nodemcu-firmware/app/modules/crypto.c

417 lines
11 KiB
C

// Module for cryptography
#include <errno.h>
#include "module.h"
#include "lauxlib.h"
#include "platform.h"
#include "c_types.h"
#include <stdlib.h>
#include "vfs.h"
#include "../crypto/digests.h"
#include "../crypto/mech.h"
#include "lmem.h"
#include "user_interface.h"
#include "rom.h"
typedef struct {
const digest_mech_info_t *mech_info;
void *ctx;
uint8_t *k_opad;
} digest_user_datum_t;
/**
* 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 )
{
SHA1_CTX ctx;
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;
}
#ifdef LUA_USE_MODULES_ENCODER
static int call_encoder( lua_State* L, const char *function ) {
if (lua_gettop(L) != 1) {
luaL_error(L, "%s must have one argument", function);
}
lua_getfield(L, LUA_GLOBALSINDEX, "encoder");
if (!lua_istable(L, -1) && !lua_isrotable(L, -1)) { // also need table just in case encoder has been overloaded
luaL_error(L, "Cannot find encoder.%s", function);
}
lua_getfield(L, -1, function);
lua_insert(L, 1); //move function below the argument
lua_pop(L, 1); //and dump the encoder rotable from stack.
lua_call(L,1,1); // call encoder.xxx(string)
return 1;
}
static int crypto_base64_encode (lua_State* L) {
return call_encoder(L, "toBase64");
}
static int crypto_hex_encode (lua_State* L) {
return call_encoder(L, "toHex");
}
#else
static const char* bytes64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* encoded = crypto.toBase64(raw)
*
* Encodes raw binary string as base64 string.
*/
static int crypto_base64_encode( lua_State* L )
{
int len, i;
const char* msg = luaL_checklstring(L, 1, &len);
luaL_Buffer out;
luaL_buffinit(L, &out);
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;
luaL_addchar(&out, bytes64[a >> 2]);
luaL_addchar(&out, bytes64[((a & 3) << 4) | (b >> 4)]);
luaL_addchar(&out, (i + 1 < len) ? bytes64[((b & 15) << 2) | (c >> 6)] : 61);
luaL_addchar(&out, (i + 2 < len) ? bytes64[(c & 63)] : 61);
}
luaL_pushresult(&out);
return 1;
}
/**
* encoded = crypto.toHex(raw)
*
* Encodes raw binary string as hex string.
*/
static int crypto_hex_encode( lua_State* L)
{
int len, i;
const char* msg = luaL_checklstring(L, 1, &len);
luaL_Buffer out;
luaL_buffinit(L, &out);
for (i = 0; i < len; i++) {
luaL_addchar(&out, crypto_hexbytes[msg[i] >> 4]);
luaL_addchar(&out, crypto_hexbytes[msg[i] & 0xf]);
}
luaL_pushresult(&out);
return 1;
}
#endif
/**
* masked = crypto.mask(message, mask)
*
* Apply a mask (repeated if shorter than message) as XOR to each byte.
