From 8352d31a8666e328e399ba1d2ae581c8f0021e48 Mon Sep 17 00:00:00 2001 From: Neels Hofmeyr Date: Thu, 2 Feb 2017 20:05:14 +0100 Subject: 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 --- utils/osmo-auc-gen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'utils') 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; -- cgit v1.2.3