summaryrefslogtreecommitdiffabout
path: root/pwmanager/libcrypt/crypt/sexp.c
authorzautrix <zautrix>2004-10-19 20:16:14 (UTC)
committer zautrix <zautrix>2004-10-19 20:16:14 (UTC)
commiteca49bb06a71980ef61d078904573f25890fc7f2 (patch) (side-by-side diff)
treec5338e3b12430248979a9ac2c1c7e6646ea9ecdf /pwmanager/libcrypt/crypt/sexp.c
parent53cc32b6e7b1f672bf91b2baf2df6c1e8baf3e0a (diff)
downloadkdepimpi-eca49bb06a71980ef61d078904573f25890fc7f2.zip
kdepimpi-eca49bb06a71980ef61d078904573f25890fc7f2.tar.gz
kdepimpi-eca49bb06a71980ef61d078904573f25890fc7f2.tar.bz2
Initial revision
Diffstat (limited to 'pwmanager/libcrypt/crypt/sexp.c') (more/less context) (ignore whitespace changes)
-rw-r--r--pwmanager/libcrypt/crypt/sexp.c1804
1 files changed, 1804 insertions, 0 deletions
diff --git a/pwmanager/libcrypt/crypt/sexp.c b/pwmanager/libcrypt/crypt/sexp.c
new file mode 100644
index 0000000..c19dc33
--- a/dev/null
+++ b/pwmanager/libcrypt/crypt/sexp.c
@@ -0,0 +1,1804 @@
+/* sexp.c - S-Expression handling
+ * Copyright (C) 1999, 2000, 2001, 2002, 2003,
+ * 2004 Free Software Foundation, Inc.
+ *
+ * This file is part of Libgcrypt.
+ *
+ * Libgcrypt is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser general Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * Libgcrypt 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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 <stdarg.h>
+#include <ctype.h>
+#include <assert.h>
+
+#define GCRYPT_NO_MPI_MACROS 1
+#include "g10lib.h"
+#include "memory.h"
+
+typedef struct gcry_sexp *NODE;
+typedef unsigned short DATALEN;
+
+struct gcry_sexp
+{
+ byte d[1];
+};
+
+#define ST_STOP 0
+#define ST_DATA 1 /* datalen follows */
+#define ST_HINT 2 /* datalen follows */
+#define ST_OPEN 3
+#define ST_CLOSE 4
+
+/* the atoi macros assume that the buffer has only valid digits */
+#define atoi_1(p) (*(p) - '0' )
+#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))
+
+#define TOKEN_SPECIALS "-./_:*+="
+
+static gcry_error_t
+sexp_sscan (gcry_sexp_t *retsexp, size_t *erroff,
+ const char *buffer, size_t length, int argflag,
+ va_list arg_ptr, void **arg_list);
+
+#if 0
+static void
+dump_mpi( gcry_mpi_t a )
+{
+ char buffer[1000];
+ size_t n = 1000;
+
+ if( !a )
+ fputs("[no MPI]", stderr );
+ else if( gcry_mpi_print( GCRYMPI_FMT_HEX, buffer, &n, a ) )
+ fputs("[MPI too large to print]", stderr );
+ else
+ fputs( buffer, stderr );
+}
+#endif
+
+static void
+dump_string (const byte *p, size_t n, int delim )
+{
+ for (; n; n--, p++ )
+ {
+ if ((*p & 0x80) || iscntrl( *p ) || *p == delim )
+ {
+ if( *p == '\n' )
+ log_printf ("\\n");
+ else if( *p == '\r' )
+ log_printf ("\\r");
+ else if( *p == '\f' )
+ log_printf ("\\f");
+ else if( *p == '\v' )
+ log_printf ("\\v");
+ else if( *p == '\b' )
+ log_printf ("\\b");
+ else if( !*p )
+ log_printf ("\\0");
+ else
+ log_printf ("\\x%02x", *p );
+ }
+ else
+ log_printf ("%c", *p);
+ }
+}
+
+
+void
+gcry_sexp_dump (const gcry_sexp_t a)
+{
+ const byte *p;
+ int indent = 0;
+ int type;
+
+ if (!a)
+ {
+ log_printf ( "[nil]\n");
+ return;
+ }
+
+ p = a->d;
+ while ( (type = *p) != ST_STOP )
+ {
+ p++;
+ switch ( type )
+ {
+ case ST_OPEN:
+ log_printf ("%*s[open]\n", 2*indent, "");
+ indent++;
+ break;
+ case ST_CLOSE:
+ if( indent )
+ indent--;
+ log_printf ("%*s[close]\n", 2*indent, "");
+ break;
+ case ST_DATA: {
+ DATALEN n;
+ memcpy ( &n, p, sizeof n );
+ p += sizeof n;
+ log_printf ("%*s[data=\"", 2*indent, "" );
+ dump_string (p, n, '\"' );
+ log_printf ("\"]\n");
+ p += n;
+ }
+ break;
+ default:
+ log_printf ("%*s[unknown tag %d]\n", 2*indent, "", type);
+ break;
+ }
+ }
+}
+
+/****************
+ * Pass list through except when it is an empty list - in that case
+ * return NULL and release the passed list.
