This commit was manufactured by cvs2svn to create branch

'GNUPG-1-9-BRANCH'.

1 files changed, 1238 insertions, 0 deletions

diff --git a/g10/passphrase.c b/g10/passphrase.c
new file mode 100644
index 000000000..769276221
--- /dev/null
+++ b/g10/passphrase.c
@@ -0,0 +1,1238 @@
+/* passphrase.c -  Get a passphrase
+ * Copyright (C) 1998,1999,2000,2001,2002,2003 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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.
+ *
+ * GnuPG 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; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#if !defined(HAVE_DOSISH_SYSTEM) && !defined(__riscos__)
+#include <sys/socket.h>
+#include <sys/un.h>
+#endif
+#if defined (__MINGW32__) || defined (__CYGWIN32__)
+# include <windows.h>
+#endif
+#include <errno.h>
+#ifdef HAVE_LOCALE_H
+#include <locale.h>
+#endif
+#ifdef HAVE_LANGINFO_CODESET
+#include <langinfo.h>
+#endif
+
+#include "util.h"
+#include "memory.h"
+#include "options.h"
+#include "ttyio.h"
+#include "cipher.h"
+#include "keydb.h"
+#include "main.h"
+#include "i18n.h"
+#include "status.h"
+
+
+enum gpga_protocol_codes {
+    /* Request codes */
+    GPGA_PROT_GET_VERSION     = 1,
+    GPGA_PROT_GET_PASSPHRASE  = 2,
+    GPGA_PROT_CLEAR_PASSPHRASE= 3,
+    GPGA_PROT_SHUTDOWN        = 4,
+    GPGA_PROT_FLUSH           = 5,
+
+    /* Reply codes */
+    GPGA_PROT_REPLY_BASE     = 0x10000,
+    GPGA_PROT_OKAY           = 0x10001,
+    GPGA_PROT_GOT_PASSPHRASE = 0x10002,
+
+    /* Error codes */
+    GPGA_PROT_ERROR_BASE     = 0x20000,
+    GPGA_PROT_PROTOCOL_ERROR = 0x20001,
+    GPGA_PROT_INVALID_REQUEST= 0x20002,
+    GPGA_PROT_CANCELED       = 0x20003,    
+    GPGA_PROT_NO_PASSPHRASE  = 0x20004,    
+    GPGA_PROT_BAD_PASSPHRASE = 0x20005,
+    GPGA_PROT_INVALID_DATA   = 0x20006,
+    GPGA_PROT_NOT_IMPLEMENTED= 0x20007,
+    GPGA_PROT_UI_PROBLEM     = 0x20008
+};
+
+
+#define buftou32( p )  ((*(byte*)(p) << 24) | (*((byte*)(p)+1)<< 16) | \
+		       (*((byte*)(p)+2) << 8) | (*((byte*)(p)+3)))
+#define u32tobuf( p, a ) do { 			                \
+			    ((byte*)p)[0] = (byte)((a) >> 24);	\
+			    ((byte*)p)[1] = (byte)((a) >> 16);	\
+			    ((byte*)p)[2] = (byte)((a) >>  8);	\
+			    ((byte*)p)[3] = (byte)((a) 	    );	\
+			} while(0)
+
+#define digitp(p)   (*(p) >= '0' && *(p) <= '9')
+#define hexdigitp(a) (digitp (a)                     \
+                      || (*(a) >= 'A' && *(a) <= 'F')  \
+                      || (*(a) >= 'a' && *(a) <= 'f'))
+#define xtoi_1(p)   (*(p) <= '9'? (*(p)- '0'): \
+                     *(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
+#define xtoi_2(p)   ((xtoi_1(p) * 16) + xtoi_1((p)+1))
+
+
+
+static char *fd_passwd = NULL;
+static char *next_pw = NULL;
+static char *last_pw = NULL;
+
+#if defined (__MINGW32__)
+static int read_fd = 0;
+static int write_fd = 0;
+#endif
+
+static void hash_passphrase( DEK *dek, char *pw, STRING2KEY *s2k, int create );
+
+int
+have_static_passphrase()
+{
+    if ( opt.use_agent )
+        return 0;
+    return !!fd_passwd;
+}
+
+/****************
+ * Set the passphrase to be used for the next query and only for the next
+ * one.
+ */
+void
+set_next_passphrase( const char *s )
+{
+    m_free(next_pw);
+    next_pw = NULL;
+    if( s ) {
+	next_pw = m_alloc_secure( strlen(s)+1 );
+	strcpy(next_pw, s );
+    }
+}
+
+/****************
+ * Get the last passphrase used in passphrase_to_dek.
