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de29a50e7c
* agent/protect.c (s2k_calibration_time): New file global var. (calibrate_s2k_count): Use it here. (get_calibrated_s2k_count): Replace function static var by ... (s2k_calibrated_count): new file global var. (set_s2k_calibration_time): New function. * agent/gpg-agent.c (oS2KCalibration): New const. (opts): New option --s2k-calibration. (parse_rereadable_options): Parse that option. -- Note that using an unrelistic high value (like 60000) takes quite some time for calibration. GnuPG-bug-id: 3399 Signed-off-by: Werner Koch <wk@gnupg.org> (cherry picked from commit cbcc8c19541fe8407f3b6588fce1535c64cf6b25)
1761 lines
48 KiB
C
1761 lines
48 KiB
C
/* protect.c - Un/Protect a secret key
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* Copyright (C) 1998-2003, 2007, 2009, 2011 Free Software Foundation, Inc.
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* Copyright (C) 1998-2003, 2007, 2009, 2011, 2013-2015 Werner Koch
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <ctype.h>
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#include <assert.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#ifdef HAVE_W32_SYSTEM
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# ifdef HAVE_WINSOCK2_H
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# include <winsock2.h>
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# endif
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# include <windows.h>
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#else
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# include <sys/times.h>
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#endif
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#include "agent.h"
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#include "cvt-openpgp.h"
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#include "../common/sexp-parse.h"
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/* The protection mode for encryption. The supported modes for
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decryption are listed in agent_unprotect(). */
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#define PROT_CIPHER GCRY_CIPHER_AES128
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#define PROT_CIPHER_STRING "aes"
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#define PROT_CIPHER_KEYLEN (128/8)
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/* Decode an rfc4880 encoded S2K count. */
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#define S2K_DECODE_COUNT(_val) ((16ul + ((_val) & 15)) << (((_val) >> 4) + 6))
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/* A table containing the information needed to create a protected
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private key. */
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static const struct {
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const char *algo;
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const char *parmlist;
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int prot_from, prot_to;
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int ecc_hack;
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} protect_info[] = {
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{ "rsa", "nedpqu", 2, 5 },
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{ "dsa", "pqgyx", 4, 4 },
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{ "elg", "pgyx", 3, 3 },
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{ "ecdsa","pabgnqd", 6, 6, 1 },
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{ "ecdh", "pabgnqd", 6, 6, 1 },
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{ "ecc", "pabgnqd", 6, 6, 1 },
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{ NULL }
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};
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/* The number of milliseconds we use in the S2K function and the
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* calibrated count value. A count value of zero indicates that the
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* calibration has not yet been done or needs to be done again. */
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static unsigned int s2k_calibration_time = AGENT_S2K_CALIBRATION;
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static unsigned long s2k_calibrated_count;
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/* A helper object for time measurement. */
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struct calibrate_time_s
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{
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#ifdef HAVE_W32_SYSTEM
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FILETIME creation_time, exit_time, kernel_time, user_time;
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#else
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clock_t ticks;
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#endif
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};
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static int
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hash_passphrase (const char *passphrase, int hashalgo,
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int s2kmode,
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const unsigned char *s2ksalt, unsigned long s2kcount,
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unsigned char *key, size_t keylen);
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/* Get the process time and store it in DATA. */
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static void
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calibrate_get_time (struct calibrate_time_s *data)
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{
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#ifdef HAVE_W32_SYSTEM
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# ifdef HAVE_W32CE_SYSTEM
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GetThreadTimes (GetCurrentThread (),
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&data->creation_time, &data->exit_time,
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&data->kernel_time, &data->user_time);
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# else
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GetProcessTimes (GetCurrentProcess (),
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&data->creation_time, &data->exit_time,
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&data->kernel_time, &data->user_time);
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# endif
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#elif defined (CLOCK_THREAD_CPUTIME_ID)
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struct timespec tmp;
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clock_gettime (CLOCK_THREAD_CPUTIME_ID, &tmp);
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data->ticks = (clock_t)(((unsigned long long)tmp.tv_sec * 1000000000 +
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tmp.tv_nsec) * CLOCKS_PER_SEC / 1000000000);
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#else
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data->ticks = clock ();
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#endif
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}
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static unsigned long
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calibrate_elapsed_time (struct calibrate_time_s *starttime)
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{
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struct calibrate_time_s stoptime;
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calibrate_get_time (&stoptime);
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#ifdef HAVE_W32_SYSTEM
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{
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unsigned long long t1, t2;
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t1 = (((unsigned long long)starttime->kernel_time.dwHighDateTime << 32)
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+ starttime->kernel_time.dwLowDateTime);
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t1 += (((unsigned long long)starttime->user_time.dwHighDateTime << 32)
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+ starttime->user_time.dwLowDateTime);
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t2 = (((unsigned long long)stoptime.kernel_time.dwHighDateTime << 32)
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+ stoptime.kernel_time.dwLowDateTime);
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t2 += (((unsigned long long)stoptime.user_time.dwHighDateTime << 32)
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+ stoptime.user_time.dwLowDateTime);
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return (unsigned long)((t2 - t1)/10000);
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}
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#else
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return (unsigned long)((((double) (stoptime.ticks - starttime->ticks))
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/CLOCKS_PER_SEC)*1000);
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#endif
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}
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/* Run a test hashing for COUNT and return the time required in
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milliseconds. */
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static unsigned long
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calibrate_s2k_count_one (unsigned long count)
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{
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int rc;
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char keybuf[PROT_CIPHER_KEYLEN];
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struct calibrate_time_s starttime;
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calibrate_get_time (&starttime);
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rc = hash_passphrase ("123456789abcdef0", GCRY_MD_SHA1,
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3, "saltsalt", count, keybuf, sizeof keybuf);
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if (rc)
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BUG ();
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return calibrate_elapsed_time (&starttime);
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}
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/* Measure the time we need to do the hash operations and deduce an
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S2K count which requires roughly some targeted amount of time. */
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static unsigned long
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calibrate_s2k_count (void)
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{
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unsigned long count;
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unsigned long ms;
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for (count = 65536; count; count *= 2)
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{
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ms = calibrate_s2k_count_one (count);
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if (opt.verbose > 1)
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log_info ("S2K calibration: %lu -> %lums\n", count, ms);
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if (ms > s2k_calibration_time)
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break;
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}
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count = (unsigned long)(((double)count / ms) * s2k_calibration_time);
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count /= 1024;
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count *= 1024;
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if (count < 65536)
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count = 65536;
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if (opt.verbose)
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{
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ms = calibrate_s2k_count_one (count);
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log_info ("S2K calibration: %lu -> %lums\n", count, ms);
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}
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return count;
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}
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/* Set the calibration time. This may be called early at startup or
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* at any time. Thus it should one set variables. */
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void
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set_s2k_calibration_time (unsigned int milliseconds)
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{
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if (!milliseconds)
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milliseconds = AGENT_S2K_CALIBRATION;
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else if (milliseconds > 60 * 1000)
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milliseconds = 60 * 1000; /* Cap at 60 seconds. */
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s2k_calibration_time = milliseconds;
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s2k_calibrated_count = 0; /* Force re-calibration. */
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}
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/* Return the calibrated S2K count. This is only public for the use
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* of the Assuan getinfo s2k_count_cal command. */
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unsigned long
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get_calibrated_s2k_count (void)
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{
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if (!s2k_calibrated_count)
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s2k_calibrated_count = calibrate_s2k_count ();
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/* Enforce a lower limit. */
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return s2k_calibrated_count < 65536 ? 65536 : s2k_calibrated_count;
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}
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/* Return the standard S2K count. */
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unsigned long
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get_standard_s2k_count (void)
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{
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if (opt.s2k_count)
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return opt.s2k_count < 65536 ? 65536 : opt.s2k_count;
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return get_calibrated_s2k_count ();
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}
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/* Return the milliseconds required for the standard S2K
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* operation. */
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unsigned long
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get_standard_s2k_time (void)
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{
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return calibrate_s2k_count_one (get_standard_s2k_count ());
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}
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/* Same as get_standard_s2k_count but return the count in the encoding
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as described by rfc4880. */
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unsigned char
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get_standard_s2k_count_rfc4880 (void)
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{
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unsigned long iterations;
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unsigned int count;
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unsigned char result;
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unsigned char c=0;
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iterations = get_standard_s2k_count ();
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if (iterations >= 65011712)
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return 255;
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/* Need count to be in the range 16-31 */
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for (count=iterations>>6; count>=32; count>>=1)
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c++;
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result = (c<<4)|(count-16);
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if (S2K_DECODE_COUNT(result) < iterations)
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result++;
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return result;
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}
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/* Calculate the MIC for a private key or shared secret S-expression.
