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| -rw-r--r-- | lib/crypto/gnutls_helpers.h | 236 |
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diff --git a/lib/crypto/gnutls_helpers.h b/lib/crypto/gnutls_helpers.h new file mode 100644 index 0000000..0362d5e --- /dev/null +++ b/lib/crypto/gnutls_helpers.h @@ -0,0 +1,236 @@ +/* + * Copyright (c) 2019 Andreas Schneider <asn@samba.org> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef _GNUTLS_HELPERS_H +#define _GNUTLS_HELPERS_H + +#include <gnutls/gnutls.h> + +#include "libcli/util/ntstatus.h" +#include "libcli/util/werror.h" +#include "lib/util/data_blob.h" + +/* Those macros are only available in GnuTLS >= 3.6.4 */ +#ifndef GNUTLS_FIPS140_SET_LAX_MODE +#define GNUTLS_FIPS140_SET_LAX_MODE() +#endif + +#ifndef GNUTLS_FIPS140_SET_STRICT_MODE +#define GNUTLS_FIPS140_SET_STRICT_MODE() +#endif + +#ifdef DOXYGEN +/** + * @brief Convert a gnutls error code to a corresponding NTSTATUS. + * + * @param[in] gnutls_rc The GnuTLS return code. + * + * @param[in] blocked_status The NTSTATUS return code which should be returned + * in case the e.g. the cipher might be blocked due + * to FIPS mode. + * + * @return A corresponding NTSTATUS code. + */ +NTSTATUS gnutls_error_to_ntstatus(int gnutls_rc, NTSTATUS blocked_status); +#else +NTSTATUS _gnutls_error_to_ntstatus(int gnutls_rc, + NTSTATUS blocked_status, + const char *function, + const char *location); +#define gnutls_error_to_ntstatus(gnutls_rc, blocked_status) \ + _gnutls_error_to_ntstatus(gnutls_rc, \ + blocked_status, \ + __FUNCTION__, \ + __location__) +#endif + +#ifdef DOXYGEN +/** + * @brief Convert a gnutls error code to a corresponding WERROR. + * + * @param[in] gnutls_rc The GnuTLS return code. + * + * @param[in] blocked_werr The WERROR code which should be returned if e.g + * the cipher we want to used it not allowed to be + * used because of FIPS mode. + * + * @return A corresponding WERROR code. + */ +WERROR gnutls_error_to_werror(int gnutls_rc, WERROR blocked_werr); +#else +WERROR _gnutls_error_to_werror(int gnutls_rc, + WERROR blocked_werr, + const char *function, + const char *location); +#define gnutls_error_to_werror(gnutls_rc, blocked_werr) \ + _gnutls_error_to_werror(gnutls_rc, \ + blocked_werr, \ + __FUNCTION__, \ + __location__) +#endif + +enum samba_gnutls_direction { SAMBA_GNUTLS_ENCRYPT, SAMBA_GNUTLS_DECRYPT }; + +/** + * @brief Encrypt or decrypt a data blob using RC4 with a key and salt. + * + * One of the key input should be a session key and the other a confounder + * (aka salt). Which one depends on the implementation details of the + * protocol. + * + * @param[in] key_input1 Either a session_key or a confounder. + * + * @param[in] key_input2 Either a session_key or a confounder. + * + * @param[in] data The data blob to either encrypt or decrypt. The data + * will be encrypted or decrypted in place. + * + * @param[in] encrypt The encryption direction. + * + * @return A gnutls error code. + */ +int samba_gnutls_arcfour_confounded_md5(const DATA_BLOB *key_input1, + const DATA_BLOB *key_input2, + DATA_BLOB *data, + enum samba_gnutls_direction encrypt); + +/** + * @brief Encrypted a secret plaintext using AEAD_AES_256_CBC_HMAC_SHA512 and + * the session key. + * + * This encrypts a secret plaintext using AEAD_AES_256_CBC_HMAC_SHA512 with a + * key (can be the session key or PBKDF2 password). This is used in SAMR and + * LSA. + * + * @param mem_ctx The memory context to allocate the cipher text pointer. + * + * @param