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Make use of gcry_kdf_derive.
Factoring common code out is always a Good Thing. Also added a configure test to print an error if gcry_kdf_derive is missing in Libgcrypt.
This commit is contained in:
Werner Koch
parent
35c731d889
commit
b9bcc77d6c
@ -1,3 +1,7 @@
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2011-03-10 Werner Koch <wk@g10code.com>
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* protect.c (hash_passphrase): Use the new gcry_kdf_derive.
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2011-03-08 Werner Koch <wk@g10code.com>
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* cvt-openpgp.c (GCRY_PK_ECDH) [!HAVE_GCRY_PK_ECDH]: Remove.
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@ -1023,70 +1023,13 @@ hash_passphrase (const char *passphrase, int hashalgo,
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unsigned long s2kcount,
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unsigned char *key, size_t keylen)
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{
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int rc;
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gcry_md_hd_t md;
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int pass, i;
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int used = 0;
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int pwlen = strlen (passphrase);
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if ( (s2kmode != 0 && s2kmode != 1 && s2kmode != 3)
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|| !hashalgo || !keylen || !key || !passphrase)
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return gpg_error (GPG_ERR_INV_VALUE);
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if ((s2kmode == 1 ||s2kmode == 3) && !s2ksalt)
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return gpg_error (GPG_ERR_INV_VALUE);
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rc = gcry_md_open (&md, hashalgo, GCRY_MD_FLAG_SECURE);
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if (rc)
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return rc;
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for (pass=0; used < keylen; pass++)
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{
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if (pass)
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{
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gcry_md_reset (md);
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for (i=0; i < pass; i++) /* preset the hash context */
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gcry_md_putc (md, 0);
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}
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if (s2kmode == 1 || s2kmode == 3)
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{
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int len2 = pwlen + 8;
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unsigned long count = len2;
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if (s2kmode == 3)
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{
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count = s2kcount;
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if (count < len2)
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count = len2;
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}
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while (count > len2)
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{
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gcry_md_write (md, s2ksalt, 8);
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gcry_md_write (md, passphrase, pwlen);
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count -= len2;
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}
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if (count < 8)
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gcry_md_write (md, s2ksalt, count);
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else
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{
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gcry_md_write (md, s2ksalt, 8);
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count -= 8;
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gcry_md_write (md, passphrase, count);
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}
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}
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else
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gcry_md_write (md, passphrase, pwlen);
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gcry_md_final (md);
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i = gcry_md_get_algo_dlen (hashalgo);
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if (i > keylen - used)
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i = keylen - used;
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memcpy (key+used, gcry_md_read (md, hashalgo), i);
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used += i;
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}
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gcry_md_close(md);
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return 0;
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return gcry_kdf_derive (passphrase, strlen (passphrase),
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s2kmode == 3? GCRY_KDF_ITERSALTED_S2K :
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s2kmode == 1? GCRY_KDF_SALTED_S2K :
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s2kmode == 0? GCRY_KDF_SIMPLE_S2K : GCRY_KDF_NONE,
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hashalgo, s2ksalt, 8, s2kcount,
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keylen, key);
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}
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25
configure.ac
25
configure.ac
@ -742,6 +742,22 @@ AM_PATH_GPG_ERROR("$NEED_GPG_ERROR_VERSION",
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AM_PATH_LIBGCRYPT("$NEED_LIBGCRYPT_API:$NEED_LIBGCRYPT_VERSION",
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have_libgcrypt=yes,have_libgcrypt=no)
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# FIxme: Remove this test after libgcrypt 1.5.0 has been released.
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AC_CACHE_CHECK([whether Libgcrypt has gcry_kdf_derive],
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gnupg_cv_gcry_kdf_derive,
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[ _gnupg_gcry_save_cflags=$CFLAGS
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_gnupg_gcry_save_libs=$LIBS
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CFLAGS="$CFLAGS $LIBGCRYPT_CFLAGS"
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LIBS="$LIBS $LIBGCRYPT_LIBS"
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AC_TRY_LINK(
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[#include <gcrypt.h>],
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[ return gcry_kdf_derive (NULL,0,0,0,NULL,0,0,0,NULL); ],
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gnupg_cv_gcry_kdf_derive=yes,
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gnupg_cv_gcry_kdf_derive=no)
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LIBS=$_gnupg_gcry_save_libs
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CFLAGS=$_gnupg_gcry_save_cflags])
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#
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# libassuan is used for IPC
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#
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@ -1605,6 +1621,15 @@ if test "$have_libgcrypt" = "no"; then
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*** ftp://ftp.gnupg.org/gcrypt/alpha/libgcrypt/
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*** (at least version $NEED_LIBGCRYPT_VERSION using API $NEED_LIBGCRYPT_API is required.)
