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-rw-r--r--g10/armor.c696
1 files changed, 696 insertions, 0 deletions
diff --git a/g10/armor.c b/g10/armor.c
new file mode 100644
index 000000000..f6e6305d4
--- /dev/null
+++ b/g10/armor.c
@@ -0,0 +1,696 @@
+/* armor.c - Armor filter
+ * Copyright (c) 1997 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 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.
+ *
+ * G10 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 <errno.h>
+#include <assert.h>
+
+#include "errors.h"
+#include "iobuf.h"
+#include "memory.h"
+#include "util.h"
+#include "filter.h"
+#include "packet.h"
+#include "options.h"
+
+
+
+
+#define CRCINIT 0xB704CE
+#define CRCPOLY 0X864CFB
+#define CRCUPDATE(a,c) do { \
+ a = ((a) << 8) ^ crc_table[((a)&0xff >> 16) ^ (c)]; \
+ a &= 0x00ffffff; \
+ } while(0)
+static u32 crc_table[256];
+static byte bintoasc[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
+static byte asctobin[256]; /* runtime initialized */
+static int is_initialized;
+
+typedef enum {
+ fhdrINIT=0,
+ fhdrLF,
+ fhdrWAIT,
+ fhdrWAITINFO,
+ fhdrWAITCLEARSIG,
+ fhdrDASH,
+ fhdrHEAD,
+ fhdrDASH2,
+ fhdrINFO
+} fhdr_state_t;
+
+struct fhdr_struct {
+ fhdr_state_t state;
+ int count;
+ int hdr_line; /* number of the header line */
+ char buf[256];
+};
+
+
+/* if we encounter this armor string with this index, go
+ * into a mode, which fakes packets and wait for the next armor */
+#define BEGIN_SIGNED_MSG_IDX 3
+static char *head_strings[] = {
+ "BEGIN PGP MESSAGE",
+ "BEGIN PGP PUBLIC KEY BLOCK",
+ "BEGIN PGP SIGNATURE",
+ "BEGIN PGP SIGNED MESSAGE",
+ NULL
+};
+static char *tail_strings[] = {
+ "END PGP MESSAGE",
+ "END PGP PUBLIC KEY BLOCK",
+ "END PGP SIGNATURE",
+ NULL
+};
+
+
+static void
+initialize(void)
+{
+ int i, j;
+ u32 t;
+ byte *s;
+
+ /* init the crc lookup table */
+ crc_table[0] = 0;
+ for(i=j=0; j < 128; j++ ) {
+ t = crc_table[j];
+ if( t & 0x00800000 ) {
+ t <<= 1;
+ crc_table[i++] = t ^ CRCPOLY;
+ crc_table[i++] = t;
+ }
+ else {
+ t <<= 1;
+ crc_table[i++] = t;
+ crc_table[i++] = t ^ CRCPOLY;
+ }
+ }
+ /* build the helptable for radix64 to bin conversion */
+ for(i=0; i < 256; i++ )
+ asctobin[i] = 255; /* used to detect invalid characters */
+ for(s=bintoasc,i=0; *s; s++,i++ )
+ asctobin[*s] = i;
+
+ is_initialized=1;
+}
+
+/****************
+ * Check wether this is a armored file or not
+ * See also parse-packet.c for details on this code
+ * Returns: True if it seems to be armored
+ */
+static int
+is_armored( byte *buf, size_t len )
+{
+ int ctb, pkttype;
+
+ if( len < 28 )