+ */
+static gcry_sexp_t
+normalize ( gcry_sexp_t list )
+{
+ char *p;
+ if ( !list )
+ return NULL;
+ p = list->d;
+ if ( *p == ST_STOP ) {
+ /* this is "" */
+ gcry_sexp_release ( list );
+ return NULL;
+ }
+ if( *p == ST_OPEN && p[1] == ST_CLOSE ) {
+ /* this is "()" */
+ gcry_sexp_release ( list );
+ return NULL;
+ }
+
+ return list;
+}
+
+/* Create a new S-expression object by reading LENGTH bytes from
+ BUFFER, assuming it is canonilized encoded or autodetected encoding
+ when AUTODETECT is set to 1. With FREEFNC not NULL, ownership of
+ the buffer is transferred to tyhe newle created object. FREEFNC
+ should be the freefnc used to release BUFFER; there is no guarantee
+ at which point this function is called; most likey you want to use
+ free() or gcry_free().
+
+ Passing LENGTH and AUTODETECT as 0 is allowed to indicate that
+ BUFFER points to a valid canonical encoded S-expression. A LENGTH
+ of 0 and AUTODETECT 1 indicates that buffer points to a
+ null-terminated string.
+
+ This function returns 0 and and the pointer to the new object in
+ RETSEXP or an error code in which case RETSEXP is set to NULL. */
+gcry_error_t
+gcry_sexp_create (gcry_sexp_t *retsexp, void *buffer, size_t length,
+ int autodetect, void (*freefnc)(void*) )
+{
+ gcry_error_t errcode;
+ gcry_sexp_t se;
+ volatile va_list dummy_arg_ptr;
+
+ if (!retsexp)
+ return gcry_error (GPG_ERR_INV_ARG);
+ *retsexp = NULL;
+ if (autodetect < 0 || autodetect > 1 || !buffer)
+ return gcry_error (GPG_ERR_INV_ARG);
+
+ if (!length && !autodetect)
+ { /* What a brave caller to assume that there is really a canonical
+ encoded S-expression in buffer */
+ length = gcry_sexp_canon_len (buffer, 0, NULL, &errcode);
+ if (!length)
+ return errcode;
+ }
+ else if (!length && autodetect)
+ { /* buffer is a string */
+ length = strlen ((char *)buffer);
+ }
+
+ errcode = sexp_sscan (&se, NULL, buffer, length, 0, dummy_arg_ptr, NULL);
+ if (errcode)
+ return errcode;
+
+ *retsexp = se;
+ if (freefnc)
+ {
+ /* For now we release the buffer immediately. As soon as we
+ have changed the internal represenation of S-expression to
+ the canoncial format - which has the advantage of faster
+ parsing - we will use this function as a closure in our
+ GCRYSEXP object and use the BUFFER directly */
+ freefnc (buffer);
+ }
+ return gcry_error (GPG_ERR_NO_ERROR);
+}
+
+/* Same as gcry_sexp_create but don't transfer ownership */
+gcry_error_t
+gcry_sexp_new (gcry_sexp_t *retsexp, const void *buffer, size_t length,
+ int autodetect)
+{
+ return gcry_sexp_create (retsexp, (void *)buffer, length, autodetect, NULL);
+}
+
+
+/****************
+ * Release resource of the given SEXP object.