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***]])
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elif test "$gnupg_cv_gcry_kdf_derive" = no; then
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die=yes
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AC_MSG_NOTICE([[
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***
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*** Libgcrypt 1.5.0 has not yet been released and thus the API
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*** is a bit in a flux. Your version misses the function
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*** gcry_kdf_derive
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*** You need to install a newer Libgcrypt version.
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***]])
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fi
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if test "$have_libassuan" = "no"; then
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die=yes
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@ -1,3 +1,8 @@
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2011-03-10 Werner Koch <wk@g10code.com>
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* passphrase.c (hash_passphrase): Remove.
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(passphrase_to_dek_ext): Use gcry_kdf_derive.
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2011-03-03 Werner Koch <wk@g10code.com>
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* keylist.c (print_card_key_info): Re-implement using the agent.
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@ -1,6 +1,6 @@
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/* passphrase.c - Get a passphrase
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* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
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* 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
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* 2005, 2006, 2007, 2009, 2011 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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@ -101,81 +101,6 @@ encode_s2k_iterations (int iterations)
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}
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/* Hash a passphrase using the supplied s2k.
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Always needs: dek->algo, s2k->mode, s2k->hash_algo. */
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static void
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hash_passphrase ( DEK *dek, char *pw, STRING2KEY *s2k)
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{
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gcry_md_hd_t md;
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int pass, i;
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int used = 0;
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int pwlen = strlen(pw);
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assert ( s2k->hash_algo );
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dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
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if ( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
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BUG();
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if (gcry_md_open (&md, s2k->hash_algo, 1))
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BUG ();
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for (pass=0; used < dek->keylen ; pass++ )
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{
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if ( pass )
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{
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gcry_md_reset (md);
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for (i=0; i < pass; i++ ) /* Preset the hash context. */
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gcry_md_putc (md, 0 );
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}
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if ( s2k->mode == 1 || s2k->mode == 3 )
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{
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int len2 = pwlen + 8;
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ulong count = len2;
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if ( s2k->mode == 3 )
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{
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count = S2K_DECODE_COUNT(s2k->count);
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if ( count < len2 )
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count = len2;
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}
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/* Fixme: To avoid DoS attacks by sending an sym-encrypted
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packet with a very high S2K count, we should either cap
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the iteration count or CPU seconds based timeout. */
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/* A little bit complicated because we need a ulong for count. */
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while ( count > len2 ) /* maybe iterated+salted */
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{
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gcry_md_write ( md, s2k->salt, 8 );
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gcry_md_write ( md, pw, pwlen );
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count -= len2;
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}
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if ( count < 8 )
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gcry_md_write ( md, s2k->salt, count );
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else
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{
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gcry_md_write ( md, s2k->salt, 8 );
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count -= 8;
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gcry_md_write ( md, pw, count );
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}
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}
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else
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gcry_md_write ( md, pw, pwlen );
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gcry_md_final( md );
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i = gcry_md_get_algo_dlen ( s2k->hash_algo );
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if ( i > dek->keylen - used )
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i = dek->keylen - used;
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memcpy (dek->key+used, gcry_md_read (md, s2k->hash_algo), i);
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used += i;
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}
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gcry_md_close(md);
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}
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int
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have_static_passphrase()
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{
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@ -655,7 +580,24 @@ passphrase_to_dek_ext (u32 *keyid, int pubkey_algo,
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if ( (!pw || !*pw) && (mode == 2 || mode == 4))
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dek->keylen = 0;
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else
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hash_passphrase (dek, pw, s2k);
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{
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dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
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if (!(dek->keylen > 0 && dek->keylen <= DIM(dek->key)))
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BUG ();
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if (gcry_kdf_derive (pw, strlen (pw),
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s2k->mode == 3? GCRY_KDF_ITERSALTED_S2K :
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s2k->mode == 1? GCRY_KDF_SALTED_S2K :
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/* */ GCRY_KDF_SIMPLE_S2K,
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s2k->hash_algo, s2k->salt, 8,
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S2K_DECODE_COUNT(s2k->count),
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dek->keylen, dek->key))
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{
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xfree (pw);
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xfree (dek);
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write_status( STATUS_MISSING_PASSPHRASE );
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return NULL;
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}
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}
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if (s2k_cacheid)
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memcpy (dek->s2k_cacheid, s2k_cacheid, sizeof dek->s2k_cacheid);
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xfree(last_pw);
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