+ return 0; /* not even enough space for the "---BEGIN"... */
+
+ ctb = *buf;
+ if( !(ctb & 0x80) )
+ return 1; /* invalid packet: assume it is armored */
+ pkttype = ctb & 0x40 ? (ctb & 0x3f) : ((ctb>>2)&0xf);
+ /*lenbytes = (ctb & 0x40) || ((ctb&3)==3)? 0 : (1<<(ctb & 3));*/
+ switch( pkttype ) {
+ case PKT_PUBLIC_CERT:
+ case PKT_SECRET_CERT:
+ case PKT_PUBKEY_ENC:
+ case PKT_SIGNATURE:
+ case PKT_COMMENT:
+ case PKT_PLAINTEXT:
+ case PKT_COMPRESSED:
+ case PKT_ENCRYPTED:
+ return 0; /* seems to be a regular packet: not armored */
+ }
+
+ return 1;
+}
+
+
+
+
+static int
+find_header( struct fhdr_struct *fhdr, int c )
+{
+ int i;
+ const char *s;
+
+ if( c == '\n' ) {
+ switch( fhdr->state ) {
+ case fhdrINFO:
+ if( !fhdr->count )
+ return 1; /* blank line: data starts with the next line */
+ fhdr->buf[fhdr->count] = 0;
+ log_debug("armor line: '%s'\n", fhdr->buf );
+ /* fall through */
+ case fhdrWAITINFO:
+ fhdr->state = fhdrINFO;
+ fhdr->count = 0;
+ break;
+ case fhdrWAITCLEARSIG:
+ if( fhdr->count++ == 1 ) /* skip the empty line */
+ return 1; /* clear signed text follows */
+ else if( fhdr->count > 1 )
+ fhdr->state = fhdrWAIT; /* was not valid */
+ break;
+ default:
+ fhdr->state = fhdrLF;
+ break;
+ }
+ }
+ else {
+ switch( fhdr->state ) {
+ case fhdrINIT:
+ case fhdrLF:
+ if( c == '-' ) {
+ fhdr->state = fhdrDASH;
+ fhdr->count = 1;
+ }
+ else
+ fhdr->state = fhdrWAIT;
+ break;
+ case fhdrWAIT:
+ case fhdrWAITINFO:
+ case fhdrWAITCLEARSIG:
+ break;
+ case fhdrDASH:
+ if( c == '-' ) {
+ if( ++fhdr->count == 5 ) {
+ fhdr->state = fhdrHEAD;
+ fhdr->count = 0;
+ }
+ }
+ else
+ fhdr->state = fhdrWAIT;
+ break;
+ case fhdrHEAD:
+ if( c != '-' ) {
+ if( fhdr->count < DIM(fhdr->buf)-1 )
+ fhdr->buf[fhdr->count++] = c;
+ }
+ else {
+ fhdr->buf[fhdr->count] = 0;
+ for(i=0; (s=head_strings[i]); i++ )
+ if( !strcmp(s,fhdr->buf) )
+ break;
+ if( s ) { /* found string; wait for trailing dashes */
+ fhdr->hdr_line = i;
+ fhdr->state = fhdrDASH2;
+ fhdr->count = 1;
+ }
+ else
+ fhdr->state = fhdrWAIT;
+ }
+ break;
+
+ case fhdrDASH2:
+ if( c == '-' ) {
+ if( ++fhdr->count == 5 ) {
+ fhdr->state = fhdrWAITINFO;
+ log_debug("armor head: '%s'\n",
+ head_strings[fhdr->hdr_line]);
+ fhdr->state = fhdr->hdr_line == BEGIN_SIGNED_MSG_IDX
+ ? fhdrWAITCLEARSIG : fhdrWAITINFO;
+ if( fhdr->state == fhdrWAITCLEARSIG )
+ fhdr->count = 0;
+ }
+ }
+ else
+ fhdr->state = fhdrWAIT;
+ break;
+
+ case fhdrINFO:
+ if( fhdr->count < DIM(fhdr->buf)-1 )
+ fhdr->buf[fhdr->count++] = c;
+ break;
+
+ default: abort();
+ }
+ }
+ return 0;
+}
+
+/****************
+ * check wether the trailer is okay.
