/* passphrase.c - Get a passphrase * Copyright (C) 1998, 1999, 2000, 2001 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 #include #include #include #include #include #include #if !defined(HAVE_DOSISH_SYSTEM) && !defined(__riscos__) #include #include #endif #include #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) static char *fd_passwd = NULL; static char *next_pw = NULL; static char *last_pw = NULL; 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 ) return; /* not used here */ 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; } #if !defined(HAVE_DOSISH_SYSTEM) && !defined(__riscos__) static int writen ( int fd, const void *buf, size_t nbytes ) { 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 ( "writen() failed: %s\n", strerror (errno) ); return -1; } } nleft -= nwritten; buf = (const char*)buf + nwritten; } return 0; } static int readn ( int fd, void *buf, size_t buflen, size_t *ret_nread ) { 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; return 0; } /* * 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 (void) { int fd; char *infostr, *p; struct sockaddr_un client_addr; size_t len; infostr = getenv ( "GPG_AGENT_INFO" ); if ( !infostr ) { log_error (_("gpg-agent is not available in this session\n")); 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 ); return -1; } *p = 0; if( (fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1 ) { log_error ("can't create socket: %s\n", strerror(errno) ); m_free (infostr ); 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 ); return -1; } m_free (infostr); if ( writen ( fd, "GPGA\0\0\0\x01", 8 ) ) { close (fd); fd = -1; } return fd; } static void agent_close ( int fd ) { close (fd); } #endif /* !HAVE_DOSISH_SYSTEM && !__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" */ static char * agent_get_passphrase ( u32 *keyid, int mode ) { #if defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__) return NULL; #else size_t n; char *atext; char buf[50]; int fd = -1; size_t nread; u32 reply; char *pw = NULL; PKT_public_key *pk = m_alloc_clear( sizeof *pk ); byte fpr[MAX_FINGERPRINT_LEN]; #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 ) ) pk = NULL; /* oops: no key for some reason */ if ( !mode && pk ) { 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 ); } } else if (mode == 1 ) atext = m_strdup ( _("Enter passphrase\n") ); else atext = m_strdup ( _("Repeat passphrase\n") ); if ( (fd = agent_open ()) == -1 ) goto failure; 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 ); return pw; } else if ( reply == GPGA_PROT_CANCELED ) { log_info ( _("cancelled by user\n") ); } else { log_error ( _("problem with the agent: agent returns 0x%lx\n"), (ulong)reply ); } failure: m_free (atext); if ( fd != -1 ) agent_close (fd); m_free (pw ); free_public_key( pk ); return NULL; #endif } /* * Clear the cached passphrase */ void passphrase_clear_cache ( u32 *keyid, int algo ) { #if defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__) return ; #else size_t n; char buf[50]; int fd = -1; size_t nread; u32 reply; PKT_public_key *pk; byte fpr[MAX_FINGERPRINT_LEN]; #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 ()) == -1 ) goto failure; 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 ); } failure: if ( fd != -1 ) agent_close (fd); free_public_key( pk ); #endif } /**************** * Get a passphrase for the secret key with KEYID, display TEXT * if the user needs to enter the passphrase. * mode 0 = standard, 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. */ DEK * passphrase_to_dek( u32 *keyid, int pubkey_algo, int cipher_algo, STRING2KEY *s2k, int mode ) { char *pw = NULL; DEK *dek; STRING2KEY help_s2k; if( !s2k ) { /* This is used for the old rfc1991 mode * Note: This must match the code in encode.c with opt.rfc1991 set */ int algo = opt.def_digest_algo ? opt.def_digest_algo : opt.s2k_digest_algo; s2k = &help_s2k; s2k->mode = 0; s2k->hash_algo = 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 ) { 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 ); } if( next_pw ) { pw = next_pw; next_pw = NULL; } else if ( opt.use_agent ) { pw = agent_get_passphrase ( keyid, mode == 2? 1: 0 ); if ( !pw ) pw = m_strdup (""); if( *pw && mode == 2 ) { char *pw2 = agent_get_passphrase ( keyid, 2 ); if ( !pw2 ) 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 ) { if( (opt.emulate_bugs & EMUBUG_3DESS2K)) { int tmp = md->finalized; md_reset( md ); md->finalized = tmp; } else 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); }