+ */
+void
+gcry_sexp_release( gcry_sexp_t sexp )
+{
+ if (sexp)
+ {
+ if (gcry_is_secure (sexp))
+ {
+ /* Extra paranoid wiping. */
+ const byte *p = sexp->d;
+ int type;
+
+ while ( (type = *p) != ST_STOP )
+ {
+ p++;
+ switch ( type )
+ {
+ case ST_OPEN:
+ break;
+ case ST_CLOSE:
+ break;
+ case ST_DATA:
+ {
+ DATALEN n;
+ memcpy ( &n, p, sizeof n );
+ p += sizeof n;
+ p += n;
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ wipememory (sexp->d, p - sexp->d);
+ }
+ gcry_free ( sexp );
+ }
+}
+
+
+/****************
+ * Make a pair from lists a and b, don't use a or b later on.
+ * Special behaviour: If one is a single element list we put the
+ * element straight into the new pair.
+ */
+gcry_sexp_t
+gcry_sexp_cons( const gcry_sexp_t a, const gcry_sexp_t b )
+{
+ /* NYI: Implementation should be quite easy with our new data
+ representation */
+ BUG ();
+ return NULL;
+}
+
+
+/****************
+ * Make a list from all items in the array the end of the array is marked
+ * with a NULL.
+ */
+gcry_sexp_t
+gcry_sexp_alist( const gcry_sexp_t *array )
+{
+ /* NYI: Implementation should be quite easy with our new data
+ representation. */
+ BUG ();
+ return NULL;
+}
+
+/****************
+ * Make a list from all items, the end of list is indicated by a NULL
+ */
+gcry_sexp_t
+gcry_sexp_vlist( const gcry_sexp_t a, ... )
+{
+ /* NYI: Implementation should be quite easy with our new data
+ representation. */
+ BUG ();
+ return NULL;
+}
+
+
+/****************
+ * Append n to the list a
+ * Returns: a new ist (which maybe a)
+ */
+gcry_sexp_t
+gcry_sexp_append( const gcry_sexp_t a, const gcry_sexp_t n )
+{
+ /* NYI: Implementation should be quite easy with our new data
+ representation. */
+ BUG ();
+ return NULL;
+}
+
+gcry_sexp_t
+gcry_sexp_prepend( const gcry_sexp_t a, const gcry_sexp_t n )
+{
+ /* NYI: Implementation should be quite easy with our new data
+ representation. */
+ BUG ();
+ return NULL;
+}
+
+
+
+/****************
+ * Locate token in a list. The token must be the car of a sublist.
+ * Returns: A new list with this sublist or NULL if not found.
+ */
+gcry_sexp_t
+gcry_sexp_find_token( const gcry_sexp_t list, const char *tok, size_t toklen )
+{
+ const byte *p;
+ DATALEN n;
+
+ if ( !list )
+ return NULL;
+
+ if( !toklen )
+ toklen = strlen(tok);
+ p = list->d;
+ while ( *p != ST_STOP ) {
+ if ( *p == ST_OPEN && p[1] == ST_DATA ) {
+ const byte *head = p;
+
+ p += 2;
+ memcpy ( &n, p, sizeof n ); p += sizeof n;
+ if ( n == toklen && !memcmp( p, tok, toklen ) ) { /* found it */
+ gcry_sexp_t newlist;
+ byte *d;
+ int level = 1;
+
+ /* look for the end of the list */
+ for ( p += n; level; p++ ) {
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--; /* compensate for later increment */
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ }
+ else if ( *p == ST_STOP ) {
+ BUG ();
+ }
+ } while ( level );
+ n = p - head;
+
+ newlist = gcry_xmalloc ( sizeof *newlist + n );
+ d = newlist->d;
+ memcpy ( d, head, n ); d += n;
+ *d++ = ST_STOP;
+ return normalize ( newlist );
+ }
+ p += n;
+ }
+ else if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n ); p += sizeof n;
+ p += n;
+ }
+ else
+ p++;
+ }
+ return NULL;
+}
+
+/****************
+ * Return the length of the given list
+ */
+int
+gcry_sexp_length( const gcry_sexp_t list )
+{
+ const byte *p;
+ DATALEN n;
