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ntfs-3g/ntfsprogs/decrypt.c

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/*
* decrypt.c - $EFS decryption routines. Part of the Linux-NTFS project.
*
* Copyright (c) 2005 Yuval Fledel
* Copyright (c) 2005 Anton Altaparmakov
*
* 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 2 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 (in the main directory of the Linux-NTFS distribution
* in the file COPYING); if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include <stdio.h>
#include <errno.h>
#include <gcrypt.h>
#include <openssl/md5.h>
#include "decrypt.h"
#ifdef __CYGWIN__
#define _WIN32_WINNT 0x501
#define WINVER 0x501
#include <windows.h>
#include <wincrypt.h>
/* Missing cygwin macros */
#ifndef CERT_SYSTEM_STORE_CURRENT_USER
#define CERT_SYSTEM_STORE_CURRENT_USER 0x00010000
#endif
#ifndef CERT_CLOSE_STORE_CHECK_FLAG
#define CERT_CLOSE_STORE_CHECK_FLAG 2
#endif
#ifndef CRYPT_ACQUIRE_CACHE_FLAG
#define CRYPT_ACQUIRE_CACHE_FLAG 1
#endif
/* Windows 2k+ imports. */
typedef BOOL(WINAPI *LPFN_CryptAcquireCertificatePrivateKey)(PCCERT_CONTEXT,
DWORD, void *, HCRYPTPROV *, DWORD *, BOOL *);
typedef BOOL(WINAPI *LPFN_CertCloseStore)(HCERTSTORE, DWORD);
typedef PCCERT_CONTEXT(WINAPI *LPFN_CertFindCertificateInStore)(HCERTSTORE,
DWORD, DWORD, DWORD, const void *, PCCERT_CONTEXT);
typedef BOOL(WINAPI *LPFN_CertFreeCertificateContext)(PCCERT_CONTEXT);
typedef HCERTSTORE(WINAPI *LPFN_CertOpenStore)(LPCSTR, DWORD, HCRYPTPROV,
DWORD, const void *);
// NT4SP3+ WINME or 95+ w/ IE5+
static LPFN_CryptAcquireCertificatePrivateKey
fnCryptAcquireCertificatePrivateKey;
// osr2+ NT4SP3+ or NT4 w/ IE3.02:
static LPFN_CertCloseStore fnCertCloseStore;
static LPFN_CertFindCertificateInStore fnCertFindCertificateInStore;
static LPFN_CertFreeCertificateContext fnCertFreeCertificateContext;
static LPFN_CertOpenStore fnCertOpenStore;
/* Global variable: Handle to crypt32.dll */
static HMODULE hCrypt32 = INVALID_HANDLE_VALUE;
#else /* !defined(__CYGWIN__) */
#include <malloc.h>
#include <string.h>
#define CALG_DES (0x6601)
/* If not one of the below three, fall back to standard Des. */
#define CALG_3DES (0x6603)
#define CALG_DESX (0x6604)
#define CALG_AES_256 (0x6610)
#endif /* !defined(__CYGWIN__) */
/* This must be after windows.h include. */
#include "types.h"
typedef struct {
#ifdef __CYGWIN__
HCERTSTORE hSystemStore;
#else /* !defined(__CYGWIN__) */
int nothing; /* unused */
#endif /* !defined(__CYGWIN__) */
} NTFS_DECRYPT_USER_KEY_SESSION;
typedef struct {
gcry_sexp_t sexp_key; // the user's RSA key.
