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ntfs-3g/ntfsprogs/ntfsdecrypt.c
uvman a117a21941 Comment documentation fixes.
2006-09-25 16:58:38 +00:00

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/**
* ntfsdecrypt - Decrypt ntfs encrypted files. Part of the Linux-NTFS project.
*
* Copyright (c) 2005 Yuval Fledel
* Copyright (c) 2005 Anton Altaparmakov
*
* This utility will decrypt files and print the decrypted data on the standard
* output.
*
* 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"
#if !defined(HAVE_GCRYPT_H) || !defined(HAVE_GNUTLS_PKCS12_H)
#error A required header file is missing. Aborting.
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_GCRYPT_H
#include <gcrypt.h>
#endif
#ifdef HAVE_GNUTLS_PKCS12_H
#include <gnutls/pkcs12.h>
#endif
#include "types.h"
#include "attrib.h"
#include "utils.h"
#include "volume.h"
#include "debug.h"
#include "dir.h"
#include "layout.h"
#include "version.h"
typedef gcry_sexp_t ntfs_rsa_private_key;
/**
* enum NTFS_CRYPTO_ALGORITHMS - List of crypto algorithms used by EFS (32 bit)
*
* To choose which one is used in Windows, create or set the REG_DWORD registry
* key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\EFS\
* AlgorithmID to the value of your chosen crypto algorithm, e.g. to use DesX,
* set AlgorithmID to 0x6604.
*
* Note that the Windows versions I have tried so far (all are high crypto
* enabled) ignore the AlgorithmID value if it is not one of CALG_3DES,
* CALG_DESX, or CALG_AES_256, i.e. you cannot select CALG_DES at all using
* this registry key. It would be interesting to check out encryption on one
* of the "crippled" crypto Windows versions...
*/
typedef enum {
CALG_DES = const_cpu_to_le32(0x6601),
/* If not one of the below three, fall back to standard Des. */
CALG_3DES = const_cpu_to_le32(0x6603),
CALG_DESX = const_cpu_to_le32(0x6604),
CALG_AES_256 = const_cpu_to_le32(0x6610),
} NTFS_CRYPTO_ALGORITHMS;
/**
* struct ntfs_fek - Decrypted, in-memory file encryption key.
*/
typedef struct {
gcry_cipher_hd_t gcry_cipher_hd;
u32 alg_id;
u8 *key_data;
gcry_cipher_hd_t *des_gcry_cipher_hd_ptr;
} ntfs_fek;
/* DESX-MS128 implementation for libgcrypt. */
static gcry_module_t ntfs_desx_module;
static unsigned ntfs_desx_algorithm_id = -1;
typedef struct {
u64 in_whitening, out_whitening;
gcry_cipher_hd_t gcry_cipher_hd;
} ntfs_desx_ctx;
struct options {
char *keyfile; /* .pfx file containing the user's private key. */
char *device; /* Device/File to work with */
char *file; /* File to display */
s64 inode; /* Inode to work with */
ATTR_TYPES attr; /* Attribute type to display */
int force; /* Override common sense */
int quiet; /* Less output */
int verbose; /* Extra output */
};
static const char *EXEC_NAME = "ntfsdecrypt";
static struct options opts;
static ntfschar EFS[5] = {
const_cpu_to_le16('$'), const_cpu_to_le16('E'), const_cpu_to_le16('F'),
const_cpu_to_le16('S'), const_cpu_to_le16('\0')
};
/**
* version - Print version information about the program
*
* Print a copyright statement and a brief description of the program.
*
* Return: none
*/
static void version(void)
{
ntfs_log_info("\n%s v%s (libntfs %s) - Decrypt files and print on the "
"standard output.\n\n", EXEC_NAME, VERSION,
ntfs_libntfs_version());
ntfs_log_info("Copyright (c) 2005 Yuval Fledel\n");
ntfs_log_info("Copyright (c) 2005 Anton Altaparmakov\n");
ntfs_log_info("\n%s\n%s%s\n", ntfs_gpl, ntfs_bugs, ntfs_home);
}
/**
* usage - Print a list of the parameters to the program
*
* Print a list of the parameters and options for the program.
*
* Return: none
*/
static void usage(void)
{
ntfs_log_info("\nUsage: %s [options] -k name.pfx device [file]\n\n"
" -i, --inode num Display this inode\n\n"
" -k --keyfile name.pfx Use file name as the user's private key file.\n"
" -f --force Use less caution\n"
" -h --help Print this help\n"
" -q --quiet Less output\n"
" -V --version Version information\n"
" -v --verbose More output\n\n",
EXEC_NAME);
ntfs_log_info("%s%s\n", ntfs_bugs, ntfs_home);
}
/**
* parse_options - Read and validate the programs command line
*
* Read the command line, verify the syntax and parse the options.
