nodemcu-firmware/app/modules/crypto.c

268 lines
6.5 KiB
C

// Module for cryptography
#include <c_errno.h>
#include "module.h"
#include "lauxlib.h"
#include "platform.h"
#include "c_types.h"
#include "c_stdlib.h"
#include "flash_fs.h"
#include "../crypto/digests.h"
#include "../crypto/mech.h"
#include "user_interface.h"
#include "rom.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 )
{
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;
}
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;
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;
}
/**
* encoded = crypto.toHex(raw)
*
* Encodes raw binary string as hex string.
*/
static int crypto_hex_encode( lua_State* L)
{
int len;
const char* msg = luaL_checklstring(L, 1, &len);
char* out = (char*)c_malloc(len * 2);
int i, j = 0;
for (i = 0; i < len; i++) {
out[j++] = crypto_hexbytes[msg[i] >> 4];
out[j++] = crypto_hexbytes[msg[i] & 0xf];
}
lua_pushlstring(L, out, len*2);
c_free(out);
return 1;
}
/**
* 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;
const char* msg = luaL_checklstring(L, 1, &len);
const char* mask = luaL_checklstring(L, 2, &mask_len);
int i;
char* copy = (char*)c_malloc(len);
for (i = 0; i < len; i++) {
copy[i] = msg[i] ^ mask[i % 4];
}
lua_pushlstring(L, copy, len);
c_free(copy);
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;
}
/* 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 = fs_open (filename, FS_RDONLY);
if(file_fd < FS_OPEN_OK) {
return bad_file(L);
}
// Compute hash
uint8_t digest[mi->digest_size];
int returncode = crypto_fhash (mi, &fs_read, file_fd, digest);
// Finish up
fs_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;
const char *key = luaL_checklstring (L, 2, &klen);
size_t dlen;
const char *data = luaL_checklstring (L, 3, &dlen);
size_t ivlen;
const char *iv = luaL_optlstring (L, 4, "", &ivlen);
size_t bs = mech->block_size;
size_t outlen = ((dlen + bs -1) / bs) * bs;
char *buf = (char *)os_zalloc (outlen);
if (!buf)
return luaL_error (L, "crypto init failed");
crypto_op_t op =
{
key, klen,
iv, ivlen,
data, dlen,
buf, outlen,
enc ? OP_ENCRYPT : OP_DECRYPT
};
if (!mech->run (&op))
{
os_free (buf);
return luaL_error (L, "crypto op failed");
}
else
{
lua_pushlstring (L, buf, outlen);
// note: if lua_pushlstring runs out of memory, we leak buf :(
os_free (buf);
return 1;
}
}
static int lcrypto_encrypt (lua_State *L)
{
return crypto_encdec (L, true);
}
static int lcrypto_decrypt (lua_State *L)
{
return crypto_encdec (L, false);
}
// Module function map
static const LUA_REG_TYPE crypto_map[] = {
{ LSTRKEY( "sha1" ), LFUNCVAL( crypto_sha1 ) },
{ LSTRKEY( "toBase64" ), LFUNCVAL( crypto_base64_encode ) },
{ LSTRKEY( "toHex" ), LFUNCVAL( crypto_hex_encode ) },
{ LSTRKEY( "mask" ), LFUNCVAL( crypto_mask ) },
{ LSTRKEY( "hash" ), LFUNCVAL( crypto_lhash ) },
{ LSTRKEY( "fhash" ), LFUNCVAL( crypto_flhash ) },
{ LSTRKEY( "hmac" ), LFUNCVAL( crypto_lhmac ) },
{ LSTRKEY( "encrypt" ), LFUNCVAL( lcrypto_encrypt ) },
{ LSTRKEY( "decrypt" ), LFUNCVAL( lcrypto_decrypt ) },
{ LNILKEY, LNILVAL }
};
NODEMCU_MODULE(CRYPTO, "crypto", crypto_map, NULL);