diff options
Diffstat (limited to 'util-src/crypto.c')
| -rw-r--r-- | util-src/crypto.c | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/util-src/crypto.c b/util-src/crypto.c new file mode 100644 index 00000000..dce1a740 --- /dev/null +++ b/util-src/crypto.c @@ -0,0 +1,595 @@ +/* Prosody IM +-- Copyright (C) 2022 Matthew Wild +-- +-- This project is MIT/X11 licensed. Please see the +-- COPYING file in the source package for more information. +-- +*/ + +/* +* crypto.c +* Lua library for cryptographic operations using OpenSSL +*/ + +#include <string.h> +#include <stdlib.h> + +#ifdef _MSC_VER +typedef unsigned __int32 uint32_t; +#else +#include <inttypes.h> +#endif + +#include "lua.h" +#include "lauxlib.h" +#include <openssl/crypto.h> +#include <openssl/ecdsa.h> +#include <openssl/err.h> +#include <openssl/evp.h> +#include <openssl/obj_mac.h> +#include <openssl/pem.h> + +#if (LUA_VERSION_NUM == 501) +#define luaL_setfuncs(L, R, N) luaL_register(L, NULL, R) +#endif + +/* The max size of an encoded 'R' or 'S' value. P-521 = 521 bits = 66 bytes */ +#define MAX_ECDSA_SIG_INT_BYTES 66 + +#include "managed_pointer.h" + +#define PKEY_MT_TAG "util.crypto key" + +static BIO* new_memory_BIO() { + return BIO_new(BIO_s_mem()); +} + +MANAGED_POINTER_ALLOCATOR(new_managed_EVP_MD_CTX, EVP_MD_CTX*, EVP_MD_CTX_new, EVP_MD_CTX_free) +MANAGED_POINTER_ALLOCATOR(new_managed_BIO_s_mem, BIO*, new_memory_BIO, BIO_free) +MANAGED_POINTER_ALLOCATOR(new_managed_EVP_CIPHER_CTX, EVP_CIPHER_CTX*, EVP_CIPHER_CTX_new, EVP_CIPHER_CTX_free) + +#define CRYPTO_KEY_TYPE_ERR "unexpected key type: got '%s', expected '%s'" + +static EVP_PKEY* pkey_from_arg(lua_State *L, int idx, const int type, const int require_private) { + EVP_PKEY *pkey = *(EVP_PKEY**)luaL_checkudata(L, idx, PKEY_MT_TAG); + int got_type; + if(type || require_private) { + lua_getuservalue(L, idx); + if(type != 0) { + lua_getfield(L, -1, "type"); + got_type = lua_tointeger(L, -1); + if(got_type != type) { + const char *got_key_type_name = OBJ_nid2sn(got_type); + const char *want_key_type_name = OBJ_nid2sn(type); + lua_pushfstring(L, CRYPTO_KEY_TYPE_ERR, got_key_type_name, want_key_type_name); + luaL_argerror(L, idx, lua_tostring(L, -1)); + } + lua_pop(L, 1); + } + if(require_private != 0) { + lua_getfield(L, -1, "private"); + if(lua_toboolean(L, -1) != 1) { + luaL_argerror(L, idx, "private key expected, got public key only"); + } + lua_pop(L, 1); + } + lua_pop(L, 1); + } + return pkey; +} + +static int Lpkey_finalizer(lua_State *L) { + EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0); + EVP_PKEY_free(pkey); + return 0; +} + +static int Lpkey_meth_get_type(lua_State *L) { + EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0); + + int key_type = EVP_PKEY_id(pkey); + lua_pushstring(L, OBJ_nid2sn(key_type)); + return 1; +} + +static int base_evp_sign(lua_State *L, const int key_type, const EVP_MD *digest_type) { + EVP_PKEY *pkey = pkey_from_arg(L, 1, (key_type!=NID_rsassaPss)?key_type:NID_rsaEncryption, 1); + luaL_Buffer sigbuf; + + size_t msg_len; + const unsigned char* msg = (unsigned char*)lua_tolstring(L, 2, &msg_len); + + size_t sig_len; + unsigned char *sig = NULL; + EVP_MD_CTX *md_ctx = new_managed_EVP_MD_CTX(L); + + if(EVP_DigestSignInit(md_ctx, NULL, digest_type, NULL, pkey) != 1) { + lua_pushnil(L); + return 1; + } + if(key_type == NID_rsassaPss) { + EVP_PKEY_CTX_set_rsa_padding(EVP_MD_CTX_pkey_ctx(md_ctx), RSA_PKCS1_PSS_PADDING); + } + if(EVP_DigestSign(md_ctx, NULL, &sig_len, msg, msg_len) != 1) { + lua_pushnil(L); + return 1; + } + + // COMPAT w/ Lua 5.1 + luaL_buffinit(L, &sigbuf); + sig = memset(luaL_prepbuffer(&sigbuf), 0, sig_len); + + if(EVP_DigestSign(md_ctx, sig, &sig_len, msg, msg_len) != 1) { + lua_pushnil(L); + } + else { + luaL_addsize(&sigbuf, sig_len); + luaL_pushresult(&sigbuf); + return 1; + } + + return 1; +} + +static int base_evp_verify(lua_State *L, const int key_type, const EVP_MD *digest_type) { + EVP_PKEY *pkey = pkey_from_arg(L, 1, (key_type!