* This function is very long, but quite simple.
*
* Return: 1 Success
* 0 Error, one or more problems
*/
static int parse_options(int argc, char **argv)
{
static const char *sopt = "-fh?i:k:qVv";
static const struct option lopt[] = {
{"force", no_argument, NULL, 'f'},
{"help", no_argument, NULL, 'h'},
{"inode", required_argument, NULL, 'i'},
{"keyfile", required_argument, NULL, 'k'},
{"quiet", no_argument, NULL, 'q'},
{"version", no_argument, NULL, 'V'},
{"verbose", no_argument, NULL, 'v'},
{NULL, 0, NULL, 0}
};
int c = -1;
int err = 0;
int ver = 0;
int help = 0;
opterr = 0; /* We'll handle the errors, thank you. */
opts.inode = -1;
while ((c = getopt_long(argc, argv, sopt, lopt, NULL)) != -1) {
switch (c) {
case 1: /* A non-option argument */
if (!opts.device)
opts.device = argv[optind - 1];
else if (!opts.file)
opts.file = argv[optind - 1];
else {
ntfs_log_error("You must specify exactly one "
"file.\n");
err++;
}
break;
case 'f':
opts.force++;
break;
case 'h':
case '?':
help++;
break;
case 'k':
if (!opts.keyfile)
opts.keyfile = argv[optind - 1];
else {
ntfs_log_error("You must specify exactly one "
"key file.\n");
err++;
}
break;
case 'i':
if (opts.inode != -1)
ntfs_log_error("You must specify exactly one "
"inode.\n");
else if (utils_parse_size(optarg, &opts.inode, FALSE))
break;
else
ntfs_log_error("Couldn't parse inode number.\n");
err++;
break;
case 'q':
opts.quiet++;
ntfs_log_clear_levels(NTFS_LOG_LEVEL_QUIET);
break;
case 'V':
ver++;
break;
case 'v':
opts.verbose++;
ntfs_log_set_levels(NTFS_LOG_LEVEL_VERBOSE);
break;
default:
ntfs_log_error("Unknown option '%s'.\n",
argv[optind - 1]);
err++;
break;
}
}
if (help || ver) {
opts.quiet = 0;
ntfs_log_set_levels(NTFS_LOG_LEVEL_QUIET);
} else {
if (!opts.keyfile) {
ntfs_log_error("You must specify a key file.\n");
err++;
} else if (opts.device == NULL) {
ntfs_log_error("You must specify a device.\n");
err++;
} else if (opts.file == NULL && opts.inode == -1) {
ntfs_log_error("You must specify a file or inode with "
"the -i option.\n");
err++;
} else if (opts.file != NULL && opts.inode != -1) {
ntfs_log_error("You can't specify both a file and "
"inode.\n");
err++;
}
if (opts.quiet && opts.verbose) {
ntfs_log_error("You may not use --quiet and --verbose "
"at the same time.\n");
err++;
}
}
if (ver)
version();
if (help || err)
usage();
return (!err && !help && !ver);
}
/**
* ntfs_pkcs12_load_pfxfile
*/
static int ntfs_pkcs12_load_pfxfile(const char *keyfile, u8 **pfx,
unsigned *pfx_size)
{
int f, to_read, total, attempts, br;
struct stat key_stat;
if (!keyfile || !pfx || !pfx_size) {
ntfs_log_error("You have to specify the key file, a pointer "
"to hold the key file contents, and a pointer "
"to hold the size of the key file contents.\n");
return -1;
}
f = open(keyfile, O_RDONLY);
if (f == -1) {
ntfs_log_perror("Failed to open key file");
return -1;
}
if (fstat(f, &key_stat) == -1) {
ntfs_log_perror("Failed to stat key file");
goto file_out;
}
if (!S_ISREG(key_stat.st_mode)) {
ntfs_log_error("Key file is not a regular file, cannot read "
"it.\n");
goto file_out;
}
if (!key_stat.st_size) {
ntfs_log_error("Key file has zero size.\n");
goto file_out;
}
*pfx = malloc(key_stat.st_size + 1);
if (!*pfx) {
ntfs_log_perror("Failed to allocate buffer for key file "
"contents");
goto file_out;
}
to_read = key_stat.st_size;
total = attempts = 0;
do {
br = read(f, *pfx + total, to_read);
if (br == -1) {
ntfs_log_perror("Failed to read from key file");
goto free_out;
}
if (!br)
attempts++;
to_read -= br;
