From c161b7d6fe142231346cc1844e6e27c0ab7718c1 Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Fri, 16 Sep 2022 15:53:42 +0200
Subject: 2022-09-16 14:41:00

---
 source/luametatex/source/luarest/lmtaeslib.c | 115 +++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 source/luametatex/source/luarest/lmtaeslib.c

(limited to 'source/luametatex/source/luarest/lmtaeslib.c')

diff --git a/source/luametatex/source/luarest/lmtaeslib.c b/source/luametatex/source/luarest/lmtaeslib.c
new file mode 100644
index 000000000..5dbd3556a
--- /dev/null
+++ b/source/luametatex/source/luarest/lmtaeslib.c
@@ -0,0 +1,115 @@
+/*
+    See license.txt in the root of this project.
+*/
+
+# include "luametatex.h"
+
+# include <utilcrypt.h>
+
+// AES_HAS_IV AES_INLINE_IV AES_CONTINUE AES_NULL_PADDING
+
+static const uint8_t nulliv[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+
+typedef size_t aes_coder (
+    const void *input,
+    size_t      length,
+    void       *output,
+    const void *key,
+    size_t      keylength,
+    const void *iv,
+    int         flags
+);
+
+/* data key [block] [inline] [padding] */ /* key : 16 24 32 */
+
+/* random_bytes is taken from pplib */
+
+static int aeslib_aux_code(lua_State *L, aes_coder code) {
+    size_t inputlength = 0;
+    const char *input = lua_tolstring(L, 1, &inputlength);
+    if (inputlength) {
+        size_t keylength = 0;
+        const char *key = lua_tolstring(L, 2, &keylength);
+        if (keylength == 16 || keylength == 24 || keylength == 32) {
+            luaL_Buffer buffer;
+            /* always */
+            int flags = 0;
+            /* the same length as input plus optional 16 from iv */
+            char *output = NULL;
+            size_t outputlength = 0;
+            /* this is optional, iv get copied in aes */
+            const uint8_t *iv = NULL;
+            switch (lua_type(L, 3)) {
+                case LUA_TSTRING:
+                    {
+                        size_t ivlength = 0;
+                        iv = (const uint8_t *) lua_tolstring(L, 3, &ivlength);
+                        if (ivlength != 16) {
+                            iv = nulliv;
+                        }
+                        break;
+                    }
+                case LUA_TBOOLEAN:
+                    if (lua_toboolean(L, 3)) {
+                        uint8_t randiv[16];
+                        random_bytes(randiv, 16);
+                        iv = (const uint8_t *) randiv;
+                        break;
+                    }
+                    // fall through
+                default:
+                    iv = nulliv;
+            }
+            if (lua_toboolean(L, 4)) {
+               flags |= AES_INLINE_IV;
+            }
+            if (! lua_toboolean(L, 5)) {
+               flags |= AES_NULL_PADDING;
+            }
+            /* always multiples of 16 and we might have the iv too */
+            output = luaL_buffinitsize(L, &buffer, inputlength + 32);
+            outputlength = code(input, inputlength, output, key, keylength, iv, flags);
+            if (outputlength) {
+                luaL_pushresultsize(&buffer, outputlength);
+                return 1;
+            }
+        } else {
+            luaL_error(L, "aeslib: key of length 16, 24 or 32 expected");
+        }
+    }
+    lua_pushnil(L);
+    return 1;
+}
+
+static int aeslib_encode(lua_State *L) {
+    return aeslib_aux_code(L, &aes_encode_data);
+}
+
+static int aeslib_decode(lua_State *L) {
+    return aeslib_aux_code(L, &aes_decode_data);
+}
+
+static int aeslib_random(lua_State *L) {
+    uint8_t iv[32];
+    int n = (int) luaL_optinteger(L, 1, 16);
+    if (n > 32) {
+        n = 32;
+    }
+    random_bytes(iv, n);
+    lua_pushlstring(L, (const char *) iv, n);
+    return 1;
+}
+
+static struct luaL_Reg aeslib_function_list[] = {
+    /*tex We started out with this: */
+    { "encode", aeslib_encode },
+    { "decode", aeslib_decode },
+    { "random", aeslib_random },
+    { NULL,     NULL          },
+};
+
+int luaopen_aes(lua_State *L) {
+    lua_newtable(L);
+    luaL_setfuncs(L, aeslib_function_list, 0);
+    return 1;
+}
-- 
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