=NID_rsassaPss)?key_type:NID_rsaEncryption, 0); + + size_t msg_len; + const unsigned char *msg = (unsigned char*)luaL_checklstring(L, 2, &msg_len); + + size_t sig_len; + const unsigned char *sig = (unsigned char*)luaL_checklstring(L, 3, &sig_len); + + EVP_MD_CTX *md_ctx = EVP_MD_CTX_new(); + + if(EVP_DigestVerifyInit(md_ctx, NULL, digest_type, NULL, pkey) != 1) { + lua_pushnil(L); + goto cleanup; + } + if(key_type == NID_rsassaPss) { + EVP_PKEY_CTX_set_rsa_padding(EVP_MD_CTX_pkey_ctx(md_ctx), RSA_PKCS1_PSS_PADDING); + } + int result = EVP_DigestVerify(md_ctx, sig, sig_len, msg, msg_len); + if(result == 0) { + lua_pushboolean(L, 0); + } else if(result != 1) { + lua_pushnil(L); + } + else { + lua_pushboolean(L, 1); + } +cleanup: + EVP_MD_CTX_free(md_ctx); + return 1; +} + +static int Lpkey_meth_public_pem(lua_State *L) { + char *data; + size_t bytes; + EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 0); + BIO *bio = new_managed_BIO_s_mem(L); + if(PEM_write_bio_PUBKEY(bio, pkey)) { + bytes = BIO_get_mem_data(bio, &data); + if (bytes > 0) { + lua_pushlstring(L, data, bytes); + } + else { + lua_pushnil(L); + } + } + else { + lua_pushnil(L); + } + return 1; +} + +static int Lpkey_meth_private_pem(lua_State *L) { + char *data; + size_t bytes; + EVP_PKEY *pkey = pkey_from_arg(L, 1, 0, 1); + BIO *bio = new_managed_BIO_s_mem(L); + + if(PEM_write_bio_PrivateKey(bio, pkey, NULL, NULL, 0, NULL, NULL)) { + bytes = BIO_get_mem_data(bio, &data); + if (bytes > 0) { + lua_pushlstring(L, data, bytes); + } + else { + lua_pushnil(L); + } + } + else { + lua_pushnil(L); + } + return 1; +} + +static int push_pkey(lua_State *L, EVP_PKEY *pkey, const int type, const int privkey) { + EVP_PKEY **ud = lua_newuserdata(L, sizeof(EVP_PKEY*)); + *ud = pkey; + luaL_newmetatable(L, PKEY_MT_TAG); + lua_setmetatable(L, -2); + + /* Set some info about the key and attach it as a user value */ + lua_newtable(L); + if(type != 0) { + lua_pushinteger(L, type); + lua_setfield(L, -2, "type"); + } + if(privkey != 0) { + lua_pushboolean(L, 1); + lua_setfield(L, -2, "private"); + } + lua_setuservalue(L, -2); + return 1; +} + +static int Lgenerate_ed25519_keypair(lua_State *L) { + EVP_PKEY *pkey = NULL; + EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(EVP_PKEY_ED25519, NULL); + + /* Generate key */ + EVP_PKEY_keygen_init(pctx); + EVP_PKEY_keygen(pctx, &pkey); + EVP_PKEY_CTX_free(pctx); + + push_pkey(L, pkey, NID_ED25519, 1); + return 1; +} + +static int Limport_private_pem(lua_State *L) { + EVP_PKEY *pkey = NULL; + + size_t privkey_bytes; + const char* privkey_data; + BIO *bio = new_managed_BIO_s_mem(L); + + privkey_data = luaL_checklstring(L, 1, &privkey_bytes); + BIO_write(bio, privkey_data, privkey_bytes); + pkey = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL); + if (pkey) { + push_pkey(L, pkey, EVP_PKEY_id(pkey), 1); + } + else { + lua_pushnil(L); + } + + return 1; +} + +static int Limport_public_pem(lua_State *L) { + EVP_PKEY *pkey = NULL; + + size_t