total += br;
} while (to_read > 0 && attempts < 3);
close(f);
/* Make sure it is zero terminated. */
(*pfx)[key_stat.st_size] = 0;
*pfx_size = key_stat.st_size;
return 0;
free_out:
free(*pfx);
file_out:
close(f);
return -1;
}
/**
* ntfs_crypto_init
*/
static int ntfs_crypto_init(void)
{
int err;
/* Initialize gcrypt library. Note: Must come before GNU TLS init. */
if (gcry_control(GCRYCTL_DISABLE_SECMEM, 0) != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to initialize the gcrypt library.\n");
return -1;
}
/* Initialize GNU TLS library. Note: Must come after libgcrypt init. */
err = gnutls_global_init();
if (err < 0) {
ntfs_log_error("Failed to initialize GNU TLS library: %s\n",
gnutls_strerror(err));
return -1;
}
return 0;
}
/**
* ntfs_crypto_deinit
*/
static void ntfs_crypto_deinit(void)
{
gnutls_global_deinit();
if (ntfs_desx_module) {
gcry_cipher_unregister(ntfs_desx_module);
ntfs_desx_module = NULL;
ntfs_desx_algorithm_id = -1;
}
}
/**
* ntfs_rsa_private_key_import_from_gnutls
*/
static ntfs_rsa_private_key ntfs_rsa_private_key_import_from_gnutls(
gnutls_x509_privkey_t priv_key)
{
int i, j;
size_t tmp_size;
gnutls_datum_t rd[6];
gcry_mpi_t rm[6];
gcry_sexp_t rsa_key;
/* Extract the RSA parameters from the GNU TLS private key. */
if (gnutls_x509_privkey_export_rsa_raw(priv_key, &rd[0], &rd[1],
&rd[2], &rd[3], &rd[4], &rd[5])) {
ntfs_log_error("Failed to export rsa parameters. (Is the "
"key an RSA private key?)\n");
return NULL;
}
/* Convert each RSA parameter to mpi format. */
for (i = 0; i < 6; i++) {
if (gcry_mpi_scan(&rm[i], GCRYMPI_FMT_USG, rd[i].data,
rd[i].size, &tmp_size) != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to convert RSA parameter %i "
"to mpi format (size %d)\n", i,
rd[i].size);
rsa_key = NULL;
break;
}
}
/* Release the no longer needed datum values. */
for (j = 0; j < 6; j++) {
if (rd[j].data && rd[j].size)
gnutls_free(rd[j].data);
}
/*
* Build the gcrypt private key, note libgcrypt uses p and q inversed
* to what gnutls uses.
*/
if (i == 6 && gcry_sexp_build(&rsa_key, NULL,
"(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
rm[0], rm[1], rm[2], rm[4], rm[3], rm[5]) !=
GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to build RSA private key s-exp.\n");
rsa_key = NULL;
}
/* Release the no longer needed mpi values. */
for (j = 0; j < i; j++)
gcry_mpi_release(rm[j]);
return (ntfs_rsa_private_key)rsa_key;
}
/**
* ntfs_pkcs12_extract_rsa_key
*/
static ntfs_rsa_private_key ntfs_pkcs12_extract_rsa_key(u8 *pfx, int pfx_size,
char *password)
{
int err, bag_index, flags;
gnutls_datum_t dpfx, dkey;
gnutls_pkcs12_t pkcs12;
gnutls_pkcs12_bag_t bag;
gnutls_x509_privkey_t pkey;
ntfs_rsa_private_key rsa_key = NULL;
/* Create a pkcs12 structure. */
err = gnutls_pkcs12_init(&pkcs12);
if (err) {
ntfs_log_error("Failed to initialize PKCS#12 structure: %s\n",
gnutls_strerror(err));
return NULL;
}
/* Convert the PFX file (DER format) to native pkcs12 format. */
dpfx.data = pfx;
dpfx.size = pfx_size;
err = gnutls_pkcs12_import(pkcs12, &dpfx, GNUTLS_X509_FMT_DER, 0);
if (err) {
ntfs_log_error("Failed to convert the PFX file from DER to "
"native PKCS#12 format: %s\n",
gnutls_strerror(err));
goto out;
}
/*
* Verify that the password is correct and that the key file has not
* been tampered with. Note if the password has zero length and the
* verification fails, retry with password set to NULL. This is needed
* to get passwordless .pfx files generated with Windows XP SP1 (and
* probably earlier versions of Windows) to work.