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SHA1HASH should point to a 20 byte buffer. This function is
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suitable for all algorithms. */
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static gpg_error_t
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calculate_mic (const unsigned char *plainkey, unsigned char *sha1hash)
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{
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const unsigned char *hash_begin, *hash_end;
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const unsigned char *s;
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size_t n;
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int is_shared_secret;
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s = plainkey;
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if (*s != '(')
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return gpg_error (GPG_ERR_INV_SEXP);
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s++;
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n = snext (&s);
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if (!n)
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return gpg_error (GPG_ERR_INV_SEXP);
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if (smatch (&s, n, "private-key"))
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is_shared_secret = 0;
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else if (smatch (&s, n, "shared-secret"))
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is_shared_secret = 1;
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else
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return gpg_error (GPG_ERR_UNKNOWN_SEXP);
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if (*s != '(')
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return gpg_error (GPG_ERR_UNKNOWN_SEXP);
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hash_begin = s;
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if (!is_shared_secret)
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{
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s++;
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n = snext (&s);
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if (!n)
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return gpg_error (GPG_ERR_INV_SEXP);
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s += n; /* Skip the algorithm name. */
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}
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while (*s == '(')
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{
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s++;
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n = snext (&s);
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if (!n)
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return gpg_error (GPG_ERR_INV_SEXP);
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s += n;
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n = snext (&s);
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if (!n)
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return gpg_error (GPG_ERR_INV_SEXP);
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s += n;
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if ( *s != ')' )
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return gpg_error (GPG_ERR_INV_SEXP);
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s++;
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}
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if (*s != ')')
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return gpg_error (GPG_ERR_INV_SEXP);
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s++;
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hash_end = s;
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gcry_md_hash_buffer (GCRY_MD_SHA1, sha1hash,
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hash_begin, hash_end - hash_begin);
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return 0;
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}
|
||
|
||
|
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/* Encrypt the parameter block starting at PROTBEGIN with length
|
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PROTLEN using the utf8 encoded key PASSPHRASE and return the entire
|
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encrypted block in RESULT or return with an error code. SHA1HASH
|
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is the 20 byte SHA-1 hash required for the integrity code.
|
||
|
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The parameter block is expected to be an incomplete canonical
|
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encoded S-Expression of the form (example in advanced format):
|
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|
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(d #046129F..[some bytes not shown]..81#)
|
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(p #00e861b..[some bytes not shown]..f1#)
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(q #00f7a7c..[some bytes not shown]..61#)
|
||
(u #304559a..[some bytes not shown]..9b#)
|
||
|
||
the returned block is the S-Expression:
|
||
|
||
(protected mode (parms) encrypted_octet_string)
|
||
|
||
*/
|
||
static int
|
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do_encryption (const unsigned char *hashbegin, size_t hashlen,
|
||
const unsigned char *protbegin, size_t protlen,
|
||
const char *passphrase,
|
||
const char *timestamp_exp, size_t timestamp_exp_len,
|
||
unsigned char **result, size_t *resultlen,
|
||
unsigned long s2k_count, int use_ocb)
|
||
{
|
||
gcry_cipher_hd_t hd;
|
||
const char *modestr;
|
||
unsigned char hashvalue[20];
|
||
int blklen, enclen, outlen;
|
||
unsigned char *iv = NULL;
|
||
unsigned int ivsize; /* Size of the buffer allocated for IV. */
|
||
const unsigned char *s2ksalt; /* Points into IV. */
|
||
int rc;
|
||
char *outbuf = NULL;
|
||
char *p;
|
||
int saltpos, ivpos, encpos;
|
||
|
||
s2ksalt = iv; /* Silence compiler warning. */
|
||
|
||
*resultlen = 0;
|
||
*result = NULL;
|
||
|
||
modestr = (use_ocb? "openpgp-s2k3-ocb-aes"
|
||
/* */: "openpgp-s2k3-sha1-" PROT_CIPHER_STRING "-cbc");
|
||
|
||
rc = gcry_cipher_open (&hd, PROT_CIPHER,
|
||
use_ocb? GCRY_CIPHER_MODE_OCB :
|
||
GCRY_CIPHER_MODE_CBC,
|
||
GCRY_CIPHER_SECURE);
|
||
if (rc)
|
||
return rc;
|
||
|
||
/* We need to work on a copy of the data because this makes it
|
||
* easier to add the trailer and the padding and more important we
|
||
* have to prefix the text with 2 parenthesis. In CBC mode we
|
||
* have to allocate enough space for:
|
||
*
|
||
* ((<parameter_list>)(4:hash4:sha120:<hashvalue>)) + padding
|
||
*
|
||
* we always append a full block of random bytes as padding but