pubkey_bytes; + const char* pubkey_data; + BIO *bio = new_managed_BIO_s_mem(L); + + pubkey_data = luaL_checklstring(L, 1, &pubkey_bytes); + BIO_write(bio, pubkey_data, pubkey_bytes); + pkey = PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL); + if (pkey) { + push_pkey(L, pkey, EVP_PKEY_id(pkey), 0); + } + else { + lua_pushnil(L); + } + + return 1; +} + +static int Led25519_sign(lua_State *L) { + return base_evp_sign(L, NID_ED25519, NULL); +} + +static int Led25519_verify(lua_State *L) { + return base_evp_verify(L, NID_ED25519, NULL); +} + +/* gcm_encrypt(key, iv, plaintext) */ +static int Laes_gcm_encrypt(lua_State *L, const EVP_CIPHER *cipher, const unsigned char expected_key_len) { + EVP_CIPHER_CTX *ctx; + luaL_Buffer ciphertext_buffer; + + size_t key_len, iv_len, plaintext_len; + int ciphertext_len, final_len; + + const unsigned char *key = (unsigned char*)luaL_checklstring(L, 1, &key_len); + const unsigned char *iv = (unsigned char*)luaL_checklstring(L, 2, &iv_len); + const unsigned char *plaintext = (unsigned char*)luaL_checklstring(L, 3, &plaintext_len); + + if(key_len != expected_key_len) { + return luaL_error(L, "key must be %d bytes", expected_key_len); + } + luaL_argcheck(L, iv_len == 12, 2, "iv must be 12 bytes"); + if(lua_gettop(L) > 3) { + return luaL_error(L, "Expected 3 arguments, got %d", lua_gettop(L)); + } + + // Create and initialise the context + ctx = new_managed_EVP_CIPHER_CTX(L); + + // Initialise the encryption operation + if(1 != EVP_EncryptInit_ex(ctx, cipher, NULL, NULL, NULL)) { + return luaL_error(L, "Error while initializing encryption engine"); + } + + // Initialise key and IV + if(1 != EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv)) { + return luaL_error(L, "Error while initializing key/iv"); + } + + luaL_buffinit(L, &ciphertext_buffer); + unsigned char *ciphertext = (unsigned char*)luaL_prepbuffsize(&ciphertext_buffer, plaintext_len+16); + + if(1 != EVP_EncryptUpdate(ctx, ciphertext, &ciphertext_len, plaintext, plaintext_len)) { + return luaL_error(L, "Error while encrypting data"); + } + + /* + * Finalise the encryption. Normally ciphertext bytes may be written at + * this stage, but this does not occur in GCM mode + */ + if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + ciphertext_len, &final_len)) { + return luaL_error(L, "Error while encrypting final data"); + } + if(final_len != 0) { + return luaL_error(L, "Non-zero final data"); + } + + /* Get the tag */ + if(1 != EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, 16, ciphertext + ciphertext_len)) { + return luaL_error(L, "Unable to read AEAD tag of encrypted data"); + } + + luaL_addsize(&ciphertext_buffer, ciphertext_len + 16); + luaL_pushresult(&ciphertext_buffer); + + return 1; +} + +static int Laes_128_gcm_encrypt(lua_State *L) { + return Laes_gcm_encrypt(L, EVP_aes_128_gcm(), 16); +} + +static int Laes_256_gcm_encrypt(lua_State *L) { + return Laes_gcm_encrypt(L, EVP_aes_256_gcm(), 32); +} + +/* gcm_decrypt(key, iv, ciphertext) */ +static int Laes_gcm_decrypt(lua_State *L, const EVP_CIPHER *cipher, const unsigned char expected_key_len) { + EVP_CIPHER_CTX *ctx; + luaL_Buffer plaintext_buffer; + + size_t key_len, iv_len, ciphertext_len; + int plaintext_len, final_len; + + const unsigned char *key = (unsigned char*)luaL_checklstring(L, 1, &key_len); + const unsigned char *iv = (unsigned char*)luaL_checklstring(L, 2, &iv_len); + const unsigned char *ciphertext = (unsigned char*)luaL_checklstring(L, 