+ int type;
+ int length = 0;
+ int level = 0;
+
+ if ( !list )
+ return 0;
+
+ p = list->d;
+ while ( (type=*p) != ST_STOP ) {
+ p++;
+ if ( type == ST_DATA ) {
+ memcpy ( &n, p, sizeof n );
+ p += sizeof n + n;
+ if ( level == 1 )
+ length++;
+ }
+ else if ( type == ST_OPEN ) {
+ if ( level == 1 )
+ length++;
+ level++;
+ }
+ else if ( type == ST_CLOSE ) {
+ level--;
+ }
+ }
+ return length;
+}
+
+
+
+/****************
+ * Extract the CAR of the given list
+ */
+gcry_sexp_t
+gcry_sexp_nth( const gcry_sexp_t list, int number )
+{
+ const byte *p;
+ DATALEN n;
+ gcry_sexp_t newlist;
+ byte *d;
+ int level = 0;
+
+ if ( !list || list->d[0] != ST_OPEN )
+ return NULL;
+ p = list->d;
+
+ while ( number > 0 ) {
+ p++;
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_STOP ) {
+ return NULL;
+ }
+ }
+ p++;
+
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, p, sizeof n ); p += sizeof n;
+ newlist = gcry_xmalloc ( sizeof *newlist + n + 1 );
+ d = newlist->d;
+ memcpy ( d, p, n ); d += n;
+ *d++ = ST_STOP;
+ }
+ else if ( *p == ST_OPEN ) {
+ const byte *head = p;
+
+ level = 1;
+ do {
+ p++;
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ }
+ else if ( *p == ST_STOP ) {
+ BUG ();
+ }
+ } while ( level );
+ n = p + 1 - head;
+
+ newlist = gcry_xmalloc ( sizeof *newlist + n );
+ d = newlist->d;
+ memcpy ( d, head, n ); d += n;
+ *d++ = ST_STOP;
+ }
+ else
+ newlist = NULL;
+
+ return normalize (newlist);
+}
+
+gcry_sexp_t
+gcry_sexp_car( const gcry_sexp_t list )
+{
+ return gcry_sexp_nth ( list, 0 );
+}
+
+/****************
+ * Get data from the car. The returned value is valid as long as the list
+ * is not modified.
+ */
+const char *
+gcry_sexp_nth_data( const gcry_sexp_t list, int number, size_t *datalen )
+{
+ const byte *p;
+ DATALEN n;
+ int level = 0;
+
+ *datalen = 0;
+ if ( !list ) {
+ return NULL;
+ }
+ p = list->d;
+ if ( *p == ST_OPEN )
+ p++; /* yep, a list */
+ else if (number )
+ return NULL; /* not a list but an n > 0 element requested */
+
+ /* skip n elements */
+ while ( number > 0 ) {
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_STOP ) {
+ return NULL;
+ }
+ p++;
+ }
+
+
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ *datalen = n;
+ return p + sizeof n;
+ }
+
+ return NULL;
+}
+
+/****************
+ * Get a MPI from the car
+ */
+gcry_mpi_t
+gcry_sexp_nth_mpi( gcry_sexp_t list, int number, int mpifmt )
+{
+ const byte *p;
+ DATALEN n;
+ int level = 0;
+
+ if ( !list )
+ return NULL;
+ if ( !mpifmt )
+ mpifmt = GCRYMPI_FMT_STD;
+
+ p = list->d;
+ if ( *p == ST_OPEN )
+ p++; /* yep, a list */
+ else if (number )
+ return NULL; /* not a list but an n > 0 element requested */
+
+ /* skip n elements */
+ while ( number > 0 ) {
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ if ( !level )
+ number--;
+ }
+ else if ( *p == ST_STOP ) {
+ return NULL;
+ }
+ p++;
+ }
+
+ if ( *p == ST_DATA ) {
+ gcry_mpi_t a;
+ size_t nbytes;
+
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n;
+ nbytes = n;
+ if( !gcry_mpi_scan( &a, mpifmt, p, n, &nbytes ) )
+ return a;
+ }
+
+ return NULL;
+}
+
+
+/****************
+ * Get the CDR
+ */
+gcry_sexp_t
+gcry_sexp_cdr( const gcry_sexp_t list )
+{
+ const byte *p;
+ const byte *head;
+ DATALEN n;
+ gcry_sexp_t newlist;
+ byte *d;
+ int level = 0;
+ int skip = 1;
+
+ if ( !list || list->d[0] != ST_OPEN )