*/
retry_verify:
err = gnutls_pkcs12_verify_mac(pkcs12, password);
if (err) {
if (err == GNUTLS_E_MAC_VERIFY_FAILED &&
password && !strlen(password)) {
password = NULL;
goto retry_verify;
}
ntfs_log_error("Failed to verify the MAC (%s). Is the "
"password correct?\n", gnutls_strerror(err));
goto out;
}
for (bag_index = 0; ; bag_index++) {
err = gnutls_pkcs12_bag_init(&bag);
if (err) {
ntfs_log_error("Failed to initialize PKCS#12 Bag "
"structure: %s\n",
gnutls_strerror(err));
goto out;
}
err = gnutls_pkcs12_get_bag(pkcs12, bag_index, bag);
if (err) {
if (err == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
break;
ntfs_log_error("Failed to obtain Bag from PKCS#12 "
"structure: %s\n",
gnutls_strerror(err));
goto bag_out;
}
check_again:
err = gnutls_pkcs12_bag_get_count(bag);
if (err < 0) {
ntfs_log_error("Failed to obtain Bag count: %s\n",
gnutls_strerror(err));
goto bag_out;
}
err = gnutls_pkcs12_bag_get_type(bag, 0);
if (err < 0) {
ntfs_log_error("Failed to determine Bag type: %s\n",
gnutls_strerror(err));
goto bag_out;
}
flags = 0;
switch (err) {
case GNUTLS_BAG_PKCS8_KEY:
flags = GNUTLS_PKCS_PLAIN;
case GNUTLS_BAG_PKCS8_ENCRYPTED_KEY:
err = gnutls_pkcs12_bag_get_data(bag, 0, &dkey);
if (err < 0) {
ntfs_log_error("Failed to obtain Bag data: "
"%s\n", gnutls_strerror(err));
goto bag_out;
}
err = gnutls_x509_privkey_init(&pkey);
if (err) {
ntfs_log_error("Failed to initialized "
"private key structure: %s\n",
gnutls_strerror(err));
goto bag_out;
}
/* Decrypt the private key into GNU TLS format. */
err = gnutls_x509_privkey_import_pkcs8(pkey, &dkey,
GNUTLS_X509_FMT_DER, password, flags);
if (err) {
ntfs_log_error("Failed to convert private "
"key from DER to GNU TLS "
"format: %s\n",
gnutls_strerror(err));
goto key_out;
}
#if 0
/*
* Export the key again, but unencrypted, and output it
* to stderr. Note the output has an RSA header so to
* compare to openssl pkcs12 -nodes -in myfile.pfx
* output need to ignore the part of the key between
* the first "MII..." up to the second "MII...". The
* actual RSA private key begins at the second "MII..."
* and in my testing at least was identical to openssl
* output and was also identical both on big and little
* endian so gnutls should be endianness safe.
*/
char *buf = malloc(8192);
size_t bufsize = 8192;
err = gnutls_x509_privkey_export_pkcs8(pkey,
GNUTLS_X509_FMT_PEM, "", GNUTLS_PKCS_PLAIN, buf,
&bufsize);
if (err) {
ntfs_log_error("eek1\n");
exit(1);
}
ntfs_log_error("%s\n", buf);
free(buf);
#endif
/* Convert the private key to our internal format. */
rsa_key = ntfs_rsa_private_key_import_from_gnutls(pkey);
goto key_out;
case GNUTLS_BAG_ENCRYPTED:
err = gnutls_pkcs12_bag_decrypt(bag, password);
if (err) {
ntfs_log_error("Failed to decrypt Bag: %s\n",
gnutls_strerror(err));
goto bag_out;
}
goto check_again;
default:
/* We do not care about other types. */
break;
}
gnutls_pkcs12_bag_deinit(bag);
}
key_out:
gnutls_x509_privkey_deinit(pkey);
bag_out:
gnutls_pkcs12_bag_deinit(bag);
out:
gnutls_pkcs12_deinit(pkcs12);
return rsa_key;
}
/**
* ntfs_rsa_private_key_release
*/
static void ntfs_rsa_private_key_release(ntfs_rsa_private_key rsa_key)
{
gcry_sexp_release((gcry_sexp_t)rsa_key);
}
/**
* ntfs_buffer_reverse -
*
* 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 ntfs_buffer_reverse(u8 *buf, unsigned buf_size)
{
unsigned i;
u8 t;
for (i = 0; i < buf_size / 2; i++) {
t = buf[i];
buf[i] = buf[buf_size - i - 1];
buf[buf_size - i - 1] = t;
}
}
#ifndef HAVE_STRNLEN
/**
* strnlen - strnlen is a gnu extension so emulate it if not present
*/
static size_t strnlen(const char *s, size_t maxlen)
{
const char *p, *end;
/* Look for a '\0' character. */
for (p = s, end = s + maxlen; p < end && *p; p++)
;
return p - s;
}
#endif /* ! HAVE_STRNLEN */
/**
* ntfs_raw_fek_decrypt -
*
* Note: decrypting into the input buffer.