|
||
* encrypt only what is needed for a full blocksize. In OCB mode we
|
||
* have to allocate enough space for just:
|
||
*
|
||
* ((<parameter_list>))
|
||
*/
|
||
blklen = gcry_cipher_get_algo_blklen (PROT_CIPHER);
|
||
if (use_ocb)
|
||
{
|
||
/* (( )) */
|
||
outlen = 2 + protlen + 2 ;
|
||
enclen = outlen + 16 /* taglen */;
|
||
outbuf = gcry_malloc_secure (enclen);
|
||
}
|
||
else
|
||
{
|
||
/* (( )( 4:hash 4:sha1 20:<hash> )) <padding> */
|
||
outlen = 2 + protlen + 2 + 6 + 6 + 23 + 2 + blklen;
|
||
enclen = outlen/blklen * blklen;
|
||
outbuf = gcry_malloc_secure (outlen);
|
||
}
|
||
if (!outbuf)
|
||
{
|
||
rc = out_of_core ();
|
||
goto leave;
|
||
}
|
||
|
||
/* Allocate a buffer for the nonce and the salt. */
|
||
if (!rc)
|
||
{
|
||
/* Allocate random bytes to be used as IV, padding and s2k salt
|
||
* or in OCB mode for a nonce and the s2k salt. The IV/nonce is
|
||
* set later because for OCB we need to set the key first. */
|
||
ivsize = (use_ocb? 12 : (blklen*2)) + 8;
|
||
iv = xtrymalloc (ivsize);
|
||
if (!iv)
|
||
rc = gpg_error_from_syserror ();
|
||
else
|
||
{
|
||
gcry_create_nonce (iv, ivsize);
|
||
s2ksalt = iv + ivsize - 8;
|
||
}
|
||
}
|
||
|
||
/* Hash the passphrase and set the key. */
|
||
if (!rc)
|
||
{
|
||
unsigned char *key;
|
||
size_t keylen = PROT_CIPHER_KEYLEN;
|
||
|
||
key = gcry_malloc_secure (keylen);
|
||
if (!key)
|
||
rc = out_of_core ();
|
||
else
|
||
{
|
||
rc = hash_passphrase (passphrase, GCRY_MD_SHA1,
|
||
3, s2ksalt,
|
||
s2k_count? s2k_count:get_standard_s2k_count(),
|
||
key, keylen);
|
||
if (!rc)
|
||
rc = gcry_cipher_setkey (hd, key, keylen);
|
||
xfree (key);
|
||
}
|
||
}
|
||
|
||
if (rc)
|
||
goto leave;
|
||
|
||
/* Set the IV/nonce. */
|
||
rc = gcry_cipher_setiv (hd, iv, use_ocb? 12 : blklen);
|
||
if (rc)
|
||
goto leave;
|
||
|
||
if (use_ocb)
|
||
{
|
||
/* In OCB Mode we use only the public key parameters as AAD. */
|
||
rc = gcry_cipher_authenticate (hd, hashbegin, protbegin - hashbegin);
|
||
if (!rc)
|
||
rc = gcry_cipher_authenticate (hd, timestamp_exp, timestamp_exp_len);
|
||
if (!rc)
|
||
rc = gcry_cipher_authenticate
|
||
(hd, protbegin+protlen, hashlen - (protbegin+protlen - hashbegin));
|
||
}
|
||
else
|
||
{
|
||
/* Hash the entire expression for CBC mode. Because
|
||
* TIMESTAMP_EXP won't get protected, we can't simply hash a
|
||
* continuous buffer but need to call md_write several times. */
|
||
gcry_md_hd_t md;
|
||
|
||
rc = gcry_md_open (&md, GCRY_MD_SHA1, 0 );
|
||
if (!rc)
|
||
{
|
||
gcry_md_write (md, hashbegin, protbegin - hashbegin);
|
||
gcry_md_write (md, protbegin, protlen);
|
||
gcry_md_write (md, timestamp_exp, timestamp_exp_len);
|
||
gcry_md_write (md, protbegin+protlen,
|
||
hashlen - (protbegin+protlen - hashbegin));
|
||
memcpy (hashvalue, gcry_md_read (md, GCRY_MD_SHA1), 20);
|
||
gcry_md_close (md);
|
||
}
|
||
}
|
||
|
||
|
||
/* Encrypt. */
|
||
if (!rc)
|
||
{
|
||
p = outbuf;
|
||
*p++ = '(';
|
||
*p++ = '(';
|
||
memcpy (p, protbegin, protlen);
|
||
p += protlen;
|
||
if (use_ocb)
|
||
{
|
||
*p++ = ')';
|
||
*p++ = ')';
|
||
}
|
||
else
|
||
{
|
||
memcpy (p, ")(4:hash4:sha120:", 17);
|
||
p += 17;
|
||
memcpy (p, hashvalue, 20);
|
||
p += 20;
|
||
*p++ = ')';
|
||
*p++ = ')';
|
||
memcpy (p, iv+blklen, blklen); /* Add padding. */
|
||
p += blklen;
|
||
}
|
||
assert ( p - outbuf == outlen);
|
||
if (use_ocb)
|
||
{
|
||
gcry_cipher_final (hd);
|
||
rc = gcry_cipher_encrypt (hd, outbuf, outlen, NULL, 0);
|
||
if (!rc)
|
||
{
|
||
log_assert (outlen + 16 == enclen);
|
||
rc = gcry_cipher_gettag (hd, outbuf + outlen, 16);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
rc = gcry_cipher_encrypt (hd, outbuf, enclen, NULL, 0);
|
||
}
|
||
}
|
||
|
||
if (rc)
|
||
goto leave;
|
||
|
||
/* Release cipher handle and check for errors. */
|
||
gcry_cipher_close (hd);
|
||
|
||
/* Now allocate the buffer we want to return. This is
|
||
|
||
(protected openpgp-s2k3-sha1-aes-cbc
|
||
((sha1 salt no_of_iterations) 16byte_iv)
|
||
encrypted_octet_string)
|
||
|
||
in canoncical format of course. We use asprintf and %n modifier
|
||
and dummy values as placeholders. */
|
||
{
|
||
char countbuf[35];
|
||
|
||
snprintf (countbuf, sizeof countbuf, "%lu",
|
||
s2k_count ? s2k_count : get_standard_s2k_count ());
|
||
p = xtryasprintf
|
||
("(9:protected%d:%s((4:sha18:%n_8bytes_%u:%s)%d:%n%*s)%d:%n%*s)",
|
||
(int)strlen (modestr), modestr,
|
||
&saltpos,
|
||
(unsigned int)strlen (countbuf), countbuf,
|
||
use_ocb? 12 : blklen, &ivpos, use_ocb? 12 : blklen, "",
|
||
enclen, &encpos, enclen, "");
|
||
if (!p)
|
||
{
|
||
gpg_error_t tmperr = out_of_core ();
|
||
xfree (iv);
|
||
xfree (outbuf);
|
||
return tmperr;
|
||
}
|
||
|
||
}
|
||
*resultlen = strlen (p);
|
||
*result = (unsigned char*)p;
|
||
memcpy (p+saltpos, s2ksalt, 8);
|
||
memcpy (p+ivpos, iv, use_ocb? 12 : blklen);
|
||
memcpy (p+encpos, outbuf, enclen);
|
||
xfree (iv);
|
||
xfree (outbuf);
|
||
return 0;
|
||
|
||
leave:
|
||
gcry_cipher_close (hd);
|
||
xfree (iv);
|
||
xfree (outbuf);
|
||
return rc;
|
||
}
|
||
|
||
|
||
|
||
/* Protect the key encoded in canonical format in PLAINKEY. We assume
|
||
a valid S-Exp here. With USE_UCB set to -1 the default scheme is
|
||
used (ie. either CBC or OCB), set to 0 the old CBC mode is used,
|
||
and set to 1 OCB is used. */
|
||
int
|
||
agent_protect (const unsigned char *plainkey, const char *passphrase,
|
||
unsigned char **result, size_t *resultlen,
|
||
unsigned long s2k_count, int use_ocb)
|
||
{
|
||
int rc;
|
||
const char *parmlist;
|
||
int prot_from_idx, prot_to_idx;
|
||
const unsigned char *s;
|
||
const unsigned char *hash_begin, *hash_end;
|
||
const unsigned char *prot_begin, *prot_end, *real_end;
|
||
size_t n;
|
||
int c, infidx, i;
|
||
char timestamp_exp[35];
|
||
unsigned char *protected;
|
||
size_t protectedlen;
|
||
int depth = 0;
|
||
unsigned char *p;
|
||
int have_curve = 0;
|
||
|
||
if (use_ocb == -1)
|
||
use_ocb = opt.enable_extended_key_format;
|
||
|
||
/* Create an S-expression with the protected-at timestamp. */
|
||
memcpy (timestamp_exp, "(12:protected-at15:", 19);
|
||
gnupg_get_isotime (timestamp_exp+19);
|
||
timestamp_exp[19+15] = ')';
|
||
|
||
/* Parse original key. */
|
||
s = plainkey;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (!smatch (&s, n, "private-key"))
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
depth++;
|
||
hash_begin = s;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
for (infidx=0; protect_info[infidx].algo
|
||
&& !smatch (&s, n, protect_info[infidx].algo); infidx++)
|
||
;
|
||
if (!protect_info[infidx].algo)
|
||
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
|
||
|
||
/* The parser below is a complete mess: To make it robust for ECC
|
||
use we should reorder the s-expression to include only what we
|
||
really need and thus guarantee the right order for saving stuff.