*/
static int crypto_mask( lua_State* L )
{
int len, mask_len, i;
const char* msg = luaL_checklstring(L, 1, &len);
const char* mask = luaL_checklstring(L, 2, &mask_len);
luaL_Buffer b;
if(mask_len <= 0)
return luaL_error(L, "invalid argument: mask");
luaL_buffinit(L, &b);
for (i = 0; i < len; i++) {
luaL_addchar(&b, msg[i] ^ mask[i % mask_len]);
}
luaL_pushresult(&b);
return 1;
}
static inline int bad_mech (lua_State *L) { return luaL_error (L, "unknown hash mech"); }
static inline int bad_mem (lua_State *L) { return luaL_error (L, "insufficient memory"); }
static inline int bad_file (lua_State *L) { return luaL_error (L, "file does not exist"); }
/* rawdigest = crypto.hash("MD5", str)
* strdigest = crypto.toHex(rawdigest)
*/
static int crypto_lhash (lua_State *L)
{
const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
if (!mi)
return bad_mech (L);
size_t len = 0;
const char *data = luaL_checklstring (L, 2, &len);
uint8_t digest[mi->digest_size];
if (crypto_hash (mi, data, len, digest) != 0)
return bad_mem (L);
lua_pushlstring (L, digest, sizeof (digest));
return 1;
}
/* General Usage for extensible hash functions:
* sha = crypto.new_hash("MD5")
* sha.update("Data")
* sha.update("Data2")
* strdigest = crypto.toHex(sha.finalize())
*/
#define WANT_HASH 0
#define WANT_HMAC 1
static int crypto_new_hash_hmac (lua_State *L, int what)
{
// get pointer to relevant hash_mechs table entry in app/crypto/digest.c. Note that
// the size of the table needed is dependent on the the digest type
const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
if (!mi)
return bad_mech (L);
size_t len = 0, k_opad_len = 0, udlen;
const char *key = NULL;
uint8_t *k_opad = NULL;
if (what == WANT_HMAC)
{ // The key and k_opad are only used for HMAC; these default to NULLs for HASH
key = luaL_checklstring (L, 2, &len);
k_opad_len = mi->block_size;
}
// create a userdatum with specific metatable. This comprises the ud header,
// the encrypto context block, and an optional HMAC block as a single allocation
// unit
udlen = sizeof(digest_user_datum_t) + mi->ctx_size + k_opad_len;
digest_user_datum_t *dudat = (digest_user_datum_t *)lua_newuserdata(L, udlen);
luaL_getmetatable(L, "crypto.hash"); // and set its metatable to the crypto.hash table
lua_setmetatable(L, -2);
void *ctx = dudat + 1; // The context block immediately follows the digest_user_datum
mi->create (ctx);
if (what == WANT_HMAC) {
// The k_opad block immediately follows the context block
k_opad = (char *)ctx + mi->ctx_size;
crypto_hmac_begin (ctx, mi, key, len, k_opad);
}
// Set pointers to the mechanics and CTX
dudat->mech_info = mi;
dudat->ctx = ctx;
dudat->k_opad = k_opad;
return 1; // Pass userdata object back
}
/* crypto.new_hash("MECHTYPE") */
static int crypto_new_hash (lua_State *L)
{
return crypto_new_hash_hmac (L, WANT_HASH);
}
/* crypto.new_hmac("MECHTYPE", "KEY") */
static int crypto_new_hmac (lua_State *L)
{
return crypto_new_hash_hmac (L, WANT_HMAC);
}
/* Called as object, params:
1 - userdata "this"
2 - new string to add to the hash state */
static int crypto_hash_update (lua_State *L)
{
NODE_DBG("enter crypto_hash_update.\n");
digest_user_datum_t *dudat;
size_t sl;
dudat = (digest_user_datum_t *)luaL_checkudata(L, 1, "crypto.hash");
const digest_mech_info_t *mi = dudat->mech_info;
size_t len = 0;
const char *data = luaL_checklstring (L, 2, &len);
mi->update (dudat->ctx, data, len);
return 0; // No return value
}
/* Called as object, no params. Returns digest of default size. */
static int crypto_hash_finalize (lua_State *L)
{
NODE_DBG("enter crypto_hash_update.\n");
digest_user_datum_t *dudat;
size_t sl;