+ * Note: This removes the passphrase from this modules and
+ * the caller must free the result.  May return NULL:
+ */
+char *
+get_last_passphrase()
+{
+    char *p = last_pw;
+    last_pw = NULL;
+    return p;
+}
+
+
+void
+read_passphrase_from_fd( int fd )
+{
+  int i, len;
+  char *pw;
+  
+  if ( opt.use_agent ) 
+    { /* Not used but we have to do a dummy read, so that it won't end
+         up at the begin of the message if the quite usual trick to
+         prepend the passphtrase to the message is used. */
+      char buf[1];
+
+      while (!(read (fd, buf, 1) != 1 || *buf == '\n' ))
+        ;
+      *buf = 0;
+      return; 
+    }
+
+  if (!opt.batch )
+	tty_printf("Reading passphrase from file descriptor %d ...", fd );
+  for (pw = NULL, i = len = 100; ; i++ ) 
+    {
+      if (i >= len-1 ) 
+        {
+          char *pw2 = pw;
+          len += 100;
+          pw = m_alloc_secure( len );
+          if( pw2 )
+            memcpy(pw, pw2, i );
+          else
+            i=0;
+	}
+      if (read( fd, pw+i, 1) != 1 || pw[i] == '\n' )
+        break;
+    }
+  pw[i] = 0;
+  if (!opt.batch)
+    tty_printf("\b\b\b   \n" );
+
+  m_free( fd_passwd );
+  fd_passwd = pw;
+}
+
+static int
+writen ( int fd, const void *buf, size_t nbytes )
+{
+#if defined (__MINGW32__)
+    DWORD nwritten, nleft = nbytes;
+    
+    while (nleft > 0) {
+    	if ( !WriteFile( (HANDLE)write_fd, buf, nleft, &nwritten, NULL) ) {
+    		log_error("write failed: ec=%d\n", (int)GetLastError());
+    		return -1;
+    	}
+    	/*log_info("** WriteFile fd=%d nytes=%d nwritten=%d\n",
+    		 write_fd, nbytes, (int)nwritten);*/
+    	Sleep(100);
+    	
+    	nleft -= nwritten;
+    	buf = (const BYTE *)buf + nwritten;
+    }
+#elif defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
+    /* not implemented */
+#else
+    size_t nleft = nbytes;
+    int nwritten;
+
+    while( nleft > 0 ) {
+        nwritten = write( fd, buf, nleft );
+        if( nwritten < 0 ) {
+            if ( errno == EINTR )
+                nwritten = 0;
+            else {
+                log_error ( "write() failed: %s\n", strerror (errno) );
+                return -1;
+            }
+        }
+        nleft -= nwritten;
+        buf = (const char*)buf + nwritten;
+    }
+#endif
+    
+    return 0;
+}
+
+
+static int
+readn ( int fd, void *buf, size_t buflen, size_t *ret_nread )
+{
+#if defined (__MINGW32__)
+    DWORD nread, nleft = buflen;
+    
+    while (nleft > 0) {
+    	if ( !ReadFile( (HANDLE)read_fd, buf, nleft, &nread, NULL) ) {
+            log_error("read() error: ec=%d\n", (int)GetLastError());
+            return -1;
+    	}
+    	if (!nread || GetLastError() == ERROR_BROKEN_PIPE)
+            break;
+    	/*log_info("** ReadFile fd=%d buflen=%d nread=%d\n",
+          read_fd, buflen, (int)nread);*/
+    	Sleep(100);
+    	
+    	nleft -= nread;
+    	buf = (BYTE *)buf + nread;
+    }    	
+    if (ret_nread)
+    	*ret_nread = buflen - nleft;
+
+#elif defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
+    /* not implemented */
+#else
+    size_t nleft = buflen;
+    int nread;
+    char *p;
+
+    p = buf;
+    while( nleft > 0 ) {
+        nread = read ( fd, buf, nleft );
+        if( nread < 0 ) {
+            if (nread == EINTR)
+                nread = 0;
+            else {
+                log_error ( "read() error: %s\n", strerror (errno) );
+                return -1;
+            }
+        }
+        else if( !nread )
+            break; /* EOF */
+        nleft -= nread;
+        buf = (char*)buf + nread;
+    }
+    if( ret_nread )
+        *ret_nread = buflen - nleft;
+#endif
+    
+    return 0;
+}
+
+/* read an entire line */
+static int
+readline (int fd, char *buf, size_t buflen)
+{
+  size_t nleft = buflen;
+  char *p;
+  int nread = 0;
+
+  while (nleft > 0)
+    {
+      int n = read (fd, buf, nleft);
+      if (n < 0)
+        {
+          if (errno == EINTR)
+            continue;
+          return -1; /* read error */
+        }
+      else if (!n)
+        {
+          return -1; /* incomplete line */
+        }
+      p = buf;
+      nleft -= n;
+      buf += n;
+      nread += n;
+      
+      for (; n && *p != '\n'; n--, p++)
+        ;
+      if (n)
+        {
+          break; /* at least one full line available - that's enough.
