developer: add --dev-force-channel-secrets.

We don't have this on a per-channel basis (yet), but it's sufficient for testing
now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

common/derive_basepoints.c

@@ -4,19 +4,73 @@
 #include <common/utils.h>
 #include <wire/wire.h>
 
+#if DEVELOPER
+/* If they specify --dev-force-channel-secrets it ends up in here. */
+struct secrets *dev_force_channel_secrets;
+struct sha256 *dev_force_channel_secrets_shaseed;
+
+void towire_secrets(u8 **pptr, const struct secrets *s)
+{
+	towire_privkey(pptr, &s->funding_privkey);
+	towire_secret(pptr, &s->revocation_basepoint_secret);
+	towire_secret(pptr, &s->payment_basepoint_secret);
+	towire_secret(pptr, &s->delayed_payment_basepoint_secret);
+	towire_secret(pptr, &s->htlc_basepoint_secret);
+}
+
+void fromwire_secrets(const u8 **ptr, size_t *max, struct secrets *s)
+{
+	fromwire_privkey(ptr, max, &s->funding_privkey);
+	fromwire_secret(ptr, max, &s->revocation_basepoint_secret);
+	fromwire_secret(ptr, max, &s->payment_basepoint_secret);
+	fromwire_secret(ptr, max, &s->delayed_payment_basepoint_secret);
+	fromwire_secret(ptr, max, &s->htlc_basepoint_secret);
+}
+#else /* !DEVELOPER */
+/* Generate code refers to this, but should never be called! */
+void towire_secrets(u8 **pptr, const struct secrets *s)
+{
+	abort();
+}
+
+void fromwire_secrets(const u8 **ptr, size_t *max, struct secrets *s)
+{
+	abort();
+}
+#endif
+
+struct keys {
+	struct privkey f, r, h, p, d;
+	struct sha256 shaseed;
+};
+
+static void derive_keys(const struct secret *seed, struct keys *keys)
+{
+	hkdf_sha256(keys, sizeof(*keys), NULL, 0, seed, sizeof(*seed),
+		    "c-lightning", strlen("c-lightning"));
+
+#if DEVELOPER
+	if (dev_force_channel_secrets) {
+		keys->f = dev_force_channel_secrets->funding_privkey;
+		keys->r.secret = dev_force_channel_secrets->revocation_basepoint_secret;
+		keys->p.secret = dev_force_channel_secrets->payment_basepoint_secret;
+		keys->h.secret = dev_force_channel_secrets->htlc_basepoint_secret;
+		keys->d.secret = dev_force_channel_secrets->delayed_payment_basepoint_secret;
+	}
+	if (dev_force_channel_secrets_shaseed)
+		keys->shaseed = *dev_force_channel_secrets_shaseed;
+#endif
+}
+
 bool derive_basepoints(const struct secret *seed,
 		       struct pubkey *funding_pubkey,
 		       struct basepoints *basepoints,
 		       struct secrets *secrets,
 		       struct sha256 *shaseed)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (secrets) {
 		secrets->funding_privkey = keys.f;
@@ -95,13 +149,9 @@ bool derive_payment_basepoint(const struct secret *seed,
 			      struct pubkey *payment_basepoint,
 			      struct secret *payment_secret)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (payment_basepoint) {
 		if (!pubkey_from_privkey(&keys.p, payment_basepoint))
@@ -118,13 +168,9 @@ bool derive_delayed_payment_basepoint(const struct secret *seed,
 				      struct pubkey *delayed_payment_basepoint,
 				      struct secret *delayed_payment_secret)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (delayed_payment_basepoint) {
 		if (!pubkey_from_privkey(&keys.d, delayed_payment_basepoint))
@@ -139,13 +185,10 @@ bool derive_delayed_payment_basepoint(const struct secret *seed,
 
 bool derive_shaseed(const struct secret *seed, struct sha256 *shaseed)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
+
+	derive_keys(seed, &keys);
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
 	*shaseed = keys.shaseed;
 	return true;
 }
@@ -154,18 +197,17 @@ bool derive_funding_key(const struct secret *seed,
 			struct pubkey *funding_pubkey,
 			struct privkey *funding_privkey)
 {
-	struct privkey f;
+	struct keys keys;
 
-	hkdf_sha256(&f, sizeof(f), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (funding_pubkey) {
-		if (!pubkey_from_privkey(&f, funding_pubkey))
+		if (!pubkey_from_privkey(&keys.f, funding_pubkey))
 			return false;
 	}
 
 	if (funding_privkey)
-		*funding_privkey = f;
+		*funding_privkey = keys.f;
 
 	return true;
 }
@@ -174,13 +216,9 @@ bool derive_revocation_basepoint(const struct secret *seed,
 				 struct pubkey *revocation_basepoint,
 				 struct secret *revocation_secret)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (revocation_basepoint) {
 		if (!pubkey_from_privkey(&keys.r, revocation_basepoint))
@@ -197,13 +235,9 @@ bool derive_htlc_basepoint(const struct secret *seed,
 			   struct pubkey *htlc_basepoint,
 			   struct secret *htlc_secret)
 {
-	struct keys {
-		struct privkey f, r, h, p, d;
-		struct sha256 shaseed;
-	} keys;
+	struct keys keys;
 