} NTFS_DECRYPT_USER_KEY;
typedef struct {
u8 *key_data;
u32 alg_id;
gcry_cipher_hd_t gcry_cipher_hd;
gcry_cipher_hd_t *des_gcry_cipher_hd_ptr;
} NTFS_DECRYPT_DATA_KEY;
/* DESX-MS128 implementation for libgcrypt. */
static gcry_module_t ntfs_desx_module;
static int ntfs_desx_algorithm_id = -1;
static int ntfs_desx_module_count;
typedef struct {
u64 in_whitening, out_whitening;
gcry_cipher_hd_t gcry_cipher_hd;
} ntfs_desx_ctx;
#ifdef __CYGWIN__
static int cryptoAPI_init_imports(void)
{
if (hCrypt32 == INVALID_HANDLE_VALUE)
hCrypt32 = LoadLibrary("crypt32.dll");
if (!fnCryptAcquireCertificatePrivateKey)
fnCryptAcquireCertificatePrivateKey =
(LPFN_CryptAcquireCertificatePrivateKey)
GetProcAddress(hCrypt32,
"CryptAcquireCertificatePrivateKey");
if (!fnCertCloseStore)
fnCertCloseStore = (LPFN_CertCloseStore)
GetProcAddress(hCrypt32, "CertCloseStore");
if (!fnCertFindCertificateInStore)
fnCertFindCertificateInStore = (LPFN_CertFindCertificateInStore)
GetProcAddress(hCrypt32,
"CertFindCertificateInStore");
if (!fnCertFreeCertificateContext)
fnCertFreeCertificateContext = (LPFN_CertFreeCertificateContext)
GetProcAddress(hCrypt32,
"CertFreeCertificateContext");
if (!fnCertOpenStore)
fnCertOpenStore = (LPFN_CertOpenStore)GetProcAddress(hCrypt32,
"CertOpenStore");
return fnCryptAcquireCertificatePrivateKey && fnCertCloseStore &&
fnCertFindCertificateInStore &&
fnCertFreeCertificateContext && fnCertOpenStore;
}
#endif /* defined(__CYGWIN__) */
ntfs_decrypt_user_key_session *ntfs_decrypt_user_key_session_open(void)
{
ntfs_decrypt_user_key_session *session;
#ifdef __CYGWIN__
HCERTSTORE hSystemStore;
/*
* FIXME: This really needs locking and reference counting so it is
* safe from races.
*/
if (!cryptoAPI_init_imports()) {
fprintf(stderr, "Some imports do not exist.\n");
errno = EINVAL;
return NULL;
}
if (!(hSystemStore = fnCertOpenStore(((LPCSTR)CERT_STORE_PROV_SYSTEM),
0, 0, CERT_SYSTEM_STORE_CURRENT_USER, L"MY"))) {
fprintf(stderr, "Could not open system store.\n");
errno = EINVAL;
return NULL;
}
#endif /* defined(__CYGWIN__) */
session = malloc(sizeof(NTFS_DECRYPT_USER_KEY_SESSION));
#ifdef __CYGWIN__
((NTFS_DECRYPT_USER_KEY_SESSION*)session)->hSystemStore = hSystemStore;
#endif /* defined(__CYGWIN__) */
gcry_control(GCRYCTL_DISABLE_SECMEM, 0);
return session;
}
void ntfs_decrypt_user_key_session_close(ntfs_decrypt_user_key_session *session)
{
#ifdef __CYGWIN__
HMODULE tmp;
if (((NTFS_DECRYPT_USER_KEY_SESSION*)session)->hSystemStore)
fnCertCloseStore(((NTFS_DECRYPT_USER_KEY_SESSION*)session)->
hSystemStore, CERT_CLOSE_STORE_CHECK_FLAG);
/*
* FIXME: This really needs locking and reference counting so it is
* safe from races.
*/
tmp = hCrypt32;
hCrypt32 = INVALID_HANDLE_VALUE;
FreeLibrary(tmp);
#endif /* defined(__CYGWIN__) */
free(session);
}
/**
* reverse_buffer -
*
* This is a utility function for reversing the order of a buffer in place.
* Users of this function should be very careful not to sweep byte order
* problems under the rug.
