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From: Anton A. <an...@us...> - 2005-07-21 12:13:49
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Changes by: antona Update of /cvsroot/linux-ntfs/ntfsprogs/ntfsprogs In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv537/ntfsprogs Modified Files: Makefile.am Makefile.in decrypt.c ntfsdecrypt.c Log Message: Add a function to ntfsprogs/decrypt.c that expands an on-disk desx key from 128 bits to the needed 192 bits so it can be used for {en,de}cryption. Note I couldn't face using the completely insane libgcrypt api so I used openssl's libcrypto instead... Anyone feel free to swap once we have it working. Index: Makefile.am =================================================================== RCS file: /cvsroot/linux-ntfs/ntfsprogs/ntfsprogs/Makefile.am,v retrieving revision 1.38 retrieving revision 1.39 diff -u -p -r1.38 -r1.39 --- Makefile.am 16 Jul 2005 06:53:53 -0000 1.38 +++ Makefile.am 21 Jul 2005 12:12:48 -0000 1.39 @@ -89,7 +89,7 @@ endif ntfsdecrypt_SOURCES = ntfsdecrypt.c decrypt.c decrypt.h utils.c utils.h ntfsdecrypt_LDADD = $(AM_LIBS) -ntfsdecrypt_LDFLAGS = $(AM_LFLAGS) -lgcrypt +ntfsdecrypt_LDFLAGS = $(AM_LFLAGS) -lgcrypt -lcrypto ntfsrm_SOURCES = ntfsrm.c ntfsrm.h utils.c utils.h ntfsrm_LDADD = $(AM_LIBS) Index: Makefile.in =================================================================== RCS file: /cvsroot/linux-ntfs/ntfsprogs/ntfsprogs/Makefile.in,v retrieving revision 1.81 retrieving revision 1.82 diff -u -p -r1.81 -r1.82 --- Makefile.in 20 Jul 2005 19:06:49 -0000 1.81 +++ Makefile.in 21 Jul 2005 12:12:48 -0000 1.82 @@ -246,7 +246,6 @@ ac_ct_CXX = @ac_ct_CXX@ ac_ct_F77 = @ac_ct_F77@ ac_ct_RANLIB = @ac_ct_RANLIB@ ac_ct_STRIP = @ac_ct_STRIP@ -ac_pt_PKG_CONFIG = @ac_pt_PKG_CONFIG@ all_includes = @all_includes@ all_libraries = @all_libraries@ am__fastdepCC_FALSE = @am__fastdepCC_FALSE@ @@ -351,7 +350,7 @@ ntfscp_LDFLAGS = $(AM_LFLAGS) # We don't distribute these ntfsdecrypt_SOURCES = ntfsdecrypt.c decrypt.c decrypt.h utils.c utils.h ntfsdecrypt_LDADD = $(AM_LIBS) -ntfsdecrypt_LDFLAGS = $(AM_LFLAGS) -lgcrypt +ntfsdecrypt_LDFLAGS = $(AM_LFLAGS) -lgcrypt -lcrypto ntfsrm_SOURCES = ntfsrm.c ntfsrm.h utils.c utils.h ntfsrm_LDADD = $(AM_LIBS) ntfsrm_LDFLAGS = $(AM_LFLAGS) Index: decrypt.c =================================================================== RCS file: /cvsroot/linux-ntfs/ntfsprogs/ntfsprogs/decrypt.c,v retrieving revision 1.4 retrieving revision 1.5 diff -u -p -r1.4 -r1.5 --- decrypt.c 20 Jul 2005 10:59:06 -0000 1.4 +++ decrypt.c 21 Jul 2005 12:12:48 -0000 1.5 @@ -26,6 +26,7 @@ #include <stdio.h> #include <errno.h> #include <gcrypt.h> +#include <openssl/md5.h> #include "decrypt.h" @@ -425,16 +426,12 @@ unsigned int decrypt_decrypt_sector(decr fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2); } - if (dkey->gcry_algo == GCRY_CIPHER_DES_SK) { - /* CALG_DESX */ - fprintf(stderr, "DESX is not supported yet.