From 644e77ccb3a45ce50ce50b253d5ee22770e66109 Mon Sep 17 00:00:00 2001
From: = <tim@creationix.com>
Date: Mon, 25 May 2015 23:06:49 -0500
Subject: [PATCH] Add crypto module initially containing sha1 and
 base64_encode.

---
 app/include/user_modules.h |  1 +
 app/modules/crypto.c       | 90 ++++++++++++++++++++++++++++++++++++++
 app/modules/modules.h      | 11 ++++-
 3 files changed, 101 insertions(+), 1 deletion(-)
 create mode 100644 app/modules/crypto.c

diff --git a/app/include/user_modules.h b/app/include/user_modules.h
index d8ddc654..e0d0b40c 100644
--- a/app/include/user_modules.h
+++ b/app/include/user_modules.h
@@ -31,6 +31,7 @@
 #define LUA_USE_MODULES_U8G
 #define LUA_USE_MODULES_WS2812
 #define LUA_USE_MODULES_CJSON
+#define LUA_USE_MODULES_CRYPTO
 #endif /* LUA_USE_MODULES */
 
 #endif	/* __USER_MODULES_H__ */
diff --git a/app/modules/crypto.c b/app/modules/crypto.c
new file mode 100644
index 00000000..f8c89697
--- /dev/null
+++ b/app/modules/crypto.c
@@ -0,0 +1,90 @@
+// Module for cryptography
+
+//#include "lua.h"
+#include "lualib.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "auxmods.h"
+#include "lrotable.h"
+
+#include "c_types.h"
+#include "c_stdlib.h"
+
+#include "user_interface.h"
+
+/**
+  * hash = crypto.sha1(input)
+  *
+  *	Calculates raw SHA1 hash of input string.
+  * Input is arbitrary string, output is raw 20-byte hash as string.
+  */
+static int crypto_sha1( lua_State* L )
+{
+  // We only need a data buffer large enough to match SHA1_CTX in the rom.
+  // I *think* this is a 92-byte netbsd struct.
+  uint8_t ctx[100];
+  uint8_t digest[20];
+  // Read the string from lua (with length)
+  int len;
+  const char* msg = luaL_checklstring(L, 1, &len);
+  // Use the SHA* functions in the rom
+  SHA1Init(ctx);
+  SHA1Update(ctx, msg, len);
+  SHA1Final(digest, ctx);
+
+  // Push the result as a lua string
+  lua_pushlstring(L, digest, 20);
+  return 1;
+}
+
+static const char* bytes64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+/**
+  * encoded = crypto.base64_encode(raw)
+  *
+  * Encodes raw binary string as base64 string.
+  */
+static int crypto_base64_encode( lua_State* L )
+{
+  int len;
+  const char* msg = luaL_checklstring(L, 1, &len);
+  int blen = (len + 2) / 3 * 4;
+  char* out = (char*)c_malloc(blen);
+  int j = 0, i;
+  for (i = 0; i < len; i += 3) {
+    int a = msg[i];
+    int b = (i + 1 < len) ? msg[i + 1] : 0;
+    int c = (i + 2 < len) ? msg[i + 2] : 0;
+    out[j++] = bytes64[a >> 2];
+    out[j++] = bytes64[((a & 3) << 4) | (b >> 4)];
+    out[j++] = (i + 1 < len) ? bytes64[((b & 15) << 2) | (c >> 6)] : 61;
+    out[j++] = (i + 2 < len) ? bytes64[(c & 63)] : 61;
+  }
+  lua_pushlstring(L, out, j);
+  c_free(out);
+  return 1;
+}
+
+// Module function map
+#define MIN_OPT_LEVEL 2
+#include "lrodefs.h"
+const LUA_REG_TYPE crypto_map[] =
+{
+  { LSTRKEY( "sha1" ), LFUNCVAL( crypto_sha1 ) },
+  { LSTRKEY( "base64Encode" ), LFUNCVAL( crypto_base64_encode ) },
+#if LUA_OPTIMIZE_MEMORY > 0
+
+#endif
+  { LNILKEY, LNILVAL }
+};
+
+LUALIB_API int luaopen_crypto( lua_State *L )
+{
+#if LUA_OPTIMIZE_MEMORY > 0
+  return 0;
+#else // #if LUA_OPTIMIZE_MEMORY > 0
+  luaL_register( L, AUXLIB_CRYPTO, crypto_map );
+  // Add constants
+
+  return 1;
+#endif // #if LUA_OPTIMIZE_MEMORY > 0
+}
diff --git a/app/modules/modules.h b/app/modules/modules.h
index fddc45cc..a823d360 100644
--- a/app/modules/modules.h
+++ b/app/modules/modules.h
@@ -149,6 +149,14 @@
 #define ROM_MODULES_CJSON
 #endif
 
+#if defined(LUA_USE_MODULES_CRYPTO)
+#define MODULES_CRYPTO       "crypto"
+#define ROM_MODULES_CRYPTO   \
+    _ROM(MODULES_CRYPTO, luaopen_crypto, crypto_map)
+#else
+#define ROM_MODULES_CRYPTO
+#endif
+
 #define LUA_MODULES_ROM     \
         ROM_MODULES_GPIO    \
         ROM_MODULES_PWM		\
@@ -167,7 +175,8 @@
         ROM_MODULES_OW      \
         ROM_MODULES_BIT     \
         ROM_MODULES_WS2812  \
-        ROM_MODULES_CJSON
+        ROM_MODULES_CJSON  \
+        ROM_MODULES_CRYPTO
 
 #endif