|
||
This should be done before calling this function and maybe with
|
||
the help of the new gcry_sexp_extract_param. */
|
||
parmlist = protect_info[infidx].parmlist;
|
||
prot_from_idx = protect_info[infidx].prot_from;
|
||
prot_to_idx = protect_info[infidx].prot_to;
|
||
prot_begin = prot_end = NULL;
|
||
for (i=0; (c=parmlist[i]); i++)
|
||
{
|
||
if (i == prot_from_idx)
|
||
prot_begin = s;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (n != 1 || c != *s)
|
||
{
|
||
if (n == 5 && !memcmp (s, "curve", 5)
|
||
&& !i && protect_info[infidx].ecc_hack)
|
||
{
|
||
/* This is a private ECC key but the first parameter is
|
||
the name of the curve. We change the parameter list
|
||
here to the one we expect in this case. */
|
||
have_curve = 1;
|
||
parmlist = "?qd";
|
||
prot_from_idx = 2;
|
||
prot_to_idx = 2;
|
||
}
|
||
else if (n == 5 && !memcmp (s, "flags", 5)
|
||
&& i == 1 && have_curve)
|
||
{
|
||
/* "curve" followed by "flags": Change again. */
|
||
parmlist = "??qd";
|
||
prot_from_idx = 3;
|
||
prot_to_idx = 3;
|
||
}
|
||
else
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
}
|
||
s += n;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s +=n; /* skip value */
|
||
if (*s != ')')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth--;
|
||
if (i == prot_to_idx)
|
||
prot_end = s;
|
||
s++;
|
||
}
|
||
if (*s != ')' || !prot_begin || !prot_end )
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth--;
|
||
hash_end = s;
|
||
s++;
|
||
/* Skip to the end of the S-expression. */
|
||
assert (depth == 1);
|
||
rc = sskip (&s, &depth);
|
||
if (rc)
|
||
return rc;
|
||
assert (!depth);
|
||
real_end = s-1;
|
||
|
||
rc = do_encryption (hash_begin, hash_end - hash_begin + 1,
|
||
prot_begin, prot_end - prot_begin + 1,
|
||
passphrase, timestamp_exp, sizeof (timestamp_exp),
|
||
&protected, &protectedlen, s2k_count, use_ocb);
|
||
if (rc)
|
||
return rc;
|
||
|
||
/* Now create the protected version of the key. Note that the 10
|
||
extra bytes are for the inserted "protected-" string (the
|
||
beginning of the plaintext reads: "((11:private-key(" ). The 35
|
||
term is the space for (12:protected-at15:<timestamp>). */
|
||
*resultlen = (10
|
||
+ (prot_begin-plainkey)
|
||
+ protectedlen
|
||
+ 35
|
||
+ (real_end-prot_end));
|
||
*result = p = xtrymalloc (*resultlen);
|
||
if (!p)
|
||
{
|
||
gpg_error_t tmperr = out_of_core ();
|
||
xfree (protected);
|
||
return tmperr;
|
||
}
|
||
memcpy (p, "(21:protected-", 14);
|
||
p += 14;
|
||
memcpy (p, plainkey+4, prot_begin - plainkey - 4);
|
||
p += prot_begin - plainkey - 4;
|
||
memcpy (p, protected, protectedlen);
|
||
p += protectedlen;
|
||
|
||
memcpy (p, timestamp_exp, 35);
|
||
p += 35;
|
||
|
||
memcpy (p, prot_end+1, real_end - prot_end);
|
||
p += real_end - prot_end;
|
||
assert ( p - *result == *resultlen);
|
||
xfree (protected);
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
|
||
/* Do the actual decryption and check the return list for consistency. */
|
||
static gpg_error_t
|
||
do_decryption (const unsigned char *aad_begin, size_t aad_len,
|
||
const unsigned char *aadhole_begin, size_t aadhole_len,
|
||
const unsigned char *protected, size_t protectedlen,
|
||
const char *passphrase,
|
||
const unsigned char *s2ksalt, unsigned long s2kcount,
|
||
const unsigned char *iv, size_t ivlen,
|
||
int prot_cipher, int prot_cipher_keylen, int is_ocb,
|
||
unsigned char **result)
|
||
{
|
||
int rc;
|
||
int blklen;
|
||
gcry_cipher_hd_t hd;
|
||
unsigned char *outbuf;
|
||
size_t reallen;
|
||
|
||
blklen = gcry_cipher_get_algo_blklen (prot_cipher);
|
||
if (is_ocb)
|
||
{
|
||
/* OCB does not require a multiple of the block length but we
|
||
* check that it is long enough for the 128 bit tag and that we
|
||
* have the 96 bit nonce. */
|
||
if (protectedlen < (4 + 16) || ivlen != 12)
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
}
|
||
else
|
||
{
|
||
if (protectedlen < 4 || (protectedlen%blklen))
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
}
|
||
|
||
rc = gcry_cipher_open (&hd, prot_cipher,
|
||
is_ocb? GCRY_CIPHER_MODE_OCB :
|
||
GCRY_CIPHER_MODE_CBC,
|
||
GCRY_CIPHER_SECURE);
|
||
if (rc)
|
||
return rc;
|
||
|
||
outbuf = gcry_malloc_secure (protectedlen);
|
||
if (!outbuf)
|
||
rc = out_of_core ();
|
||
|
||
/* Hash the passphrase and set the key. */
|
||
if (!rc)
|
||
{
|
||
unsigned char *key;
|
||
|
||
key = gcry_malloc_secure (prot_cipher_keylen);
|
||
if (!key)
|
||
rc = out_of_core ();
|
||
else
|
||
{
|
||
rc = hash_passphrase (passphrase, GCRY_MD_SHA1,
|
||
3, s2ksalt, s2kcount, key, prot_cipher_keylen);
|
||
if (!rc)
|
||
rc = gcry_cipher_setkey (hd, key, prot_cipher_keylen);
|
||
xfree (key);
|
||
}
|
||
}
|
||
|
||
/* Set the IV/nonce. */
|
||
if (!rc)
|
||
{
|
||
rc = gcry_cipher_setiv (hd, iv, ivlen);
|
||
}
|
||
|
||
/* Decrypt. */
|
||
if (!rc)
|
||
{
|
||
if (is_ocb)
|
||
{
|
||
rc = gcry_cipher_authenticate (hd, aad_begin,
|
||
aadhole_begin - aad_begin);
|
||
if (!rc)
|
||
rc = gcry_cipher_authenticate
|
||
(hd, aadhole_begin + aadhole_len,
|
||
aad_len - (aadhole_begin+aadhole_len - aad_begin));
|
||
|
||
if (!rc)
|
||
{
|
||
gcry_cipher_final (hd);
|
||
rc = gcry_cipher_decrypt (hd, outbuf, protectedlen - 16,
|
||
protected, protectedlen - 16);
|
||
}
|
||
if (!rc)
|
||
{
|
||
rc = gcry_cipher_checktag (hd, protected + protectedlen - 16, 16);
|
||
if (gpg_err_code (rc) == GPG_ERR_CHECKSUM)
|
||
{
|
||
/* Return Bad Passphrase instead of checksum error */
|
||
rc = gpg_error (GPG_ERR_BAD_PASSPHRASE);
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
rc = gcry_cipher_decrypt (hd, outbuf, protectedlen,
|
||
protected, protectedlen);
|
||
}
|
||
}
|
||
|
||
/* Release cipher handle and check for errors. */
|
||
gcry_cipher_close (hd);
|
||
if (rc)
|
||
{
|
||
xfree (outbuf);
|
||
return rc;
|
||
}
|
||
|
||
/* Do a quick check on the data structure. */
|
||
if (*outbuf != '(' && outbuf[1] != '(')
|
||
{
|
||
xfree (outbuf);
|
||
return gpg_error (GPG_ERR_BAD_PASSPHRASE);
|
||
}
|
||
|
||
/* Check that we have a consistent S-Exp. */
|
||
reallen = gcry_sexp_canon_len (outbuf, protectedlen, NULL, NULL);
|
||
if (!reallen || (reallen + blklen < protectedlen) )
|
||
{
|
||
xfree (outbuf);
|
||
return gpg_error (GPG_ERR_BAD_PASSPHRASE);
|
||
}
|
||
*result = outbuf;
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Merge the parameter list contained in CLEARTEXT with the original
|
||
* protect lists PROTECTEDKEY by replacing the list at REPLACEPOS.
