Refactor COMP128v23 implementation and add test suit

.gitignore

@@ -62,6 +62,7 @@ tests/ussd/ussd_test
 tests/smscb/smscb_test
 tests/bits/bitrev_test
 tests/a5/a5_test
+tests/comp128/comp128_test
 tests/auth/milenage_test
 tests/conv/conv_test
 tests/lapd/lapd_test

include/osmocom/gsm/comp128v23.h

@@ -13,11 +13,11 @@
  * Performs the COMP128 version 2 and 3 algorithm (used as A3/A8)
  * ki    : uint8_t [16]
  * srand : uint8_t [16]
- * version : uint8_t (2 or 3)
  * sres  : uint8_t [4]
  * kc    : uint8_t [8]
  * returns 1 if not version 2 or 3 specified
  */
-int comp128v23(const uint8_t *ki, const uint8_t *rand, uint8_t version, uint8_t *sres, uint8_t *kc);
+int comp128v2(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc);
+int comp128v3(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc);
 
 #endif /* __COMP128V23_H__ */

src/gsm/auth_comp128v23.c

@@ -31,7 +31,7 @@ static int c128v2_gen_vec(struct osmo_auth_vector *vec,
 			  struct osmo_sub_auth_data *aud,
 			  const uint8_t *_rand)
 {
-	comp128v23(aud->u.gsm.ki, _rand, 2, vec->sres, vec->kc);
+	comp128v2(aud->u.gsm.ki, _rand, vec->sres, vec->kc);
 	vec->auth_types = OSMO_AUTH_TYPE_GSM;
 
 	return 0;
@@ -48,7 +48,7 @@ static int c128v3_gen_vec(struct osmo_auth_vector *vec,
 			  struct osmo_sub_auth_data *aud,
 			  const uint8_t *_rand)
 {
-	comp128v23(aud->u.gsm.ki, _rand, 3, vec->sres, vec->kc);
+	comp128v3(aud->u.gsm.ki, _rand, vec->sres, vec->kc);
 	vec->auth_types = OSMO_AUTH_TYPE_GSM;
 
 	return 0;

src/gsm/comp128v23.c

@@ -64,21 +64,17 @@ static const uint8_t table0[256] = {
 	218, 160, 187, 106, 35, 87, 105, 96, 145, 199, 159, 12, 121, 103, 112
 };
 
-#define RAND_SIZE 16
-#define KI_SIZE 16
-#define SRES_SIZE 4
-#define KC_SIZE 8
 
 static void
 _comp128v23_internal(uint8_t *output, const uint8_t *kxor, const uint8_t *rand)
 {
-	uint8_t temp[RAND_SIZE];
-	uint8_t km_rm[RAND_SIZE+KI_SIZE];
+	uint8_t temp[16];
+	uint8_t km_rm[32];
 	uint8_t i,j,k,z;
 
-	memset(temp,0,sizeof(temp)/sizeof(uint8_t));
-	memcpy(km_rm,rand,RAND_SIZE);
-	memcpy(km_rm+RAND_SIZE,kxor,KI_SIZE);
+	memset(temp, 0, sizeof(temp));
+	memcpy(km_rm, rand, 16);
+	memcpy(km_rm + 16, kxor, 16);
 
 	for (i=0; i<5; i++) {
 		for (z=0; z<16; z++) {
@@ -106,21 +102,18 @@ _comp128v23_internal(uint8_t *output, const uint8_t *kxor, const uint8_t *rand)
 }
 
 int
-comp128v23(const uint8_t *ki, const uint8_t *rand, uint8_t version, uint8_t *sres, uint8_t *kc)
+comp128v3(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
 {
-	uint8_t k_mix[KI_SIZE];
-	uint8_t rand_mix[RAND_SIZE];
-	uint8_t katyvasz[KI_SIZE];
-	uint8_t output[KI_SIZE];
-	uint8_t i,s;
+	uint8_t k_mix[16];
+	uint8_t rand_mix[16];
+	uint8_t katyvasz[16];
+	uint8_t output[16];
+	uint8_t i;
 