\n"); - errno = -1; - return 0; - } else { - if ((gcry_error2 = gcry_cipher_decrypt(dkey->gcry_cipher_hd, - data, 512, NULL, 0))) { - fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2); - } + // FIXME: Why are we not calling gcry_cipher_setiv() here instead of + // doing it by hand after the decryption? + + if ((gcry_error2 = gcry_cipher_decrypt(dkey->gcry_cipher_hd, + data, 512, NULL, 0))) { + fprintf(stderr, "gcry_error2 is %u.\n", gcry_error2); } if (dkey->gcry_algo == GCRY_CIPHER_AES256) { @@ -450,6 +447,43 @@ unsigned int decrypt_decrypt_sector(decr return 512; } +/** + * desx_key_expand - expand a 128-bit desx key to the needed 192-bit key + * @src: source buffer containing 128-bit key + * @dst: destination buffer to write 192-bit key to + * + * Expands the on-disk 128-bit desx key to the needed full 192-bit desx key + * required to perform desx {de,en}cryption. + * + * FIXME: Is this endianness safe? I think so but I may be wrong... + */ +void desx_key_expand(u8 *src, u8* dst) { + static const int salt_len = 12; + static const u8 *salt1 = "Dan Simon "; + static const u8 *salt2 = "Scott Field"; + u8 md[16]; + 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(md, &ctx1); + ((u32*)dst)[0] = ((u32*)md)[0] ^ ((u32*)md)[1]; + ((u32*)dst)[1] = ((u32*)md)[2] ^ ((u32*)md)[3]; + + /* Hash with the second salt and store the result. */ + MD5_Update(&ctx2, salt2, salt_len); + MD5_Final(md, &ctx2); + memcpy(dst + 8, md, sizeof(md)); + + return; +} + static decrypt_key *decrypt_make_gcry_key(char *key_data, int gcry_algo) { int gcry_mode, gcry_length; gcry_error_t gcry_error2; @@ -462,9 +496,8 @@ static decrypt_key *decrypt_make_gcry_ke switch (gcry_algo) { case GCRY_CIPHER_DES_SK: - /* FIXME: This should be MODE_CBC, no? */ - gcry_mode = GCRY_CIPHER_MODE_ECB; - gcry_length = 8; + gcry_mode = GCRY_CIPHER_MODE_CBC; + gcry_length = 24; break; case GCRY_CIPHER_3DES: gcry_mode = GCRY_CIPHER_MODE_CBC; @@ -481,7 +514,7 @@ static decrypt_key *decrypt_make_gcry_ke } if ((gcry_error2 = gcry_cipher_open(&key->gcry_cipher_hd, gcry_algo, - gcry_mode, 0))!=GPG_ERR_NO_ERROR) { + gcry_mode, 0)) != GPG_ERR_NO_ERROR) { errno = -1; return 0; } @@ -502,6 +535,7 @@ decrypt_key *decrypt_make_key( void *data) { unsigned int key_size, alg_id; char *key_data; + u8 desx_key[192 / 16]; key_size = *((unsigned int *)data); alg_id = *(((unsigned int *)data) + 2); @@ -509,10 +543,10 @@ decrypt_key *decrypt_make_key( switch (alg_id) { case CALG_DESX: + desx_key_expand(key_data, desx_key); //fprintf(stderr, "DESX key of %u bytes\n", key_size); - fprintf(stderr, "DESX is not supported yet.\n"); - errno = ENOTSUP; - return 0; + return decrypt_make_gcry_key(desx_key, + GCRY_CIPHER_DES_SK); case CALG_3DES: //fprintf(stderr, "3DES Key of %u bytes\n", key_size); return decrypt_make_gcry_key(key_data, Index: ntfsdecrypt.c =================================================================== RCS file: /cvsroot/linux-ntfs/ntfsprogs/ntfsprogs/ntfsdecrypt.c,v retrieving revision 1.2 retrieving revision 1.3 diff -u -p -r1.2 -r1.3 --- ntfsdecrypt.c 16 Jul 2005 07:00:57 -0000 1.2 +++ ntfsdecrypt.c 21 Jul 2005 12:12:48 -0000 1.3 @@ -400,7 +400,7 @@ int main (int argc, char *argv[]) result = cat_decrypt (inode, fek); decrypt_user_key_close(fek); } else { - Eprintf("Could not obtain FEK."); + Eprintf("Could not obtain FEK.\n"); result = 1; } |