+ * Returns: 0 := still in trailer
+ * -1 := Okay
+ * 1 := Error in trailer
+ */
+static int
+check_trailer( struct fhdr_struct *fhdr, int c )
+{
+ return -1;
+ /* FIXME: implement this ! */
+}
+
+
+/* figure out wether the data is armored or not */
+static int
+check_input( armor_filter_context_t *afx, IOBUF a )
+{
+ int rc = 0;
+ int c;
+ size_t n = 0, nn=0, nn_limit=0;
+ struct fhdr_struct fhdr;
+
+ assert( DIM(afx->helpbuf) >= 50 );
+ memset( &fhdr, 0, sizeof(fhdr) );
+
+ /* read a couple of bytes */
+ for( n=0; n < DIM(afx->helpbuf); n++ ) {
+ if( (c=iobuf_get(a)) == -1 )
+ break;
+ afx->helpbuf[n] = c & 0xff;
+ }
+
+ if( !n )
+ rc = -1;
+ else if( is_armored( afx->helpbuf, n ) ) {
+ for(nn=0; nn < n; nn++ )
+ if( find_header( &fhdr, afx->helpbuf[nn] ) )
+ break;
+ if( nn == n ) { /* continue read */
+ while( (c=iobuf_get(a)) != -1 )
+ if( find_header( &fhdr, c ) )
+ break;
+ if( c == -1 )
+ rc = -1; /* eof */
+ }
+ if( !rc && fhdr.hdr_line == BEGIN_SIGNED_MSG_IDX ) {
+ /* start fake package mode (for clear signatures) */
+ nn++;
+ afx->helplen = n;
+ afx->helpidx = nn;
+ afx->templen = 0;
+ afx->tempidx = 0;
+ afx->fake = m_alloc_clear( sizeof(struct fhdr_struct) );
+ }
+ else if( !rc ) {
+ /* next byte to read or helpbuf[nn+1]
+ * is the first rad64 byte */
+ nn++;
+ afx->inp_checked = 1;
+ afx->crc = CRCINIT;
+ afx->idx = 0;
+ afx->radbuf[0] = 0;
+ afx->helplen = n;
+ afx->helpidx = nn;
+ }
+ }
+ else {
+ afx->inp_checked = 1;
+ afx->inp_bypass = 1;
+ }
+
+ return rc;
+}
+
+
+
+/* fake a literal data packet and wait for an armor line */
+static int
+fake_packet( armor_filter_context_t *afx, IOBUF a,
+ size_t *retn, byte *buf, size_t size )
+{
+ int rc = 0;
+ int c;
+ size_t n = 0, nn=0, nn_limit=0;
+ struct fhdr_struct *fhdr = afx->fake;
+ byte *helpbuf = afx->helpbuf;
+ int helpidx = afx->helpidx;
+ int helplen = afx->helplen;
+ byte *tempbuf = afx->tempbuf;
+ int tempidx = afx->tempidx;
+ int templen = afx->templen;
+ int defer=1;
+
+ /* FIXME: have to read one ahead or do some other mimic to
+ * get rid of the lf before the "begin signed message"
+ */
+ size = 100; /* FIXME: only used for testing (remove it) */
+ n = 2; /* reserve 2 bytes for the length header */
+ while( n < size-2 ) { /* and 2 for the term header */
+ if( templen && (fhdr->state == fhdrWAIT || fhdr->state == fhdrLF) ) {
+ if( tempidx < templen ) {
+ buf[n++] = tempbuf[tempidx++];
+ continue;
+ }
+ tempidx = templen = 0;
+ }
+
+ if( helpidx < helplen )
+ c = helpbuf[helpidx++];
+ else if( (c=iobuf_get(a)) == -1 )
+ break;
+ if( find_header( fhdr, c ) ) {