+                    This function is just a temporary hack until we use
+                    the assuna lib in gpg.  So it is okay to forget
+                    about pending bytes */
+        }
+    }
+
+  return nread; 
+}
+
+
+
+#if !defined (__riscos__)
+
+#if !defined (__MINGW32__)
+/* For the new Assuan protocol we may have to send options */
+static int
+agent_send_option (int fd, const char *name, const char *value)
+{
+  char buf[200];
+  int nread;
+  char *line;
+  int i; 
+  
+  line = m_alloc (7 + strlen (name) + 1 + strlen (value) + 2);
+  strcpy (stpcpy (stpcpy (stpcpy (
+                     stpcpy (line, "OPTION "), name), "="), value), "\n");
+  i = writen (fd, line, strlen (line));
+  m_free (line);
+  if (i)
+    return -1;
+  
+  /* get response */
+  nread = readline (fd, buf, DIM(buf)-1);
+  if (nread < 3)
+    return -1;
+  
+  if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n')) 
+    return 0; /* okay */
+
+  return -1;
+}
+
+static int 
+agent_send_all_options (int fd)
+{
+  char *dft_display = NULL;
+  const char *dft_ttyname = NULL;
+  char *dft_ttytype = NULL;
+  char *old_lc = NULL;
+  char *dft_lc = NULL;
+  int rc = 0;
+
+  dft_display = getenv ("DISPLAY");
+  if (opt.display || dft_display)
+    {
+      if (agent_send_option (fd, "display",
+                             opt.display ? opt.display : dft_display))
+        return -1;
+    }
+
+  if (!opt.ttyname)
+    dft_ttyname = tty_get_ttyname ();
+  if (opt.ttyname || dft_ttyname)
+    {
+      if (agent_send_option (fd, "ttyname",
+                             opt.ttyname ? opt.ttyname : dft_ttyname))
+        return -1;
+    }
+
+  dft_ttytype = getenv ("TERM");
+  if (opt.ttytype || (dft_ttyname && dft_ttytype))
+    {
+      if (agent_send_option (fd, "ttytype",
+                             opt.ttyname ? opt.ttytype : dft_ttytype))
+        return -1;
+    }
+
+#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
+  old_lc = setlocale (LC_CTYPE, NULL);
+  if (old_lc)
+    old_lc = m_strdup (old_lc);
+  dft_lc = setlocale (LC_CTYPE, "");
+#endif
+  if (opt.lc_ctype || (dft_ttyname && dft_lc))
+    {
+      rc = agent_send_option (fd, "lc-ctype",
+                              opt.lc_ctype ? opt.lc_ctype : dft_lc);
+    }
+#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
+  if (old_lc)
+    {
+      setlocale (LC_CTYPE, old_lc);
+      m_free (old_lc);
+    }
+#endif
+  if (rc)
+    return rc;
+
+#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
+  old_lc = setlocale (LC_MESSAGES, NULL);
+  if (old_lc)
+    old_lc = m_strdup (old_lc);
+  dft_lc = setlocale (LC_MESSAGES, "");
+#endif
+  if (opt.lc_messages || (dft_ttyname && dft_lc))
+    {
+      rc = agent_send_option (fd, "lc-messages",
+                              opt.lc_messages ? opt.lc_messages : dft_lc);
+    }
+#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
+  if (old_lc)
+    {
+      setlocale (LC_MESSAGES, old_lc);
+      m_free (old_lc);
+    }
+#endif
+  return rc;
+}
+#endif /*!__MINGW32__*/
+
+
+/*
+ * Open a connection to the agent and send the magic string
+ * Returns: -1 on error or an filedescriptor for urther processing
+ */
+
+static int
+agent_open (int *ret_prot)
+{
+#if defined (__MINGW32__)
+    int fd;
+    char *infostr, *p;
+    HANDLE h;
+    char pidstr[128];
+
+    *ret_prot = 0;
+    if ( !(infostr = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
+                                              "agentPID")) 
+         || *infostr == '0') {
+    	log_error( _("gpg-agent is not available in this session\n"));
+    	return -1;
+    }
+    free(infostr);
+    
+    sprintf(pidstr, "%u", (unsigned int)GetCurrentProcessId());
+    if (write_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
+                                  "agentCID", pidstr)) {
+        log_error( _("can't set client pid for the agent\n") );
+        return -1;
+    }
+    h = OpenEvent(EVENT_ALL_ACCESS, FALSE, "gpg_agent");
+    SetEvent(h);
+    Sleep(50); /* some time for the server */ 
+    if ( !(p = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
+                                        "agentReadFD")) ) {
+    	log_error( _("can't get server read FD for the agent\n") );
+    	return -1;
+    }
+    read_fd = atol(p);
+    free(p);    
+    if ( !(p = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
+                                        "agentWriteFD")) ) {
+    	log_error ( _("can't get server write FD for the agent\n") );
+    	return -1;
+    }
+    write_fd = atol(p);
+    free(p);
+    fd = 0;
+
+    if ( writen ( fd, "GPGA\0\0\0\x01", 8 ) ) {
+        fd = -1;
+    }
+#else /* Posix */
+
+    int fd;
+    char *infostr, *p;
+    struct sockaddr_un client_addr;
+    size_t len;
+    int prot;
+
+    if (opt.gpg_agent_info)
+      infostr = m_strdup (opt.gpg_agent_info);
+    else
+      {
+        infostr = getenv ( "GPG_AGENT_INFO" );
+        if ( !infostr ) {
+          log_error (_("gpg-agent is not available in this session\n"));
+          opt.use_agent = 0;
+          return -1;
+        }
+        infostr = m_strdup ( infostr );
+      }
+
+    if ( !(p = strchr ( infostr, ':')) || p == infostr
+         || (p-infostr)+1 >= sizeof client_addr.sun_path ) {
+        log_error( _("malformed GPG_AGENT_INFO environment variable\n"));
+        m_free (infostr );
+        opt.use_agent = 0;
+        return -1;
+    }
+    *p++ = 0;
+    /* See whether this is the new gpg-agent using the Assuna protocl.
