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gnupg/g10/misc.c
David Shaw 3b9a04844c * parse-packet.c (parse_plaintext), packet.h, plaintext.c 
(handle_plaintext): Fix bug in handling literal packets with zero-length
data (no data was being confused with partial body length).

* misc.c (pct_expando), options.skel: %t means extension ("jpg"). %T means
MIME type ("image/jpeg").

* import.c (import_one): Only trigger trust update if the keyring is
actually changed.

* export.c (do_export_stream): Missing a m_free.
2002-04-23 02:48:44 +00:00

596 lines
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/* 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. */
#define LARGEST_EXPANDO (MAX_FINGERPRINT_LEN*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*2;
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*2;
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;
/* photo types. For now, it's always jpeg so this is
easy! */
case 't':
if(idx+3>maxlen)
goto fail;
strcpy(&ret[idx],"jpg");
idx+=3;
break;
case 'T':
if(idx+10>maxlen)
goto fail;
strcpy(&ret[idx],"image/jpeg");
idx+=10;
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;
}
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