*/
static inline void reverse_buffer(unsigned char *buf, unsigned buf_size)
{
unsigned char t;
unsigned i;
for (i = 0; i < buf_size / 2; i++) {
t = buf[i];
buf[i] = buf[buf_size - i - 1];
buf[buf_size - i - 1] = t;
}
}
ntfs_decrypt_user_key *ntfs_decrypt_user_key_open(
ntfs_decrypt_user_key_session *session __attribute__((unused)),
unsigned char *thumb_print, unsigned thumb_size)
{
#ifdef __CYGWIN__
CRYPT_HASH_BLOB hash_blob;
HCRYPTPROV hCryptProv;
PCCERT_CONTEXT pCert;
BOOL fCallerFreeProv;
HCRYPTKEY hCryptKey;
ntfs_decrypt_user_key *key;
DWORD dwKeySpec;
DWORD key_size;
BYTE key_blob[1000];
RSAPUBKEY *rsa_pub_key;
gcry_ac_handle_t gcry_handle;
unsigned char *mpi_data;
gcry_mpi_t n, e, d, p, q, u;
gcry_sexp_t sexp_key;
gcry_error_t err;
size_t size;
int rc;
hash_blob.cbData = thumb_size;
hash_blob.pbData = thumb_print;
if (!(pCert = fnCertFindCertificateInStore(
((NTFS_DECRYPT_USER_KEY_SESSION*)session)->hSystemStore,
(PKCS_7_ASN_ENCODING | X509_ASN_ENCODING), 0,
CERT_FIND_HASH, &hash_blob, NULL))) {
fprintf(stderr, "Could not find cert in store.\n");
goto decrypt_key_open_err;
}
dwKeySpec = AT_KEYEXCHANGE;
if (!fnCryptAcquireCertificatePrivateKey(pCert,
CRYPT_ACQUIRE_CACHE_FLAG, NULL, &hCryptProv,
&dwKeySpec, &fCallerFreeProv)) {
fprintf(stderr, "Could not aquire private key from cert.\n");
goto decrypt_key_open_err;
}
if (!CryptGetUserKey(hCryptProv, AT_KEYEXCHANGE, &hCryptKey)) {
fprintf(stderr, "Could not aquire user key.\n");
goto decrypt_key_open_err;
}
key_size = sizeof(key_blob);
if (!CryptExportKey(hCryptKey, 0, PRIVATEKEYBLOB, 0, key_blob,
&key_size)) {
fprintf(stderr, "Could not export key: Error 0x%x\n",
(unsigned)GetLastError());
errno = EINVAL;
return NULL;
}
CryptDestroyKey(hCryptKey);
rsa_pub_key = (RSAPUBKEY*)(key_blob + sizeof(PUBLICKEYSTRUC));
if ((err = gcry_ac_open(&gcry_handle, GCRY_AC_RSA, 0))) {
fprintf(stderr, "Could not init gcrypt handle\n");
errno = EINVAL;
return NULL;
}
gcry_control(GCRYCTL_DISABLE_SECMEM, 0);
e = gcry_mpi_set_ui(NULL, rsa_pub_key->pubexp);
mpi_data = (key_blob + 0x14);
size = rsa_pub_key->bitlen / 8;
reverse_buffer(mpi_data, size);
if ((rc = gcry_mpi_scan(&n, GCRYMPI_FMT_USG, mpi_data, size, &size)))
fprintf(stderr, "error scanning n.\n");
mpi_data += (rsa_pub_key->bitlen / 8);
size = rsa_pub_key->bitlen / 16;
reverse_buffer(mpi_data, size);
if ((rc = gcry_mpi_scan(&q, GCRYMPI_FMT_USG, mpi_data, size, &size)))
fprintf(stderr, "error scanning p.\n");
mpi_data += (rsa_pub_key->bitlen / 16);
size = rsa_pub_key->bitlen / 16;
reverse_buffer(mpi_data, size);
if ((rc = gcry_mpi_scan(&p, GCRYMPI_FMT_USG, mpi_data, size, &size)))
fprintf(stderr, "error scanning q.\n");
mpi_data += (rsa_pub_key->bitlen / 16) * 3;
size = rsa_pub_key->bitlen / 16;
reverse_buffer(mpi_data, size);
if ((rc = gcry_mpi_scan(&u, GCRYMPI_FMT_USG, mpi_data, size, &size)))
fprintf(stderr, "error scanning u.\n");
mpi_data += (rsa_pub_key->bitlen / 16);
size = rsa_pub_key->bitlen / 8;
reverse_buffer(mpi_data, size);
if ((rc = gcry_mpi_scan(&d, GCRYMPI_FMT_USG, mpi_data, size, &size)))
fprintf(stderr, "error scanning d.\n");