*/
static unsigned ntfs_raw_fek_decrypt(u8 *fek, u32 fek_size,
ntfs_rsa_private_key rsa_key)
{
gcry_mpi_t fek_mpi;
gcry_sexp_t fek_sexp, fek_sexp2;
gcry_error_t err;
size_t size, padding;
/* Reverse the raw FEK. */
ntfs_buffer_reverse(fek, fek_size);
/* Convert the FEK to internal MPI format. */
err = gcry_mpi_scan(&fek_mpi, GCRYMPI_FMT_USG, fek, fek_size, NULL);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to convert file encryption key to "
"internal MPI format: %s\n",
gcry_strerror(err));
return 0;
}
/* Create an internal S-expression from the FEK. */
err = gcry_sexp_build(&fek_sexp, NULL,
"(enc-val (flags) (rsa (a %m)))", fek_mpi);
gcry_mpi_release(fek_mpi);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to create internal S-expression of "
"the file encryption key: %s\n",
gcry_strerror(err));
return 0;
}
/* Decrypt the FEK. */
err = gcry_pk_decrypt(&fek_sexp2, fek_sexp, (gcry_sexp_t)rsa_key);
gcry_sexp_release(fek_sexp);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to decrypt the file encryption key: "
"%s\n", gcry_strerror(err));
return 0;
}
/* Extract the actual FEK from the decrypted raw S-expression. */
fek_sexp = gcry_sexp_find_token(fek_sexp2, "value", 0);
gcry_sexp_release(fek_sexp2);
if (!fek_sexp) {
ntfs_log_error("Failed to find the decrypted file encryption "
"key in the internal S-expression.\n");
return 0;
}
/* Convert the decrypted FEK S-expression into MPI format. */
fek_mpi = gcry_sexp_nth_mpi(fek_sexp, 1, GCRYMPI_FMT_USG);
gcry_sexp_release(fek_sexp);
if (!fek_mpi) {
ntfs_log_error("Failed to convert the decrypted file "
"encryption key S-expression to internal MPI "
"format.\n");
return 0;
}
/* Convert the decrypted FEK from MPI format to binary data. */
err = gcry_mpi_print(GCRYMPI_FMT_USG, fek, fek_size, &size, fek_mpi);
gcry_mpi_release(fek_mpi);
if (err != GPG_ERR_NO_ERROR || !size) {
ntfs_log_error("Failed to convert decrypted file encryption "
"key from internal MPI format to binary data: "
"%s\n", gcry_strerror(err));
return 0;
}
/*
* Finally, remove the PKCS#1 padding and return the size of the
* decrypted FEK.
*/
padding = strnlen((char *)fek, size) + 1;
if (padding > size) {
ntfs_log_error("Failed to remove PKCS#1 padding from "
"decrypted file encryption key.\n");
return 0;
}
size -= padding;
memmove(fek, fek + padding, size);
return size;
}
/**
* 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 = (const u8*)"Dan Simon ";
static const u8 *salt2 = (const u8*)"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) {
ntfs_log_error("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) {
ntfs_log_error("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) {
ntfs_log_error("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) {
ntfs_log_error("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) {
ntfs_log_error("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) {
ntfs_log_error("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;
}
/**
* ntfs_desx_decrypt
*/
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)
ntfs_log_error("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)
ntfs_log_error("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 */
/**
* ntfs_desx_key_expand_test
*/
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;
ntfs_log_error("Testing whether ntfs_desx_key_expand() works: %s\n",
res ? "SUCCESS" : "FAILED");
return res;
}
/**
* ntfs_des_test
*/
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) {
ntfs_log_error("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) {
ntfs_log_error("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) {
ntfs_log_error("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));
ntfs_log_error("Testing whether des decryption works: %s\n",
res ? "SUCCESS" : "FAILED");
return res;
}
#else /* !defined(DO_CRYPTO_TESTS) */
/**
* ntfs_desx_key_expand_test
*/
static inline BOOL ntfs_desx_key_expand_test(void)
{
return TRUE;
}
/**
* ntfs_des_test
*/
static inline BOOL ntfs_des_test(void)
{
return TRUE;
}
#endif /* !defined(DO_CRYPTO_TESTS) */
/**
* ntfs_fek_import_from_raw
*/
static ntfs_fek *ntfs_fek_import_from_raw(u8 *fek_buf,
unsigned fek_size __attribute__((unused)))
{
ntfs_fek *fek;
u32 key_size, wanted_key_size, gcry_algo;
gcry_error_t err;
// TODO: Sanity checking of sizes and offsets.