|
||
* Return the new list in RESULT and the MIC value in the 20 byte
|
||
* buffer SHA1HASH; if SHA1HASH is NULL no MIC will be computed.
|
||
* CUTOFF and CUTLEN will receive the offset and the length of the
|
||
* resulting list which should go into the MIC calculation but then be
|
||
* removed. */
|
||
static gpg_error_t
|
||
merge_lists (const unsigned char *protectedkey,
|
||
size_t replacepos,
|
||
const unsigned char *cleartext,
|
||
unsigned char *sha1hash,
|
||
unsigned char **result, size_t *resultlen,
|
||
size_t *cutoff, size_t *cutlen)
|
||
{
|
||
size_t n, newlistlen;
|
||
unsigned char *newlist, *p;
|
||
const unsigned char *s;
|
||
const unsigned char *startpos, *endpos;
|
||
int i, rc;
|
||
|
||
*result = NULL;
|
||
*resultlen = 0;
|
||
*cutoff = 0;
|
||
*cutlen = 0;
|
||
|
||
if (replacepos < 26)
|
||
return gpg_error (GPG_ERR_BUG);
|
||
|
||
/* Estimate the required size of the resulting list. We have a large
|
||
safety margin of >20 bytes (FIXME: MIC hash from CLEARTEXT and the
|
||
removed "protected-" */
|
||
newlistlen = gcry_sexp_canon_len (protectedkey, 0, NULL, NULL);
|
||
if (!newlistlen)
|
||
return gpg_error (GPG_ERR_BUG);
|
||
n = gcry_sexp_canon_len (cleartext, 0, NULL, NULL);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_BUG);
|
||
newlistlen += n;
|
||
newlist = gcry_malloc_secure (newlistlen);
|
||
if (!newlist)
|
||
return out_of_core ();
|
||
|
||
/* Copy the initial segment */
|
||
strcpy ((char*)newlist, "(11:private-key");
|
||
p = newlist + 15;
|
||
memcpy (p, protectedkey+15+10, replacepos-15-10);
|
||
p += replacepos-15-10;
|
||
|
||
/* Copy the cleartext. */
|
||
s = cleartext;
|
||
if (*s != '(' && s[1] != '(')
|
||
return gpg_error (GPG_ERR_BUG); /*we already checked this */
|
||
s += 2;
|
||
startpos = s;
|
||
while ( *s == '(' )
|
||
{
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
goto invalid_sexp;
|
||
s += n;
|
||
n = snext (&s);
|
||
if (!n)
|
||
goto invalid_sexp;
|
||
s += n;
|
||
if ( *s != ')' )
|
||
goto invalid_sexp;
|
||
s++;
|
||
}
|
||
if ( *s != ')' )
|
||
goto invalid_sexp;
|
||
endpos = s;
|
||
s++;
|
||
|
||
/* Intermezzo: Get the MIC if requested. */
|
||
if (sha1hash)
|
||
{
|
||
if (*s != '(')
|
||
goto invalid_sexp;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!smatch (&s, n, "hash"))
|
||
goto invalid_sexp;
|
||
n = snext (&s);
|
||
if (!smatch (&s, n, "sha1"))
|
||
goto invalid_sexp;
|
||
n = snext (&s);
|
||
if (n != 20)
|
||
goto invalid_sexp;
|
||
memcpy (sha1hash, s, 20);
|
||
s += n;
|
||
if (*s != ')')
|
||
goto invalid_sexp;
|
||
}
|
||
|
||
/* Append the parameter list. */
|
||
memcpy (p, startpos, endpos - startpos);
|
||
p += endpos - startpos;
|
||
|
||
/* Skip over the protected list element in the original list. */
|
||
s = protectedkey + replacepos;
|
||
assert (*s == '(');
|
||
s++;
|
||
i = 1;
|
||
rc = sskip (&s, &i);
|
||
if (rc)
|
||
goto failure;
|
||
/* Record the position of the optional protected-at expression. */
|
||
if (*s == '(')
|
||
{
|
||
const unsigned char *save_s = s;
|
||
s++;
|
||
n = snext (&s);
|
||
if (smatch (&s, n, "protected-at"))
|
||
{
|
||
i = 1;
|
||
rc = sskip (&s, &i);
|
||
if (rc)
|
||
goto failure;
|
||
*cutlen = s - save_s;
|
||
}
|
||
s = save_s;
|
||
}
|
||
startpos = s;
|
||
i = 2; /* we are inside this level */
|
||
rc = sskip (&s, &i);
|
||
if (rc)
|
||
goto failure;
|
||
assert (s[-1] == ')');
|
||
endpos = s; /* one behind the end of the list */
|
||
|
||
/* Append the rest. */
|
||
if (*cutlen)
|
||
*cutoff = p - newlist;
|
||
memcpy (p, startpos, endpos - startpos);
|
||
p += endpos - startpos;
|
||
|
||
|
||
/* ready */
|
||
*result = newlist;
|
||
*resultlen = newlistlen;
|
||
return 0;
|
||
|
||
failure:
|
||
wipememory (newlist, newlistlen);
|
||
xfree (newlist);
|
||
return rc;
|
||
|
||
invalid_sexp:
|
||
wipememory (newlist, newlistlen);
|
||
xfree (newlist);
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
}
|
||
|
||
|
||
|
||
/* Unprotect the key encoded in canonical format. We assume a valid
|
||
S-Exp here. If a protected-at item is available, its value will
|
||
be stored at protected_at unless this is NULL. */
|
||
gpg_error_t
|
||
agent_unprotect (ctrl_t ctrl,
|
||
const unsigned char *protectedkey, const char *passphrase,
|
||
gnupg_isotime_t protected_at,
|
||
unsigned char **result, size_t *resultlen)
|
||
{
|
||
static const struct {
|
||
const char *name; /* Name of the protection method. */
|
||
int algo; /* (A zero indicates the "openpgp-native" hack.) */
|
||
int keylen; /* Used key length in bytes. */
|
||
unsigned int is_ocb:1;
|
||
} algotable[] = {
|
||
{ "openpgp-s2k3-sha1-aes-cbc", GCRY_CIPHER_AES128, (128/8)},
|
||
{ "openpgp-s2k3-sha1-aes256-cbc", GCRY_CIPHER_AES256, (256/8)},
|
||
{ "openpgp-s2k3-ocb-aes", GCRY_CIPHER_AES128, (128/8), 1},
|
||
{ "openpgp-native", 0, 0 }
|
||
};
|
||
int rc;
|
||
const unsigned char *s;
|
||
const unsigned char *protect_list;
|
||
size_t n;
|
||
int infidx, i;
|
||
unsigned char sha1hash[20], sha1hash2[20];
|
||
const unsigned char *s2ksalt;
|
||
unsigned long s2kcount;
|
||
const unsigned char *iv;
|
||
int prot_cipher, prot_cipher_keylen;
|
||
int is_ocb;
|
||
const unsigned char *aad_begin, *aad_end, *aadhole_begin, *aadhole_end;
|
||
const unsigned char *prot_begin;
|
||
unsigned char *cleartext;
|
||
unsigned char *final;
|
||
size_t finallen;
|
||
size_t cutoff, cutlen;
|
||
|
||
if (protected_at)
|
||
*protected_at = 0;
|
||
|
||
s = protectedkey;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (!smatch (&s, n, "protected-private-key"))
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
{
|
||
aad_begin = aad_end = s;
|
||
aad_end++;
|
||
i = 1;
|
||
rc = sskip (&aad_end, &i);
|
||
if (rc)
|
||
return rc;
|
||
}
|
||
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
for (infidx=0; protect_info[infidx].algo
|
||
&& !smatch (&s, n, protect_info[infidx].algo); infidx++)
