X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fcrypto%2Fshachain%2Fshachain.c;h=8c9fdcf50fe2de50f72ce64524e2e9c216f1e827;hb=0a76c98f726514245389587c1d361d9281198280;hp=c66196f71d881ce5e19b9bc088d66b9d2fc8b03b;hpb=954082d1b37e2e0be7816f53255965a99dd1b2ee;p=ccan

diff --git a/ccan/crypto/shachain/shachain.c b/ccan/crypto/shachain/shachain.c
index c66196f7..8c9fdcf5 100644
--- a/ccan/crypto/shachain/shachain.c
+++ b/ccan/crypto/shachain/shachain.c
@@ -33,7 +33,7 @@ static void derive(shachain_index_t from, shachain_index_t to,
 	for (i = ilog64(branches) - 1; i >= 0; i--) {
 		if (((branches >> i) & 1)) {
 			change_bit(hash->u.u8, i);
-			sha256(hash, hash, 1);
+			sha256(hash, hash, sizeof(*hash));
 		}
 	}
 }
@@ -44,21 +44,34 @@ void shachain_from_seed(const struct sha256 *seed, shachain_index_t index,
 	derive((shachain_index_t)-1ULL, index, seed, hash);
 }
 
-void shachain_init(struct shachain *shachain)
+void shachain_init(struct shachain *chain)
 {
-	shachain->num_valid = 0;
+	chain->num_valid = 0;
+	chain->max_index = 0;
 }
 
-void shachain_add_hash(struct shachain *chain,
+bool shachain_add_hash(struct shachain *chain,
 		       shachain_index_t index, const struct sha256 *hash)
 {
 	int i;
 
+	/* You have to insert them in order! */
+	assert(index == chain->max_index + 1 ||
+	       (index == 0 && chain->num_valid == 0));
+	
 	for (i = 0; i < chain->num_valid; i++) {
 		/* If we could derive this value, we don't need it,
 		 * not any others (since they're in order). */
-		if (can_derive(index, chain->known[i].index))
+		if (can_derive(index, chain->known[i].index)) {
+			struct sha256 expect;
+
+			/* Make sure the others derive as expected! */
+			derive(index, chain->known[i].index, hash, &expect);
+			if (memcmp(&expect, &chain->known[i].hash,
+				   sizeof(expect)) != 0)
+				return false;
 			break;
+		}
 	}
 
 	/* This can happen if you skip indices! */
@@ -66,6 +79,8 @@ void shachain_add_hash(struct shachain *chain,
 	chain->known[i].index = index;
 	chain->known[i].hash = *hash;
 	chain->num_valid = i+1;
+	chain->max_index = index;
+	return true;
 }
 
 bool shachain_get_hash(const struct shachain *chain,