+ return NULL;
+ p = list->d;
+
+ while ( skip > 0 ) {
+ p++;
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ if ( !level )
+ skip--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ if ( !level )
+ skip--;
+ }
+ else if ( *p == ST_STOP ) {
+ return NULL;
+ }
+ }
+ p++;
+
+ head = p;
+ level = 0;
+ do {
+ if ( *p == ST_DATA ) {
+ memcpy ( &n, ++p, sizeof n );
+ p += sizeof n + n;
+ p--;
+ }
+ else if ( *p == ST_OPEN ) {
+ level++;
+ }
+ else if ( *p == ST_CLOSE ) {
+ level--;
+ }
+ else if ( *p == ST_STOP ) {
+ return NULL;
+ }
+ p++;
+ } while ( level );
+ n = p - head;
+
+ newlist = gcry_xmalloc ( sizeof *newlist + n + 2 );
+ d = newlist->d;
+ *d++ = ST_OPEN;
+ memcpy ( d, head, n ); d += n;
+ *d++ = ST_CLOSE;
+ *d++ = ST_STOP;
+
+ return normalize (newlist);
+}
+
+gcry_sexp_t
+gcry_sexp_cadr ( const gcry_sexp_t list )
+{
+ gcry_sexp_t a, b;
+
+ a = gcry_sexp_cdr ( list );
+ b = gcry_sexp_car ( a );
+ gcry_sexp_release ( a );
+ return b;
+}
+
+
+
+static int
+hextobyte( const byte *s )
+{
+ int c=0;
+
+ 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');
+ }
+ 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';
+ }
+ return c;
+}
+
+struct make_space_ctx {
+ gcry_sexp_t sexp;
+ size_t allocated;
+ byte *pos;
+};
+
+static void
+make_space ( struct make_space_ctx *c, size_t n )
+{
+ size_t used = c->pos - c->sexp->d;
+
+ if ( used + n + sizeof(DATALEN) + 1 >= c->allocated ) {
+ gcry_sexp_t newsexp;
+ byte *newhead;
+
+ c->allocated += 2*(n+sizeof(DATALEN)+1);
+ newsexp = gcry_xrealloc ( c->sexp, sizeof *newsexp + c->allocated - 1 );
+ newhead = newsexp->d;
+ c->pos = newhead + used;
+ c->sexp = newsexp;
+ }
+}
+
+
+/* Unquote STRING of LENGTH and store it into BUF. The surrounding
+ quotes are must already be removed from STRING. We assume that the
+ quoted string is syntacillay correct. */
+static size_t
+unquote_string (const unsigned char *string, size_t length, unsigned char *buf)
+{
+ int esc = 0;
+ const unsigned char *s = string;
+ unsigned char *d = buf;
+ size_t n = length;
+
+ for (; n; n--, s++)
+ {
+ if (esc)
+ {
+ switch (*s)
+ {
+ case 'b': *d++ = '\b'; break;
+ case 't': *d++ = '\t'; break;
+ case 'v': *d++ = '\v'; break;
+ case 'n': *d++ = '\n'; break;
+ case 'f': *d++ = '\f'; break;
+ case 'r': *d++ = '\r'; break;
+ case '"': *d++ = '\"'; break;
+ case '\'': *d++ = '\''; break;
+ case '\\': *d++ = '\\'; break;
+
+ case '\r': /* ignore CR[,LF] */
+ if (n>1 && s[1] == '\n')
+ {
+ s++; n--;
+ }
+ esc = 0;
+ break;
+
+ case '\n': /* ignore LF[,CR] */
+ if (n>1 && s[1] == '\r')
+ {
+ s++; n--;
+ }
+ break;
+
+ case 'x': /* hex value */
+ if (n>2 && hexdigitp (s+1) && hexdigitp (s+2))
+ {
+ s++; n--;
+ *d++ = xtoi_2 (s);
+ s++; n--;
+ }
+ break;
+
+ default:
+ if (n>2 && octdigitp (s) && octdigitp (s+1) && octdigitp (s+2))
+ {
+ *d++ = (atoi_1 (s)*64) + (atoi_1 (s+1)*8) + atoi_1 (s+2);
+ s += 2;
+ n -= 2;
+ }
+ break;
+ }
+ esc = 0;
+ }
+ else if( *s == '\\' )
+ esc = 1;
+ else
+ *d++ = *s;
+ }
+
+ return d - buf;
+}
+
+/****************
+ * Scan the provided buffer and return the S expression in our internal
+ * format. Returns a newly allocated expression. If erroff is not NULL and
+ * a parsing error has occured, the offset into buffer will be returned.
+ * If ARGFLAG is true, the function supports some printf like
+ * expressions.
