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authorNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-02-02 20:05:14 +0100
committerNeels Hofmeyr <nhofmeyr@sysmocom.de>2017-02-02 20:34:16 +0100
commit8352d31a8666e328e399ba1d2ae581c8f0021e48 (patch)
tree8a3599765d6481fdbfeeb481d221bfcd97712b7e
parent4a7f87cdc848891f7306109a009e51684b6c5c0e (diff)
GSUP, OAP, osmo-gen-vec: fix AUTS length to 14, not 16
GSUP transmits AUTS for UMTS authentication procedures, and OAP uses the same procedures to authenticate. osmo-gen-vec is a utility program that passes AUTS to our osmo_auth_gen_vec_auts() API. According to 3GPP 33.102 6.3.3, AUTS = SQN^AK || MAC-S, which are 6 || 8 == 14 bytes. This is confirmed by 24.008 9.2.3a where the TLV has 16 bytes, TL = 2 and AUTS being the V = 14. It is not harmful for milenage_gen_vec_auts() to pass two more AUTS bytes. But writing 16 bytes to a GSUP struct is a potential problem when passing in a 14 byte long AUTS buffer to the GSUP API, which then reads past the AUTS buffer. The API implies the length, so far to be 16, so passing in a 14 byte buffer to GSUP would require copying to a larger buffer first. Fix this by using a length of 14 for AUTS everywhere instead. This constitues an ABI breakage, we may handle it as a "fix before an official release", otherwise we need a version bump. The OAP protocol document has also been updated, needs an update in the osmo-gsm-manuals as well. Change-Id: If25b173d9ec57ea4c504d860954912b7d82af455
-rw-r--r--TODO-RELEASE3
-rw-r--r--doc/osmocom-authn-protocol.txt2
-rw-r--r--include/osmocom/gsm/oap.h2
-rw-r--r--src/gsm/gsup.c2
-rw-r--r--tests/oap/oap_test.c4
-rw-r--r--tests/oap/oap_test.ok2
-rw-r--r--utils/osmo-auc-gen.c2
7 files changed, 10 insertions, 7 deletions
diff --git a/TODO-RELEASE b/TODO-RELEASE
index 5c6bfa3c..a23fcea7 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -8,3 +8,6 @@
# If any interfaces have been removed or changed since the last public release: c:r:0.
#library what description / commit summary line
libosmocore new function osmo_sock_get_name()
+libosmogsm/gsup ABI change fix AUTS length to 14, not 16 (length is implicit)
+libosmogsm/oap ABI change fix AUTS length to 14, not 16 (length is implicit)
+osmo-auc-gen UI change fix AUTS length to 14, not 16 (length is implicit)
diff --git a/doc/osmocom-authn-protocol.txt b/doc/osmocom-authn-protocol.txt
index 6d057bea..ad4fba0f 100644
--- a/doc/osmocom-authn-protocol.txt
+++ b/doc/osmocom-authn-protocol.txt
@@ -181,7 +181,7 @@ Client -> Server
IEI Info Element Type Pres. Format Length
Message type 4.2.1 M V 1
- 20 AUTS octet string (16) M TLV 18
+ 20 AUTS octet string (14) M TLV 16
3.2.8. Sync Error
diff --git a/include/osmocom/gsm/oap.h b/include/osmocom/gsm/oap.h
index d973013a..ff561bf1 100644
--- a/include/osmocom/gsm/oap.h
+++ b/include/osmocom/gsm/oap.h
@@ -64,7 +64,7 @@ struct osmo_oap_message {
int xres_present;
uint8_t xres[8];
int auts_present;
- uint8_t auts[16];
+ uint8_t auts[14];
};
int osmo_oap_decode(struct osmo_oap_message *oap_msg, const uint8_t *data,
diff --git a/src/gsm/gsup.c b/src/gsm/gsup.c
index 22f57ab7..b1b97ca5 100644
--- a/src/gsm/gsup.c
+++ b/src/gsm/gsup.c
@@ -497,7 +497,7 @@ void osmo_gsup_encode(struct msgb *msg, const struct osmo_gsup_message *gsup_msg
}
if (gsup_msg->auts)
- msgb_tlv_put(msg, OSMO_GSUP_AUTS_IE, 16, gsup_msg->auts);
+ msgb_tlv_put(msg, OSMO_GSUP_AUTS_IE, 14, gsup_msg->auts);
if (gsup_msg->rand)
msgb_tlv_put(msg, OSMO_GSUP_RAND_IE, 16, gsup_msg->rand);
diff --git a/tests/oap/oap_test.c b/tests/oap/oap_test.c
index ccf49069..0c4c16ea 100644
--- a/tests/oap/oap_test.c
+++ b/tests/oap/oap_test.c
@@ -155,8 +155,8 @@ static void test_oap_messages_dec_enc(void)
printf("- Sync Request\n");
CLEAR();
oap_msg.message_type = OAP_MSGT_SYNC_REQUEST;
- osmo_hexparse("102030405060708090a0b0c0d0e0f001",
- oap_msg.auts, 16);
+ osmo_hexparse("102030405060708090a0b0c0d0e0",
+ oap_msg.auts, 14);
oap_msg.auts_present = 1;
CHECK();
diff --git a/tests/oap/oap_test.ok b/tests/oap/oap_test.ok
index 9260d442..4c099290 100644
--- a/tests/oap/oap_test.ok
+++ b/tests/oap/oap_test.ok
@@ -37,6 +37,6 @@ encoded message:
ok
- Sync Request
encoded message:
-0c 25 10 10 20 30 40 50 60 70 80 90 a0 b0 c0 d0 e0 f0 01
+0c 25 0e 10 20 30 40 50 60 70 80 90 a0 b0 c0 d0 e0
ok
Done.
diff --git a/utils/osmo-auc-gen.c b/utils/osmo-auc-gen.c
index 3b3e5577..4c3e891b 100644
--- a/utils/osmo-auc-gen.c
+++ b/utils/osmo-auc-gen.c
@@ -87,7 +87,7 @@ int main(int argc, char **argv)
{
struct osmo_auth_vector _vec;
struct osmo_auth_vector *vec = &_vec;
- uint8_t _rand[16], _auts[16];
+ uint8_t _rand[16], _auts[14];
int rc, option_index;
int rand_is_set = 0;
int auts_is_set = 0;