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gnupg/g10/misc.c
David Shaw 6deb95687d Treat key lists internally as fingerprints when possible. All this is via
KEYDB_SEARCH_DESC - no point in reinventing the wheel. This allows the
helper program to search the keyserver by fingerprint if desired (and the
keyserver supports it).  Note that automatic fingerprint promotion during
refresh only applies to v4 keys as a v4 fingerprint can be easily changed
into a long or short key id, and a v3 cannot.

Take two copies of hextobyte() from pubkey-enc.c and getkey.c and make
them into one copy in misc.c.
2002-02-26 01:00:12 +00:00

578 lines
12 KiB
C

/* misc.c - miscellaneous functions
* 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 <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#ifdef HAVE_STAT
#include <sys/stat.h>
#endif
#if defined(__linux__) && defined(__alpha__) && __GLIBC__ < 2
#include <asm/sysinfo.h>
#include <asm/unistd.h>
#endif
#ifdef HAVE_SETRLIMIT
#include <time.h>
#include <sys/time.h>
#include <sys/resource.h>
#endif
#include "util.h"
#include "main.h"
#include "options.h"
#include "i18n.h"
const char *g10m_revision_string(int);
const char *g10c_revision_string(int);
const char *g10u_revision_string(int);
#ifdef __GNUC__
volatile
#endif
void
pull_in_libs(void)
{
g10m_revision_string(0);
g10c_revision_string(0);
g10u_revision_string(0);
}
#if defined(__linux__) && defined(__alpha__) && __GLIBC__ < 2
#warning using trap_unaligned
static int
setsysinfo(unsigned long op, void *buffer, unsigned long size,
int *start, void *arg, unsigned long flag)
{
return syscall(__NR_osf_setsysinfo, op, buffer, size, start, arg, flag);
}
void
trap_unaligned(void)
{
unsigned int buf[2];
buf[0] = SSIN_UACPROC;
buf[1] = UAC_SIGBUS | UAC_NOPRINT;
setsysinfo(SSI_NVPAIRS, buf, 1, 0, 0, 0);
}
#else
void
trap_unaligned(void)
{ /* dummy */
}
#endif
int
disable_core_dumps()
{
#ifdef HAVE_DOSISH_SYSTEM
return 0;
#else
#ifdef HAVE_SETRLIMIT
struct rlimit limit;
limit.rlim_cur = 0;
limit.rlim_max = 0;
if( !setrlimit( RLIMIT_CORE, &limit ) )
return 0;
if( errno != EINVAL && errno != ENOSYS )
log_fatal(_("can't disable core dumps: %s\n"), strerror(errno) );
#endif
return 1;
#endif
}
u16
checksum_u16( unsigned n )
{
u16 a;
a = (n >> 8) & 0xff;
if( opt.emulate_bugs & EMUBUG_GPGCHKSUM ) {
a |= n & 0xff;
log_debug("csum_u16 emulated for n=%u\n", n);
}
else
a += n & 0xff;
return a;
}
static u16
checksum_u16_nobug( unsigned n )
{
u16 a;
a = (n >> 8) & 0xff;
a += n & 0xff;
return a;
}
u16
checksum( byte *p, unsigned n )
{
u16 a;
for(a=0; n; n-- )
a += *p++;
return a;
}
u16
checksum_mpi( MPI a )
{
u16 csum;
byte *buffer;
unsigned nbytes;
unsigned nbits;
buffer = mpi_get_buffer( a, &nbytes, NULL );
/* some versions of gpg encode wrong values for the length of an mpi
* so that mpi_get_nbits() which counts the mpi yields another (shorter)
* value than the one store with the mpi. mpi_get_nbit_info() returns
* this stored value if it is still available.
