const * number, PhoneEncoding * encoding, char ** buf,
size_t * len);
static int _smscrypt_event_sms_sending(SMSCrypt * smscrypt,
static int _smscrypt_event_sms_sending(PhonePlugin * plugin,
char const * number, PhoneEncoding * encoding, char ** buf,
size_t * len);
static int _smscrypt_event(PhonePlugin * plugin, PhoneEvent event, ...)
{
int ret = 0;
SMSCrypt * smscrypt = plugin->priv;
va_list ap;
char const * number;
PhoneEncoding * encoding;
@ -129,7 +117,7 @@ static int _smscrypt_event(PhonePlugin * plugin, PhoneEvent event, ...)
encoding = va_arg(ap, PhoneEncoding *);
buf = va_arg(ap, char **);
len = va_arg(ap, size_t *);
ret = _smscrypt_event_sms_receiving(smscrypt, number,
ret = _smscrypt_event_sms_receiving(plugin, number,
encoding, buf, len);
break;
case PHONE_EVENT_SMS_SENDING:
@ -137,7 +125,7 @@ static int _smscrypt_event(PhonePlugin * plugin, PhoneEvent event, ...)
encoding = va_arg(ap, PhoneEncoding *);
buf = va_arg(ap, char **);
len = va_arg(ap, size_t *);
ret = _smscrypt_event_sms_sending(smscrypt, number,
ret = _smscrypt_event_sms_sending(plugin, number,
encoding, buf, len);
break;
/* ignore the rest */
@ -148,10 +136,11 @@ static int _smscrypt_event(PhonePlugin * plugin, PhoneEvent event, ...)
return ret;
}
static int _smscrypt_event_sms_receiving(SMSCrypt * smscrypt,
static int _smscrypt_event_sms_receiving(PhonePlugin * plugin,
char const * number, PhoneEncoding * encoding, char ** buf,
size_t * len)
{
SMSCrypt * smscrypt = plugin->priv;
size_t i;
size_t j = 0;
@ -161,37 +150,66 @@ static int _smscrypt_event_sms_receiving(SMSCrypt * smscrypt,
#endif
if(*encoding != PHONE_ENCODING_DATA)
return 0; /* not for us */
if(_smscrypt_secret(plugin, number) != 0)
return 0; /* XXX warn */
for(i = 0; i < *len; i++)
{
(*buf)[i] ^= smscrypt->secret[j++];
j %= smscrypt->secret_len;
(*buf)[i] ^= smscrypt->buf[j++];
j %= smscrypt->len;
}
*encoding = PHONE_ENCODING_UTF8;
return 0;
}
static int _smscrypt_event_sms_sending(SMSCrypt * smscrypt,
static int _smscrypt_event_sms_sending(PhonePlugin * plugin,
char const * number, PhoneEncoding * encoding, char ** buf,
size_t * len)
{
SMSCrypt * smscrypt = plugin->priv;
size_t i;
size_t j = 0;
#ifdef DEBUG
fprintf(stderr, "DEBUG: %s(%u, buf, %lu)\n", __func__, *encoding, *len);
fprintf(stderr, "DEBUG: %s(\"%s\", %u, buf, %lu)\n", __func__, number,
*encoding, *len);
#endif
if(*encoding != PHONE_ENCODING_UTF8)
return 0; /* not for us */
if(_smscrypt_secret(plugin, number) != 0)
return 0; /* XXX warn */
*encoding = PHONE_ENCODING_DATA;
for(i = 0; i < *len; i++)
{
(*buf)[i] ^= smscrypt->secret[j++];
j %= smscrypt->secret_len;
(*buf)[i] ^= smscrypt->buf[j++];
j %= smscrypt->len;
}
*encoding = PHONE_ENCODING_DATA;
return 0;
}
/* smscrypt_secret */
static int _smscrypt_secret(PhonePlugin * plugin, char const * number)
{
SMSCrypt * smscrypt = plugin->priv;
char const * secret = NULL;
SHA_CTX sha1;
if(number != NULL)
secret = plugin->helper->config_get(plugin->helper->phone,
"smscrypt", number);
if(secret == NULL)
secret = plugin->helper->config_get(plugin->helper->phone,
"smscrypt", "secret");
if(secret == NULL)
return 1;
SHA1_Init(&sha1);
SHA1_Update(&sha1, (unsigned char const *)secret, strlen(secret));
SHA1_Final(smscrypt->buf, &sha1);
return 0;
}
/* smscrypt_settings */
static void _smscrypt_settings(PhonePlugin * plugin)
{