key_size = le32_to_cpup(fek_buf);
//ntfs_log_debug("key_size 0x%x\n", key_size);
fek = malloc(((((sizeof(*fek) + 7) & ~7) + key_size + 7) & ~7) +
sizeof(gcry_cipher_hd_t));
if (!fek) {
errno = ENOMEM;
return NULL;
}
fek->alg_id = *(u32*)(fek_buf + 8);
//ntfs_log_debug("alg_id 0x%x\n", le32_to_cpu(fek->alg_id));
fek->key_data = (u8*)fek + ((sizeof(*fek) + 7) & ~7);
memcpy(fek->key_data, fek_buf + 16, key_size);
fek->des_gcry_cipher_hd_ptr = NULL;
*(gcry_cipher_hd_t***)(fek->key_data + ((key_size + 7) & ~7)) =
&fek->des_gcry_cipher_hd_ptr;
switch (fek->alg_id) {
case CALG_DESX:
if (!ntfs_desx_module) {
if (!ntfs_desx_key_expand_test() || !ntfs_des_test()) {
err = EINVAL;
goto out;
}
err = gcry_cipher_register(&ntfs_desx_cipher,
&ntfs_desx_algorithm_id,
&ntfs_desx_module);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to register desx "
"cipher: %s\n",
gcry_strerror(err));
err = EINVAL;
goto out;
}
}
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;
if (fek->alg_id == CALG_DES)
ntfs_log_error("DES is not supported at present\n");
else
ntfs_log_error("Unknown crypto algorithm 0x%x\n",
le32_to_cpu(fek->alg_id));
ntfs_log_error(". Please email %s and say that you saw this "
"message. We will then try to implement "
"support for this algorithm.\n", NTFS_DEV_LIST);
err = EOPNOTSUPP;
goto out;
}
if (key_size != wanted_key_size) {
ntfs_log_error("%s key of %u bytes but needed size is %u "
"bytes, assuming corrupt key. Aborting.\n",
gcry_cipher_algo_name(gcry_algo),
(unsigned)key_size, (unsigned)wanted_key_size);
err = EIO;
goto out;
}
err = gcry_cipher_open(&fek->gcry_cipher_hd, gcry_algo,
GCRY_CIPHER_MODE_CBC, 0);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("gcry_cipher_open() failed: %s\n",
gcry_strerror(err));
err = EINVAL;
goto out;
}
err = gcry_cipher_setkey(fek->gcry_cipher_hd, fek->key_data, key_size);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("gcry_cipher_setkey() failed: %s\n",
gcry_strerror(err));
gcry_cipher_close(fek->gcry_cipher_hd);
err = EINVAL;
goto out;
}
return fek;
out:
free(fek);
errno = err;
return NULL;
}
/**
* ntfs_fek_release
*/
static void ntfs_fek_release(ntfs_fek *fek)
{
if (fek->des_gcry_cipher_hd_ptr)
gcry_cipher_close(*fek->des_gcry_cipher_hd_ptr);
gcry_cipher_close(fek->gcry_cipher_hd);
free(fek);
}
/**
* ntfs_df_array_fek_get
*/
static ntfs_fek *ntfs_df_array_fek_get(EFS_DF_ARRAY_HEADER *df_array,
ntfs_rsa_private_key rsa_key)
{
EFS_DF_HEADER *df_header;
EFS_DF_CREDENTIAL_HEADER *df_cred;
EFS_DF_CERT_THUMBPRINT_HEADER *df_cert;
u8 *fek_buf;
ntfs_fek *fek;
u32 df_count, fek_size;
unsigned i;
df_header = (EFS_DF_HEADER*)(df_array + 1);
df_count = le32_to_cpu(df_array->df_count);
for (i = 0; i < df_count; i++) {
df_cred = (EFS_DF_CREDENTIAL_HEADER*)((u8*)df_header +
le32_to_cpu(df_header->cred_header_offset));
df_cert = (EFS_DF_CERT_THUMBPRINT_HEADER*)((u8*)df_cred +
le32_to_cpu(
df_cred->cert_thumbprint_header_offset));
fek_size = le32_to_cpu(df_header->fek_size);