+       This agent identifies itself by have an info string with a
+       version number in the 3rd field. */
+    while (*p && *p != ':')
+      p++;
+    prot = *p? atoi (p+1) : 0;
+    if ( prot < 0 || prot > 1) {
+        log_error (_("gpg-agent protocol version %d is not supported\n"),prot);
+        m_free (infostr );
+        opt.use_agent = 0;
+        return -1;
+    }
+    *ret_prot = prot;
+       
+    if( (fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1 ) {
+        log_error ("can't create socket: %s\n", strerror(errno) );
+        m_free (infostr );
+        opt.use_agent = 0;
+        return -1;
+    }
+    
+    memset( &client_addr, 0, sizeof client_addr );
+    client_addr.sun_family = AF_UNIX;
+    strcpy( client_addr.sun_path, infostr );
+    len = offsetof (struct sockaddr_un, sun_path)
+        + strlen(client_addr.sun_path) + 1;
+    
+    if( connect( fd, (struct sockaddr*)&client_addr, len ) == -1 ) {
+        log_error ( _("can't connect to `%s': %s\n"), 
+                    infostr, strerror (errno) );
+        m_free (infostr );
+        close (fd );
+        opt.use_agent = 0;
+        return -1;
+    }
+    m_free (infostr);
+
+    if (!prot) {
+        if ( writen ( fd, "GPGA\0\0\0\x01", 8 ) ) {
+          close (fd);
+          fd = -1;
+        }
+    }
+    else { /* assuan based gpg-agent */
+      char line[200];
+      int nread;
+
+      nread = readline (fd, line, DIM(line));
+      if (nread < 3 || !(line[0] == 'O' && line[1] == 'K'
+                         && (line[2] == '\n' || line[2] == ' ')) ) {
+        log_error ( _("communication problem with gpg-agent\n"));
+        close (fd );
+        opt.use_agent = 0;
+        return -1;
+      }
+
+      if (agent_send_all_options (fd)) {
+        log_error (_("problem with the agent - disabling agent use\n"));
+        close (fd);
+        opt.use_agent = 0;
+        return -1;
+      }
+        
+    }
+#endif
+
+    return fd;
+}
+
+
+static void
+agent_close ( int fd )
+{
+#if defined (__MINGW32__)
+    HANDLE h = OpenEvent(EVENT_ALL_ACCESS, FALSE, "gpg_agent");
+    ResetEvent(h);
+#else
+    close (fd);
+#endif
+}
+#endif /* !__riscos__ */
+
+
+
+/*
+ * Ask the GPG Agent for the passphrase.
+ * Mode 0:  Allow cached passphrase
+ *      1:  No cached passphrase FIXME: Not really implemented
+ *      2:  Ditto, but change the text to "repeat entry"
+ *
+ * Note that TRYAGAIN_TEXT must not be translated.  If canceled is not
+ * NULL, the function does set it to 1 if the user canceled the
+ * operation.
