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Add kernel backend for Bitlk key decryption.

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This commit is contained in:
Milan Broz
2019-11-09 21:59:53 +01:00
parent bb8088ca0f
commit 494d8ec04c
3 changed files with 73 additions and 12 deletions
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4
lib/crypto_backend/crypto_backend_internal.h
View File

@@ -55,5 +55,9 @@ int crypt_cipher_decrypt_kernel(struct crypt_cipher_kernel *ctx,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length);
void crypt_cipher_destroy_kernel(struct crypt_cipher_kernel *ctx);
int crypt_bitlk_decrypt_key_kernel(const void *key, size_t key_length,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length,
const char *tag, size_t tag_length);
#endif /* _CRYPTO_BACKEND_INTERNAL_H */

78
lib/crypto_backend/crypto_cipher_kernel.c
View File

@@ -49,7 +49,7 @@
*/
static int _crypt_cipher_init(struct crypt_cipher_kernel *ctx,
const void *key, size_t key_length,
struct sockaddr_alg *sa)
size_t tag_length, struct sockaddr_alg *sa)
{
if (!ctx)
return -EINVAL;
@@ -71,6 +71,11 @@ static int _crypt_cipher_init(struct crypt_cipher_kernel *ctx,
return -EINVAL;
}
if (tag_length && setsockopt(ctx->tfmfd, SOL_ALG, ALG_SET_AEAD_AUTHSIZE, NULL, tag_length) < 0) {
crypt_cipher_destroy_kernel(ctx);
return -EINVAL;
}
ctx->opfd = accept(ctx->tfmfd, NULL, 0);
if (ctx->opfd < 0) {
crypt_cipher_destroy_kernel(ctx);
@@ -93,12 +98,13 @@ int crypt_cipher_init_kernel(struct crypt_cipher_kernel *ctx, const char *name,
snprintf((char *)sa.salg_name, sizeof(sa.salg_name), "%s(%s)", mode, name);
return _crypt_cipher_init(ctx, key, key_length, &sa);
return _crypt_cipher_init(ctx, key, key_length, 0, &sa);
}
/* The in/out should be aligned to page boundary */
static int _crypt_cipher_crypt(struct crypt_cipher_kernel *ctx,
const char *in, char *out, size_t length,
const char *in, size_t in_length,
char *out, size_t out_length,
const char *iv, size_t iv_length,
uint32_t direction)
{
@@ -109,7 +115,7 @@ static int _crypt_cipher_crypt(struct crypt_cipher_kernel *ctx,
uint32_t *type;
struct iovec iov = {
.iov_base = (void*)(uintptr_t)in,
.iov_len = length,
.iov_len = in_length,
};
int iv_msg_size = iv ? CMSG_SPACE(sizeof(*alg_iv) + iv_length) : 0;
char buffer[CMSG_SPACE(sizeof(*type)) + iv_msg_size];
@@ -120,7 +126,7 @@ static int _crypt_cipher_crypt(struct crypt_cipher_kernel *ctx,
.msg_iovlen = 1,
};
if (!in || !out || !length)
if (!in || !out || !in_length)
return -EINVAL;
if ((!iv && iv_length) || (iv && !iv_length))
@@ -151,13 +157,13 @@ static int _crypt_cipher_crypt(struct crypt_cipher_kernel *ctx,
}
len = sendmsg(ctx->opfd, &msg, 0);
if (len != (ssize_t)length) {
if (len != (ssize_t)(in_length)) {
r = -EIO;
goto bad;
}
len = read(ctx->opfd, out, length);
if (len != (ssize_t)length)
len = read(ctx->opfd, out, out_length);
if (len != (ssize_t)out_length)
r = -EIO;
bad:
crypt_backend_memzero(buffer, sizeof(buffer));
@@ -168,7 +174,7 @@ int crypt_cipher_encrypt_kernel(struct crypt_cipher_kernel *ctx,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length)
{
return _crypt_cipher_crypt(ctx, in, out, length,
return _crypt_cipher_crypt(ctx, in, length, out, length,
iv, iv_length, ALG_OP_ENCRYPT);
}
@@ -176,7 +182,7 @@ int crypt_cipher_decrypt_kernel(struct crypt_cipher_kernel *ctx,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length)
{
return _crypt_cipher_crypt(ctx, in, out, length,
return _crypt_cipher_crypt(ctx, in, length, out, length,
iv, iv_length, ALG_OP_DECRYPT);
}
@@ -243,13 +249,56 @@ int crypt_cipher_check_kernel(const char *name, const char *mode,
memset(key, 0xab, key_length);
*key = 0xef;
r = _crypt_cipher_init(&c, key, key_length, &sa);
r = _crypt_cipher_init(&c, key, key_length, 0, &sa);
crypt_cipher_destroy_kernel(&c);
free(key);
return r;
}
int crypt_bitlk_decrypt_key_kernel(const void *key, size_t key_length,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length,
const char *tag, size_t tag_length)
{
struct crypt_cipher_kernel c;
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "aead",
.salg_name = "ccm(aes)",
};
int r;
char buffer[128], ccm_iv[16];
if (length + tag_length > sizeof(buffer))
return -EINVAL;
if (iv_length > sizeof(ccm_iv) - 1)
return -EINVAL;
r = _crypt_cipher_init(&c, key, key_length, tag_length, &sa);
if (r < 0)
return r;
memcpy(buffer, in, length);
memcpy(buffer + length, tag, tag_length);
/* CCM IV - RFC3610 */
memset(ccm_iv, 0, sizeof(ccm_iv));
ccm_iv[0] = 15 - iv_length - 1;
memcpy(ccm_iv + 1, iv, iv_length);
memset(ccm_iv + 1 + iv_length, 0, ccm_iv[0] + 1);
iv_length = sizeof(ccm_iv);
r = _crypt_cipher_crypt(&c, buffer, length + tag_length, out, length,
ccm_iv, iv_length, ALG_OP_DECRYPT);
crypt_cipher_destroy_kernel(&c);
crypt_backend_memzero(buffer, sizeof(buffer));
return r;
}
#else /* ENABLE_AF_ALG */
int crypt_cipher_init_kernel(struct crypt_cipher_kernel *ctx, const char *name,
const char *mode, const void *key, size_t key_length)
@@ -280,4 +329,11 @@ int crypt_cipher_check_kernel(const char *name, const char *mode,
/* Cannot check, expect success. */
return 0;
}
int crypt_bitlk_decrypt_key_kernel(const void *key, size_t key_length,
const char *in, char *out, size_t length,
const char *iv, size_t iv_length,
const char *tag, size_t tag_length)
{
return -ENOTSUP;
}
#endif

3
lib/crypto_backend/crypto_kernel.c
View File

@@ -398,5 +398,6 @@ int crypt_bitlk_decrypt_key(const void *key, size_t key_length,
const char *iv, size_t iv_length,
const char *tag, size_t tag_length)
{
return -ENOTSUP;
return crypt_bitlk_decrypt_key_kernel(key, key_length, in, out, length,
iv, iv_length, tag, tag_length);
}