347 lines
8.6 KiB
C
347 lines
8.6 KiB
C
// Module for cryptography
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#include <errno.h>
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#include "module.h"
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#include "lauxlib.h"
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#include "platform.h"
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#include <stdint.h>
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#include <stddef.h>
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#include "vfs.h"
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#include "../crypto/digests.h"
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#include "../crypto/mech.h"
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#include "lmem.h"
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#include "user_interface.h"
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#include "rom.h"
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typedef struct {
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const digest_mech_info_t *mech_info;
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void *ctx;
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uint8_t *k_opad;
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} digest_user_datum_t;
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/**
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* hash = crypto.sha1(input)
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*
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* Calculates raw SHA1 hash of input string.
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* Input is arbitrary string, output is raw 20-byte hash as string.
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*/
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static int crypto_sha1( lua_State* L )
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{
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SHA1_CTX ctx;
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uint8_t digest[20];
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// Read the string from lua (with length)
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int len;
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const char* msg = luaL_checklstring(L, 1, &len);
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// Use the SHA* functions in the rom
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SHA1Init(&ctx);
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SHA1Update(&ctx, msg, len);
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SHA1Final(digest, &ctx);
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// Push the result as a lua string
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lua_pushlstring(L, digest, 20);
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return 1;
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}
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/**
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* masked = crypto.mask(message, mask)
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*
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* Apply a mask (repeated if shorter than message) as XOR to each byte.
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*/
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static int crypto_mask( lua_State* L )
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{
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int len, mask_len, i;
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const char* msg = luaL_checklstring(L, 1, &len);
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const char* mask = luaL_checklstring(L, 2, &mask_len);
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luaL_Buffer b;
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if(mask_len <= 0)
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return luaL_error(L, "invalid argument: mask");
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luaL_buffinit(L, &b);
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for (i = 0; i < len; i++) {
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luaL_addchar(&b, msg[i] ^ mask[i % mask_len]);
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}
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luaL_pushresult(&b);
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return 1;
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}
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static inline int bad_mech (lua_State *L) { return luaL_error (L, "unknown hash mech"); }
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static inline int bad_mem (lua_State *L) { return luaL_error (L, "insufficient memory"); }
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static inline int bad_file (lua_State *L) { return luaL_error (L, "file does not exist"); }
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/* rawdigest = crypto.hash("MD5", str)
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* strdigest = encoder.toHex(rawdigest)
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*/
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static int crypto_lhash (lua_State *L)
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{
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const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
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if (!mi)
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return bad_mech (L);
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size_t len = 0;
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const char *data = luaL_checklstring (L, 2, &len);
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uint8_t digest[mi->digest_size];
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if (crypto_hash (mi, data, len, digest) != 0)
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return bad_mem (L);
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lua_pushlstring (L, digest, sizeof (digest));
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return 1;
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}
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/* General Usage for extensible hash functions:
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* sha = crypto.new_hash("MD5")
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* sha.update("Data")
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* sha.update("Data2")
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* strdigest = encoder.toHex(sha.finalize())
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*/
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#define WANT_HASH 0
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#define WANT_HMAC 1
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static int crypto_new_hash_hmac (lua_State *L, int what)
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{
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// get pointer to relevant hash_mechs table entry in app/crypto/digest.c. Note that
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// the size of the table needed is dependent on the the digest type
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const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
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if (!mi)
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return bad_mech (L);
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size_t len = 0, k_opad_len = 0, udlen;
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const char *key = NULL;
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uint8_t *k_opad = NULL;
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if (what == WANT_HMAC)
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{ // The key and k_opad are only used for HMAC; these default to NULLs for HASH
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key = luaL_checklstring (L, 2, &len);
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k_opad_len = mi->block_size;
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}
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// create a userdatum with specific metatable. This comprises the ud header,
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// the encrypto context block, and an optional HMAC block as a single allocation
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// unit
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udlen = sizeof(digest_user_datum_t) + mi->ctx_size + k_opad_len;
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digest_user_datum_t *dudat = (digest_user_datum_t *)lua_newuserdata(L, udlen);
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luaL_getmetatable(L, "crypto.hash"); // and set its metatable to the crypto.hash table
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lua_setmetatable(L, -2);
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void *ctx = dudat + 1; // The context block immediately follows the digest_user_datum
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mi->create (ctx);
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if (what == WANT_HMAC) {
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// The k_opad block immediately follows the context block
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k_opad = (char *)ctx + mi->ctx_size;
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crypto_hmac_begin (ctx, mi, key, len, k_opad);
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}
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// Set pointers to the mechanics and CTX
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dudat->mech_info = mi;
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dudat->ctx = ctx;
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dudat->k_opad = k_opad;
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return 1; // Pass userdata object back
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}
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/* crypto.new_hash("MECHTYPE") */
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static int crypto_new_hash (lua_State *L)
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{
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return crypto_new_hash_hmac (L, WANT_HASH);
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}
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/* crypto.new_hmac("MECHTYPE", "KEY") */
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static int crypto_new_hmac (lua_State *L)
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{
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return crypto_new_hash_hmac (L, WANT_HMAC);
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}
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/* Called as object, params:
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1 - userdata "this"
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2 - new string to add to the hash state */
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static int crypto_hash_update (lua_State *L)
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{
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NODE_DBG("enter crypto_hash_update.\n");