3, &ciphertext_len); + + if(key_len != expected_key_len) { + return luaL_error(L, "key must be %d bytes", expected_key_len); + } + luaL_argcheck(L, iv_len == 12, 2, "iv must be 12 bytes"); + luaL_argcheck(L, ciphertext_len > 16, 3, "ciphertext must be at least 16 bytes (including tag)"); + if(lua_gettop(L) > 3) { + return luaL_error(L, "Expected 3 arguments, got %d", lua_gettop(L)); + } + + /* Create and initialise the context */ + ctx = new_managed_EVP_CIPHER_CTX(L); + + /* Initialise the decryption operation. */ + if(!EVP_DecryptInit_ex(ctx, cipher, NULL, NULL, NULL)) { + return luaL_error(L, "Error while initializing decryption engine"); + } + + /* Initialise key and IV */ + if(!EVP_DecryptInit_ex(ctx, NULL, NULL, key, iv)) { + return luaL_error(L, "Error while initializing key/iv"); + } + + luaL_buffinit(L, &plaintext_buffer); + unsigned char *plaintext = (unsigned char*)luaL_prepbuffsize(&plaintext_buffer, ciphertext_len); + + /* + * Provide the message to be decrypted, and obtain the plaintext output. + * EVP_DecryptUpdate can be called multiple times if necessary + */ + if(!EVP_DecryptUpdate(ctx, plaintext, &plaintext_len, ciphertext, ciphertext_len-16)) { + return luaL_error(L, "Error while decrypting data"); + } + + /* Set expected tag value. Works in OpenSSL 1.0.1d and later */ + if(!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, 16, (unsigned char*)ciphertext + (ciphertext_len-16))) { + return luaL_error(L, "Error while processing authentication tag"); + } + + /* + * Finalise the decryption. A positive return value indicates success, + * anything else is a failure - the plaintext is not trustworthy. + */ + int ret = EVP_DecryptFinal_ex(ctx, plaintext + plaintext_len, &final_len); + + if(ret <= 0) { + /* Verify failed */ + lua_pushnil(L); + lua_pushliteral(L, "verify-failed"); + return 2; + } + + luaL_addsize(&plaintext_buffer, plaintext_len + final_len); + luaL_pushresult(&plaintext_buffer); + return 1; +} + +static int Laes_128_gcm_decrypt(lua_State *L) { + return Laes_gcm_decrypt(L, EVP_aes_128_gcm(), 16); +} + +static int Laes_256_gcm_decrypt(lua_State *L) { + return Laes_gcm_decrypt(L, EVP_aes_256_gcm(), 32); +} + +/* r, s = parse_ecdsa_sig(sig_der) */ +static int Lparse_ecdsa_signature(lua_State *L) { + ECDSA_SIG *sig; + size_t sig_der_len; + const unsigned char *sig_der = (unsigned char*)luaL_checklstring(L, 1, &sig_der_len); + const size_t sig_int_bytes = luaL_checkinteger(L, 2); + const BIGNUM *r, *s; + int rlen, slen; + unsigned char rb[MAX_ECDSA_SIG_INT_BYTES]; + unsigned char sb[MAX_ECDSA_SIG_INT_BYTES]; + + if(sig_int_bytes > MAX_ECDSA_SIG_INT_BYTES) { + luaL_error(L, "requested signature size exceeds supported limit"); + } + + sig = d2i_ECDSA_SIG(NULL, &sig_der, sig_der_len); + + if(sig == NULL) { + lua_pushnil(L); + return 1; + } + + ECDSA_SIG_get0(sig, &r, &s); + + rlen = BN_bn2binpad(r, rb, sig_int_bytes); + slen = BN_bn2binpad(s, sb, sig_int_bytes); + + if (rlen == -1 || slen == -1) { + ECDSA_SIG_free(sig); + luaL_error(L, "encoded integers exceed requested size"); + } + + ECDSA_SIG_free(sig); + + lua_pushlstring(L, (const char*)rb, rlen); + lua_pushlstring(L, (const char*)sb, slen); + + return 2; +} + +/* sig_der = build_ecdsa_signature(r, s) */ +static int Lbuild_ecdsa_signature(lua_State *L) { + ECDSA_SIG *sig = ECDSA_SIG_new(); + BIGNUM *r, *s; + luaL_Buffer sigbuf; + + size_t rlen, slen; + const unsigned char *rbin, *sbin; + + rbin = (unsigned char*)luaL_checklstring(L, 1, &rlen); + sbin = (unsigned