-	hkdf_sha256(&keys, sizeof(keys), NULL, 0, seed, sizeof(*seed),
-		    "c-lightning", strlen("c-lightning"));
+	derive_keys(seed, &keys);
 
 	if (htlc_basepoint) {
 		if (!pubkey_from_privkey(&keys.h, htlc_basepoint))

common/derive_basepoints.h

@@ -155,4 +155,14 @@ void towire_basepoints(u8 **pptr, const struct basepoints *b);
 void fromwire_basepoints(const u8 **ptr, size_t *max,
 			 struct basepoints *b);
 
+/* For --dev-force-channel-secrets. */
+#if DEVELOPER
+extern struct secrets *dev_force_channel_secrets;
+extern struct sha256 *dev_force_channel_secrets_shaseed;
+#endif
+
+/* Note: these abort if !DEVELOPER */
+void towire_secrets(u8 **pptr, const struct secrets *s);
+void fromwire_secrets(const u8 **ptr, size_t *max, struct secrets *s);
+
 #endif /* LIGHTNING_COMMON_DERIVE_BASEPOINTS_H */

common/test/run-derive_basepoints.c

@@ -11,12 +11,24 @@
 /* Generated stub for fromwire_fail */
 const void *fromwire_fail(const u8 **cursor UNNEEDED, size_t *max UNNEEDED)
 { fprintf(stderr, "fromwire_fail called!\n"); abort(); }
+/* Generated stub for fromwire_privkey */
+void fromwire_privkey(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct privkey *privkey UNNEEDED)
+{ fprintf(stderr, "fromwire_privkey called!\n"); abort(); }
 /* Generated stub for fromwire_pubkey */
 void fromwire_pubkey(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct pubkey *pubkey UNNEEDED)
 { fprintf(stderr, "fromwire_pubkey called!\n"); abort(); }
+/* Generated stub for fromwire_secret */
+void fromwire_secret(const u8 **cursor UNNEEDED, size_t *max UNNEEDED, struct secret *secret UNNEEDED)
+{ fprintf(stderr, "fromwire_secret called!\n"); abort(); }
+/* Generated stub for towire_privkey */
+void towire_privkey(u8 **pptr UNNEEDED, const struct privkey *privkey UNNEEDED)
+{ fprintf(stderr, "towire_privkey called!\n"); abort(); }
 /* Generated stub for towire_pubkey */
 void towire_pubkey(u8 **pptr UNNEEDED, const struct pubkey *pubkey UNNEEDED)
 { fprintf(stderr, "towire_pubkey called!\n"); abort(); }
+/* Generated stub for towire_secret */
+void towire_secret(u8 **pptr UNNEEDED, const struct secret *secret UNNEEDED)
+{ fprintf(stderr, "towire_secret called!\n"); abort(); }
 /* AUTOGENERATED MOCKS END */
 
 STRUCTEQ_DEF(basepoints, 0,

hsmd/hsm_wire.csv

@@ -11,6 +11,8 @@ hsm_init,11
 hsm_init,,bip32_key_version,struct bip32_key_version
 hsm_init,,dev_force_privkey,?struct privkey
 hsm_init,,dev_force_bip32_seed,?struct secret
+hsm_init,,dev_force_channel_secrets,?struct secrets
+hsm_init,,dev_force_channel_secrets_shaseed,?struct sha256
 
 #include <common/bip32.h>
 hsm_init_reply,111

hsmd/hsmd.c

@@ -572,6 +572,8 @@ static struct io_plan *init_hsm(struct io_conn *conn,
 	struct pubkey key;
 	struct privkey *privkey;
 	struct secret *seed;
+	struct secrets *secrets;
+	struct sha256 *shaseed;
 
 	/* This must be lightningd. */
 	assert(is_lightningd(c));
@@ -581,12 +583,14 @@ static struct io_plan *init_hsm(struct io_conn *conn,
 	 * an extension of the simple comma-separated format output by the
 	 * BOLT tools/extract-formats.py tool. */
 	if (!fromwire_hsm_init(NULL, msg_in, &bip32_key_version,
-			       &privkey, &seed))
+			       &privkey, &seed, &secrets, &shaseed))
 		return bad_req(conn, c, msg_in);
 