fek_buf = (u8*)df_header + le32_to_cpu(df_header->fek_offset);
/* Decrypt the FEK. Note: This is done in place. */
fek_size = ntfs_raw_fek_decrypt(fek_buf, fek_size, rsa_key);
if (fek_size) {
/* Convert the FEK to our internal format. */
fek = ntfs_fek_import_from_raw(fek_buf, fek_size);
if (fek)
return fek;
ntfs_log_error("Failed to convert the decrypted file "
"encryption key to internal format.\n");
} else
ntfs_log_error("Failed to decrypt the file "
"encryption key.\n");
df_header = (EFS_DF_HEADER*)((u8*)df_header +
le32_to_cpu(df_header->df_length));
}
return NULL;
}
/**
* ntfs_inode_fek_get -
*/
static ntfs_fek *ntfs_inode_fek_get(ntfs_inode *inode,
ntfs_rsa_private_key rsa_key)
{
EFS_ATTR_HEADER *efs;
EFS_DF_ARRAY_HEADER *df_array;
ntfs_fek *fek = NULL;
/* Obtain the $EFS contents. */
efs = ntfs_attr_readall(inode, AT_LOGGED_UTILITY_STREAM, EFS, 4, NULL);
if (!efs) {
ntfs_log_perror("Failed to read $EFS attribute");
return NULL;
}
/* Iterate through the DDFs & DRFs until we obtain a key. */
if (efs->offset_to_ddf_array) {
df_array = (EFS_DF_ARRAY_HEADER*)((u8*)efs +
le32_to_cpu(efs->offset_to_ddf_array));
fek = ntfs_df_array_fek_get(df_array, rsa_key);
}
if (!fek && efs->offset_to_drf_array) {
df_array = (EFS_DF_ARRAY_HEADER*)((u8*)efs +
le32_to_cpu(efs->offset_to_drf_array));
fek = ntfs_df_array_fek_get(df_array, rsa_key);
}
free(efs);
return fek;
}
/**
* ntfs_fek_decrypt_sector
*/
static int ntfs_fek_decrypt_sector(ntfs_fek *fek, u8 *data, const u64 offset)
{
gcry_error_t err;
err = gcry_cipher_reset(fek->gcry_cipher_hd);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Failed to reset cipher: %s\n",
gcry_strerror(err));
return -1;
}
/*
* Note: You may wonder why we are 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.
*/
err = gcry_cipher_decrypt(fek->gcry_cipher_hd, data, 512, NULL, 0);
if (err != GPG_ERR_NO_ERROR) {
ntfs_log_error("Decryption failed: %s\n", gcry_strerror(err));
return -1;
}
/* Apply the IV. */
if (fek->alg_id == CALG_AES_256) {
((u64*)data)[0] ^= cpu_to_le64(0x5816657be9161312ULL + offset);
((u64*)data)[1] ^= cpu_to_le64(0x1989adbe44918961ULL + offset);
} else {
/* All other algos (Des, 3Des, DesX) use the same IV. */
((u64*)data)[0] ^= cpu_to_le64(0x169119629891ad13ULL + offset);
}
return 512;
}
/**
* ntfs_cat_decrypt - Decrypt the contents of an encrypted file to stdout.
* @inode: An encrypted file's inode structure, as obtained by
* ntfs_inode_open().
* @fek: A file encryption key. As obtained by ntfs_inode_fek_get().
*/
static int ntfs_cat_decrypt(ntfs_inode *inode, ntfs_fek *fek)
{
int bufsize = 512;
unsigned char *buffer;
ntfs_attr *attr;
s64 bytes_read, written, offset, total;
s64 old_data_size, old_initialized_size;
int i;
buffer = malloc(bufsize);
if (!buffer)
return 1;
attr = ntfs_attr_open(inode, AT_DATA, NULL, 0);
if (!attr) {
ntfs_log_error("Cannot cat a directory.\n");
free(buffer);
return 1;
}
total = attr->data_size;
// hack: make sure attr will not be commited to disk if you use this.
