ussd: Add a test case, switch parsing to use a gsm48_hdr and len

The current USSD code is not doing any size checks, add a test
case to find out how easily we access the data out of bounds.
Begin to use the length in some places.
This commit is contained in:
Holger Hans Peter Freyther 2010-10-11 07:56:06 +02:00
parent 00cb5700e6
commit daa653fc22
6 changed files with 98 additions and 22 deletions

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@ -112,4 +112,5 @@ AC_OUTPUT(
tests/timer/Makefile
tests/sms/Makefile
tests/msgfile/Makefile
tests/ussd/Makefile
Makefile)

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@ -2,6 +2,8 @@
#define gsm0480_h
#include "msgb.h"
#include "protocol/gsm_04_08.h"
#include "protocol/gsm_04_80.h"
#define MAX_LEN_USSD_STRING 31
@ -11,7 +13,7 @@ struct ussd_request {
uint8_t invoke_id;
};
int gsm0480_decode_ussd_request(const struct msgb *msg,
int gsm0480_decode_ussd_request(const struct gsm48_hdr *hdr, uint16_t len,
struct ussd_request *request);
struct msgb *gsm0480_create_unstructuredSS_Notify(int alertPattern, const char *text);

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@ -192,25 +192,26 @@ struct msgb *gsm0480_create_notifySS(const char *text)
}
/* Forward declarations */
static int parse_ussd(uint8_t *ussd, struct ussd_request *req);
static int parse_ussd_info_elements(uint8_t *ussd_ie,
static int parse_ussd(const struct gsm48_hdr *hdr,
uint16_t len, struct ussd_request *req);
static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
struct ussd_request *req);
static int parse_facility_ie(uint8_t *facility_ie, uint8_t length,
static int parse_facility_ie(const uint8_t *facility_ie, uint8_t length,
struct ussd_request *req);
static int parse_ss_invoke(uint8_t *invoke_data, uint8_t length,
static int parse_ss_invoke(const uint8_t *invoke_data, uint8_t length,
struct ussd_request *req);
static int parse_process_uss_req(uint8_t *uss_req_data, uint8_t length,
static int parse_process_uss_req(const uint8_t *uss_req_data, uint8_t length,
struct ussd_request *req);
/* Decode a mobile-originated USSD-request message */
int gsm0480_decode_ussd_request(const struct msgb *msg, struct ussd_request *req)
int gsm0480_decode_ussd_request(const struct gsm48_hdr *hdr, uint16_t len,
struct ussd_request *req)
{
int rc = 0;
uint8_t *parse_ptr = msgb_l3(msg);
if ((*parse_ptr & 0x0F) == GSM48_PDISC_NC_SS) {
req->transaction_id = *parse_ptr & 0x70;
rc = parse_ussd(parse_ptr+1, req);
if ((hdr->proto_discr & 0x0f) == GSM48_PDISC_NC_SS) {
req->transaction_id = hdr->proto_discr & 0x70;
rc = parse_ussd(hdr, len, req);
}
if (!rc)
@ -219,10 +220,10 @@ int gsm0480_decode_ussd_request(const struct msgb *msg, struct ussd_request *req
return rc;
}
static int parse_ussd(uint8_t *ussd, struct ussd_request *req)
static int parse_ussd(const struct gsm48_hdr *hdr, uint16_t len, struct ussd_request *req)
{
int rc = 1;
uint8_t msg_type = ussd[0] & 0xBF; /* message-type - section 3.4 */
uint8_t msg_type = hdr->msg_type & 0xBF; /* message-type - section 3.4 */
switch (msg_type) {
case GSM0480_MTYPE_RELEASE_COMPLETE:
@ -232,11 +233,11 @@ static int parse_ussd(uint8_t *ussd, struct ussd_request *req)
break;
case GSM0480_MTYPE_REGISTER:
case GSM0480_MTYPE_FACILITY:
rc &= parse_ussd_info_elements(ussd+1, req);
rc &= parse_ussd_info_elements(&hdr->data[0], len - sizeof(*hdr), req);
break;
default:
LOGP(0, LOGL_DEBUG, "Unknown GSM 04.80 message-type field 0x%02x\n",
ussd[0]);
hdr->msg_type);
rc = 0;
break;
}
@ -244,12 +245,16 @@ static int parse_ussd(uint8_t *ussd, struct ussd_request *req)
return rc;
}
static int parse_ussd_info_elements(uint8_t *ussd_ie, struct ussd_request *req)
static int parse_ussd_info_elements(const uint8_t *ussd_ie, uint16_t len,
struct ussd_request *req)
{
int rc = -1;
/* Information Element Identifier - table 3.2 & GSM 04.08 section 10.5 */
uint8_t iei = ussd_ie[0];
uint8_t iei_length = ussd_ie[1];
uint8_t iei;
uint8_t iei_length;
iei = ussd_ie[0];
iei_length = ussd_ie[1];
switch (iei) {
case GSM48_IE_CAUSE:
@ -269,7 +274,7 @@ static int parse_ussd_info_elements(uint8_t *ussd_ie, struct ussd_request *req)
return rc;
}
static int parse_facility_ie(uint8_t *facility_ie, uint8_t length,
static int parse_facility_ie(const uint8_t *facility_ie, uint8_t length,
struct ussd_request *req)
{
int rc = 1;
@ -305,7 +310,7 @@ static int parse_facility_ie(uint8_t *facility_ie, uint8_t length,
}
/* Parse an Invoke component - see table 3.3 */
static int parse_ss_invoke(uint8_t *invoke_data, uint8_t length,
static int parse_ss_invoke(const uint8_t *invoke_data, uint8_t length,
struct ussd_request *req)
{
int rc = 1;
@ -350,7 +355,7 @@ static int parse_ss_invoke(uint8_t *invoke_data, uint8_t length,
}
/* Parse the parameters of a Process UnstructuredSS Request */
static int parse_process_uss_req(uint8_t *uss_req_data, uint8_t length,
static int parse_process_uss_req(const uint8_t *uss_req_data, uint8_t length,
struct ussd_request *req)
{
int rc = 0;