+ */
+static char *
+agent_get_passphrase ( u32 *keyid, int mode, const char *tryagain_text,
+                       int *canceled)
+{
+#if defined(__riscos__)
+  return NULL;
+#else
+  size_t n;
+  char *atext = NULL;
+  char buf[50];
+  int fd = -1;
+  int nread;
+  u32 reply;
+  char *pw = NULL;
+  PKT_public_key *pk = m_alloc_clear( sizeof *pk );
+  byte fpr[MAX_FINGERPRINT_LEN];
+  int have_fpr = 0;
+  int prot;
+  char *orig_codeset = NULL;
+
+  if (canceled)
+    *canceled = 0;
+
+#if MAX_FINGERPRINT_LEN < 20
+#error agent needs a 20 byte fingerprint
+#endif
+
+  memset (fpr, 0, MAX_FINGERPRINT_LEN );
+  if( keyid && get_pubkey( pk, keyid ) )
+    {
+      free_public_key( pk );      
+      pk = NULL; /* oops: no key for some reason */
+    }
+  
+#ifdef ENABLE_NLS
+  /* The Assuan agent protol requires us to trasnmit utf-8 strings */
+  orig_codeset = bind_textdomain_codeset (PACKAGE, NULL);
+#ifdef HAVE_LANGINFO_CODESET
+  if (!orig_codeset)
+    orig_codeset = nl_langinfo (CODESET);
+#endif
+  if (orig_codeset)
+    { /* We only switch when we are able to restore the codeset later. */
+      orig_codeset = m_strdup (orig_codeset);
+      if (!bind_textdomain_codeset (PACKAGE, "utf-8"))
+        orig_codeset = NULL; 
+    }
+#endif
+
+  if ( (fd = agent_open (&prot)) == -1 ) 
+    goto failure;
+
+  if ( !mode && pk && keyid )
+    { 
+      char *uid;
+      size_t uidlen;
+      const char *algo_name = pubkey_algo_to_string ( pk->pubkey_algo );
+      const char *timestr;
+      char *maink;
+      const char *fmtstr;
+      
+      if ( !algo_name )
+        algo_name = "?";
+      
+      fmtstr = _(" (main key ID %08lX)");
+      maink = m_alloc ( strlen (fmtstr) + 20 );
+      if( keyid[2] && keyid[3] && keyid[0] != keyid[2] 
+          && keyid[1] != keyid[3] )
+        sprintf( maink, fmtstr, (ulong)keyid[3] );
+      else
+        *maink = 0;
+      
+      uid = get_user_id ( keyid, &uidlen ); 
+      timestr = strtimestamp (pk->timestamp);
+      fmtstr = _("You need a passphrase to unlock the"
+                 " secret key for user:\n"
+                 "\"%.*s\"\n"
+                 "%u-bit %s key, ID %08lX, created %s%s\n" );
+      atext = m_alloc ( 100 + strlen (fmtstr)  
+                        + uidlen + 15 + strlen(algo_name) + 8
+                        + strlen (timestr) + strlen (maink) );
+      sprintf (atext, fmtstr,
+               uidlen, uid,
+               nbits_from_pk (pk), algo_name, (ulong)keyid[1], timestr,
+               maink  );
+      m_free (uid);
+      m_free (maink);
+      
+      { 
+        size_t dummy;
+        fingerprint_from_pk( pk, fpr, &dummy );
+        have_fpr = 1;
+      }
+      
+    }
+  else if (mode == 2 ) 
+    atext = m_strdup ( _("Repeat passphrase\n") );
+  else
+    atext = m_strdup ( _("Enter passphrase\n") );
+                
+  if (!prot)
+    { /* old style protocol */
+      n = 4 + 20 + strlen (atext);
+      u32tobuf (buf, n );
+      u32tobuf (buf+4, GPGA_PROT_GET_PASSPHRASE );
+      memcpy (buf+8, fpr, 20 );
+      if ( writen ( fd, buf, 28 ) || writen ( fd, atext, strlen (atext) ) ) 
+        goto failure;
+      m_free (atext); atext = NULL;
+      
+      /* get response */
+      if ( readn ( fd, buf, 12, &nread ) ) 
+        goto failure;
+      
+      if ( nread < 8 ) 
+        {
+          log_error ( "response from agent too short\n" );
+          goto failure;
+        }
+      n = buftou32 ( buf );
+      reply = buftou32 ( buf + 4 );
+      if ( reply == GPGA_PROT_GOT_PASSPHRASE ) 
+        {
+          size_t pwlen;
+          size_t nn;
+          
+          if ( nread < 12 || n < 8 ) 
+            {
+              log_error ( "response from agent too short\n" );
+              goto failure;
+            }
+          pwlen = buftou32 ( buf + 8 );
+          nread -= 12;
+          n -= 8;
+          if ( pwlen > n || n > 1000 ) 
+            {
+              log_error (_("passphrase too long\n"));
+              /* or protocol error */
+              goto failure;
+            }
+          /* we read the whole block in one chunk to give no hints
+           * on how long the passhrase actually is - this wastes some bytes
+           * but because we already have this padding we should not loosen
+           * this by issuing 2 read calls */