// clear the encrypted bit, otherwise the library won't allow reading.
NAttrClearEncrypted(attr);
// extend the size, we may need to read past the end of the stream.
old_data_size = attr->data_size;
old_initialized_size = attr->initialized_size;
attr->data_size = attr->initialized_size = attr->allocated_size;
offset = 0;
while (total > 0) {
bytes_read = ntfs_attr_pread(attr, offset, 512, buffer);
if (bytes_read == -1) {
ntfs_log_perror("ERROR: Couldn't read file");
break;
}
if (!bytes_read)
break;
if ((i = ntfs_fek_decrypt_sector(fek, buffer, offset)) <
bytes_read) {
ntfs_log_perror("ERROR: Couldn't decrypt all data!");
ntfs_log_error("%u/%lld/%lld/%lld\n", i,
(long long)bytes_read, (long long)offset,
(long long)total);
break;
}
if (bytes_read > total)
bytes_read = total;
written = fwrite(buffer, 1, bytes_read, stdout);
if (written != bytes_read) {
ntfs_log_perror("ERROR: Couldn't output all data!");
break;
}
offset += bytes_read;
total -= bytes_read;
}
attr->data_size = old_data_size;
attr->initialized_size = old_initialized_size;
NAttrSetEncrypted(attr);
ntfs_attr_close(attr);
free(buffer);
return 0;
}
/**
* main - Begin here
*
* Start from here.
*
* Return: 0 Success, the program worked
* 1 Error, something went wrong
*/
int main(int argc, char *argv[])
{
u8 *pfx_buf;
char *password;
ntfs_rsa_private_key rsa_key;
ntfs_volume *vol;
ntfs_inode *inode;
ntfs_fek *fek;
unsigned pfx_size;
int res;
ntfs_log_set_handler(ntfs_log_handler_stderr);
if (!parse_options(argc, argv))
return 1;
utils_set_locale();
/* Initialize crypto in ntfs. */
if (ntfs_crypto_init()) {
ntfs_log_error("Failed to initialize crypto. Aborting.\n");
return 1;
}
/* Load the PKCS#12 (.pfx) file containing the user's private key. */
if (ntfs_pkcs12_load_pfxfile(opts.keyfile, &pfx_buf, &pfx_size)) {
ntfs_log_error("Failed to load key file. Aborting.\n");
ntfs_crypto_deinit();
return 1;
}
/* Ask the user for their password. */
password = getpass("Enter the password with which the private key was "
"encrypted: ");
if (!password) {
ntfs_log_perror("Failed to obtain user password");
free(pfx_buf);
ntfs_crypto_deinit();
return 1;
}
/* Obtain the user's private RSA key from the key file. */
rsa_key = ntfs_pkcs12_extract_rsa_key(pfx_buf, pfx_size, password);
/* Destroy the password. */
memset(password, 0, strlen(password));
/* No longer need the pfx file contents. */
free(pfx_buf);
if (!rsa_key) {
ntfs_log_error("Failed to extract the private RSA key. Did "
"you perhaps mistype the password?\n");
ntfs_crypto_deinit();
return 1;
}
/* Mount the ntfs volume. */
vol = utils_mount_volume(opts.device, MS_RDONLY, opts.force);
if (!vol) {
ntfs_log_error("Failed to mount ntfs volume. Aborting.\n");
ntfs_rsa_private_key_release(rsa_key);
ntfs_crypto_deinit();
return 1;
}
/* Open the encrypted ntfs file. */
if (opts.inode != -1)
inode = ntfs_inode_open(vol, opts.inode);
else
inode = ntfs_pathname_to_inode(vol, NULL, opts.file);
if (!inode) {
ntfs_log_error("Failed to open encrypted file. Aborting.\n");
ntfs_umount(vol, FALSE);
ntfs_rsa_private_key_release(rsa_key);
ntfs_crypto_deinit();
return 1;
}
/* Obtain the file encryption key of the encrypted file. */
fek = ntfs_inode_fek_get(inode, rsa_key);
ntfs_rsa_private_key_release(rsa_key);
if (fek) {
res = ntfs_cat_decrypt(inode, fek);
ntfs_fek_release(fek);
} else {
ntfs_log_error("Failed to obtain file encryption key. "
"Aborting.\n");
res = 1;
}
ntfs_inode_close(inode);
ntfs_umount(vol, FALSE);
ntfs_crypto_deinit();
return res;
}
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