|
||
;
|
||
if (!protect_info[infidx].algo)
|
||
return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
|
||
|
||
/* See wether we have a protected-at timestamp. */
|
||
protect_list = s; /* Save for later. */
|
||
if (protected_at)
|
||
{
|
||
while (*s == '(')
|
||
{
|
||
prot_begin = s;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (smatch (&s, n, "protected-at"))
|
||
{
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (n != 15)
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
memcpy (protected_at, s, 15);
|
||
protected_at[15] = 0;
|
||
break;
|
||
}
|
||
s += n;
|
||
i = 1;
|
||
rc = sskip (&s, &i);
|
||
if (rc)
|
||
return rc;
|
||
}
|
||
}
|
||
|
||
/* Now find the list with the protected information. Here is an
|
||
example for such a list:
|
||
(protected openpgp-s2k3-sha1-aes-cbc
|
||
((sha1 <salt> <count>) <Initialization_Vector>)
|
||
<encrypted_data>)
|
||
*/
|
||
s = protect_list;
|
||
for (;;)
|
||
{
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
prot_begin = s;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (smatch (&s, n, "protected"))
|
||
break;
|
||
s += n;
|
||
i = 1;
|
||
rc = sskip (&s, &i);
|
||
if (rc)
|
||
return rc;
|
||
}
|
||
/* found */
|
||
{
|
||
aadhole_begin = aadhole_end = prot_begin;
|
||
aadhole_end++;
|
||
i = 1;
|
||
rc = sskip (&aadhole_end, &i);
|
||
if (rc)
|
||
return rc;
|
||
}
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
/* Lookup the protection algo. */
|
||
prot_cipher = 0; /* (avoid gcc warning) */
|
||
prot_cipher_keylen = 0; /* (avoid gcc warning) */
|
||
is_ocb = 0;
|
||
for (i=0; i < DIM (algotable); i++)
|
||
if (smatch (&s, n, algotable[i].name))
|
||
{
|
||
prot_cipher = algotable[i].algo;
|
||
prot_cipher_keylen = algotable[i].keylen;
|
||
is_ocb = algotable[i].is_ocb;
|
||
break;
|
||
}
|
||
if (i == DIM (algotable))
|
||
return gpg_error (GPG_ERR_UNSUPPORTED_PROTECTION);
|
||
|
||
if (!prot_cipher) /* This is "openpgp-native". */
|
||
{
|
||
gcry_sexp_t s_prot_begin;
|
||
|
||
rc = gcry_sexp_sscan (&s_prot_begin, NULL,
|
||
prot_begin,
|
||
gcry_sexp_canon_len (prot_begin, 0,NULL,NULL));
|
||
if (rc)
|
||
return rc;
|
||
|
||
rc = convert_from_openpgp_native (ctrl, s_prot_begin, passphrase, &final);
|
||
gcry_sexp_release (s_prot_begin);
|
||
if (!rc)
|
||
{
|
||
*result = final;
|
||
*resultlen = gcry_sexp_canon_len (final, 0, NULL, NULL);
|
||
}
|
||
return rc;
|
||
}
|
||
|
||
if (*s != '(' || s[1] != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s += 2;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (!smatch (&s, n, "sha1"))
|
||
return gpg_error (GPG_ERR_UNSUPPORTED_PROTECTION);
|
||
n = snext (&s);
|
||
if (n != 8)
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
s2ksalt = s;
|
||
s += n;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
/* We expect a list close as next, so we can simply use strtoul()
|
||
here. We might want to check that we only have digits - but this
|
||
is nothing we should worry about */
|
||
if (s[n] != ')' )
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
/* Old versions of gpg-agent used the funny floating point number in
|
||
a byte encoding as specified by OpenPGP. However this is not
|
||
needed and thus we now store it as a plain unsigned integer. We
|
||
can easily distinguish the old format by looking at its value:
|
||
Less than 256 is an old-style encoded number; other values are
|
||
plain integers. In any case we check that they are at least
|
||
65536 because we never used a lower value in the past and we
|
||
should have a lower limit. */
|
||
s2kcount = strtoul ((const char*)s, NULL, 10);
|
||
if (!s2kcount)
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
if (s2kcount < 256)
|
||
s2kcount = (16ul + (s2kcount & 15)) << ((s2kcount >> 4) + 6);
|
||
if (s2kcount < 65536)
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
|
||
s += n;
|
||
s++; /* skip list end */
|
||
|
||
n = snext (&s);
|
||
if (is_ocb)
|
||
{
|
||
if (n != 12) /* Wrong size of the nonce. */
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
}
|
||
else
|
||
{
|
||
if (n != 16) /* Wrong blocksize for IV (we support only 128 bit). */
|
||
return gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
}
|
||
iv = s;
|
||
s += n;
|
||
if (*s != ')' )
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
cleartext = NULL; /* Avoid cc warning. */
|
||
rc = do_decryption (aad_begin, aad_end - aad_begin,
|
||
aadhole_begin, aadhole_end - aadhole_begin,
|
||
s, n,
|
||
passphrase, s2ksalt, s2kcount,
|
||
iv, is_ocb? 12:16,
|
||
prot_cipher, prot_cipher_keylen, is_ocb,
|
||
&cleartext);
|
||
if (rc)
|
||
return rc;
|
||
|
||
rc = merge_lists (protectedkey, prot_begin-protectedkey, cleartext,
|
||
is_ocb? NULL : sha1hash,
|
||
&final, &finallen, &cutoff, &cutlen);
|
||
/* Albeit cleartext has been allocated in secure memory and thus
|
||
xfree will wipe it out, we do an extra wipe just in case
|
||
somethings goes badly wrong. */
|
||
wipememory (cleartext, n);
|
||
xfree (cleartext);
|
||
if (rc)
|
||
return rc;
|
||
|
||
if (!is_ocb)
|
||
{
|
||
rc = calculate_mic (final, sha1hash2);
|
||
if (!rc && memcmp (sha1hash, sha1hash2, 20))
|
||
rc = gpg_error (GPG_ERR_CORRUPTED_PROTECTION);
|
||
if (rc)
|
||
{
|
||
wipememory (final, finallen);
|
||
xfree (final);
|
||
return rc;
|
||
}
|
||
}
|
||
|
||
/* Now remove the part which is included in the MIC but should not
|
||
go into the final thing. */
|
||
if (cutlen)
|
||
{
|
||
memmove (final+cutoff, final+cutoff+cutlen, finallen-cutoff-cutlen);
|
||
finallen -= cutlen;
|
||
}
|
||
|
||
*result = final;
|
||
*resultlen = gcry_sexp_canon_len (final, 0, NULL, NULL);
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Check the type of the private key, this is one of the constants:
|
||
PRIVATE_KEY_UNKNOWN if we can't figure out the type (this is the
|
||
value 0), PRIVATE_KEY_CLEAR for an unprotected private key.
