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Diffstat (limited to '')
| -rw-r--r-- | wsutil/wsgcrypt.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/wsutil/wsgcrypt.c b/wsutil/wsgcrypt.c new file mode 100644 index 0000000..3fbf9e5 --- /dev/null +++ b/wsutil/wsgcrypt.c @@ -0,0 +1,214 @@ +/* wsgcrypt.c + * Helper functions for libgcrypt + * By Erik de Jong <erikdejong@gmail.com> + * Copyright 2017 Erik de Jong + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "wsgcrypt.h" + +gcry_error_t ws_hmac_buffer(int algo, void *digest, const void *buffer, size_t length, const void *key, size_t keylen) +{ + gcry_md_hd_t hmac_handle; + gcry_error_t result = gcry_md_open(&hmac_handle, algo, GCRY_MD_FLAG_HMAC); + if (result) { + return result; + } + result = gcry_md_setkey(hmac_handle, key, keylen); + if (result) { + gcry_md_close(hmac_handle); + return result; + } + gcry_md_write(hmac_handle, buffer, length); + memcpy(digest, gcry_md_read(hmac_handle, 0), gcry_md_get_algo_dlen(algo)); + gcry_md_close(hmac_handle); + return GPG_ERR_NO_ERROR; +} + +gcry_error_t ws_cmac_buffer(int algo, void *digest, const void *buffer, size_t length, const void *key, size_t keylen) +{ + gcry_mac_hd_t cmac_handle; + gcry_error_t result = gcry_mac_open(&cmac_handle, algo, 0, NULL); + if (result) { + return result; + } + result = gcry_mac_setkey(cmac_handle, key, keylen); + if (result) { + gcry_mac_close(cmac_handle); + return result; + } + gcry_mac_write(cmac_handle, buffer, length); + result = gcry_mac_read(cmac_handle, digest, &keylen); + gcry_mac_close(cmac_handle); + return result; +} + +void crypt_des_ecb(uint8_t *output, const uint8_t *buffer, const uint8_t *key56) +{ + uint8_t key64[8]; + gcry_cipher_hd_t handle; + + memset(output, 0x00, 8); + + /* Transform 56 bits key into 64 bits DES key */ + key64[0] = key56[0]; + key64[1] = (key56[0] << 7) | (key56[1] >> 1); + key64[2] = (key56[1] << 6) | (key56[2] >> 2); + key64[3] = (key56[2] << 5) | (key56[3] >> 3); + key64[4] = (key56[3] << 4) | (key56[4] >> 4); + key64[5] = (key56[4] << 3) | (key56[5] >> 5); + key64[6] = (key56[5] << 2) | (key56[6] >> 6); + key64[7] = (key56[6] << 1); + + if (gcry_cipher_open(&handle, GCRY_CIPHER_DES, GCRY_CIPHER_MODE_ECB, 0)) { + return; + } + if (gcry_cipher_setkey(handle, key64, 8)) { + gcry_cipher_close(handle); + return; + } + gcry_cipher_encrypt(handle, output, 8, buffer, 8); + gcry_cipher_close(handle); +} + +size_t rsa_decrypt_inplace(const unsigned len, unsigned char* data, gcry_sexp_t pk, bool pkcs1_padding, char **err) +{ + int rc = 0; + size_t decr_len = 0, i = 0; + gcry_sexp_t s_data = NULL, s_plain = NULL; + gcry_mpi_t encr_mpi = NULL, text = NULL; + + *err = NULL; + + /* create mpi representation of encrypted data */ + rc = gcry_mpi_scan(&encr_mpi, GCRYMPI_FMT_USG, data, len, NULL); + if (rc != 0 ) { + *err = ws_strdup_printf("can't convert data to mpi (size %d):%s", len, gcry_strerror(rc)); + return 0; + } + + /* put the data into a simple list */ + rc = gcry_sexp_build(&s_data, NULL, "(enc-val(rsa(a%m)))", encr_mpi); + if (rc != 0) { + *err = ws_strdup_printf("can't build encr_sexp:%s", gcry_strerror(rc)); + decr_len = 0; + goto out; + } + + /* pass it to libgcrypt */ + rc = gcry_pk_decrypt(&s_plain, s_data, pk); + if (rc != 0) + { + *err = ws_strdup_printf("can't decrypt key:%s", gcry_strerror(rc)); + decr_len = 0; + goto out; + } + + /* convert plain text sexp to mpi format */ + text = gcry_sexp_nth_mpi(s_plain, 0, 0); + if (! text) { + *err = g_strdup("can't convert sexp to mpi"); + decr_len = 0; + goto out; + } + + /* compute size requested for plaintext buffer */ + rc = gcry_mpi_print(GCRYMPI_FMT_USG, NULL, 0, &decr_len, text); + if (rc != 0) { + *err = ws_strdup_printf("can't compute decr size:%s", gcry_strerror(rc)); + decr_len = 0; + goto out; + } + + /* sanity check on out buffer */ + if (decr_len > len) { + *err = ws_strdup_printf("decrypted data is too long ?!? (%zu max %d)", decr_len, len); + decr_len = 0; + goto out; + } + + /* write plain text to newly allocated buffer */ + rc = gcry_mpi_print(GCRYMPI_FMT_USG, data, len, &decr_len, text); + if (rc != 0) { + *err = ws_strdup_printf("can't print decr data to mpi (size %zu):%s", decr_len, gcry_strerror(rc)); + decr_len = 0; + goto out; + } + + if (pkcs1_padding) { + /* strip the padding*/ + rc = 0; + for (i = 1; i < decr_len; i++) { + if (data[i] == 0) { + rc = (int) i+1; + break; + } + } + + decr_len -= rc; + memmove(data, data+rc, decr_len); + } + +out: + gcry_sexp_release(s_data); + gcry_sexp_release(s_plain); + gcry_mpi_release(encr_mpi); + gcry_mpi_release(text); + return decr_len; +} + +gcry_error_t +hkdf_expand(int hashalgo, const uint8_t *prk, unsigned prk_len, const uint8_t *info, unsigned info_len, + uint8_t *out, unsigned out_len) +{ + // Current maximum hash output size: 48 bytes for SHA-384. + unsigned char lastoutput[48]; + gcry_md_hd_t h; + gcry_error_t err; + const unsigned hash_len = gcry_md_get_algo_dlen(hashalgo); + + /* Some sanity checks */ + if (!(out_len > 0 && out_len <= 255 * hash_len) || + !(hash_len > 0 && hash_len <= sizeof(lastoutput))) { + return GPG_ERR_INV_ARG; + } + + err = gcry_md_open(&h, hashalgo, GCRY_MD_FLAG_HMAC); + if (err) { + return err; + } + + for (unsigned offset = 0; offset < out_len; offset += hash_len) { + gcry_md_reset(h); + gcry_md_setkey(h, prk, prk_len); /* Set PRK */ + if (offset > 0) { + gcry_md_write(h, lastoutput, hash_len); /* T(1..N) */ + } + gcry_md_write(h, info, info_len); /* info */ + gcry_md_putc(h, (uint8_t) (offset / hash_len + 1)); /* constant 0x01..N */ + + memcpy(lastoutput, gcry_md_read(h, hashalgo), hash_len); + memcpy(out + offset, lastoutput, MIN(hash_len, out_len - offset)); + } + + gcry_md_close(h); + return 0; +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 8 + * tab-width: 8 + * indent-tabs-mode: t + * End: + * + * vi: set shiftwidth=8 tabstop=8 noexpandtab: + * :indentSize=8:tabSize=8:noTabs=false: + */ |