 #if DEVELOPER
 	dev_force_privkey = privkey;
 	dev_force_bip32_seed = seed;
+	dev_force_channel_secrets = secrets;
+	dev_force_channel_secrets_shaseed = shaseed;
 #endif
 	maybe_create_new_hsm();
 	load_hsm();

lightningd/hsm_control.c

@@ -97,9 +97,11 @@ void hsm_init(struct lightningd *ld)
 				  &ld->topology->bitcoind->chainparams->bip32_key_version,
 #if DEVELOPER
 							 ld->dev_force_privkey,
-							 ld->dev_force_bip32_seed
+							 ld->dev_force_bip32_seed,
+							 ld->dev_force_channel_secrets,
+							 ld->dev_force_channel_secrets_shaseed
 #else
-							 NULL, NULL
+							 NULL, NULL, NULL, NULL
 #endif
 				     )))
 		err(1, "Writing init msg to hsm");

lightningd/lightningd.c

@@ -120,6 +120,8 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->dev_gossip_time = 0;
 	ld->dev_force_privkey = NULL;
 	ld->dev_force_bip32_seed = NULL;
+	ld->dev_force_channel_secrets = NULL;
+	ld->dev_force_channel_secrets_shaseed = NULL;
 #endif
 
 	/*~ These are CCAN lists: an embedded double-linked list.  It's not

lightningd/lightningd.h

@@ -211,6 +211,10 @@ struct lightningd {
 
 	/* This is the forced bip32 seed for the node. */
 	struct secret *dev_force_bip32_seed;
+
+	/* These are the forced channel secrets for the node. */
+	struct secrets *dev_force_channel_secrets;
+	struct sha256 *dev_force_channel_secrets_shaseed;
 #endif /* DEVELOPER */
 
 	/* tor support */

lightningd/options.c

@@ -12,6 +12,7 @@
 #include <ccan/tal/path/path.h>
 #include <ccan/tal/str/str.h>
 #include <common/configdir.h>
+#include <common/derive_basepoints.h>
 #include <common/json_command.h>
 #include <common/jsonrpc_errors.h>
 #include <common/memleak.h>
@@ -460,6 +461,42 @@ static char *opt_force_bip32_seed(const char *optarg, struct lightningd *ld)
 	return NULL;
 }
 
+static char *opt_force_channel_secrets(const char *optarg,
+				       struct lightningd *ld)
+{
+	char **strs;
+	tal_free(ld->dev_force_channel_secrets);
+	tal_free(ld->dev_force_channel_secrets_shaseed);
+	ld->dev_force_channel_secrets = tal(ld, struct secrets);
+	ld->dev_force_channel_secrets_shaseed = tal(ld, struct sha256);
+
+	strs = tal_strsplit(tmpctx, optarg, "/", STR_EMPTY_OK);
+	if (tal_count(strs) != 7) /* Last is NULL */
+		return "Expected 6 hex secrets separated by /";
+
+	if (!hex_decode(strs[0], strlen(strs[0]),
+			&ld->dev_force_channel_secrets->funding_privkey,
+			sizeof(ld->dev_force_channel_secrets->funding_privkey))
+	    || !hex_decode(strs[1], strlen(strs[1]),
+			   &ld->dev_force_channel_secrets->revocation_basepoint_secret,
+			   sizeof(ld->dev_force_channel_secrets->revocation_basepoint_secret))
+	    || !hex_decode(strs[2], strlen(strs[2]),
+			   &ld->dev_force_channel_secrets->payment_basepoint_secret,
+			   sizeof(ld->dev_force_channel_secrets->payment_basepoint_secret))
+	    || !hex_decode(strs[3], strlen(strs[3]),
+			   &ld->dev_force_channel_secrets->delayed_payment_basepoint_secret,
+			   sizeof(ld->dev_force_channel_secrets->delayed_payment_basepoint_secret))
+	    || !hex_decode(strs[4], strlen(strs[4]),
+			   &ld->dev_force_channel_secrets->htlc_basepoint_secret,
+			   sizeof(ld->dev_force_channel_secrets->htlc_basepoint_secret))
+	    || !hex_decode(strs[5], strlen(strs[5]),
+			   ld->dev_force_channel_secrets_shaseed,
+			   sizeof(*ld->dev_force_channel_secrets_shaseed)))
+		return "Expected 6 hex secrets separated by /";
+
+	return NULL;
+}
+
 static void dev_register_opts(struct lightningd *ld)
 {
 	opt_register_noarg("--dev-no-reconnect", opt_set_invbool,
@@ -500,6 +537,8 @@ static void dev_register_opts(struct lightningd *ld)
 			 "Force HSM to use this as node private key");
 	opt_register_arg("--dev-force-bip32-seed", opt_force_bip32_seed, NULL, ld,
 			 "Force HSM to use this as bip32 seed");
+	opt_register_arg("--dev-force-channel-secrets", opt_force_channel_secrets, NULL, ld,
+			 "Force HSM to use these for all per-channel secrets");
 }
 #endif