+          pw = m_alloc_secure ( n+1 );
+          if ( readn ( fd, pw, n, &nn ) )
+            goto failure;
+          if ( n != nn ) 
+            {
+              log_error (_("invalid response from agent\n"));
+              goto failure;           
+            }
+          pw[pwlen] = 0; /* make a C String */
+          agent_close (fd);
+          free_public_key( pk );
+#ifdef ENABLE_NLS
+          if (orig_codeset)
+            bind_textdomain_codeset (PACKAGE, orig_codeset);
+#endif
+          m_free (orig_codeset);
+          return pw;
+        }
+      else if ( reply == GPGA_PROT_CANCELED ) 
+        {
+          log_info ( _("cancelled by user\n") );
+          if (canceled)
+            *canceled = 1;
+        }
+      else 
+        log_error ( _("problem with the agent: agent returns 0x%lx\n"),
+                    (ulong)reply );
+    }
+  else
+    { /* The new Assuan protocol */
+      char *line, *p;
+      const unsigned char *s;
+      int i; 
+
+      if (!tryagain_text)
+        tryagain_text = "X";
+      else
+        tryagain_text = _(tryagain_text);
+
+      /* We allocate 2 time the needed space for atext so that there
+         is nenough space for escaping */
+      line = m_alloc (15 + 46 
+                      +  3*strlen (tryagain_text) + 3*strlen (atext) + 2);
+      strcpy (line, "GET_PASSPHRASE ");
+      p = line+15;
+      if (!mode && have_fpr)
+        {
+          for (i=0; i < 20; i++, p +=2 )
+            sprintf (p, "%02X", fpr[i]);
+        }
+      else
+        *p++ = 'X'; /* no caching */
+      *p++ = ' ';
+      for (i=0, s=tryagain_text; *s; s++)
+        {
+          if (*s < ' ' || *s == '+')
+            {
+              sprintf (p, "%%%02X", *s);
+              p += 3;
+            }
+          else if (*s == ' ')
+            *p++ = '+';
+          else
+            *p++ = *s;
+        }
+      *p++ = ' ';
+      *p++ = 'X'; /* Use the standard prompt */
+      *p++ = ' ';
+      /* copy description */
+      for (i=0, s= atext; *s; s++)
+        {
+          if (*s < ' ' || *s == '+')
+            {
+              sprintf (p, "%%%02X", *s);
+              p += 3;
+            }
+          else if (*s == ' ')
+            *p++ = '+';
+          else
+            *p++ = *s;
+        }
+      *p++ = '\n';
+      i = writen (fd, line, p - line);
+      m_free (line);
+      if (i)
+        goto failure;
+      m_free (atext); atext = NULL;
+      
+      /* get response */
+      pw = m_alloc_secure (500);
+      nread = readline (fd, pw, 499);
+      if (nread < 3)
+        goto failure;
+      
+      if (pw[0] == 'O' && pw[1] == 'K' && pw[2] == ' ') 
+        { /* we got a passphrase - convert it back from hex */
+          size_t pwlen = 0;
+
+          for (i=3; i < nread && hexdigitp (pw+i); i+=2)
+            pw[pwlen++] = xtoi_2 (pw+i);
+          pw[pwlen] = 0; /* make a C String */
+          agent_close (fd);
+          free_public_key( pk );
+#ifdef ENABLE_NLS
+          if (orig_codeset)
+            bind_textdomain_codeset (PACKAGE, orig_codeset);
+#endif
+          m_free (orig_codeset);
+          return pw;
+        }
+      else if (nread > 7 && !memcmp (pw, "ERR 111", 7)
+               && (pw[7] == ' ' || pw[7] == '\n') ) 
+        {
+          log_info (_("cancelled by user\n") );
+          if (canceled)
+            *canceled = 1;
+        }
+      else 
+        {
+          log_error (_("problem with the agent - disabling agent use\n"));
+          opt.use_agent = 0;
+        }
+    }
+      
+        
+ failure:
+#ifdef ENABLE_NLS
+  if (orig_codeset)
+    bind_textdomain_codeset (PACKAGE, orig_codeset);
+#endif
+  m_free (atext);
+  if ( fd != -1 )
+    agent_close (fd);
+  m_free (pw );
+  free_public_key( pk );
+  
+  return NULL;
+#endif /* Posix or W32 */
+}
+
+/*
+ * Clear the cached passphrase
+ */
+void
+passphrase_clear_cache ( u32 *keyid, int algo )
+{
+#if defined(__riscos__)
+  return ;
+#else
+  size_t n;
+  char buf[200];
+  int fd = -1;
+  size_t nread;
+  u32 reply;
+  PKT_public_key *pk;
+  byte fpr[MAX_FINGERPRINT_LEN];
+  int prot;
+  
+#if MAX_FINGERPRINT_LEN < 20
+#error agent needs a 20 byte fingerprint
+#endif
+    
+  if (!opt.use_agent)
+    return;
+  
+  pk = m_alloc_clear ( sizeof *pk );