*/
if( opt.emulate_bugs & EMUBUG_GPGCHKSUM )
nbits = 0;
else
nbits = mpi_get_nbit_info(a);
if( !nbits )
nbits = mpi_get_nbits(a);
csum = checksum_u16( nbits );
csum += checksum( buffer, nbytes );
m_free( buffer );
return csum;
}
/****************
* This is the correct function
*/
u16
checksum_mpi_counted_nbits( MPI a )
{
u16 csum;
byte *buffer;
unsigned nbytes;
unsigned nbits;
buffer = mpi_get_buffer( a, &nbytes, NULL );
nbits = mpi_get_nbits(a);
mpi_set_nbit_info(a,nbits);
csum = checksum_u16_nobug( nbits );
csum += checksum( buffer, nbytes );
m_free( buffer );
return csum;
}
u32
buffer_to_u32( const byte *buffer )
{
unsigned long a;
a = *buffer << 24;
a |= buffer[1] << 16;
a |= buffer[2] << 8;
a |= buffer[3];
return a;
}
static void
no_exp_algo(void)
{
static int did_note = 0;
if( !did_note ) {
did_note = 1;
log_info(_("Experimental algorithms should not be used!\n"));
}
}
void
print_pubkey_algo_note( int algo )
{
if( algo >= 100 && algo <= 110 )
no_exp_algo();
}
void
print_cipher_algo_note( int algo )
{
if( algo >= 100 && algo <= 110 )
no_exp_algo();
else if( algo == CIPHER_ALGO_3DES
|| algo == CIPHER_ALGO_CAST5
|| algo == CIPHER_ALGO_BLOWFISH
|| algo == CIPHER_ALGO_TWOFISH
|| algo == CIPHER_ALGO_RIJNDAEL
|| algo == CIPHER_ALGO_RIJNDAEL192
|| algo == CIPHER_ALGO_RIJNDAEL256
)
;
else {
static int did_note = 0;
if( !did_note ) {
did_note = 1;
log_info(_("this cipher algorithm is deprecated; "
"please use a more standard one!\n"));
}
}
}
void
print_digest_algo_note( int algo )
{
if( algo >= 100 && algo <= 110 )
no_exp_algo();
}
/* Return a string which is used as a kind of process ID */
const byte *
get_session_marker( size_t *rlen )
{
static byte marker[SIZEOF_UNSIGNED_LONG*2];
static int initialized;
if ( !initialized ) {
volatile ulong aa, bb; /* we really want the uninitialized value */
ulong a, b;
initialized = 1;
/* also this marker is guessable it is not easy to use this
* for a faked control packet because an attacker does not
* have enough control about the time the verification does
* take place. Of course, we can add just more random but
* than we need the random generator even for verification
* tasks - which does not make sense. */
a = aa ^ (ulong)getpid();
b = bb ^ (ulong)time(NULL);
memcpy( marker, &a, SIZEOF_UNSIGNED_LONG );
memcpy( marker+SIZEOF_UNSIGNED_LONG, &b, SIZEOF_UNSIGNED_LONG );
}
*rlen = sizeof(marker);
return marker;
}
/****************
* Wrapper around the libgcrypt function with addional checks on
* openPGP contraints for the algo ID.
*/
int
openpgp_cipher_test_algo( int algo )
{
if( algo < 0 || algo > 110 )
return G10ERR_CIPHER_ALGO;
return check_cipher_algo(algo);
}
int
openpgp_pk_test_algo( int algo, unsigned int usage_flags )
{
if( algo < 0 || algo > 110 )
return G10ERR_PUBKEY_ALGO;
return check_pubkey_algo2( algo, usage_flags );
}
int
openpgp_pk_algo_usage ( int algo )
{
int use = 0;
/* they are hardwired in gpg 1.0 */
switch ( algo ) {
case PUBKEY_ALGO_RSA:
use = PUBKEY_USAGE_SIG | PUBKEY_USAGE_ENC;
break;
case PUBKEY_ALGO_RSA_E:
use = PUBKEY_USAGE_ENC;
break;
case PUBKEY_ALGO_RSA_S:
use = PUBKEY_USAGE_SIG;
break;
case PUBKEY_ALGO_ELGAMAL_E:
use = PUBKEY_USAGE_ENC;
break;
case PUBKEY_ALGO_DSA:
use = PUBKEY_USAGE_SIG;
break;
case PUBKEY_ALGO_ELGAMAL:
use = PUBKEY_USAGE_SIG | PUBKEY_USAGE_ENC;
break;
default:
break;
}
return use;
}
int
openpgp_md_test_algo( int algo )
{
if( algo < 0 || algo > 110 )
return G10ERR_DIGEST_ALGO;
return check_digest_algo(algo);
}
int
check_permissions(const char *path,int extension,int checkonly)
{
#if defined(HAVE_STAT) && !defined(HAVE_DOSISH_SYSTEM)
char *tmppath;
struct stat statbuf;
int ret=1;
int isdir=0;
if(opt.no_perm_warn)
return 0;
if(extension && path[0]!=DIRSEP_C)
{
if(strchr(path,DIRSEP_C))
tmppath=make_filename(path,NULL);
else
tmppath=make_filename(GNUPG_LIBDIR,path,NULL);
}
else
tmppath=m_strdup(path);
/* It's okay if the file doesn't exist */
if(stat(tmppath,&statbuf)!=0)
{
ret=0;
goto end;
}
isdir=S_ISDIR(statbuf.st_mode);
/* Per-user files must be owned by the user. Extensions must be
owned by the user or root. */
if((!extension && statbuf.st_uid != getuid()) ||
(extension && statbuf.st_uid!=0 && statbuf.st_uid!=getuid()))
{
if(!checkonly)
log_info(_("Warning: unsafe ownership on %s \"%s\"\n"),
isdir?"directory":extension?"extension":"file",path);
goto end;
}
/* This works for both directories and files - basically, we don't
care what the owner permissions are, so long as the group and
other permissions are 0 for per-user files, and non-writable for
extensions. */
if((extension && (statbuf.st_mode & (S_IWGRP|S_IWOTH)) !=0) ||
(!extension && (statbuf.st_mode & (S_IRWXG|S_IRWXO)) != 0))
{
char *dir;
/* However, if the directory the directory/file is in is owned
by the user and is 700, then this is not a problem.
