fuzz: target for tx_signatures

Fuzz the decoding and encoding of tx_signatures.

tests/fuzz/fuzz-wire-tx_signatures.c

@@ -0,0 +1,72 @@
+#include "config.h"
+#include <assert.h>
+#include <ccan/mem/mem.h>
+#include <stdint.h>
+#include <tests/fuzz/libfuzz.h>
+#include <tests/fuzz/wire.h>
+#include <wire/peer_wire.h>
+
+struct tx_signatures {
+	struct channel_id channel_id;
+	struct bitcoin_txid txid;
+	struct witness **witnesses;
+	struct tlv_txsigs_tlvs *tlvs;
+};
+
+static void *encode(const tal_t *ctx, const struct tx_signatures *s)
+{
+	return towire_tx_signatures(ctx, &s->channel_id, &s->txid,
+				    (const struct witness **)s->witnesses,
+				    s->tlvs);
+}
+
+static struct tx_signatures *decode(const tal_t *ctx, const void *p)
+{
+	struct tx_signatures *s = tal(ctx, struct tx_signatures);
+
+	if (fromwire_tx_signatures(s, p, &s->channel_id, &s->txid,
+				   &s->witnesses, &s->tlvs))
+		return s;
+	return tal_free(s);
+}
+
+static bool witnesses_equal(struct witness **x, struct witness **y)
+{
+	if (!x && !y)
+		return true;
+	if (!x || !y)
+		return false;
+
+	if (tal_count(x) != tal_count(y))
+		return false;
+
+	for (size_t i = 0; i < tal_count(x); ++i) {
+		assert(x[i] && y[i]);
+		if (!memeq(x[i]->witness_data, tal_bytelen(x[i]->witness_data),
+			   y[i]->witness_data, tal_bytelen(y[i]->witness_data)))
+			return false;
+	}
+	return true;
+}
+
+static bool equal(const struct tx_signatures *x, const struct tx_signatures *y)
+{
+	size_t upto_witnesses = (uintptr_t)&x->witnesses - (uintptr_t)x;
+	if (memcmp(x, y, upto_witnesses) != 0)
+		return false;
+
+	if (!witnesses_equal(x->witnesses, y->witnesses))
+		return false;
+
+	assert(x->tlvs && y->tlvs);
+	return memeq(x->tlvs->funding_outpoint_sig,
+		     tal_bytelen(x->tlvs->funding_outpoint_sig),
+		     y->tlvs->funding_outpoint_sig,
+		     tal_bytelen(y->tlvs->funding_outpoint_sig));
+}
+
+void run(const u8 *data, size_t size)
+{
+	test_decode_encode(data, size, WIRE_TX_SIGNATURES,
+			   struct tx_signatures);
+}