sexp_key = NULL;
if ((rc = gcry_sexp_build(&sexp_key, NULL, "(private-key (rsa (n %m) "
"(e %m) (d %m) (p %m) (q %m) (u %m)))", n, e, d, p, q,
u))) {
fprintf(stderr, "Could build sexp from data, (error = 0x%x)\n",
rc);
errno = EINVAL;
return NULL;
}
if ((key = (ntfs_decrypt_user_key*)
malloc(sizeof(NTFS_DECRYPT_USER_KEY))))
((NTFS_DECRYPT_USER_KEY*)key)->sexp_key = sexp_key;
// todo: release all
return key;
decrypt_key_open_err:
if (hCryptKey)
CryptDestroyKey(hCryptKey);
if (pCert)
fnCertFreeCertificateContext(pCert);
errno = EINVAL;
#else /* !defined(__CYGWIN__) */
errno = EOPNOTSUPP;
#endif /* !defined(__CYGWIN__) */
return NULL;
}
void ntfs_decrypt_user_key_close(ntfs_decrypt_user_key *key)
{
gcry_sexp_release(((NTFS_DECRYPT_USER_KEY*)key)->sexp_key);
free(key);
}
/**
* warning: decrypting into the input buffer!
*/
unsigned ntfs_decrypt_user_key_decrypt(ntfs_decrypt_user_key *key,
unsigned char *data, unsigned data_size)
{
gcry_sexp_t sexp_plain_data, sexp_enc_data;
gcry_ac_handle_t gcry_handle;
gcry_mpi_t mpi_buf;
gcry_ac_data_t in;
gcry_error_t err;
unsigned size, padding_length, i;
int rc;
if ((err = gcry_ac_open(&gcry_handle, GCRY_AC_RSA, 0))) {
fprintf(stderr, "Could not init gcrypt handle\n");
errno = EINVAL;
return 0;
}
if ((rc = gcry_ac_data_new(&in)))
fprintf(stderr, "error allocating 'in'.\n");
reverse_buffer(data, data_size);
size = data_size;
if ((rc = gcry_mpi_scan(&mpi_buf, GCRYMPI_FMT_USG, data,
(size_t)data_size, &size)))
fprintf(stderr, "error scanning 'in'.\n");
if ((rc = gcry_sexp_build(&sexp_enc_data, &size, "(enc-val (flags) "
"(rsa (a %m)))", mpi_buf))) {
fprintf(stderr, "Could build sexp from data, (error = 0x%x)\n",
rc);
errno = EINVAL;
return 0;
}
if ((rc = gcry_pk_decrypt(&sexp_plain_data, sexp_enc_data,
((NTFS_DECRYPT_USER_KEY*)key)->sexp_key))) {
fprintf(stderr, "Could not decrypt fek via s-exp, (error = "
"0x%x)\n", rc);
errno = EINVAL;
return 0;
}
sexp_plain_data = gcry_sexp_find_token(sexp_plain_data, "value", 0);
if (!mpi_buf) {
fprintf(stderr, "Could find value in s-exp, (error = 0x%x)\n",
rc);
errno = EINVAL;
return 0;
}
mpi_buf = gcry_sexp_nth_mpi(sexp_plain_data, 1, GCRYMPI_FMT_USG);
if ((rc = gcry_mpi_print(GCRYMPI_FMT_USG, data, data_size, &size,
mpi_buf))) {
fprintf(stderr, "Could copy decrypted data back, (error = "
"0x%x)\n", rc);
errno = EINVAL;
return 0;
}
// remove the pkcs1 padding
for (padding_length = 1; (padding_length < size) &&
data[padding_length]; padding_length++)
;
padding_length++;
// todo: should memcpy fit? (overlapping)
for (i = 0; i + padding_length < size; i++)
data[i] = data[padding_length + i];
// todo: mpi_buf->data
// todo: release all
gcry_ac_data_destroy(in);
return size - padding_length;
}
#if 0
// This is the old code based on OpenSSL. Please do not remove it. AIA
/**
* ntfs_desx_key_expand - expand a 128-bit desx key to the needed 192-bit key
* @src: source buffer containing 128-bit key
*
* Expands the on-disk 128-bit desx key to the needed des key, the in-, and the
* out-whitening keys required to perform desx {de,en}cryption.
