GSUP: check osmo_gsup_encode() result

Check and handle gracefully any error which might appear in
osmo_gsup_encode() - mark corresponding functions with
warn_unused_result attribute to make sure this failure is always checked
against.

Change-Id: I4551212011fb0bd898c020a183756ed7a9afb9e5
Related: OS#2864

4 files changed, 32 insertions, 16 deletions

diff --git a/src/libvlr/vlr.c b/src/libvlr/vlr.c
index 96627edcd..f73eeb4f8 100644
--- a/src/libvlr/vlr.c
+++ b/src/libvlr/vlr.c
@@ -130,7 +130,11 @@ static int vlr_tx_gsup_message(const struct vlr_instance *vlr,
 {
 	struct msgb *msg = gsup_client_msgb_alloc();
 
-	osmo_gsup_encode(msg, gsup_msg);
+	int rc = osmo_gsup_encode(msg, gsup_msg);
+	if (rc < 0) {
+		LOGP(DVLR, LOGL_ERROR, "GSUP encoding failure: %s\n", strerror(-rc));
+		return rc;
+	}
 
 	if (!vlr->gsup_client) {
 		LOGP(DVLR, LOGL_NOTICE, "GSUP link is down, cannot "
@@ -498,8 +502,10 @@ static int vlr_rx_gsup_unknown_imsi(struct vlr_instance *vlr,
 				   struct osmo_gsup_message *gsup_msg)
 {
 	if (OSMO_GSUP_IS_MSGT_REQUEST(gsup_msg->message_type)) {
-		vlr_tx_gsup_error_reply(vlr, gsup_msg,
-					GMM_CAUSE_IMSI_UNKNOWN);
+		int rc = vlr_tx_gsup_error_reply(vlr, gsup_msg, GMM_CAUSE_IMSI_UNKNOWN);
+		if (rc < 0)
+			LOGP(DVLR, LOGL_ERROR, "Failed to send error reply for IMSI %s\n", gsup_msg->imsi);
+
 		LOGP(DVLR, LOGL_NOTICE,
 		     "Unknown IMSI %s, discarding GSUP request "
 		     "of type 0x%02x\n",
@@ -775,7 +781,7 @@ static int vlr_subscr_handle_cancel_req(struct vlr_subscr *vsub,
 					struct osmo_gsup_message *gsup_msg)
 {
 	struct osmo_gsup_message gsup_reply = {0};
-	int is_update_procedure = !gsup_msg->cancel_type ||
+	int rc, is_update_procedure = !gsup_msg->cancel_type ||
 		gsup_msg->cancel_type == OSMO_GSUP_CANCEL_TYPE_UPDATE;
 
 	LOGVSUBP(LOGL_INFO, vsub, "Cancelling MS subscriber (%s)\n",
@@ -783,11 +789,11 @@ static int vlr_subscr_handle_cancel_req(struct vlr_subscr *vsub,
 		 "update procedure" : "subscription withdraw");
 
 	gsup_reply.message_type = OSMO_GSUP_MSGT_LOCATION_CANCEL_RESULT;
-	vlr_subscr_tx_gsup_message(vsub, &gsup_reply);
+	rc = vlr_subscr_tx_gsup_message(vsub, &gsup_reply);
 
 	vlr_subscr_cancel(vsub, gsup_msg->cause);
 
-	return 0;
+	return rc;
 }
 
 /* Incoming handler for GSUP from HLR.
@@ -812,9 +818,11 @@ int vlr_gsupc_read_cb(struct gsup_client *gsupc, struct msgb *msg)
 
 	if (!gsup.imsi[0]) {
 		LOGP(DVLR, LOGL_ERROR, "Missing IMSI in GSUP message\n");
-		if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type))
-			vlr_tx_gsup_error_reply(vlr, &gsup,
-						GMM_CAUSE_INV_MAND_INFO);
+		if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type)) {
+			rc = vlr_tx_gsup_error_reply(vlr, &gsup, GMM_CAUSE_INV_MAND_INFO);
+			if (rc < 0)
+				LOGP(DVLR, LOGL_ERROR, "Failed to send error reply for IMSI %s\n", gsup.imsi);
+		}
 		rc = -GMM_CAUSE_INV_MAND_INFO;
 		goto msgb_free_and_return;
 	}
diff --git a/src/libvlr/vlr_auth_fsm.c b/src/libvlr/vlr_auth_fsm.c
index d14ae8efb..51e22c9dc 100644
--- a/src/libvlr/vlr_auth_fsm.c
+++ b/src/libvlr/vlr_auth_fsm.c
@@ -207,8 +207,11 @@ static void auth_fsm_onenter_failed(struct osmo_fsm_inst *fi, uint32_t prev_stat
 	/* If authentication hasn't even started, e.g. the HLR sent no auth
 	 * info, then we also don't need to tell the HLR about an auth failure.
 	 */
-	if (afp->auth_requested)
-		vlr_subscr_tx_auth_fail_rep(vsub);
+	if (afp->auth_requested) {
+		int rc = vlr_subscr_tx_auth_fail_rep(vsub);
+		if (rc < 0)
+			LOGVSUBP(LOGL_ERROR, vsub, "Failed to communicate AUTH failure to HLR\n");
+	}
 }
 
