fuzz: add a target for base32/64 encoding

Signed-off-by: Antoine Poinsot <darosior@protonmail.com>

tests/fuzz/Makefile

@@ -11,6 +11,7 @@ FUZZ_COMMON_OBJS :=					\
 	common/amount.o					\
 	common/addr.o					\
 	common/base32.o					\
+	common/base64.o					\
 	common/bech32.o					\
 	common/bigsize.o				\
 	common/json.o					\

tests/fuzz/fuzz-base32-64.c

@@ -0,0 +1,26 @@
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+#include <tests/fuzz/libfuzz.h>
+
+#include <common/base32.h>
+#include <common/base64.h>
+
+void init(int *argc, char ***argv)
+{
+}
+
+void run(const uint8_t *data, size_t size)
+{
+	char *encoded;
+	uint8_t *decoded;
+
+	encoded = b32_encode(NULL, data, size);
+	decoded = b32_decode(NULL, encoded, strlen(encoded));
+	assert(memcmp(decoded, data, size) == 0);
+	tal_free(encoded);
+	tal_free(decoded);
+
+	encoded = b64_encode(NULL, data, size);
+	tal_free(encoded);
+}