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digest_user_datum_t *dudat;
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size_t sl;
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dudat = (digest_user_datum_t *)luaL_checkudata(L, 1, "crypto.hash");
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const digest_mech_info_t *mi = dudat->mech_info;
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size_t len = 0;
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const char *data = luaL_checklstring (L, 2, &len);
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mi->update (dudat->ctx, data, len);
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return 0; // No return value
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}
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/* Called as object, no params. Returns digest of default size. */
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static int crypto_hash_finalize (lua_State *L)
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{
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NODE_DBG("enter crypto_hash_update.\n");
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digest_user_datum_t *dudat;
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size_t sl;
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dudat = (digest_user_datum_t *)luaL_checkudata(L, 1, "crypto.hash");
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const digest_mech_info_t *mi = dudat->mech_info;
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uint8_t digest[mi->digest_size]; // Allocate as local
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if (dudat->k_opad)
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crypto_hmac_finalize (dudat->ctx, mi, dudat->k_opad, digest);
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else
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mi->finalize (digest, dudat->ctx);
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lua_pushlstring (L, digest, sizeof (digest));
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return 1;
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}
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static sint32_t vfs_read_wrap (int fd, void *ptr, size_t len)
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{
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return vfs_read (fd, ptr, len);
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}
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/* rawdigest = crypto.hash("MD5", filename)
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* strdigest = encoder.toHex(rawdigest)
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*/
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static int crypto_flhash (lua_State *L)
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{
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const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
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if (!mi)
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return bad_mech (L);
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const char *filename = luaL_checkstring (L, 2);
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// Open the file
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int file_fd = vfs_open (filename, "r");
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if(!file_fd) {
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return bad_file(L);
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}
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// Compute hash
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uint8_t digest[mi->digest_size];
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int returncode = crypto_fhash (mi, &vfs_read_wrap, file_fd, digest);
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// Finish up
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vfs_close(file_fd);
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if (returncode == ENOMEM)
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return bad_mem (L);
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else if (returncode == EINVAL)
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return bad_mech(L);
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else
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lua_pushlstring (L, digest, sizeof (digest));
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return 1;
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}
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/* rawsignature = crypto.hmac("SHA1", str, key)
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* strsignature = encoder.toHex(rawsignature)
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*/
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static int crypto_lhmac (lua_State *L)
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{
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const digest_mech_info_t *mi = crypto_digest_mech (luaL_checkstring (L, 1));
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if (!mi)
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return bad_mech (L);
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size_t len = 0;
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const char *data = luaL_checklstring (L, 2, &len);
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size_t klen = 0;
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const char *key = luaL_checklstring (L, 3, &klen);
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uint8_t digest[mi->digest_size];
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if (crypto_hmac (mi, data, len, key, klen, digest) != 0)
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return bad_mem (L);
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lua_pushlstring (L, digest, sizeof (digest));
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return 1;
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}
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static const crypto_mech_t *get_mech (lua_State *L, int idx)
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{
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const char *name = luaL_checkstring (L, idx);
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const crypto_mech_t *mech = crypto_encryption_mech (name);
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if (mech)
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return mech;
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luaL_error (L, "unknown cipher: %s", name);
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__builtin_unreachable ();
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}
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static int crypto_encdec (lua_State *L, bool enc)
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{
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const crypto_mech_t *mech = get_mech (L, 1);
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size_t klen, dlen, ivlen, bs = mech->block_size;
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const char *key = luaL_checklstring (L, 2, &klen);
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const char *data = luaL_checklstring (L, 3, &dlen);
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const char *iv = luaL_optlstring (L, 4, "", &ivlen);
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size_t outlen = ((dlen + bs -1) / bs) * bs;
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char *buf = luaM_newvector(L, outlen, char);
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crypto_op_t op = {
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key, klen,
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iv, ivlen,
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data, dlen,
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buf, outlen,
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enc ? OP_ENCRYPT : OP_DECRYPT
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};
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int status = mech->run (&op);
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lua_pushlstring (L, buf, outlen); /* discarded on error but what the hell */
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luaN_freearray(L, buf, outlen);
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return status ? 1 : luaL_error (L, "crypto op failed");
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}
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static int lcrypto_encrypt (lua_State *L)
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{
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return crypto_encdec (L, true);
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}
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static int lcrypto_decrypt (lua_State *L)
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{
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return crypto_encdec (L, false);
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}
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// Hash function map
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LROT_BEGIN(crypto_hash_map, NULL, LROT_MASK_INDEX)
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LROT_TABENTRY( __index, crypto_hash_map )
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LROT_FUNCENTRY( update, crypto_hash_update )
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LROT_FUNCENTRY( finalize, crypto_hash_finalize )
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LROT_END(crypto_hash_map, NULL, LROT_MASK_INDEX)
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// Module function map
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LROT_BEGIN(crypto, NULL, 0)
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LROT_FUNCENTRY( sha1, crypto_sha1 )
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LROT_FUNCENTRY( mask, crypto_mask )
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LROT_FUNCENTRY( hash, crypto_lhash )
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LROT_FUNCENTRY( fhash, crypto_flhash )
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LROT_FUNCENTRY( new_hash, crypto_new_hash )
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LROT_FUNCENTRY( hmac, crypto_lhmac )
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LROT_FUNCENTRY( new_hmac, crypto_new_hmac )
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LROT_FUNCENTRY( encrypt, lcrypto_encrypt )
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LROT_FUNCENTRY( decrypt, lcrypto_decrypt )
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LROT_END(crypto, NULL, 0)
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int luaopen_crypto ( lua_State *L )
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{
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luaL_rometatable(L, "crypto.hash", LROT_TABLEREF(crypto_hash_map));
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return 0;
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}
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NODEMCU_MODULE(CRYPTO, "crypto", crypto, luaopen_crypto);
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