From: Eric Biggers <ebiggers@kernel.org>
To: fstests@vger.kernel.org
Cc: linux-fscrypt@vger.kernel.org, Satya Tangirala <satyat@google.com>
Subject: [PATCH v2 1/5] fscrypt-crypt-util: create key_and_iv_params structure
Date: Mon, 2 Dec 2019 15:01:51 -0800 [thread overview]
Message-ID: <20191202230155.99071-2-ebiggers@kernel.org> (raw)
In-Reply-To: <20191202230155.99071-1-ebiggers@kernel.org>
From: Eric Biggers <ebiggers@google.com>
In preparation for adding 3 more input parameters to get_key_and_iv(),
create a structure to hold the input parameters so that the code doesn't
get too unwieldy.
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
src/fscrypt-crypt-util.c | 82 +++++++++++++++++++++-------------------
1 file changed, 44 insertions(+), 38 deletions(-)
diff --git a/src/fscrypt-crypt-util.c b/src/fscrypt-crypt-util.c
index f5fd8386..bafc15e0 100644
--- a/src/fscrypt-crypt-util.c
+++ b/src/fscrypt-crypt-util.c
@@ -1694,66 +1694,75 @@ static u8 parse_mode_number(const char *arg)
return num;
}
+struct key_and_iv_params {
+ u8 master_key[MAX_KEY_SIZE];
+ int master_key_size;
+ enum kdf_algorithm kdf;
+ u8 mode_num;
+ u8 file_nonce[FILE_NONCE_SIZE];
+ bool file_nonce_specified;
+};
+
/*
* Get the key and starting IV with which the encryption will actually be done.
* If a KDF was specified, a subkey is derived from the master key and the mode
* number or file nonce. Otherwise, the master key is used directly.
*/
-static void get_key_and_iv(const u8 *master_key, size_t master_key_size,
- enum kdf_algorithm kdf,
- u8 mode_num, const u8 nonce[FILE_NONCE_SIZE],
+static void get_key_and_iv(const struct key_and_iv_params *params,
u8 *real_key, size_t real_key_size,
struct fscrypt_iv *iv)
{
- bool nonce_in_iv = false;
+ bool file_nonce_in_iv = false;
struct aes_key aes_key;
u8 info[8 + 1 + FILE_NONCE_SIZE] = "fscrypt";
size_t infolen = 8;
size_t i;
- ASSERT(real_key_size <= master_key_size);
+ ASSERT(real_key_size <= params->master_key_size);
memset(iv, 0, sizeof(*iv));
- switch (kdf) {
+ switch (params->kdf) {
case KDF_NONE:
- if (mode_num != 0)
+ if (params->mode_num != 0)
die("--mode-num isn't supported with --kdf=none");
- memcpy(real_key, master_key, real_key_size);
- nonce_in_iv = true;
+ memcpy(real_key, params->master_key, real_key_size);
+ file_nonce_in_iv = true;
break;
case KDF_AES_128_ECB:
- if (nonce == NULL)
+ if (!params->file_nonce_specified)
die("--file-nonce is required with --kdf=AES-128-ECB");
- if (mode_num != 0)
+ if (params->mode_num != 0)
die("--mode-num isn't supported with --kdf=AES-128-ECB");
STATIC_ASSERT(FILE_NONCE_SIZE == AES_128_KEY_SIZE);
ASSERT(real_key_size % AES_BLOCK_SIZE == 0);
- aes_setkey(&aes_key, nonce, AES_128_KEY_SIZE);
+ aes_setkey(&aes_key, params->file_nonce, AES_128_KEY_SIZE);
for (i = 0; i < real_key_size; i += AES_BLOCK_SIZE)
- aes_encrypt(&aes_key, &master_key[i], &real_key[i]);
+ aes_encrypt(&aes_key, ¶ms->master_key[i],
+ &real_key[i]);
break;
case KDF_HKDF_SHA512:
- if (mode_num != 0) {
+ if (params->mode_num != 0) {
info[infolen++] = 3; /* HKDF_CONTEXT_PER_MODE_KEY */
- info[infolen++] = mode_num;
- nonce_in_iv = true;
- } else if (nonce != NULL) {
+ info[infolen++] = params->mode_num;
+ file_nonce_in_iv = true;
+ } else if (params->file_nonce_specified) {
info[infolen++] = 2; /* HKDF_CONTEXT_PER_FILE_KEY */
- memcpy(&info[infolen], nonce, FILE_NONCE_SIZE);
+ memcpy(&info[infolen], params->file_nonce,
+ FILE_NONCE_SIZE);
