fixes and tests to p256 zencode

typo branching for k

test file

check number of args before using lua stack

src/zen_p256.c

@@ -108,6 +108,8 @@ static int p256_pubcheck(lua_State *L)
 
 static int p256_sign(lua_State *L)
 {
+	int n_args = lua_gettop(L);
+
 	BEGIN();
 	Z(L);
 	hash256 sha256;
@@ -143,7 +145,7 @@ static int p256_sign(lua_State *L)
 	}
 	sig->len = SIG_SIZE;
 
-	if(lua_isnoneornil(L, 3)) {
+	if(n_args > 2) {
 		k = o_arg(L, 3);
 		if(k == NULL) {
 			failed_msg = "Could not allocate ephemeral key";

test/lua/crypto.bats

@@ -6,6 +6,7 @@ load ../bats_setup
     Z big_arithmetics.lua
     Z hash.lua
     Z ecdh.lua
+    Z ecdsa_p256.lua
     Z dh_session.lua
     Z ecp_generic.lua
     Z elgamal.lua

test/lua/ecdsa_p256.lua

@@ -0,0 +1,30 @@
+P256 = require('p256')
+
+alice_sk = P256.keygen()
+I.spy(alice_sk)
+alice_pk = P256.pubgen(alice_sk)
+I.spy(alice_pk)
+
+print('  DSA SIGN/VERIFY')
+
+local m = O.from_str([[
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
+eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad
+minim veniam, quis nostrud exercitation ullamco laboris nisi ut
+aliquip ex ea commodo consequat. Duis aute irure dolor in
+reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
+pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
+culpa qui officia deserunt mollit anim id est laborum.]])
+print 'iterate at least 100 tests of sign/verify'
+print 'and at least 1 tests with r or s length lower than 32 bytes'
+local tot = 0
+
+while (tot<100) do
+	sig = P256.sign(alice_sk, m)
+	assert(P256.verify(alice_pk, sig, m), "ecdh verify failed")
+	assert(not P256.verify(alice_pk, sig, sha256(m)), "ecdh verify failed")
+	tot = tot+1
+end
+
+print "OK"
+

test/vectors/check_ecdsa_p256_sign.lua

@@ -26,6 +26,7 @@ for line in newline_iter(DATA) do
     end
     if curr_fields == 7 then
         assert(test.qx .. test.qy == P256.pubgen(test.d))
+        assert(P256.verify(test.qx .. test.qy, test.r .. test.s, test.msg))
         assert(test.r .. test.s == P256.sign(test.d, test.msg, test.k))
         curr_fields = 0
         test = {}