*/
static void ntfs_desx_key_expand(const u8 *src, u32 *des_key,
u64 *out_whitening, u64 *in_whitening)
{
static const int salt_len = 12;
static const u8 *salt1 = "Dan Simon ";
static const u8 *salt2 = "Scott Field";
u32 md[4];
MD5_CTX ctx1, ctx2;
MD5_Init(&ctx1);
/* Hash the on-disk key. */
MD5_Update(&ctx1, src, 128 / 8);
memcpy(&ctx2, &ctx1, sizeof(ctx1));
/* Hash with the first salt and store the result. */
MD5_Update(&ctx1, salt1, salt_len);
MD5_Final((u8*)md, &ctx1);
des_key[0] = md[0] ^ md[1];
des_key[1] = md[2] ^ md[3];
/* Hash with the second salt and store the result. */
MD5_Update(&ctx2, salt2, salt_len);
MD5_Final((u8*)md, &ctx2);
*out_whitening = *(u64*)md;
*in_whitening = *(u64*)(md + 2);
}
#endif
/**
* ntfs_desx_key_expand - expand a 128-bit desx key to the needed 192-bit key
* @src: source buffer containing 128-bit key
*
* Expands the on-disk 128-bit desx key to the needed des key, the in-, and the
* out-whitening keys required to perform desx {de,en}cryption.
*/
static gcry_error_t ntfs_desx_key_expand(const u8 *src, u32 *des_key,
u64 *out_whitening, u64 *in_whitening)
{
static const u8 *salt1 = "Dan Simon ";
static const u8 *salt2 = "Scott Field";
static const int salt_len = 12;
gcry_md_hd_t hd1, hd2;
u32 *md;
gcry_error_t err;
err = gcry_md_open(&hd1, GCRY_MD_MD5, 0);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to open MD5 digest.\n");
return err;
}
/* Hash the on-disk key. */
gcry_md_write(hd1, src, 128 / 8);
/* Copy the current hash for efficiency. */
err = gcry_md_copy(&hd2, hd1);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to copy MD5 digest object.\n");
goto out;
}
/* Hash with the first salt and store the result. */
gcry_md_write(hd1, salt1, salt_len);
md = (u32*)gcry_md_read(hd1, 0);
des_key[0] = md[0] ^ md[1];
des_key[1] = md[2] ^ md[3];
/* Hash with the second salt and store the result. */
gcry_md_write(hd2, salt2, salt_len);
md = (u32*)gcry_md_read(hd2, 0);
*out_whitening = *(u64*)md;
*in_whitening = *(u64*)(md + 2);
gcry_md_close(hd2);
out:
gcry_md_close(hd1);
return err;
}
/**
* ntfs_desx_setkey - libgcrypt set_key implementation for DES-X-MS128
* @context: pointer to a variable of type ntfs_desx_ctx
* @key: the 128 bit DES-X-MS128 key, concated with the DES handle
* @keylen: must always be 16
*
* This is the libgcrypt set_key implementation for DES-X-MS128.