-	if (!(version==2 || version==3))
-		return 1;
-
-	memset(k_mix,0,sizeof(k_mix)/sizeof(uint8_t));
-	memset(rand_mix,0,sizeof(rand_mix)/sizeof(uint8_t));
-	memset(katyvasz,0,sizeof(katyvasz)/sizeof(uint8_t));
-	memset(output,0,sizeof(output)/sizeof(uint8_t));
+	memset(k_mix, 0, sizeof(k_mix));
+	memset(rand_mix, 0, sizeof(rand_mix));
+	memset(katyvasz, 0, sizeof(katyvasz));
+	memset(output, 0, sizeof(output));
 
 	for (i=0; i<8; i++) {
 		k_mix[i] = ki[15 - i];
@@ -144,23 +137,21 @@ comp128v23(const uint8_t *ki, const uint8_t *rand, uint8_t version, uint8_t *sre
 		output[i] = rand_mix[15-i];
 	}
 
-	if (version==2) {
-		output[15] = 0;
-		output[14] = 4*(output[14]>>2);
-	}
-
-	s = 8;
-	i = 0;
-	while (i<4) {
-		output[s+i-4] = output[s+i];
-		output[s+i] = output[s+i+4];
-		i++;
-	}
+	memmove(output + 4, output + 8, 8); /* ignore bytes 4..7 */
 
 	/* the algorithm uses 16 bytes until this point, but only 12 bytes are effective
 	 * also 12 bytes coming out from the SIM card */
-	memcpy(sres,output,SRES_SIZE*sizeof(uint8_t));
-	memcpy(kc,&output[SRES_SIZE],KC_SIZE*sizeof(uint8_t));
+	memcpy(sres, output, 4);
+	memcpy(kc, output + 4, 8);
 
 	return 0;
 }
+
+int
+comp128v2(const uint8_t *ki, const uint8_t *rand, uint8_t *sres, uint8_t *kc)
+{
+	int r = comp128v3(ki, rand, sres, kc);
+	kc[7] = 0; /* 10 last bits of Kc forced to 0 */
+	kc[6] &= 0xfc;
+	return r;
+}

tests/Makefile.am

@@ -7,7 +7,7 @@ check_PROGRAMS = timer/timer_test sms/sms_test ussd/ussd_test		\
 		 gb/bssgp_fc_test gb/gprs_ns_test                       \
 		 logging/logging_test fr/fr_test	                \
 		 loggingrb/loggingrb_test strrb/strrb_test              \
-		 vty/vty_test
+		 vty/vty_test comp128/comp128_test
 
 if ENABLE_MSGFILE
 check_PROGRAMS += msgfile/msgfile_test
@@ -16,6 +16,9 @@ endif
 a5_a5_test_SOURCES = a5/a5_test.c
 a5_a5_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
 
+comp128_comp128_test_SOURCES = comp128/comp128_test.c
+comp128_comp128_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
+
 auth_milenage_test_SOURCES = auth/milenage_test.c
 auth_milenage_test_LDADD = $(top_builddir)/src/libosmocore.la $(top_builddir)/src/gsm/libosmogsm.la
 
@@ -101,7 +104,7 @@ EXTRA_DIST = testsuite.at $(srcdir)/package.m4 $(TESTSUITE)		\
              logging/logging_test.ok logging/logging_test.err		\
              fr/fr_test.ok loggingrb/logging_test.ok			\
              loggingrb/logging_test.err	strrb/strrb_test.ok		\
-	     vty/vty_test.ok
+	     vty/vty_test.ok comp128/comp128_test.ok
 
 DISTCLEANFILES = atconfig
 

tests/testsuite.at

@@ -54,6 +54,12 @@ cat $abs_srcdir/auth/milenage_test.ok > expout
 AT_CHECK([$abs_top_builddir/tests/auth/milenage_test], [0], [expout], [ignore])
 AT_CLEANUP
 
+AT_SETUP([comp128])
+AT_KEYWORDS([comp128])
+cat $abs_srcdir/comp128/comp128_test.ok > expout
+AT_CHECK([$abs_top_builddir/tests/comp128/comp128_test], [0], [expout])
+AT_CLEANUP
+
 AT_SETUP([lapd])
 AT_KEYWORDS([lapd])
 cat $abs_srcdir/lapd/lapd_test.ok > expout