plaintext The secret to encrypt + * + * @param cek The content encryption key to encrypt the secret. + * + * @param key_salt The salt used to calculate the encryption key. + * + * @param key_salt The salt used to calculate the mac key. + + * @param iv The initialization vector used for the encryption. + * + * @param pciphertext A pointer to store the cipher text. + * + * @param pauth_tag[64] An array to store the auth tag. + * + * @return NT_STATUS_OK on success, an nt status error code otherwise. + */ +NTSTATUS +samba_gnutls_aead_aes_256_cbc_hmac_sha512_encrypt(TALLOC_CTX *mem_ctx, + const DATA_BLOB *plaintext, + const DATA_BLOB *cek, + const DATA_BLOB *key_salt, + const DATA_BLOB *mac_salt, + const DATA_BLOB *iv, + DATA_BLOB *pciphertext, + uint8_t pauth_tag[64]); + +/** + * @brief Decypt cipher text using AEAD_AES_256_CBC_HMAC_SHA512 and the session + * key. + * + * This decrypts the cipher text using AEAD_AES_256_CBC_HMAC_SHA512 with the + * given content decryption key key. The plaintext will be zeroed as soon as the + * data blob is freed. + * + * @param mem_ctx The memory context to allocate the plaintext on. + * + * @param ciphertext The cipher text to decrypt. + * + * @param cdk The content decryption key. + * + * @param key_salt The salt used to calculate the encryption key. + * + * @param key_salt The salt used to calculate the mac key. + + * @param iv The initialization vector used for the encryption. + * + * @param auth_tag[64] The authentication blob to be verified. + * + * @param pplaintext A pointer to a DATA_BLOB to store the plaintext. + * + * @return NT_STATUS_OK on success, an nt status error code otherwise. + */ +NTSTATUS +samba_gnutls_aead_aes_256_cbc_hmac_sha512_decrypt(TALLOC_CTX *mem_ctx, + const DATA_BLOB *ciphertext, + const DATA_BLOB *cdk, + const DATA_BLOB *key_salt, + const DATA_BLOB *mac_salt, + const DATA_BLOB *iv, + const uint8_t auth_tag[64], + DATA_BLOB *pplaintext); + +/** + * @brief Check if weak crypto is allowed. + * + * @return true if weak crypo is allowed, false otherwise. + */ +bool samba_gnutls_weak_crypto_allowed(void); + +/** + * @brief Derive a key using the NIST SP 800‐108 algorithm. + * + * The details of the algorithm can be found at + * https://csrc.nist.gov/pubs/sp/800/108/r1/final. + * + * @param KI The key‐derivation key used as input. + * + * @param KI_len The length of the key‐derivation key. + * + * @param FixedData If non‐NULL, specifies fixed data to be used in place of + * that constructed from the Label and Context parameters. + * + * @param FixedData_len The length of the fixed data, if it is present. + * + * @param Label A label that identifies the purpose for the derived key. + * Ignored if FixedData is non‐NULL. + * + * @param Label_len The length of the label. + * + * @param Context Information related to the derived key. Ignored if + * FixedData is non‐NULL. + * + * @param Context_len The length of the context data. + * + * @param algorithm The HMAC algorithm to use. + * + * @param KO A buffer to receive the derived key. + * + * @param KO_len The length of the key to be derived. + * + * @return NT_STATUS_OK on success, an NT status error code otherwise. + */ +NTSTATUS samba_gnutls_sp800_108_derive_key( + const uint8_t *KI, + size_t KI_len, + const uint8_t *FixedData, + size_t FixedData_len, + const uint8_t *Label, + size_t Label_len, + const uint8_t *Context, + size_t Context_len, + const gnutls_mac_algorithm_t algorithm, + uint8_t *KO, + size_t KO_len); + +#endif /* _GNUTLS_HELPERS_H */ |