*/
static gcry_err_code_t ntfs_desx_setkey(void *context, const u8 *key,
unsigned keylen)
{
ntfs_desx_ctx *ctx = context;
gcry_error_t err;
u8 des_key[8];
if (keylen != 16) {
fprintf(stderr, "Key length for desx must be 16.\n");
return GPG_ERR_INV_KEYLEN;
}
err = gcry_cipher_open(&ctx->gcry_cipher_hd, GCRY_CIPHER_DES,
GCRY_CIPHER_MODE_ECB, 0);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to open des cipher (error 0x%x).\n",
err);
return err;
}
err = ntfs_desx_key_expand(key, (u32*)des_key, &ctx->out_whitening,
&ctx->in_whitening);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to expand desx key (error 0x%x).\n",
err);
gcry_cipher_close(ctx->gcry_cipher_hd);
return err;
}
err = gcry_cipher_setkey(ctx->gcry_cipher_hd, des_key, sizeof(des_key));
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to set des key (error 0x%x).\n", err);
gcry_cipher_close(ctx->gcry_cipher_hd);
return err;
}
/*
* Take a note of the ctx->gcry_cipher_hd since we need to close it at
* ntfs_decrypt_data_key_close() time.
*/
**(gcry_cipher_hd_t***)(key + ((keylen + 7) & ~7)) =
&ctx->gcry_cipher_hd;
return GPG_ERR_NO_ERROR;
}
static void ntfs_desx_decrypt(void *context, u8 *outbuf, const u8 *inbuf)
{
ntfs_desx_ctx *ctx = context;
gcry_error_t err;
err = gcry_cipher_reset(ctx->gcry_cipher_hd);
if (err != GPG_ERR_NO_ERROR)
fprintf(stderr, "Failed to reset des cipher (error 0x%x).\n",
err);
*(u64*)outbuf = *(const u64*)inbuf ^ ctx->out_whitening;
err = gcry_cipher_encrypt(ctx->gcry_cipher_hd, outbuf, 8, NULL, 0);
if (err != GPG_ERR_NO_ERROR)
fprintf(stderr, "Des decryption failed (error 0x%x).\n", err);
*(u64*)outbuf ^= ctx->in_whitening;
}
static gcry_cipher_spec_t ntfs_desx_cipher = {
.name = "DES-X-MS128",
.blocksize = 8,
.keylen = 128,
.contextsize = sizeof(ntfs_desx_ctx),
.setkey = ntfs_desx_setkey,
.decrypt = ntfs_desx_decrypt,
};
//#define DO_CRYPTO_TESTS 1
#ifdef DO_CRYPTO_TESTS
/* Do not remove this test code from this file! AIA */
static BOOL ntfs_desx_key_expand_test(void)
{
const u8 known_desx_on_disk_key[16] = {
0xa1, 0xf9, 0xe0, 0xb2, 0x53, 0x23, 0x9e, 0x8f,
0x0f, 0x91, 0x45, 0xd9, 0x8e, 0x20, 0xec, 0x30
};
const u8 known_des_key[8] = {
0x27, 0xd1, 0x93, 0x09, 0xcb, 0x78, 0x93, 0x1f,
};
const u8 known_out_whitening[8] = {
0xed, 0xda, 0x4c, 0x47, 0x60, 0x49, 0xdb, 0x8d,
};
const u8 known_in_whitening[8] = {
0x75, 0xf6, 0xa0, 0x1a, 0xc0, 0xca, 0x28, 0x1e
};
u64 test_out_whitening, test_in_whitening;
union {
u64 u64;
u32 u32[2];
} test_des_key;
gcry_error_t err;
BOOL res;
err = ntfs_desx_key_expand(known_desx_on_disk_key, test_des_key.u32,
&test_out_whitening, &test_in_whitening);
if (err != GPG_ERR_NO_ERROR)
res = FALSE;
else
res = test_des_key.u64 == *(u64*)known_des_key &&
test_out_whitening ==
*(u64*)known_out_whitening &&
test_in_whitening ==
*(u64*)known_in_whitening;