 /* Terminate the Auth FSM Instance and notify parent */
@@ -281,7 +284,9 @@ static void auth_fsm_needs_auth(struct osmo_fsm_inst *fi, uint32_t event, void *
 	/* Check if we have vectors available */
 	if (!vlr_subscr_has_auth_tuple(vsub, afp->auth_tuple_max_reuse_count)) {
 		/* Obtain_Authentication_Sets_VLR */
-		vlr_subscr_req_sai(vsub, NULL, NULL);
+		int rc = vlr_subscr_req_sai(vsub, NULL, NULL);
+		if (rc < 0)
+			LOGPFSM(fi, "Failed to request Authentication Sets from VLR\n");
 		osmo_fsm_inst_state_chg(fi, VLR_SUB_AS_NEEDS_AUTH_WAIT_AI,
 					GSM_29002_TIMER_M, 0);
 	} else {
@@ -374,7 +379,7 @@ static void auth_fsm_wait_auth_resp(struct osmo_fsm_inst *fi, uint32_t event,
 	case VLR_AUTH_E_MS_AUTH_FAIL:
 		if (par->auts) {
 			/* First failure, start re-sync attempt */
-			vlr_subscr_req_sai(vsub, par->auts,
+			rc = vlr_subscr_req_sai(vsub, par->auts,
 					   vsub->last_tuple->vec.rand);
 			osmo_fsm_inst_state_chg(fi,
 					VLR_SUB_AS_NEEDS_AUTH_WAIT_SAI_RESYNC,
diff --git a/src/libvlr/vlr_core.h b/src/libvlr/vlr_core.h
index bf6314d92..a6585be28 100644
--- a/src/libvlr/vlr_core.h
+++ b/src/libvlr/vlr_core.h
@@ -5,9 +5,9 @@
 struct osmo_gsup_message;
 
 const char *vlr_subscr_name(struct vlr_subscr *vsub);
-int vlr_subscr_req_lu(struct vlr_subscr *vsub, bool is_ps);
+int vlr_subscr_req_lu(struct vlr_subscr *vsub, bool is_ps) __attribute__((warn_unused_result));
 int vlr_subscr_req_sai(struct vlr_subscr *vsub, const uint8_t *auts,
-		       const uint8_t *auts_rand);
+		       const uint8_t *auts_rand) __attribute__((warn_unused_result));
 struct vlr_subscr *vlr_subscr_alloc(struct vlr_instance *vlr);
 void vlr_subscr_update_tuples(struct vlr_subscr *vsub,
 			      const struct osmo_gsup_message *gsup);
diff --git a/src/libvlr/vlr_lu_fsm.c b/src/libvlr/vlr_lu_fsm.c
index 6c8b53adb..0ac5b9ad1 100644
--- a/src/libvlr/vlr_lu_fsm.c
+++ b/src/libvlr/vlr_lu_fsm.c
@@ -72,11 +72,14 @@ static void upd_hlr_vlr_fsm_init(struct osmo_fsm_inst *fi, uint32_t event,
 				 void *data)
 {
 	struct vlr_subscr *vsub = fi->priv;
+	int rc;
 
 	OSMO_ASSERT(event == UPD_HLR_VLR_E_START);
 
 	/* Send UpdateLocation to HLR */
-	vlr_subscr_req_lu(vsub, vsub->vlr->cfg.is_ps);
+	rc = vlr_subscr_req_lu(vsub, vsub->vlr->cfg.is_ps);
+	if (rc < 0)
+		LOGPFSML(fi, LOGL_ERROR, "Failed to send UpdateLocation to HLR\n");
 	osmo_fsm_inst_state_chg(fi, UPD_HLR_VLR_S_WAIT_FOR_DATA,
 				LU_TIMEOUT_LONG, 0);
 }