+  memset (fpr, 0, MAX_FINGERPRINT_LEN );
+  if( !keyid || get_pubkey( pk, keyid ) )
+    {
+      log_debug ("oops, no key in passphrase_clear_cache\n");
+      goto failure; /* oops: no key for some reason */
+    }
+  
+  {
+    size_t dummy;
+    fingerprint_from_pk( pk, fpr, &dummy );
+  }
+    
+  if ( (fd = agent_open (&prot)) == -1 ) 
+    goto failure;
+
+  if (!prot)
+    {
+      n = 4 + 20;
+      u32tobuf (buf, n );
+      u32tobuf (buf+4, GPGA_PROT_CLEAR_PASSPHRASE );
+      memcpy (buf+8, fpr, 20 );
+      if ( writen ( fd, buf, 28 ) )  
+        goto failure;
+      
+      /* get response */
+      if ( readn ( fd, buf, 8, &nread ) ) 
+        goto failure;
+      
+      if ( nread < 8 ) {
+        log_error ( "response from agent too short\n" );
+        goto failure;
+      }
+      
+      reply = buftou32 ( buf + 4 );
+      if ( reply != GPGA_PROT_OKAY && reply != GPGA_PROT_NO_PASSPHRASE )
+        {
+          log_error ( _("problem with the agent: agent returns 0x%lx\n"),
+                      (ulong)reply );
+        }
+    }
+  else 
+    { /* The assuan protocol */
+      char *line, *p;
+      int i; 
+
+      line = m_alloc (17 + 40 + 2);
+      strcpy (line, "CLEAR_PASSPHRASE ");
+      p = line+17;
+      for (i=0; i < 20; i++, p +=2 )
+        sprintf (p, "%02X", fpr[i]);
+      *p++ = '\n';
+      i = writen (fd, line, p - line);
+      m_free (line);
+      if (i)
+        goto failure;
+      
+      /* get response */
+      nread = readline (fd, buf, DIM(buf)-1);
+      if (nread < 3)
+        goto failure;
+      
+      if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n')) 
+        ;
+      else 
+        {
+          log_error (_("problem with the agent - disabling agent use\n"));
+          opt.use_agent = 0;
+        }
+    }
+        
+ failure:
+  if (fd != -1)
+    agent_close (fd);
+  free_public_key( pk );
+#endif /* Posix or W32 */
+}
+
+
+
+
+/****************
+ * Get a passphrase for the secret key with KEYID, display TEXT
+ * if the user needs to enter the passphrase.
+ * mode 0 = standard, 1 = same but don't show key info,
+ *      2 = create new passphrase
+ * Returns: a DEK with a session key; caller must free
+ *	    or NULL if the passphrase was not correctly repeated.
+ *	    (only for mode 2)
+ *	    a dek->keylen of 0 means: no passphrase entered.
+ *	    (only for mode 2)
+ *
+ * pubkey_algo is only informational.  Note that TRYAGAIN_TEXT must
+ * not be translated as this is done within this function (required to
+ * switch to utf-8 when the agent is in use).  If CANCELED is not
+ * NULL, it is set to 1 if the user choosed to cancel the operation,
+ * otherwise it will be set to 0.
+ */
+DEK *
+passphrase_to_dek( u32 *keyid, int pubkey_algo,
+		   int cipher_algo, STRING2KEY *s2k, int mode,
+                   const char *tryagain_text, int *canceled)
+{
+    char *pw = NULL;
+    DEK *dek;
+    STRING2KEY help_s2k;
+
+    if (canceled)
+      *canceled = 0;
+
+    if( !s2k ) {
+        /* This is used for the old rfc1991 mode 
+         * Note: This must match the code in encode.c with opt.rfc1991 set */
+	s2k = &help_s2k;
+	s2k->mode = 0;
+	s2k->hash_algo = opt.s2k_digest_algo;
+    }
+
+    if( !next_pw && is_status_enabled() ) {
+	char buf[50];
+
+	if( keyid ) {
+            u32 used_kid[2];
+            char *us;
+
+	    if( keyid[2] && keyid[3] ) {
+                used_kid[0] = keyid[2];
+                used_kid[1] = keyid[3];
+            }
+            else {
+                used_kid[0] = keyid[0];
+                used_kid[1] = keyid[1];
+            }
+
+            us = get_long_user_id_string( keyid );
+            write_status_text( STATUS_USERID_HINT, us );
+            m_free(us);
+
+	    sprintf( buf, "%08lX%08lX %08lX%08lX %d 0",
+                     (ulong)keyid[0], (ulong)keyid[1],
+                     (ulong)used_kid[0], (ulong)used_kid[1],
+                     pubkey_algo );
+                     
+	    write_status_text( STATUS_NEED_PASSPHRASE, buf );
+	}
+	else {
+	    sprintf( buf, "%d %d %d", cipher_algo, s2k->mode, s2k->hash_algo );
+	    write_status_text( STATUS_NEED_PASSPHRASE_SYM, buf );
+	}
+    }
+
+    if( keyid && !opt.batch && !next_pw && mode!=1 ) {
+	PKT_public_key *pk = m_alloc_clear( sizeof *pk );
+	size_t n;
+	char *p;
+