infolen += FILE_NONCE_SIZE;
} else {
die("With --kdf=HKDF-SHA512, at least one of --file-nonce and --mode-num must be specified");
}
- hkdf_sha512(master_key, master_key_size, NULL, 0,
- info, infolen, real_key, real_key_size);
+ hkdf_sha512(params->master_key, params->master_key_size,
+ NULL, 0, info, infolen, real_key, real_key_size);
break;
default:
ASSERT(0);
}
- if (nonce_in_iv && nonce != NULL)
- memcpy(&iv->bytes[8], nonce, FILE_NONCE_SIZE);
+ if (file_nonce_in_iv && params->file_nonce_specified)
+ memcpy(&iv->bytes[8], params->file_nonce, FILE_NONCE_SIZE);
}
enum {
@@ -1781,19 +1790,16 @@ int main(int argc, char *argv[])
{
size_t block_size = 4096;
bool decrypting = false;
- u8 _file_nonce[FILE_NONCE_SIZE];
- u8 *file_nonce = NULL;
- enum kdf_algorithm kdf = KDF_NONE;
- u8 mode_num = 0;
+ struct key_and_iv_params params;
size_t padding = 0;
const struct fscrypt_cipher *cipher;
- u8 master_key[MAX_KEY_SIZE];
- int master_key_size;
u8 real_key[MAX_KEY_SIZE];
struct fscrypt_iv iv;
char *tmp;
int c;
+ memset(¶ms, 0, sizeof(params));
+
aes_init();
#ifdef ENABLE_ALG_TESTS
@@ -1816,19 +1822,19 @@ int main(int argc, char *argv[])
decrypting = true;
break;
case OPT_FILE_NONCE:
- if (hex2bin(optarg, _file_nonce, FILE_NONCE_SIZE) !=
- FILE_NONCE_SIZE)
+ if (hex2bin(optarg, params.file_nonce, FILE_NONCE_SIZE)
+ != FILE_NONCE_SIZE)
die("Invalid file nonce: %s", optarg);
- file_nonce = _file_nonce;
+ params.file_nonce_specified = true;
break;
case OPT_HELP:
usage(stdout);
return 0;
case OPT_KDF:
- kdf = parse_kdf_algorithm(optarg);
+ params.kdf = parse_kdf_algorithm(optarg);
break;
case OPT_MODE_NUM:
- mode_num = parse_mode_number(optarg);
+ params.mode_num = parse_mode_number(optarg);
break;
case OPT_PADDING:
padding = strtoul(optarg, &tmp, 10);
@@ -1857,14 +1863,14 @@ int main(int argc, char *argv[])
die("Block size of %zu bytes is too small for cipher %s",
block_size, cipher->name);
- master_key_size = hex2bin(argv[1], master_key, MAX_KEY_SIZE);
- if (master_key_size < 0)
+ params.master_key_size = hex2bin(argv[1], params.master_key,
+ MAX_KEY_SIZE);
+ if (params.master_key_size < 0)
die("Invalid master_key: %s", argv[1]);
- if (master_key_size < cipher->keysize)
+ if (params.master_key_size < cipher->keysize)
die("Master key is too short for cipher %s", cipher->name);
- get_key_and_iv(master_key, master_key_size, kdf, mode_num, file_nonce,
- real_key, cipher->keysize, &iv);
+ get_key_and_iv(¶ms, real_key, cipher->keysize, &iv);
crypt_loop(cipher, real_key, &iv, decrypting, block_size, padding);
return 0;
--
2.24.0.393.g34dc348eaf-goog
next prev parent reply other threads:[~2019-12-02 23:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-02 23:01 [PATCH v2 0/5] xfstests: verify ciphertext of IV_INO_LBLK_64 encryption policies Eric Biggers
2019-12-02 23:01 ` Eric Biggers [this message]
2019-12-02 23:01 ` [PATCH v2 2/5] fscrypt-crypt-util: add HKDF context constants Eric Biggers
2019-12-02 23:01 ` [PATCH v2 3/5] common/encrypt: create named variables for UAPI constants Eric Biggers
2019-12-02 23:01 ` [PATCH v2 4/5] common/encrypt: support verifying ciphertext of IV_INO_LBLK_64 policies Eric Biggers
2019-12-02 23:01 ` [PATCH v2 5/5] generic: verify ciphertext of IV_INO_LBLK_64 encryption policies Eric Biggers
2019-12-09 18:18 ` [PATCH v2 0/5] xfstests: " Eric Biggers
2020-01-03 16:46 ` Eric Biggers
2020-01-06 2:55 ` Eryu Guan
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