char*)luaL_checklstring(L, 2, &slen); + + r = BN_bin2bn(rbin, (int)rlen, NULL); + s = BN_bin2bn(sbin, (int)slen, NULL); + + ECDSA_SIG_set0(sig, r, s); + + luaL_buffinit(L, &sigbuf); + + /* DER structure of an ECDSA signature has 7 bytes plus the integers themselves, + which may gain an extra byte once encoded */ + unsigned char *buffer = (unsigned char*)luaL_prepbuffsize(&sigbuf, (rlen+1)+(slen+1)+7); + int len = i2d_ECDSA_SIG(sig, &buffer); + luaL_addsize(&sigbuf, len); + luaL_pushresult(&sigbuf); + + ECDSA_SIG_free(sig); + + return 1; +} + +#define REG_SIGN_VERIFY(algorithm, digest) \ + { #algorithm "_" #digest "_sign", L ## algorithm ## _ ## digest ## _sign },\ + { #algorithm "_" #digest "_verify", L ## algorithm ## _ ## digest ## _verify }, + +#define IMPL_SIGN_VERIFY(algorithm, key_type, digest) \ + static int L ## algorithm ## _ ## digest ## _sign(lua_State *L) { \ + return base_evp_sign(L, key_type, EVP_ ## digest()); \ + } \ + static int L ## algorithm ## _ ## digest ## _verify(lua_State *L) { \ + return base_evp_verify(L, key_type, EVP_ ## digest()); \ + } + +IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha256) +IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha384) +IMPL_SIGN_VERIFY(ecdsa, NID_X9_62_id_ecPublicKey, sha512) + +IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha256) +IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha384) +IMPL_SIGN_VERIFY(rsassa_pkcs1, NID_rsaEncryption, sha512) + +IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha256) +IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha384) +IMPL_SIGN_VERIFY(rsassa_pss, NID_rsassaPss, sha512) + +static const luaL_Reg Reg[] = { + { "ed25519_sign", Led25519_sign }, + { "ed25519_verify", Led25519_verify }, + + REG_SIGN_VERIFY(ecdsa, sha256) + REG_SIGN_VERIFY(ecdsa, sha384) + REG_SIGN_VERIFY(ecdsa, sha512) + + REG_SIGN_VERIFY(rsassa_pkcs1, sha256) + REG_SIGN_VERIFY(rsassa_pkcs1, sha384) + REG_SIGN_VERIFY(rsassa_pkcs1, sha512) + + REG_SIGN_VERIFY(rsassa_pss, sha256) + REG_SIGN_VERIFY(rsassa_pss, sha384) + REG_SIGN_VERIFY(rsassa_pss, sha512) + + { "aes_128_gcm_encrypt", Laes_128_gcm_encrypt }, + { "aes_128_gcm_decrypt", Laes_128_gcm_decrypt }, + { "aes_256_gcm_encrypt", Laes_256_gcm_encrypt }, + { "aes_256_gcm_decrypt", Laes_256_gcm_decrypt }, + + { "generate_ed25519_keypair", Lgenerate_ed25519_keypair }, + + { "import_private_pem", Limport_private_pem }, + { "import_public_pem", Limport_public_pem }, + + { "parse_ecdsa_signature", Lparse_ecdsa_signature }, + { "build_ecdsa_signature", Lbuild_ecdsa_signature }, + { NULL, NULL } +}; + +static const luaL_Reg KeyMethods[] = { + { "private_pem", Lpkey_meth_private_pem }, + { "public_pem", Lpkey_meth_public_pem }, + { "get_type", Lpkey_meth_get_type }, + { NULL, NULL } +}; + +static const luaL_Reg KeyMetatable[] = { + { "__gc", Lpkey_finalizer }, + { NULL, NULL } +}; + +LUALIB_API int luaopen_util_crypto(lua_State *L) { +#if (LUA_VERSION_NUM > 501) + luaL_checkversion(L); +#endif + + /* Initialize pkey metatable */ + luaL_newmetatable(L, PKEY_MT_TAG); + luaL_setfuncs(L, KeyMetatable, 0); + lua_newtable(L); + luaL_setfuncs(L, KeyMethods, 0); + lua_setfield(L, -2, "__index"); + lua_pop(L, 1); + + /* Initialize lib table */ + lua_newtable(L); + luaL_setfuncs(L, Reg, 0); + lua_pushliteral(L, "-3.14"); + lua_setfield(L, -2, "version"); +#ifdef OPENSSL_VERSION + lua_pushstring(L, OpenSSL_version(OPENSSL_VERSION)); + lua_setfield(L, -2, "_LIBCRYPTO_VERSION"); +#endif + return 1; +} |