util.hashes, util.sasl.scram: Implement SCRAM-SHA1's Hi in C

2 files changed, 51 insertions, 13 deletions

diff --git a/util-src/hashes.c b/util-src/hashes.c
index 2a6625b3..8f7d7140 100644
--- a/util-src/hashes.c
+++ b/util-src/hashes.c
@@ -14,6 +14,8 @@
 */
 
 #include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
 
 #include "lua.h"
 #include "lauxlib.h"
@@ -132,6 +134,52 @@ MAKE_HMAC_FUNCTION(Lhmac_sha256, SHA256, SHA256_DIGEST_LENGTH, SHA256_CTX)
 MAKE_HMAC_FUNCTION(Lhmac_sha512, SHA512, SHA512_DIGEST_LENGTH, SHA512_CTX)
 MAKE_HMAC_FUNCTION(Lhmac_md5, MD5, MD5_DIGEST_LENGTH, MD5_CTX)
 
+static int LscramHi(lua_State *L) {
+	union xory {
+		unsigned char bytes[SHA_DIGEST_LENGTH];
+		uint32_t quadbytes[SHA_DIGEST_LENGTH/4];
+	};
+	int i;
+	SHA_CTX ctx, ctxo;
+	unsigned char Ust[SHA_DIGEST_LENGTH];
+	union xory Und;
+	union xory res;
+	size_t str_len, salt_len;
+	struct hash_desc desc;
+	const char *str = luaL_checklstring(L, 1, &str_len);
+	const char *salt = luaL_checklstring(L, 2, &salt_len);
+	char *salt2;
+	const int iter = luaL_checkinteger(L, 3);
+
+	desc.Init = (int (*)(void*))SHA1_Init;
+	desc.Update = (int (*)(void*, const void *, size_t))SHA1_Update;
+	desc.Final = (int (*)(unsigned char*, void*))SHA1_Final;
+	desc.digestLength = SHA_DIGEST_LENGTH;
+	desc.ctx = &ctx;
+	desc.ctxo = &ctxo;
+
+	salt2 = malloc(salt_len + 4);
+	if (salt2 == NULL)
+		luaL_error(L, "Out of memory in scramHi");
+	memcpy(salt2, salt, salt_len);
+	memcpy(salt2 + salt_len, "\0\0\0\1", 4);
+	hmac(&desc, str, str_len, salt2, salt_len + 4, Ust);
+	free(salt2);
+
+	memcpy(res.bytes, Ust, sizeof(res));
+	for (i = 1; i < iter; i++) {
+		int j;
+		hmac(&desc, str, str_len, (char*)Ust, sizeof(Ust), Und.bytes);
+		for (j = 0; j < SHA_DIGEST_LENGTH/4; j++)
+			res.quadbytes[j] ^= Und.quadbytes[j];
+		memcpy(Ust, Und.bytes, sizeof(Ust));
+	}
+
+	lua_pushlstring(L, (char*)res.bytes, SHA_DIGEST_LENGTH);
+
+	return 1;
+}
+
 static const luaL_Reg Reg[] =
 {
 	{ "sha1",		Lsha1		},
@@ -144,6 +192,7 @@ static const luaL_Reg Reg[] =
 	{ "hmac_sha256",	Lhmac_sha256	},
 	{ "hmac_sha512",	Lhmac_sha512	},
 	{ "hmac_md5",		Lhmac_md5	},
+	{ "scram_Hi_sha1",	LscramHi	},
 	{ NULL,			NULL		}
 };
 
diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua
index 1ba12460..cf2f0ede 100644
--- a/util/sasl/scram.lua
+++ b/util/sasl/scram.lua
@@ -17,6 +17,7 @@ local string = string
 local base64 = require "util.encodings".base64;
 local hmac_sha1 = require "util.hashes".hmac_sha1;
 local sha1 = require "util.hashes".sha1;
+local Hi = require "util.hashes".scram_Hi_sha1;
 local generate_uuid = require "util.uuid".generate;
 local saslprep = require "util.encodings".stringprep.saslprep;
 local nodeprep = require "util.encodings".stringprep.nodeprep;
@@ -65,18 +66,6 @@ local function binaryXOR( a, b )
 	return t_concat(result);
 end
 
--- hash algorithm independent Hi(PBKDF2) implementation
-function Hi(hmac, str, salt, i)
-	local Ust = hmac(str, salt.."\0\0\0\1");
-	local res = Ust;
-	for n=1,i-1 do
-		local Und = hmac(str, Ust)
-		res = binaryXOR(res, Und)
-		Ust = Und
-	end
-	return res
-end
-
 local function validate_username(username, _nodeprep)
 	-- check for forbidden char sequences
 	for eq in username:gmatch("=(.?.?)") do
@@ -110,7 +99,7 @@ function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
 	if iteration_count < 4096 then
 		log("warn", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.")
 	end
-	local salted_password = Hi(hmac_sha1, password, salt, iteration_count);
+	local salted_password = Hi(password, salt, iteration_count);
 	local stored_key = sha1(hmac_sha1(salted_password, "Client Key"))
 	local server_key = hmac_sha1(salted_password, "Server Key");
 	return true, stored_key, server_key