|
||
PRIVATE_KEY_PROTECTED for an protected private key or
|
||
PRIVATE_KEY_SHADOWED for a sub key where the secret parts are
|
||
stored elsewhere. Finally PRIVATE_KEY_OPENPGP_NONE may be returned
|
||
is the key is still in the openpgp-native format but without
|
||
protection. */
|
||
int
|
||
agent_private_key_type (const unsigned char *privatekey)
|
||
{
|
||
const unsigned char *s;
|
||
size_t n;
|
||
int i;
|
||
|
||
s = privatekey;
|
||
if (*s != '(')
|
||
return PRIVATE_KEY_UNKNOWN;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN;
|
||
if (smatch (&s, n, "protected-private-key"))
|
||
{
|
||
/* We need to check whether this is openpgp-native protected
|
||
with the protection method "none". In that case we return a
|
||
different key type so that the caller knows that there is no
|
||
need to ask for a passphrase. */
|
||
if (*s != '(')
|
||
return PRIVATE_KEY_PROTECTED; /* Unknown sexp - assume protected. */
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
s += n; /* Skip over the algo */
|
||
|
||
/* Find the (protected ...) list. */
|
||
for (;;)
|
||
{
|
||
if (*s != '(')
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
if (smatch (&s, n, "protected"))
|
||
break;
|
||
s += n;
|
||
i = 1;
|
||
if (sskip (&s, &i))
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
}
|
||
/* Found - Is this openpgp-native? */
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
if (smatch (&s, n, "openpgp-native")) /* Yes. */
|
||
{
|
||
if (*s != '(')
|
||
return PRIVATE_KEY_UNKNOWN; /* Unknown sexp. */
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
s += n; /* Skip over "openpgp-private-key". */
|
||
/* Find the (protection ...) list. */
|
||
for (;;)
|
||
{
|
||
if (*s != '(')
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
if (smatch (&s, n, "protection"))
|
||
break;
|
||
s += n;
|
||
i = 1;
|
||
if (sskip (&s, &i))
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
}
|
||
/* Found - Is the mode "none"? */
|
||
n = snext (&s);
|
||
if (!n)
|
||
return PRIVATE_KEY_UNKNOWN; /* Invalid sexp. */
|
||
if (smatch (&s, n, "none"))
|
||
return PRIVATE_KEY_OPENPGP_NONE; /* Yes. */
|
||
}
|
||
|
||
return PRIVATE_KEY_PROTECTED;
|
||
}
|
||
if (smatch (&s, n, "shadowed-private-key"))
|
||
return PRIVATE_KEY_SHADOWED;
|
||
if (smatch (&s, n, "private-key"))
|
||
return PRIVATE_KEY_CLEAR;
|
||
return PRIVATE_KEY_UNKNOWN;
|
||
}
|
||
|
||
|
||
|
||
/* Transform a passphrase into a suitable key of length KEYLEN and
|
||
store this key in the caller provided buffer KEY. The caller must
|
||
provide an HASHALGO, a valid S2KMODE (see rfc-2440) and depending on
|
||
that mode an S2KSALT of 8 random bytes and an S2KCOUNT.