Theoretically, we could walk this test up to the root
directory /, but for the sake of sanity, I'm stopping at one
level down. */
dir=make_dirname(tmppath);
if(stat(dir,&statbuf)==0 && statbuf.st_uid==getuid() &&
S_ISDIR(statbuf.st_mode) && (statbuf.st_mode & (S_IRWXG|S_IRWXO))==0)
{
m_free(dir);
ret=0;
goto end;
}
m_free(dir);
if(!checkonly)
log_info(_("Warning: unsafe permissions on %s \"%s\"\n"),
isdir?"directory":extension?"extension":"file",path);
goto end;
}
ret=0;
end:
m_free(tmppath);
return ret;
#endif /* HAVE_STAT && !HAVE_DOSISH_SYSTEM */
return 0;
}
/* Special warning for the IDEA cipher */
void
idea_cipher_warn(int show)
{
static int warned=0;
if(!warned || show)
{
log_info(_("the IDEA cipher plugin is not present\n"));
log_info(_("please see http://www.gnupg.org/why-not-idea.html "
"for more information\n"));
warned=1;
}
}
/* The largest string we have an expando for, times two. */
#define LARGEST_EXPANDO ((MAX_FINGERPRINT_LEN*2)*2)
/* Expand %-strings. Returns a string which must be m_freed. Returns
NULL if the string cannot be expanded (too large). */
char *
pct_expando(const char *string,PKT_public_key *pk)
{
const char *ch=string;
int idx=0,maxlen;
u32 keyid[2]={0,0};
char *ret;
keyid_from_pk(pk,keyid);
maxlen=LARGEST_EXPANDO;
ret=m_alloc(maxlen+1); /* one more to leave room for the trailing \0 */
ret[0]='\0';
while(*ch!='\0')
{
/* 8192 is way bigger than we'll need here */
if(maxlen-idx<LARGEST_EXPANDO && maxlen<8192)
{
maxlen+=LARGEST_EXPANDO;
ret=m_realloc(ret,maxlen+1);
}
if(*ch=='%')
{
ch++;
switch(*ch)
{
case 'k': /* short key id */
if(idx+8>maxlen)
goto fail;
sprintf(&ret[idx],"%08lX",(ulong)keyid[1]);
idx+=8;
break;
case 'K': /* long key id */
if(idx+16>maxlen)
goto fail;
sprintf(&ret[idx],"%08lX%08lX",(ulong)keyid[0],(ulong)keyid[1]);
idx+=16;
break;
case 'f': /* fingerprint */
{
byte array[MAX_FINGERPRINT_LEN];
size_t len;
int i;
fingerprint_from_pk(pk,array,&len);
if(idx+(len*2)>maxlen)
goto fail;
for(i=0;i<len;i++)
{
sprintf(&ret[idx],"%02X",array[i]);
idx+=2;
}
}
break;
case '%':
if(idx+1>maxlen)
goto fail;
ret[idx++]='%';
ret[idx]='\0';
break;
/* Any unknown %-keys (like %i, %o, %I, and %O) are
passed through for later expansion. Note this also
handles the case where the last character in the
string is a '%' - the terminating \0 will end up here
and properly terminate the string. */
default:
if(idx+2>maxlen)
goto fail;
ret[idx++]='%';
ret[idx++]=*ch;
ret[idx]='\0';
break;
}
}
else
{
if(idx+1>maxlen)
goto fail;
ret[idx++]=*ch;
ret[idx]='\0';
}
ch++;
}
return ret;
fail:
m_free(ret);
return NULL;
}
int
hextobyte( const char *s )
{
int c;
if( *s >= '0' && *s <= '9' )
c = 16 * (*s - '0');
else if( *s >= 'A' && *s <= 'F' )
c = 16 * (10 + *s - 'A');
else if( *s >= 'a' && *s <= 'f' )
c = 16 * (10 + *s - 'a');
else
return -1;
s++;
if( *s >= '0' && *s <= '9' )
c += *s - '0';
else if( *s >= 'A' && *s <= 'F' )
c += 10 + *s - 'A';
else if( *s >= 'a' && *s <= 'f' )
c += 10 + *s - 'a';
else
return -1;
return c;
}