dudat = (digest_user_datum_t *)luaL_checkudata(L, 1, "crypto.hash");
const digest_mech_info_t *mi = dudat->mech_info;
uint8_t digest[mi->digest_size]; // Allocate as local
if (dudat->k_opad)
crypto_hmac_finalize (dudat->ctx, mi, dudat->k_opad, digest);
else
mi->finalize (digest, dudat->ctx);
lua_pushlstring (L, digest, sizeof (digest));
return 1;
}
static sint32_t vfs_read_wrap (int fd, void *ptr, size_t len)
{
return vfs_read (fd, ptr, len);
}
/* rawdigest = crypto.hash("MD5", filename)
* strdigest = crypto.toHex(rawdigest)
*/
static int crypto_flhash (lua_State *L)
{
const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
if (!mi)
return bad_mech (L);
const char *filename = luaL_checkstring (L, 2);
// Open the file
int file_fd = vfs_open (filename, "r");
if(!file_fd) {
return bad_file(L);
}
// Compute hash
uint8_t digest[mi->digest_size];
int returncode = crypto_fhash (mi, &vfs_read_wrap, file_fd, digest);
// Finish up
vfs_close(file_fd);
if (returncode == ENOMEM)
return bad_mem (L);
else if (returncode == EINVAL)
return bad_mech(L);
else
lua_pushlstring (L, digest, sizeof (digest));
return 1;
}
/* rawsignature = crypto.hmac("SHA1", str, key)
* strsignature = crypto.toHex(rawsignature)
*/
static int crypto_lhmac (lua_State *L)
{
const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
if (!mi)
return bad_mech (L);
size_t len = 0;
const char *data = luaL_checklstring (L, 2, &len);
size_t klen = 0;
const char *key = luaL_checklstring (L, 3, &klen);
uint8_t digest[mi->digest_size];
if (crypto_hmac (mi, data, len, key, klen, digest) != 0)
return bad_mem (L);
lua_pushlstring (L, digest, sizeof (digest));
return 1;
}
static const crypto_mech_t *get_mech (lua_State *L, int idx)
{
const char *name = luaL_checkstring (L, idx);
const crypto_mech_t *mech = crypto_encryption_mech (name);
if (mech)
return mech;
luaL_error (L, "unknown cipher: %s", name);
__builtin_unreachable ();
}
static int crypto_encdec (lua_State *L, bool enc)
{
const crypto_mech_t *mech = get_mech (L, 1);
size_t klen, dlen, ivlen, bs = mech->block_size;
const char *key = luaL_checklstring (L, 2, &klen);
const char *data = luaL_checklstring (L, 3, &dlen);
const char *iv = luaL_optlstring (L, 4, "", &ivlen);
size_t outlen = ((dlen + bs -1) / bs) * bs;
char *buf = luaM_newvector(L, outlen, char);
crypto_op_t op = {
key, klen,
iv, ivlen,
data, dlen,
buf, outlen,
enc ? OP_ENCRYPT : OP_DECRYPT
};
int status = mech->run (&op);
lua_pushlstring (L, buf, outlen); /* discarded on error but what the hell */
luaM_freearray(L, buf, outlen, char);
return status ? 1 : luaL_error (L, "crypto op failed");
}
static int lcrypto_encrypt (lua_State *L)
{
return crypto_encdec (L, true);
}
static int lcrypto_decrypt (lua_State *L)
{
return crypto_encdec (L, false);
}
// Hash function map
LROT_BEGIN(crypto_hash)
LROT_FUNCENTRY( update, crypto_hash_update )
LROT_FUNCENTRY( finalize, crypto_hash_finalize )
LROT_TABENTRY( __index, crypto_hash )
LROT_END( crypto_hash, crypto_hash, LROT_MASK_INDEX )
// Module function map
LROT_BEGIN(crypto)
LROT_FUNCENTRY( sha1, crypto_sha1 )
LROT_FUNCENTRY( toBase64, crypto_base64_encode )
LROT_FUNCENTRY( toHex, crypto_hex_encode )
LROT_FUNCENTRY( mask, crypto_mask )
LROT_FUNCENTRY( hash, crypto_lhash )
LROT_FUNCENTRY( fhash, crypto_flhash )
LROT_FUNCENTRY( new_hash, crypto_new_hash )
LROT_FUNCENTRY( hmac, crypto_lhmac )
LROT_FUNCENTRY( new_hmac, crypto_new_hmac )
LROT_FUNCENTRY( encrypt, lcrypto_encrypt )
LROT_FUNCENTRY( decrypt, lcrypto_decrypt )
LROT_END( crypto, NULL, 0 )
int luaopen_crypto ( lua_State *L )
{
luaL_rometatable(L, "crypto.hash", LROT_TABLEREF(crypto_hash));
return 0;
}
NODEMCU_MODULE(CRYPTO, "crypto", crypto, luaopen_crypto);