From 8368e7d5d59140fc77b890493a47a08cd644e2f8 Mon Sep 17 00:00:00 2001
From: Neels Janosch Hofmeyr <nhofmeyr@sysmocom.de>
Date: Thu, 1 Dec 2022 03:05:58 +0100
Subject: fix coding of Network Instance IE

Network instance names should be coded like in DNS, where each label is
preceded by a length byte.

Related: SYS#6192
Change-Id: I9d67464ef0f92b0512cfd6e48d203f8828a82a19
---
 src/libosmo-pfcp/Makefile.am       |  2 ++
 src/libosmo-pfcp/pfcp_ies_custom.c | 21 +++++++++++++++++----
 2 files changed, 19 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/libosmo-pfcp/Makefile.am b/src/libosmo-pfcp/Makefile.am
index d202c6a..6ca88b8 100644
--- a/src/libosmo-pfcp/Makefile.am
+++ b/src/libosmo-pfcp/Makefile.am
@@ -9,12 +9,14 @@ AM_CPPFLAGS = \
 AM_CFLAGS = \
 	-Wall \
 	$(LIBOSMOCORE_CFLAGS) \
+	$(LIBOSMOGSM_CFLAGS) \
 	$(LIBOSMOVTY_CFLAGS) \
 	$(COVERAGE_CFLAGS) \
 	$(NULL)
 
 AM_LDFLAGS = \
 	$(LIBOSMOCORE_LIBS) \
+	$(LIBOSMOGSM_LIBS) \
 	$(LIBOSMOVTY_LIBS) \
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)
diff --git a/src/libosmo-pfcp/pfcp_ies_custom.c b/src/libosmo-pfcp/pfcp_ies_custom.c
index 1891902..736f39d 100644
--- a/src/libosmo-pfcp/pfcp_ies_custom.c
+++ b/src/libosmo-pfcp/pfcp_ies_custom.c
@@ -29,6 +29,7 @@
 #include <osmocom/core/logging.h>
 #include <osmocom/core/utils.h>
 #include <osmocom/core/msgb.h>
+#include <osmocom/gsm/apn.h>
 
 #include <osmocom/gtlv/gtlv.h>
 
@@ -81,6 +82,13 @@
 				     tlv->len - ((POS) - tlv->val)); \
 	} while (0)
 
+#define ENSURE_RANGE(NAME, VAL, MINVAL, MAXVAL) \
+	do { \
+		if ((VAL) < (MINVAL) || (VAL) > (MAXVAL)) \
+			RETURN_ERROR(-ERANGE, "%s == %d, should be in range %d .. %d", NAME, \
+				     (int)(VAL), (int)(MINVAL), (int)(MAXVAL)); \
+	} while (0)
+
 void osmo_pfcp_ie_f_seid_set(struct osmo_pfcp_ie_f_seid *f_seid, uint64_t seid, const struct osmo_sockaddr *remote_addr)
 {
 	*f_seid = (struct osmo_pfcp_ie_f_seid) {
@@ -698,16 +706,21 @@ int osmo_pfcp_enc_to_str_apply_action(char *buf, size_t buflen, const void *enco
 int osmo_pfcp_dec_network_inst(void *decoded_struct, void *decode_to, const struct osmo_gtlv_load *tlv)
 {
 	struct osmo_pfcp_ie_network_inst *network_inst = decode_to;
-	osmo_strlcpy(network_inst->str, (const char *)tlv->val, OSMO_MIN(sizeof(network_inst->str), tlv->len+1));
+	ENSURE_RANGE("Network Instance value length", tlv->len, 1, sizeof(network_inst->str));
+	if (osmo_apn_to_str(network_inst->str, tlv->val, tlv->len) == NULL)
+		RETURN_ERROR(-EINVAL, "osmo_apn_to_str() failed");
 	return 0;
 }
 
 int osmo_pfcp_enc_network_inst(struct osmo_gtlv_put *tlv, const void *decoded_struct, const void *encode_from)
 {
 	const struct osmo_pfcp_ie_network_inst *network_inst = encode_from;
-	unsigned int l = strlen(network_inst->str);
-	if (l)
-		memcpy(msgb_put(tlv->dst, l), network_inst->str, l);
+	int rc;
+
+	rc = osmo_apn_from_str(tlv->dst->tail, msgb_tailroom(tlv->dst), network_inst->str);
+	if (rc <= 0)
+		RETURN_ERROR(-EINVAL, "osmo_apn_from_str(\"%s\") failed", network_inst->str);
+	msgb_put(tlv->dst, rc);
 	return 0;
 }
 
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