diff options
Diffstat (limited to 'src/shared/openssl-util.c')
| -rw-r--r-- | src/shared/openssl-util.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/src/shared/openssl-util.c b/src/shared/openssl-util.c index c5566a6780..58e4ab02e9 100644 --- a/src/shared/openssl-util.c +++ b/src/shared/openssl-util.c @@ -237,6 +237,107 @@ int openssl_hmac_many( return 0; } +/* Symmetric Cipher encryption using the alg-bits-mode cipher, e.g. AES-128-CFB. The key is required and must + * be at least the minimum required key length for the cipher. The IV is optional but, if provided, it must + * be at least the minimum iv length for the cipher. If no IV is provided and the cipher requires one, a + * buffer of zeroes is used. Returns 0 on success, -EOPNOTSUPP if the cipher algorithm is not supported, or < + * 0 on any other error. */ +int openssl_cipher_many( + const char *alg, + size_t bits, + const char *mode, + const void *key, + size_t key_size, + const void *iv, + size_t iv_size, + const struct iovec data[], + size_t n_data, + void **ret, + size_t *ret_size) { + + assert(alg); + assert(bits > 0); + assert(mode); + assert(key); + assert(iv || iv_size == 0); + assert(data || n_data == 0); + assert(ret); + assert(ret_size); + + _cleanup_free_ char *cipher_alg = NULL; + if (asprintf(&cipher_alg, "%s-%zu-%s", alg, bits, mode) < 0) + return log_oom_debug(); + +#if OPENSSL_VERSION_MAJOR >= 3 + _cleanup_(EVP_CIPHER_freep) EVP_CIPHER *cipher = EVP_CIPHER_fetch(NULL, cipher_alg, NULL); +#else + const EVP_CIPHER *cipher = EVP_get_cipherbyname(cipher_alg); +#endif + if (!cipher) + return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), + "Cipher algorithm '%s' not supported.", cipher_alg); + + _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new(); + if (!ctx) + return log_openssl_errors("Failed to create new EVP_CIPHER_CTX"); + + /* Verify enough key data was provided. */ + int cipher_key_length = EVP_CIPHER_key_length(cipher); + assert(cipher_key_length >= 0); + if ((size_t) cipher_key_length > key_size) + return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), + "Not enough key bytes provided, require %d", cipher_key_length); + + /* Verify enough IV data was provided or, if no IV was provided, use a zeroed buffer for IV data. */ + int cipher_iv_length = EVP_CIPHER_iv_length(cipher); + assert(cipher_iv_length >= 0); + _cleanup_free_ void *zero_iv = NULL; + if (iv_size == 0) { + zero_iv = malloc0(cipher_iv_length); + if (!zero_iv) + return log_oom_debug(); + + iv = zero_iv; + iv_size = (size_t) cipher_iv_length; + } + if ((size_t) cipher_iv_length > iv_size) + return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), + "Not enough IV bytes provided, require %d", cipher_iv_length); + + if (!EVP_EncryptInit(ctx, cipher, key, iv)) + return log_openssl_errors("Failed to initialize EVP_CIPHER_CTX."); + + int cipher_block_size = EVP_CIPHER_CTX_block_size(ctx); + assert(cipher_block_size > 0); + + _cleanup_free_ uint8_t *buf = NULL; + size_t size = 0; + + for (size_t i = 0; i < n_data; i++) { + /* Cipher may produce (up to) input length + cipher block size of output. */ + if (!GREEDY_REALLOC(buf, size + data[i].iov_len + cipher_block_size)) + return log_oom_debug(); + + int update_size; + if (!EVP_EncryptUpdate(ctx, &buf[size], &update_size, data[i].iov_base, data[i].iov_len)) + return log_openssl_errors("Failed to update Cipher."); + + size += update_size; + } + + if (!GREEDY_REALLOC(buf, size + cipher_block_size)) + return log_oom_debug(); + + int final_size; + if (!EVP_EncryptFinal_ex(ctx, &buf[size], &final_size)) + return log_openssl_errors("Failed to finalize Cipher."); + + *ret = TAKE_PTR(buf); + *ret_size = size + final_size; + + return 0; +} + /* Perform Key-Based HMAC KDF. The mode must be "COUNTER" or "FEEDBACK". The parameter naming is from the * Openssl api, and maps to SP800-108 naming as "...key, salt, info, and seed correspond to KI, Label, * Context, and IV (respectively)...". The derive_size parameter specifies how many bytes are derived. |