+ m_free(afx->fake);
+ afx->fake = NULL;
+ afx->inp_checked = 1;
+ afx->crc = CRCINIT;
+ afx->idx = 0;
+ afx->radbuf[0] = 0;
+ /* we don't need to care about the tempbuf */
+ break;
+ }
+ if( fhdr->state == fhdrWAIT || fhdr->state == fhdrLF ) {
+ if( templen ) {
+ tempidx = 0;
+ continue;
+ }
+ buf[n++] = c;
+ }
+ else if( fhdr->state == fhdrWAITINFO
+ || fhdr->state == fhdrINFO )
+ ;
+ else { /* store it in another temp. buf */
+ assert( templen < DIM(afx->tempbuf) );
+ tempbuf[templen++] = c;
+ }
+ }
+ buf[0] = (n-2) >> 8;
+ buf[1] = (n-2);
+ if( !afx->fake ) { /* write last (ending) length header */
+ buf[n++] = 0;
+ buf[n++] = 0;
+ }
+
+ afx->helpidx = helpidx;
+ afx->helplen = helplen;
+ afx->tempidx = tempidx;
+ afx->templen = templen;
+ *retn = n;
+ return rc;
+}
+
+
+
+static int
+radix64_read( armor_filter_context_t *afx, IOBUF a, size_t *retn,
+ byte *buf, size_t size )
+{
+ byte val;
+ int c, c2;
+ int checkcrc=0;
+ int rc = 0;
+ size_t n = 0, nn=0;
+ int idx, i;
+ u32 crc;
+
+ crc = afx->crc;
+ idx = afx->idx;
+ val = afx->radbuf[0];
+ for( n=0; n < size; ) {
+ if( afx->helpidx < afx->helplen )
+ c = afx->helpbuf[afx->helpidx++];
+ else if( (c=iobuf_get(a)) == -1 )
+ break;
+ if( c == '\n' || c == ' ' || c == '\r' || c == '\t' )
+ continue;
+ else if( c == '=' ) { /* pad character: stop */
+ if( idx == 1 )
+ buf[n++] = val;
+ checkcrc++;
+ break;
+ }
+ else if( (c = asctobin[(c2=c)]) == 255 ) {
+ log_error("invalid radix64 character %02x skipped\n", c2);
+ continue;
+ }
+ switch(idx) {
+ case 0: val = c << 2; break;
+ case 1: val |= (c>>4)&3; buf[n++]=val;val=(c<<4)&0xf0;break;
+ case 2: val |= (c>>2)&15; buf[n++]=val;val=(c<<6)&0xc0;break;
+ case 3: val |= c&0x3f; buf[n++] = val; break;
+ }
+ idx = (idx+1) % 4;
+ }
+ for(i=0; i < n; i++ )
+ crc = (crc << 8) ^ crc_table[(crc >> 16)&0xff ^ buf[i]];
+ crc &= 0x00ffffff;
+ afx->crc = crc;
+ afx->idx = idx;
+ afx->radbuf[0] = val;
+ if( checkcrc ) {
+ afx->inp_eof = 1; /*assume eof */
+ for(;;) { /* skip lf and pad characters */
+ if( afx->helpidx < afx->helplen )
+ c = afx->helpbuf[afx->helpidx++];
+ else if( (c=iobuf_get(a)) == -1 )
+ break;
+ if( c == '\n' || c == ' ' || c == '\r'
+ || c == '\t' || c == '=' )
+ continue;
+ break;
+ }
+ if( c == -1 )
+ log_error("premature eof (no CRC)\n");
+ else {
+ u32 mycrc = 0;
+ idx = 0;
+ do {
+ if( (c = asctobin[c]) == 255 )
+ break;
+ switch(idx) {
+ case 0: val = c << 2; break;
+ case 1: val |= (c>>4)&3; mycrc |= val << 16;val=(c<<4)&0xf0;break;
+ case 2: val |= (c>>2)&15; mycrc |= val << 8;val=(c<<6)&0xc0;break;
+ case 3: val |= c&0x3f; mycrc |= val; break;