+	tty_printf(_("\nYou need a passphrase to unlock the secret key for\n"
+		     "user: \"") );
+	p = get_user_id( keyid, &n );
+	tty_print_utf8_string( p, n );
+	m_free(p);
+	tty_printf("\"\n");
+
+	if( !get_pubkey( pk, keyid ) ) {
+	    const char *s = pubkey_algo_to_string( pk->pubkey_algo );
+	    tty_printf( _("%u-bit %s key, ID %08lX, created %s"),
+		       nbits_from_pk( pk ), s?s:"?", (ulong)keyid[1],
+		       strtimestamp(pk->timestamp) );
+	    if( keyid[2] && keyid[3] && keyid[0] != keyid[2]
+				     && keyid[1] != keyid[3] )
+		tty_printf( _(" (main key ID %08lX)"), (ulong)keyid[3] );
+	    tty_printf("\n");
+	}
+
+	tty_printf("\n");
+	free_public_key( pk );
+    }
+
+ agent_died:
+    if( next_pw ) {
+	pw = next_pw;
+	next_pw = NULL;
+    }
+    else if ( opt.use_agent ) {
+	pw = agent_get_passphrase ( keyid, mode == 2? 1: 0,
+                                    tryagain_text, canceled );
+        if (!pw)
+          {
+            if (!opt.use_agent)
+              goto agent_died;
+            pw = m_strdup ("");
+          }
+        if( *pw && mode == 2 ) {
+	    char *pw2 = agent_get_passphrase ( keyid, 2, NULL, canceled );
+            if (!pw2)
+              {
+                if (!opt.use_agent)
+                  {
+                    m_free (pw);
+                    pw = NULL;
+                    goto agent_died;
+                  }
+                pw2 = m_strdup ("");
+              }
+	    if( strcmp(pw, pw2) ) {
+		m_free(pw2);
+		m_free(pw);
+		return NULL;
+	    }
+	    m_free(pw2);
+	}
+    }
+    else if( fd_passwd ) {
+	pw = m_alloc_secure( strlen(fd_passwd)+1 );
+	strcpy( pw, fd_passwd );
+    }
+    else if( opt.batch ) {
+	log_error(_("can't query password in batchmode\n"));
+	pw = m_strdup( "" ); /* return an empty passphrase */
+    }
+    else {
+	pw = cpr_get_hidden("passphrase.enter", _("Enter passphrase: ") );
+	tty_kill_prompt();
+	if( mode == 2 && !cpr_enabled() ) {
+	    char *pw2 = cpr_get_hidden("passphrase.repeat",
+				       _("Repeat passphrase: ") );
+	    tty_kill_prompt();
+	    if( strcmp(pw, pw2) ) {
+		m_free(pw2);
+		m_free(pw);
+		return NULL;
+	    }
+	    m_free(pw2);
+	}
+    }
+
+    if( !pw || !*pw )
+	write_status( STATUS_MISSING_PASSPHRASE );
+
+    dek = m_alloc_secure_clear ( sizeof *dek );
+    dek->algo = cipher_algo;
+    if( !*pw && mode == 2 )
+	dek->keylen = 0;
+    else
+	hash_passphrase( dek, pw, s2k, mode==2 );
+    m_free(last_pw);
+    last_pw = pw;
+    return dek;
+}
+
+
+/****************
+ * Hash a passphrase using the supplied s2k. If create is true, create
+ * a new salt or what else must be filled into the s2k for a new key.
+ * always needs: dek->algo, s2k->mode, s2k->hash_algo.
+ */
+static void
+hash_passphrase( DEK *dek, char *pw, STRING2KEY *s2k, int create )
+{
+    MD_HANDLE md;
+    int pass, i;
+    int used = 0;
+    int pwlen = strlen(pw);
+
+    assert( s2k->hash_algo );
+    dek->keylen = cipher_get_keylen( dek->algo ) / 8;
+    if( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
+	BUG();
+
+    md = md_open( s2k->hash_algo, 1);
+    for(pass=0; used < dek->keylen ; pass++ ) {
+	if( pass ) {
+            md_reset(md);
+	    for(i=0; i < pass; i++ ) /* preset the hash context */
+		md_putc(md, 0 );
+	}
+
+	if( s2k->mode == 1 || s2k->mode == 3 ) {
+	    int len2 = pwlen + 8;
+	    ulong count = len2;
+
+	    if( create && !pass ) {
+		randomize_buffer(s2k->salt, 8, 1);
+		if( s2k->mode == 3 )
+		    s2k->count = 96; /* 65536 iterations */
+	    }
+
+	    if( s2k->mode == 3 ) {
+		count = (16ul + (s2k->count & 15)) << ((s2k->count >> 4) + 6);
+		if( count < len2 )
+		    count = len2;
+	    }
+	    /* a little bit complicated because we need a ulong for count */
+	    while( count > len2 ) { /* maybe iterated+salted */
+		md_write( md, s2k->salt, 8 );
+		md_write( md, pw, pwlen );
+		count -= len2;
+	    }
+	    if( count < 8 )
+		md_write( md, s2k->salt, count );
+	    else {
+		md_write( md, s2k->salt, 8 );
+		count -= 8;
+                md_write( md, pw, count );
+	    }
+	}
+	else
+	    md_write( md, pw, pwlen );
+	md_final( md );
+	i = md_digest_length( s2k->hash_algo );
+	if( i > dek->keylen - used )
+	    i = dek->keylen - used;
+	memcpy( dek->key+used, md_read(md, s2k->hash_algo), i );
+	used += i;
+    }
+    md_close(md);
+}
+