Change in osmo-sgsn[master]: gmm: on invalid RA id reject the MS with an implicit detach

[laforge]

laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-sgsn/+/20194 )

Change subject: gmm: on invalid RA id reject the MS with an implicit detach
......................................................................

gmm: on invalid RA id reject the MS with an implicit detach

As long the SGSN doesn't support PS handover treat unknown RA as invalid
and do an implicit detach.

Fixes ttcn3 crash when an RAU happen within an Attach Request

Change-Id: I6a0b335d51f58c26349f7e0a62b2107d7d351d07
---
M src/sgsn/gprs_gmm.c
1 file changed, 20 insertions(+), 10 deletions(-)

Approvals:
  laforge: Looks good to me, approved
  pespin: Looks good to me, but someone else must approve
  Jenkins Builder: Verified



diff --git a/src/sgsn/gprs_gmm.c b/src/sgsn/gprs_gmm.c
index 182276c..86545f8 100644
--- a/src/sgsn/gprs_gmm.c
+++ b/src/sgsn/gprs_gmm.c
@@ -1663,16 +1663,26 @@
 	} else if (!gprs_ra_id_equals(&mmctx->ra, &old_ra_id) ||
 		mmctx->gmm_fsm->state == ST_GMM_DEREGISTERED)
 	{
-		/* We cannot use the mmctx */
-		LOGMMCTXP(LOGL_INFO, mmctx,
-			"The MM context cannot be used, RA: %s\n",
-			osmo_rai_name(&mmctx->ra));
-		/* mmctx is set to NULL and gprs_llgmm_unassign(llme) will be
-		   called below, let's make sure we don't keep dangling llme
-		   pointers in mmctx (OS#3957, OS#4245). */
-		if (mmctx->ran_type == MM_CTX_T_GERAN_Gb)
-			mmctx->gb.llme = NULL;
-		mmctx = NULL;
+		/* We've received either a RAU for a MS which isn't registered
+		 * or a RAU with an unknown RA ID. As long the SGSN doesn't support
+		 * PS handover we treat this as invalid RAU */
+		struct gprs_ra_id new_ra_id;
+		char new_ra[32];
+
+		bssgp_parse_cell_id(&new_ra_id, msgb_bcid(msg));
+		osmo_rai_name_buf(new_ra, sizeof(new_ra), &new_ra_id);
+
+		if (mmctx->gmm_fsm->state == ST_GMM_DEREGISTERED)
+			LOGMMCTXP(LOGL_INFO, mmctx,
+				  "Rejecting RAU - GMM state is deregistered. Old RA: %s New RA: %s\n",
+				  osmo_rai_name(&old_ra_id), new_ra);
+		else
+			LOGMMCTXP(LOGL_INFO, mmctx,
+				  "Rejecting RAU - Old RA doesn't match MM. Old RA: %s New RA: %s\n",
+				  osmo_rai_name(&old_ra_id), new_ra);
+
+		reject_cause = GMM_CAUSE_IMPL_DETACHED;
+		goto rejected;
 	}
 
 	if (!mmctx) {

-- 
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Gerrit-Project: osmo-sgsn
Gerrit-Branch: master
Gerrit-Change-Id: I6a0b335d51f58c26349f7e0a62b2107d7d351d07
Gerrit-Change-Number: 20194
Gerrit-PatchSet: 3
Gerrit-Owner: lynxis lazus <lynxis at fe80.eu>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-Reviewer: lynxis lazus <lynxis at fe80.eu>
Gerrit-Reviewer: pespin <pespin at sysmocom.de>
Gerrit-MessageType: merged
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