+ }
+ if( afx->helpidx < afx->helplen )
+ c = afx->helpbuf[afx->helpidx++];
+ else if( (c=iobuf_get(a)) == -1 )
+ break;
+ } while( ++idx < 4 );
+ if( c == -1 )
+ log_error("premature eof (in CRC)\n");
+ else if( idx != 4 )
+ log_error("malformed CRC\n");
+ else if( mycrc != afx->crc )
+ log_error("CRC error; %06lx - %06lx\n",
+ (ulong)afx->crc, (ulong)mycrc);
+ else {
+ struct fhdr_struct fhdr;
+
+ memset( &fhdr, 0, sizeof(fhdr) );
+ for(rc=0;!rc;) {
+ rc = check_trailer( &fhdr, c );
+ if( !rc ) {
+ if( afx->helpidx < afx->helplen )
+ c = afx->helpbuf[afx->helpidx++];
+ else if( (c=iobuf_get(a)) == -1 )
+ rc = 2;
+ }
+ }
+ if( rc == -1 )
+ rc = 0;
+ else if( rc == 2 )
+ log_error("premature eof (in Trailer)\n");
+ else
+ log_error("error in trailer line\n");
+ }
+ }
+ }
+
+ if( !n )
+ rc = -1;
+
+ *retn = n;
+ return rc;
+}
+
+
+/****************
+ * The filter is used to handle the armor stuff
+ */
+int
+armor_filter( void *opaque, int control,
+ IOBUF a, byte *buf, size_t *ret_len)
+{
+ size_t size = *ret_len;
+ armor_filter_context_t *afx = opaque;
+ int rc=0, i, c, c2;
+ byte radbuf[3];
+ int idx, idx2;
+ size_t n=0;
+ u32 crc;
+
+ if( DBG_FILTER )
+ log_debug("armor-filter: control: %d\n", control );
+ if( control == IOBUFCTRL_UNDERFLOW && afx->inp_bypass ) {
+ for( n=0; n < size; n++ ) {
+ if( (c=iobuf_get(a)) == -1 )
+ break;
+ buf[n] = c & 0xff;
+ }
+ if( !n )
+ rc = -1;
+ *ret_len = n;
+ }
+ else if( control == IOBUFCTRL_UNDERFLOW ) {
+ if( size < 20 )
+ log_bug(NULL); /* supplied buffer maybe too short */
+
+ if( afx->inp_eof ) {
+ *ret_len = 0;
+ if( DBG_FILTER )
+ log_debug("armor-filter: eof due to inp_eof flag\n" );
+ return -1;
+ }
+
+ if( afx->fake )
+ rc = fake_packet( afx, a, &n, buf, size );
+ else if( !afx->inp_checked ) {
+ rc = check_input( afx, a );
+ if( afx->inp_bypass )
+ ;
+ else if( afx->fake ) {
+ /* the buffer is at least 20 bytes long, so it
+ * is easy to construct a packet */
+ buf[0] = 0xaf; /* old packet format, type 11, var length */
+ buf[1] = 0; /* set the length header */
+ buf[2] = 6;
+ buf[3] = 't'; /* canonical text */
+ buf[4] = 0; /* namelength */
+ buf[5] = buf[6] = buf[7] = buf[8] = 0; /* timestamp */
+ n = 9;
+ }
+ else if( !rc )
+ rc = radix64_read( afx, a, &n, buf, size );
+ }
+ else
+ rc = radix64_read( afx, a, &n, buf, size );
+
+ *ret_len = n;
+ }
+ else if( control == IOBUFCTRL_FLUSH ) {
+ if( !afx->status ) { /* write the header line */
+ if( afx->what >= DIM(head_strings) )
+ log_bug("afx->what=%d", afx->what);
+ iobuf_writestr(a, "-----");
+ iobuf_writestr(a, head_strings[afx->what] );