|
||
|
||
Returns an error code on failure. */
|
||
static int
|
||
hash_passphrase (const char *passphrase, int hashalgo,
|
||
int s2kmode,
|
||
const unsigned char *s2ksalt,
|
||
unsigned long s2kcount,
|
||
unsigned char *key, size_t keylen)
|
||
{
|
||
/* The key derive function does not support a zero length string for
|
||
the passphrase in the S2K modes. Return a better suited error
|
||
code than GPG_ERR_INV_DATA. */
|
||
if (!passphrase || !*passphrase)
|
||
return gpg_error (GPG_ERR_NO_PASSPHRASE);
|
||
return gcry_kdf_derive (passphrase, strlen (passphrase),
|
||
s2kmode == 3? GCRY_KDF_ITERSALTED_S2K :
|
||
s2kmode == 1? GCRY_KDF_SALTED_S2K :
|
||
s2kmode == 0? GCRY_KDF_SIMPLE_S2K : GCRY_KDF_NONE,
|
||
hashalgo, s2ksalt, 8, s2kcount,
|
||
keylen, key);
|
||
}
|
||
|
||
|
||
gpg_error_t
|
||
s2k_hash_passphrase (const char *passphrase, int hashalgo,
|
||
int s2kmode,
|
||
const unsigned char *s2ksalt,
|
||
unsigned int s2kcount,
|
||
unsigned char *key, size_t keylen)
|
||
{
|
||
return hash_passphrase (passphrase, hashalgo, s2kmode, s2ksalt,
|
||
S2K_DECODE_COUNT (s2kcount),
|
||
key, keylen);
|
||
}
|
||
|
||
|
||
|
||
|
||
/* Create an canonical encoded S-expression with the shadow info from
|
||
a card's SERIALNO and the IDSTRING. */
|
||
unsigned char *
|
||
make_shadow_info (const char *serialno, const char *idstring)
|
||
{
|
||
const char *s;
|
||
char *info, *p;
|
||
char numbuf[20];
|
||
size_t n;
|
||
|
||
for (s=serialno, n=0; *s && s[1]; s += 2)
|
||
n++;
|
||
|
||
info = p = xtrymalloc (1 + sizeof numbuf + n
|
||
+ sizeof numbuf + strlen (idstring) + 1 + 1);
|
||
if (!info)
|
||
return NULL;
|
||
*p++ = '(';
|
||
p = stpcpy (p, smklen (numbuf, sizeof numbuf, n, NULL));
|
||
for (s=serialno; *s && s[1]; s += 2)
|
||
*(unsigned char *)p++ = xtoi_2 (s);
|
||
p = stpcpy (p, smklen (numbuf, sizeof numbuf, strlen (idstring), NULL));
|
||
p = stpcpy (p, idstring);
|
||
*p++ = ')';
|
||
*p = 0;
|
||
return (unsigned char *)info;
|
||
}
|
||
|
||
|
||
|
||
/* Create a shadow key from a public key. We use the shadow protocol
|
||
"t1-v1" and insert the S-expressionn SHADOW_INFO. The resulting
|
||
S-expression is returned in an allocated buffer RESULT will point
|
||
to. The input parameters are expected to be valid canonicalized
|
||
S-expressions */
|
||
int
|
||
agent_shadow_key (const unsigned char *pubkey,
|
||
const unsigned char *shadow_info,
|
||
unsigned char **result)
|
||
{
|
||
const unsigned char *s;
|
||
const unsigned char *point;
|
||
size_t n;
|
||
int depth = 0;
|
||
char *p;
|
||
size_t pubkey_len = gcry_sexp_canon_len (pubkey, 0, NULL,NULL);
|
||
size_t shadow_info_len = gcry_sexp_canon_len (shadow_info, 0, NULL,NULL);
|
||
|
||
if (!pubkey_len || !shadow_info_len)
|
||
return gpg_error (GPG_ERR_INV_VALUE);
|
||
s = pubkey;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (!smatch (&s, n, "public-key"))
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s += n; /* skip over the algorithm name */
|
||
|
||
while (*s != ')')
|
||
{
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s += n;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s +=n; /* skip value */
|
||
if (*s != ')')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth--;
|
||
s++;
|
||
}
|
||
point = s; /* insert right before the point */
|
||
depth--;
|
||
s++;
|
||
assert (depth == 1);
|
||
|
||
/* Calculate required length by taking in account: the "shadowed-"
|
||
prefix, the "shadowed", "t1-v1" as well as some parenthesis */
|
||
n = 12 + pubkey_len + 1 + 3+8 + 2+5 + shadow_info_len + 1;
|
||
*result = xtrymalloc (n);
|
||
p = (char*)*result;
|
||
if (!p)
|
||
return out_of_core ();
|
||
p = stpcpy (p, "(20:shadowed-private-key");
|
||
/* (10:public-key ...)*/
|
||
memcpy (p, pubkey+14, point - (pubkey+14));
|
||
p += point - (pubkey+14);
|
||
p = stpcpy (p, "(8:shadowed5:t1-v1");
|
||
memcpy (p, shadow_info, shadow_info_len);
|
||
p += shadow_info_len;
|
||
*p++ = ')';
|
||
memcpy (p, point, pubkey_len - (point - pubkey));
|
||
p += pubkey_len - (point - pubkey);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Parse a canonical encoded shadowed key and return a pointer to the
|
||
inner list with the shadow_info */
|
||
gpg_error_t
|
||
agent_get_shadow_info (const unsigned char *shadowkey,
|
||
unsigned char const **shadow_info)
|
||
{
|
||
const unsigned char *s;
|
||
size_t n;
|
||
int depth = 0;
|
||
|
||
s = shadowkey;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (!smatch (&s, n, "shadowed-private-key"))
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s += n; /* skip over the algorithm name */
|
||
|
||
for (;;)
|
||
{
|
||
if (*s == ')')
|
||
return gpg_error (GPG_ERR_UNKNOWN_SEXP);
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth++;
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (smatch (&s, n, "shadowed"))
|
||
break;
|
||
s += n;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s +=n; /* skip value */
|
||
if (*s != ')')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
depth--;
|
||
s++;
|
||
}
|
||
/* Found the shadowed list, S points to the protocol */
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
if (smatch (&s, n, "t1-v1"))
|
||
{
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
*shadow_info = s;
|
||
}
|
||
else
|
||
return gpg_error (GPG_ERR_UNSUPPORTED_PROTOCOL);
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Parse the canonical encoded SHADOW_INFO S-expression. On success
|
||
the hex encoded serial number is returned as a malloced strings at
|
||
R_HEXSN and the Id string as a malloced string at R_IDSTR. On
|
||
error an error code is returned and NULL is stored at the result
|
||
parameters addresses. If the serial number or the ID string is not
|
||
required, NULL may be passed for them. */
|
||
gpg_error_t
|
||
parse_shadow_info (const unsigned char *shadow_info,
|
||
char **r_hexsn, char **r_idstr, int *r_pinlen)
|
||
{
|
||
const unsigned char *s;
|
||
size_t n;
|
||
|
||
if (r_hexsn)
|
||
*r_hexsn = NULL;
|
||
if (r_idstr)
|
||
*r_idstr = NULL;
|
||
if (r_pinlen)
|
||
*r_pinlen = 0;
|
||
|
||
s = shadow_info;
|
||
if (*s != '(')
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
s++;
|
||
n = snext (&s);
|
||
if (!n)
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
|
||
if (r_hexsn)
|
||
{
|
||
*r_hexsn = bin2hex (s, n, NULL);
|
||
if (!*r_hexsn)
|
||
return gpg_error_from_syserror ();
|
||
}
|
||
s += n;
|
||
|
||
n = snext (&s);
|
||
if (!n)
|
||
{
|
||
if (r_hexsn)
|
||
{
|
||
xfree (*r_hexsn);
|
||
*r_hexsn = NULL;
|
||
}
|
||
return gpg_error (GPG_ERR_INV_SEXP);
|
||
}
|
||
|
||
if (r_idstr)
|
||
{
|
||
*r_idstr = xtrymalloc (n+1);
|
||
if (!*r_idstr)
|
||
{
|
||
if (r_hexsn)
|
||
{
|
||
xfree (*r_hexsn);
|
||
*r_hexsn = NULL;
|
||
}
|
||
return gpg_error_from_syserror ();
|
||
}
|
||
memcpy (*r_idstr, s, n);
|
||
(*r_idstr)[n] = 0;
|
||
}
|
||
|
||
/* Parse the optional PINLEN. */
|
||
n = snext (&s);
|
||
if (!n)
|
||
return 0;
|
||
|
||
if (r_pinlen)
|
||
{
|
||
char *tmpstr = xtrymalloc (n+1);
|
||
if (!tmpstr)
|
||
{
|
||
if (r_hexsn)
|
||
{
|
||
xfree (*r_hexsn);
|
||
*r_hexsn = NULL;
|
||
}
|
||
if (r_idstr)
|
||
{
|
||
xfree (*r_idstr);
|
||
*r_idstr = NULL;
|
||
}
|
||
return gpg_error_from_syserror ();
|
||
}
|
||
memcpy (tmpstr, s, n);
|
||
tmpstr[n] = 0;
|
||
|
||
*r_pinlen = (int)strtol (tmpstr, NULL, 10);
|
||
xfree (tmpstr);
|
||
}
|
||
|
||
return 0;
|
||
}
|