laforge has submitted this change. (
https://gerrit.osmocom.org/c/libosmocore/+/31451 )
Change subject: Implement the XOR-2G authentication algorithm
......................................................................
Implement the XOR-2G authentication algorithm
We've so far only been supporting XOR-3G algorithm as specified
in TS 34.108 (in both 3G and 2G-derivation mode).
However, XOR-3G used for 2G auth is different from the XOR-2G algorithm
as defined in Annex A of TS 51.010-1. Let's add support for that one,
too.
Change-Id: I0ee0565382c1e4515d44ff9b1752685c0a66ae39
---
M include/osmocom/crypt/auth.h
M src/gsm/Makefile.am
M src/gsm/auth_core.c
A src/gsm/auth_xor_2g.c
4 files changed, 98 insertions(+), 1 deletion(-)
Approvals:
Jenkins Builder: Verified
fixeria: Looks good to me, but someone else must approve
pespin: Looks good to me, approved
diff --git a/include/osmocom/crypt/auth.h b/include/osmocom/crypt/auth.h
index c653b61..4af8ca8 100644
--- a/include/osmocom/crypt/auth.h
+++ b/include/osmocom/crypt/auth.h
@@ -32,6 +32,7 @@
OSMO_AUTH_ALG_COMP128v3,
OSMO_AUTH_ALG_XOR,
OSMO_AUTH_ALG_MILENAGE,
+ OSMO_AUTH_ALG_XOR_2G,
_OSMO_AUTH_ALG_NUM,
};
diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index 798f11a..cff089b 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -26,7 +26,7 @@
gprs_cipher_core.c gprs_rlc.c gsm0480.c abis_nm.c
gsm0502.c \
gsm0411_utils.c gsm0411_smc.c gsm0411_smr.c gsm0414.c \
lapdm.c kasumi.c gsm29205.c gsm_04_08_gprs.c \
- auth_core.c auth_comp128v1.c auth_comp128v23.c
auth_xor.c \
+ auth_core.c auth_comp128v1.c auth_comp128v23.c
auth_xor.c auth_xor_2g.c \
auth_milenage.c milenage/aes-encblock.c gea.c \
milenage/aes-internal.c milenage/aes-internal-enc.c \
milenage/milenage.c gan.c ipa.c gsm0341.c apn.c \
diff --git a/src/gsm/auth_core.c b/src/gsm/auth_core.c
index f450850..af03ace 100644
--- a/src/gsm/auth_core.c
+++ b/src/gsm/auth_core.c
@@ -210,6 +210,7 @@
{ OSMO_AUTH_ALG_COMP128v3, "COMP128v3" },
{ OSMO_AUTH_ALG_XOR, "XOR" },
{ OSMO_AUTH_ALG_MILENAGE, "MILENAGE" },
+ { OSMO_AUTH_ALG_XOR_2G, "XOR-2G" },
{ 0, NULL }
};
diff --git a/src/gsm/auth_xor_2g.c b/src/gsm/auth_xor_2g.c
new file mode 100644
index 0000000..9efe5cc
--- /dev/null
+++ b/src/gsm/auth_xor_2g.c
@@ -0,0 +1,79 @@
+/*! \file auth_xor.c
+ * GSM XOR-2G algorithm as specified in Annex 4 (A.4.1.2) of 3GPP TS 51.010-1.
+ * This is implemented by typical GSM MS tester */
+
+/*
+ * (C) 2023 by Harald Welte <[email protected]>
+ *
+ * All Rights Reserved
+ *
+ * Author: Daniel Willmann <[email protected]>
+ *
+ * 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.
+ *
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include <osmocom/crypt/auth.h>
+
+/*! \addtogroup auth
+ * @{
+ */
+
+static void xor(uint8_t *out, const uint8_t *a, const uint8_t *b, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++)
+ out[i] = a[i] ^ b[i];
+}
+
+/* GSM XOR-2G algorithm as specified in Annex 4 (A.4.1.2) of 3GPP TS 51.010-1.
*/
+static int xor2g_gen_vec(struct osmo_auth_vector *vec,
+ struct osmo_sub_auth_data *aud,
+ const uint8_t *_rand)
+{
+ uint8_t res1[16];
+
+ if (aud->type != OSMO_AUTH_TYPE_GSM)
+ return -ENOTSUP;
+
+ /* Step 1: XOR to the challenge RAND, a predefined number Ki, having
the same bit length (128 bits) as
+ * RAND. */
+ xor(res1, aud->u.gsm.ki, _rand, sizeof(res1));
+
+ /* Step 2: The most significant 32 bits of RES1 form SRES. */
+ memcpy(vec->sres, res1, 4);
+ /* The next 64 bits of RES1 form Kc */
+ memcpy(vec->kc, res1+4, 8);
+
+ vec->auth_types = OSMO_AUTH_TYPE_GSM;
+ return 0;
+}
+
+static struct osmo_auth_impl xor2g_alg = {
+ .algo = OSMO_AUTH_ALG_XOR_2G,
+ .name = "XOR-2G (libosmogsm built-in)",
+ .priority = 1000,
+ .gen_vec = &xor2g_gen_vec,
+};
+
+static __attribute__((constructor)) void on_dso_load_xor(void)
+{
+ osmo_auth_register(&xor2g_alg);
+}
+
+/*! @} */
--
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Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: I0ee0565382c1e4515d44ff9b1752685c0a66ae39
Gerrit-Change-Number: 31451
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
