c backend found u64 overflow bug

smurfd · Jul 15, 2024 · 4c3b8bf · 4c3b8bf
1 parent 0fe4a04
commit 4c3b8bf
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diff --git a/lotordb/src/keys.c b/lotordb/src/keys.c
@@ -113,6 +113,8 @@ static u64 sub(u64 *a, const u64 *b, const u64 *c) {
 
 //
 // Multiply
+// BUG: Both b[j] and c[k - j] is 18446744073709551615 == u64max
+//      which is triggered once the run fails. See test howto trigger it repeadedly
 static void mul(u64 *a, const u64 *b, const u64 *c) {
   u64 r2 = 0, di22 = DIGITS * 2 - 1;
   unsigned __int128 r = 0;

diff --git a/lotordb/src/tests/tests.c b/lotordb/src/tests/tests.c
@@ -99,6 +99,11 @@ void test_keys_verify(void) {
   uint8_t sig[BYTES * 2],  pubkey[BYTES + 1],  sec[BYTES], privkey[BYTES], h[BYTES] = {0};
   u64 k[BYTES] = {0};
   u64rnd_array(h, k, BYTES);
+  // BUG: uncomment to trigger u64 overflow bug
+  //for (int i = 0; i < BYTES;++i) {
+  //  h[i] = 66;
+  //  k[i] = 99999999;
+  //}
   assert(keys_make(pubkey, privkey, k));
   assert(keys_secr(pubkey, privkey, sec, k));
   assert(keys_sign(privkey, h, sig, k));