[PATCH] osmo-sgsn[master]: Generate random IOV-UI and send it via XID

[Max]

Review at  https://gerrit.osmocom.org/5788

Generate random IOV-UI and send it via XID

This ensures that encryption is using random IV value as per-spec
instead of hard-coded 0.

Change-Id: I7b6e2268cb28451434116463ecd3ce5f68400832
Fixes: OS#1794
---
M include/osmocom/sgsn/gprs_llc.h
M src/gprs/gprs_llc.c
2 files changed, 27 insertions(+), 12 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/osmo-sgsn refs/changes/88/5788/1

diff --git a/include/osmocom/sgsn/gprs_llc.h b/include/osmocom/sgsn/gprs_llc.h
index 376ae9a..f5643da 100644
--- a/include/osmocom/sgsn/gprs_llc.h
+++ b/include/osmocom/sgsn/gprs_llc.h
@@ -238,6 +238,8 @@
 int gprs_llgmm_reset_oldmsg(struct msgb* oldmsg, uint8_t sapi,
 			    struct gprs_llc_llme *llme);
 
+bool gprs_llgmm_gen_iov_ui(struct gprs_llc_llme *llme);
+
 /* Set of LL-XID negotiation (See also: TS 101 351, Section 7.2.2.4) */
 int gprs_ll_xid_req(struct gprs_llc_lle *lle,
 		    struct gprs_llc_xid_field *l3_xid_field);
diff --git a/src/gprs/gprs_llc.c b/src/gprs/gprs_llc.c
index 6c92f83..11c5cc5 100644
--- a/src/gprs/gprs_llc.c
+++ b/src/gprs/gprs_llc.c
@@ -49,6 +49,19 @@
 
 /* BEGIN XID RELATED */
 
+bool gprs_llgmm_gen_iov_ui(struct gprs_llc_llme *llme)
+{
+	if (llme->algo != GPRS_ALGO_GEA0) {
+		int rc = osmo_get_rand_id((uint8_t *) &llme->iov_ui, 4);
+		if (rc < 0) {
+			LOGP(DLLC, LOGL_ERROR, "osmo_get_rand_id() failed for LLC XID reset: %s\n", strerror(-rc));
+			return false;
+		}
+		return true;
+	}
+	return false;
+}
+
 /* Generate XID message */
 static int gprs_llc_generate_xid(uint8_t *bytes, int bytes_len,
 				 struct gprs_llc_xid_field *l3_xid_field,
@@ -58,9 +71,15 @@
 
 	LLIST_HEAD(xid_fields);
 
+	struct gprs_llc_xid_field xid_iov_ui;
 	struct gprs_llc_xid_field xid_version;
 	struct gprs_llc_xid_field xid_n201u;
 	struct gprs_llc_xid_field xid_n201i;
+
+	bool iov = gprs_llgmm_gen_iov_ui(llme);
+	xid_iov_ui.type = GPRS_LLC_XID_T_IOV_UI;
+	xid_iov_ui.data = (uint8_t *) &llme->iov_ui;
+	xid_iov_ui.data_len = 4;
 
 	xid_version.type = GPRS_LLC_XID_T_VERSION;
 	xid_version.data = (uint8_t *) "\x00";
@@ -75,6 +94,10 @@
 	xid_n201i.data_len = 2;
 
 	/* Add locally managed XID Fields */
+	if (iov)
+		llist_add(&xid_iov_ui.list, &xid_fields);
+	LOGP(DLLC, LOGL_NOTICE, "XID gen with iov %d\n", iov);
+
 	llist_add(&xid_version.list, &xid_fields);
 	llist_add(&xid_n201u.list, &xid_fields);
 	llist_add(&xid_n201i.list, &xid_fields);
@@ -1074,12 +1097,7 @@
 	uint8_t *xid;
 
 	LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n");
-
-	rc = osmo_get_rand_id((uint8_t *) &llme->iov_ui, 4);
-	if (rc < 0) {
-		LOGP(DLLC, LOGL_ERROR, "osmo_get_rand_id() failed for LLC XID reset: %s\n", strerror(-rc));
-		return rc;
-	}
+	gprs_llgmm_gen_iov_ui(llme);
 
 	/* Generate XID message */
 	xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes,
@@ -1108,12 +1126,7 @@
 	uint8_t *xid;
 
 	LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n");
-
-	rc = osmo_get_rand_id((uint8_t *) &llme->iov_ui, 4);
-	if (rc < 0) {
-		LOGP(DLLC, LOGL_ERROR, "osmo_get_rand_id() failed for LLC XID reset: %s\n", strerror(-rc));
-		return rc;
-	}
+	gprs_llgmm_gen_iov_ui(llme);
 
 	/* Generate XID message */
 	xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes,

-- 
To view, visit https://gerrit.osmocom.org/5788
To unsubscribe, visit https://gerrit.osmocom.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: I7b6e2268cb28451434116463ecd3ce5f68400832
Gerrit-PatchSet: 1
Gerrit-Project: osmo-sgsn
Gerrit-Branch: master
Gerrit-Owner: Max <msuraev at sysmocom.de>