fuzz: Add fuzzer targeting RADIUS messages

Signed-off-by: Arthur Chan <arthur.chan@adalogics.com>

.github/workflows/cifuzz.yml

diff --git a/.github/workflows/cifuzz.yml b/.github/workflows/cifuzz.yml
index b9c1336..a2135ec 100644
--- a/.github/workflows/cifuzz.yml
+++ b/.github/workflows/cifuzz.yml
@@ -35,6 +35,7 @@
       uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
       with:
         oss-fuzz-project-name: 'strongswan'
+        report-timeouts: true
         output-sarif: true
         language: c
         sanitizer: ${{ matrix.sanitizer }}

fuzz/.gitignore

diff --git a/fuzz/.gitignore b/fuzz/.gitignore
index ca184d8..d011637 100644
--- a/fuzz/.gitignore
+++ b/fuzz/.gitignore
@@ -10,4 +10,5 @@
 fuzz_ocsp_rsp_def
 fuzz_pa_tnc
 fuzz_pb_tnc
+fuzz_radius
 fuzz_vici

fuzz/Makefile.am

diff --git a/fuzz/Makefile.am b/fuzz/Makefile.am
index dba75c8..d5aa1d6 100644
--- a/fuzz/Makefile.am
+++ b/fuzz/Makefile.am
@@ -43,6 +43,10 @@
 	$(top_builddir)/src/libradius/.libs/libradius.a \
 	$(fuzz_ldflags)
 
+radius_ldflags = \
+	$(top_builddir)/src/libradius/.libs/libradius.a \
+	$(fuzz_ldflags)
+
 # fuzzers that use crypto plugins in a significant way
 fuzzers_with_plugins = \
 	fuzz_certs fuzz_crls fuzz_ocsp_req fuzz_ocsp_rsp
@@ -51,7 +55,7 @@
 fuzzers_with_cus = $(fuzzers_with_plugins:%=%_cus)
 
 fuzzers_no_plugins = \
-	fuzz_ids fuzz_ike fuzz_pa_tnc fuzz_pb_tnc fuzz_vici
+	fuzz_ids fuzz_ike fuzz_pa_tnc fuzz_pb_tnc fuzz_radius fuzz_vici
 
 ALL_FUZZERS=$(fuzzers_with_def) $(fuzzers_with_cus) $(fuzzers_no_plugins)
 
@@ -95,6 +99,9 @@
 fuzz_ike: fuzz_ike.c ${libfuzzer}
 	$(CC) $(AM_CPPFLAGS) $(CFLAGS) -o $@ $< $(charon_ldflags)
 
+fuzz_radius: fuzz_radius.c ${libfuzzer}
+	$(CC) $(fuzz_cppflags_def) $(CFLAGS) -o $@ $< $(radius_ldflags)
+
 fuzz_vici: fuzz_vici.c ${libfuzzer}
 	$(CC) $(AM_CPPFLAGS) $(CFLAGS) -o $@ $< $(charon_ldflags)
 

fuzz/fuzz_radius.c

diff --git a/fuzz/fuzz_radius.c b/fuzz/fuzz_radius.c
new file mode 100644
index 0000000..bfaf81d
--- /dev/null
+++ b/fuzz/fuzz_radius.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2026 Arthur SC Chan
+ *
+ * Copyright (C) secunet Security Networks AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <library.h>
+#include <utils/debug.h>
+#include <radius_message.h>
+
+int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	dbg_default_set_level(-1);
+	library_init(NULL, "fuzz_radius");
+	if (!lib->plugins->load(lib->plugins, PLUGINS))
+	{
+		return 1;
+	}
+	return 0;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *buf, size_t len)
+{
+	enumerator_t *enumerator;
+	radius_message_t *msg;
+	hasher_t *hasher;
+	signer_t *signer;
+	chunk_t data, attr_data;
+	int type, count, vendor;
+
+	if (len < 20)
+	{
+		return 0;
+	}
+
+	data = chunk_create((u_char*)buf, len);
+	msg = radius_message_parse(data);
+
+	if (msg)
+	{
+		enumerator = msg->create_enumerator(msg);
+		count = 0;
+		while (count++ < 10000 &&
+			   enumerator->enumerate(enumerator, &type, &attr_data));
+		enumerator->destroy(enumerator);
+
+		enumerator = msg->create_vendor_enumerator(msg);
+		count = 0;
+		while (count++ < 10000 &&
+			   enumerator->enumerate(enumerator, &vendor, &type, &attr_data));
+		enumerator->destroy(enumerator);
+
+		hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5);
+		signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_MD5_128);
+		if (!hasher || !signer)
+		{
+			return 1;
+		}
+		msg->verify(msg, NULL, chunk_empty, hasher, signer);
+		hasher->destroy(hasher);
+		signer->destroy(signer);
+		msg->destroy(msg);
+	}
+	return 0;
+}