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@ -1,5 +1,5 @@
if ENABLE_TESTS
SUBDIRS = timer sms
SUBDIRS = timer sms ussd
if ENABLE_MSGFILE
SUBDIRS += msgfile
endif

5
tests/ussd/Makefile.am Normal file
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@ -0,0 +1,5 @@
INCLUDES = $(all_includes) -I$(top_srcdir)/include
noinst_PROGRAMS = ussd_test
ussd_test_SOURCES = ussd_test.c
ussd_test_LDADD = $(top_builddir)/src/libosmocore.la

63
tests/ussd/ussd_test.c Normal file
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@ -0,0 +1,63 @@
/*
* (C) 2010 by Holger Hans Peter Freyther
* (C) 2010 by On-Waves
* All Rights Reserved
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <osmocore/gsm0480.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static const uint8_t ussd_request[] = {
0x0b, 0x7b, 0x1c, 0x15, 0xa1, 0x13, 0x02, 0x01,
0x03, 0x02, 0x01, 0x3b, 0x30, 0x0b, 0x04, 0x01,
0x0f, 0x04, 0x06, 0x2a, 0xd5, 0x4c, 0x16, 0x1b,
0x01, 0x7f, 0x01, 0x00
};
static int parse_ussd(const uint8_t *_data, int len)
{
uint8_t *data;
int rc;
struct ussd_request req;
struct gsm48_hdr *hdr;
data = malloc(len);
memcpy(data, _data, len);
hdr = (struct gsm48_hdr *) &data[0];
rc = gsm0480_decode_ussd_request(hdr, len, &req);
free(data);
return rc;
}
int main(int argc, char **argv)
{
const int size = sizeof(ussd_request);
int i;
printf("Testing parsing a USSD request and truncated versions\n");
for (i = size; i > sizeof(struct gsm48_hdr); --i) {
int rc = parse_ussd(&ussd_request[0], i);
printf("Result for %d is %d\n", rc, i);
}
return 0;
}