+ iobuf_writestr(a, "-----\n");
+ iobuf_writestr(a, "Version: G10 pre-release " VERSION "\n");
+ iobuf_writestr(a, "Comment: This is a alpha test version!\n\n");
+ afx->status++;
+ afx->idx = 0;
+ afx->idx2 = 0;
+ afx->crc = CRCINIT;
+ }
+ crc = afx->crc;
+ idx = afx->idx;
+ idx2 = afx->idx2;
+ for(i=0; i < idx; i++ )
+ radbuf[i] = afx->radbuf[i];
+
+ for(i=0; i < size; i++ )
+ crc = (crc << 8) ^ crc_table[(crc >> 16)&0xff ^ buf[i]];
+ crc &= 0x00ffffff;
+
+ for( ; size; buf++, size-- ) {
+ radbuf[idx++] = *buf;
+ if( idx > 2 ) {
+ idx = 0;
+ c = bintoasc[(*radbuf >> 2) & 077];
+ iobuf_put(a, c);
+ c = bintoasc[(((*radbuf<<4)&060)|((radbuf[1] >> 4)&017))&077];
+ iobuf_put(a, c);
+ c = bintoasc[(((radbuf[1]<<2)&074)|((radbuf[2]>>6)&03))&077];
+ iobuf_put(a, c);
+ c = bintoasc[radbuf[2]&077];
+ iobuf_put(a, c);
+ if( ++idx2 > (72/4) ) {
+ iobuf_put(a, '\n');
+ idx2=0;
+ }
+ }
+ }
+ for(i=0; i < idx; i++ )
+ afx->radbuf[i] = radbuf[i];
+ afx->idx = idx;
+ afx->idx2 = idx2;
+ afx->crc = crc;
+ }
+ else if( control == IOBUFCTRL_INIT ) {
+ if( !is_initialized )
+ initialize();
+ }
+ else if( control == IOBUFCTRL_FREE ) {
+ if( afx->status ) { /* pad, write cecksum, and bottom line */
+ crc = afx->crc;
+ idx = afx->idx;
+ idx2 = afx->idx2;
+ for(i=0; i < idx; i++ )
+ radbuf[i] = afx->radbuf[i];
+ if( idx ) {
+ c = bintoasc[(*radbuf>>2)&077];
+ iobuf_put(a, c);
+ if( idx == 1 ) {
+ c = bintoasc[((*radbuf << 4) & 060) & 077];
+ iobuf_put(a, c);
+ iobuf_put(a, '=');
+ iobuf_put(a, '=');
+ }
+ else { /* 2 */
+ c = bintoasc[(((*radbuf<<4)&060)|((radbuf[1]>>4)&017))&077];
+ iobuf_put(a, c);
+ c = bintoasc[((radbuf[1] << 2) & 074) & 077];
+ iobuf_put(a, c);
+ iobuf_put(a, '=');
+ }
+ ++idx2;
+ }
+ /* may need a linefeed */
+ if( idx2 < (72/4) )
+ iobuf_put(a, '\n');
+ /* write the CRC */
+ iobuf_put(a, '=');
+ radbuf[0] = crc >>16;
+ radbuf[1] = crc >> 8;
+ radbuf[2] = crc;
+ c = bintoasc[(*radbuf >> 2) & 077];
+ iobuf_put(a, c);
+ c = bintoasc[(((*radbuf<<4)&060)|((radbuf[1] >> 4)&017))&077];
+ iobuf_put(a, c);
+ c = bintoasc[(((radbuf[1]<<2)&074)|((radbuf[2]>>6)&03))&077];
+ iobuf_put(a, c);
+ c = bintoasc[radbuf[2]&077];
+ iobuf_put(a, c);
+ iobuf_put(a, '\n');
+ /* and the the trailer */
+ if( afx->what >= DIM(tail_strings) )
+ log_bug("afx->what=%d", afx->what);
+ iobuf_writestr(a, "-----");
+ iobuf_writestr(a, tail_strings[afx->what] );
+ iobuf_writestr(a, "-----\n");
+ }
+ }
+ else if( control == IOBUFCTRL_DESC )
+ *(char**)buf = "armor_filter";
+ return rc;
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-05 10:48:18 +0000