80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
#include <stdlib.h>
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#include <stdbool.h>
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#include <lua.h>
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#include <lauxlib.h>
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#include <lualib.h>
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#include "ecrypt-sync.h"
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#if LUA_VERSION_NUM == 501
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#define l_setfuncs(L, funcs) luaL_register(L, NULL, funcs)
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#else
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#define l_setfuncs(L, funcs) luaL_setfuncs(L, funcs, 0)
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#endif
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static int chacha_generic_crypt(lua_State *L, bool is_ietf)
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{
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ECRYPT_ctx ctx;
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const char *key, *iv, *plaintext, *counter;
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char *ciphertext;
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size_t keysize, ivsize, msglen, countersize;
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int rounds = luaL_checkinteger(L, 1);
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/* IETF only normalizes ChaCha 20. */
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if (rounds != 20 && (is_ietf || (rounds % 2 != 0)))
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return luaL_error(L, "invalid number of rounds: %d", rounds);
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luaL_checktype(L, 2, LUA_TSTRING);
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luaL_checktype(L, 3, LUA_TSTRING);
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luaL_checktype(L, 4, LUA_TSTRING);
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key = lua_tolstring(L, 2, &keysize);
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iv = lua_tolstring(L, 3, &ivsize);
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plaintext = lua_tolstring(L, 4, &msglen);
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counter = luaL_optlstring(L, 5, NULL, &countersize);
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if (ivsize != (is_ietf ? 12 : 8))
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return luaL_error(L, "invalid IV size: %dB", (int)ivsize);
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if (keysize != 32 && (is_ietf || keysize != 16))
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return luaL_error(L, "invalid key size: %dB", (int)keysize);
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if (counter && countersize != (is_ietf ? 4 : 8))
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return luaL_error(L, "invalid counter size: %dB", (int)countersize);
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if (msglen == 0) { lua_pushlstring(L, "", 0); return 1; }
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ciphertext = malloc(msglen);
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if (!ciphertext) return luaL_error(L, "OOM");
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/* keysize and ivsize are in bits */
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ECRYPT_keysetup(&ctx, (u8*)key, 8 * keysize, 8 * ivsize);
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if (is_ietf) ECRYPT_IETF_ivsetup(&ctx, (u8*)iv, (u8*)counter);
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else ECRYPT_ivsetup(&ctx, (u8*)iv, (u8*)counter);
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ECRYPT_encrypt_bytes(&ctx, (u8*)plaintext, (u8*)ciphertext, msglen, rounds);
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lua_pushlstring(L, ciphertext, msglen);
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free(ciphertext);
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return 1;
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}
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static int chacha_ref_crypt(lua_State *L)
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{ return chacha_generic_crypt(L, false); }
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static int chacha_ietf_crypt(lua_State *L)
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{ return chacha_generic_crypt(L, true); }
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int luaopen_chacha(lua_State *L)
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{
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struct luaL_Reg l[] = {
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{ "ref_crypt", chacha_ref_crypt },
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{ "ietf_crypt", chacha_ietf_crypt },
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{ NULL, NULL }
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};
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lua_newtable(L);
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l_setfuncs(L, l);
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return 1;
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}
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