fprintf(stderr, "Testing whether ntfs_desx_key_expand() works: %s\n",
res ? "SUCCESS" : "FAILED");
return res;
}
static BOOL ntfs_des_test(void)
{
const u8 known_des_key[8] = {
0x27, 0xd1, 0x93, 0x09, 0xcb, 0x78, 0x93, 0x1f
};
const u8 known_des_encrypted_data[8] = {
0xdc, 0xf7, 0x68, 0x2a, 0xaf, 0x48, 0x53, 0x0f
};
const u8 known_decrypted_data[8] = {
0xd8, 0xd9, 0x15, 0x23, 0x5b, 0x88, 0x0e, 0x09
};
u8 test_decrypted_data[8];
int res;
gcry_error_t err;
gcry_cipher_hd_t gcry_cipher_hd;
err = gcry_cipher_open(&gcry_cipher_hd, GCRY_CIPHER_DES,
GCRY_CIPHER_MODE_ECB, 0);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to open des cipher (error 0x%x).\n",
err);
return FALSE;
}
err = gcry_cipher_setkey(gcry_cipher_hd, known_des_key,
sizeof(known_des_key));
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to set des key (error 0x%x.\n", err);
gcry_cipher_close(gcry_cipher_hd);
return FALSE;
}
/*
* Apply DES decryption (ntfs actually uses encryption when decrypting).
*/
err = gcry_cipher_encrypt(gcry_cipher_hd, test_decrypted_data,
sizeof(test_decrypted_data), known_des_encrypted_data,
sizeof(known_des_encrypted_data));
gcry_cipher_close(gcry_cipher_hd);
if (err) {
fprintf(stderr, "Failed to des decrypt test data (error "
"0x%x).\n", err);
return FALSE;
}
res = !memcmp(test_decrypted_data, known_decrypted_data,
sizeof(known_decrypted_data));
fprintf(stderr, "Testing whether des decryption works: %s\n",
res ? "SUCCESS" : "FAILED");
return res;
}
#else /* !defined(DO_CRYPTO_TESTS) */
static inline BOOL ntfs_desx_key_expand_test(void)
{
return TRUE;
}
static inline BOOL ntfs_des_test(void)
{
return TRUE;
}
#endif /* !defined(DO_CRYPTO_TESTS) */
ntfs_decrypt_data_key *ntfs_decrypt_data_key_open(unsigned char *data,
unsigned data_size __attribute__((unused)))
{
NTFS_DECRYPT_DATA_KEY *key;
unsigned key_size, wanted_key_size, gcry_algo;
gcry_error_t err;
key_size = *(u32*)data;
key = (NTFS_DECRYPT_DATA_KEY*)malloc(((((sizeof(*key) + 7) & ~7) +
key_size + 7) & ~7) + sizeof(gcry_cipher_hd_t));
if (!key) {
errno = ENOMEM;
return NULL;
}
key->alg_id = *(u32*)(data + 8);
key->key_data = (u8*)key + ((sizeof(*key) + 7) & ~7);
memcpy(key->key_data, data + 16, key_size);
key->des_gcry_cipher_hd_ptr = NULL;
*(gcry_cipher_hd_t***)(key->key_data + ((key_size + 7) & ~7)) =
&key->des_gcry_cipher_hd_ptr;
gcry_control(GCRYCTL_DISABLE_SECMEM, 0);
switch (key->alg_id) {
case CALG_DESX:
/* FIXME: This really needs locking so it is safe from races. */
if (!ntfs_desx_module_count++) {
if (!ntfs_desx_key_expand_test() || !ntfs_des_test()) {
errno = EINVAL;
return NULL;
}
err = gcry_cipher_register(&ntfs_desx_cipher,
&ntfs_desx_algorithm_id,
&ntfs_desx_module);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "Failed to register desx "
"cipher (error 0x%x).\n", err);
errno = EINVAL;
return NULL;
}
}
wanted_key_size = 16;
gcry_algo = ntfs_desx_algorithm_id;
break;
case CALG_3DES:
wanted_key_size = 24;
gcry_algo = GCRY_CIPHER_3DES;
break;
case CALG_AES_256:
wanted_key_size = 32;
gcry_algo = GCRY_CIPHER_AES256;
break;
default:
wanted_key_size = 8;
gcry_algo = GCRY_CIPHER_DES;
fprintf(stderr, "DES is not supported at present. Please "
"email linux-ntfs-dev@lists.sourceforge.net "
"and say that you saw this message. We will "
"then implement support for DES.\n");
free(key);
errno = EOPNOTSUPP;
return NULL;
}
if (key_size != wanted_key_size) {
fprintf(stderr, "%s key of %u bytes but needed size is %u "
"bytes, assuming corrupt key. Aborting.\n",
gcry_cipher_algo_name(gcry_algo), key_size,
wanted_key_size);
free(key);
errno = EIO;
return NULL;
}
err = gcry_cipher_open(&key->gcry_cipher_hd, gcry_algo,
GCRY_CIPHER_MODE_CBC, 0);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "gcry_cipher_open() failed with error 0x%x.\n",
err);
free(key);
errno = EINVAL;
return 0;
}
err = gcry_cipher_setkey(key->gcry_cipher_hd, key->key_data, key_size);
if (err != GPG_ERR_NO_ERROR) {
fprintf(stderr, "gcry_cipher_setkey() failed with error "
"0x%x.\n", err);
gcry_cipher_close(key->gcry_cipher_hd);
free(key);
errno = EINVAL;
return NULL;
}
return (ntfs_decrypt_data_key*)key;
}
void ntfs_decrypt_data_key_close(ntfs_decrypt_data_key *key)
{
NTFS_DECRYPT_DATA_KEY *dkey = (NTFS_DECRYPT_DATA_KEY*)key;
if (dkey->des_gcry_cipher_hd_ptr)
gcry_cipher_close(*dkey->des_gcry_cipher_hd_ptr);
gcry_cipher_close(dkey->gcry_cipher_hd);
free(key);
/* FIXME: This really needs locking so it is safe from races. */
if (!--ntfs_desx_module_count) {
gcry_cipher_unregister(ntfs_desx_module);
ntfs_desx_module = NULL;
ntfs_desx_algorithm_id = -1;
}
}
unsigned ntfs_decrypt_data_key_decrypt_sector(ntfs_decrypt_data_key *key,
unsigned char *data, unsigned long long offset)
{
NTFS_DECRYPT_DATA_KEY *dkey = (NTFS_DECRYPT_DATA_KEY*)key;
gcry_error_t err;
err = gcry_cipher_reset(dkey->gcry_cipher_hd);
if (err != GPG_ERR_NO_ERROR)
fprintf(stderr, "Failed to reset cipher (error 0x%x).\n", err);
/*
* Note: You may wonder why are we not calling gcry_cipher_setiv() here
* instead of doing it by hand after the decryption. The answer is
* that gcry_cipher_setiv() wants an iv of length 8 bytes but we give
* it a length of 16 for AES256 so it does not like it.
*/
if ((err = gcry_cipher_decrypt(dkey->gcry_cipher_hd, data, 512, NULL,
0)))
fprintf(stderr, "Decryption failed (error 0x%x).\n", err);
/* Apply the IV. */
if (dkey->alg_id == CALG_AES_256) {
((u64*)data)[0] ^= 0x5816657be9161312LL + offset;
((u64*)data)[1] ^= 0x1989adbe44918961LL + offset;
} else {
/* All other algos (Des, 3Des, DesX) use the same IV. */
((u64*)data)[0] ^= 0x169119629891ad13LL + offset;
}
return 512;
}
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