+ * These are:
+ * %m - MPI
+ * %s - string (no autoswitch to secure allocation)
+ * %d - integer stored as string (no autoswitch to secure allocation)
+ * %b - memory buffer; this takes _two_ arguments: an integer with the
+ * length of the buffer and a pointer to the buffer.
+ * all other format elements are currently not defined and return an error.
+ * this includes the "%%" sequence becauce the percent sign is not an
+ * allowed character.
+ * FIXME: We should find a way to store the secure-MPIs not in the string
+ * but as reference to somewhere - this can help us to save huge amounts
+ * of secure memory. The problem is, that if only one element is secure, all
+ * other elements are automagicaly copied to secure memory too, so the most
+ * common operation gcry_sexp_cdr_mpi() will always return a secure MPI
+ * regardless whether it is needed or not.
+ */
+static gcry_error_t
+sexp_sscan (gcry_sexp_t *retsexp, size_t *erroff,
+ const char *buffer, size_t length, int argflag,
+ va_list arg_ptr, void **arg_list)
+{
+ gcry_err_code_t err = GPG_ERR_NO_ERROR;
+ static const char tokenchars[] =
+ "abcdefghijklmnopqrstuvwxyz"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "0123456789-./_:*+=";
+ const char *p;
+ size_t n;
+ const char *digptr = NULL;
+ const char *quoted = NULL;
+ const char *tokenp = NULL;
+ const char *hexfmt = NULL;
+ const char *base64 = NULL;
+ const char *disphint = NULL;
+ const char *percent = NULL;
+ int hexcount = 0;
+ int quoted_esc = 0;
+ int datalen = 0;
+ size_t dummy_erroff;
+ struct make_space_ctx c;
+ int arg_counter = 0;
+ int level = 0;
+
+ /* FIXME: invent better error codes (?). */
+
+ if (! erroff)
+ erroff = &dummy_erroff;
+
+ /* Depending on wether ARG_LIST is non-zero or not, this macro gives
+ us the next argument, either from the variable argument list as
+ specified by ARG_PTR or from the argument array ARG_LIST. */
+#define ARG_NEXT(storage, type) \
+ do \
+ { \
+ if (! arg_list) \
+ storage = va_arg (arg_ptr, type); \
+ else \
+ storage = *((type *) (arg_list[arg_counter++])); \
+ } \
+ while (0)
+
+#define MAKE_SPACE(n) do { make_space ( &c, (n) ); } while (0)
+#define STORE_LEN(p,n) do { \
+ DATALEN ashort = (n); \
+ memcpy ( (p), &ashort, sizeof(ashort) ); \
+ (p) += sizeof (ashort); \
+ } while (0)
+
+ /* We assume that the internal representation takes less memory
+ * than the provided one. However, we add space for one extra datalen
+ * so that the code which does the ST_CLOSE can use MAKE_SPACE */
+ c.allocated = length + sizeof(DATALEN);
+ if (buffer && length && gcry_is_secure (buffer))
+ c.sexp = gcry_xmalloc_secure (sizeof *c.sexp + c.allocated - 1);
+ else
+ c.sexp = gcry_xmalloc (sizeof *c.sexp + c.allocated - 1);
+ c.pos = c.sexp->d;
+
+ for (p = buffer, n = length; n; p++, n--)
+ {
+ if (tokenp && (! hexfmt))
+ {
+ if (strchr (tokenchars, *p))
+ continue;
+ else
+ {
+ datalen = p - tokenp;
+ MAKE_SPACE (datalen);
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, datalen);
+ memcpy (c.pos, tokenp, datalen);
+ c.pos += datalen;
+ tokenp = NULL;
+ }
+ }
+
+ if (quoted)
+ {
+ if (quoted_esc)
+ {
+ switch (*p)
+ {
+ case 'b': case 't': case 'v': case 'n': case 'f':
+ case 'r': case '"': case '\'': case '\\':
+ quoted_esc = 0;
+ break;
+
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7':
+ if (! ((n > 2)
+ && (p[1] >= '0') && (p[1] <= '7')
+ && (p[2] >= '0') && (p[2] <= '7')))
+ {
+ *erroff = p - buffer;
+ /* Invalid octal value. */
+ err = GPG_ERR_SEXP_BAD_QUOTATION;
+ //return gcry_error (GPG_ERR_SEXP_BAD_QUOTATION);
+ }
+ p += 2;
+ n -= 2;
+ quoted_esc = 0;
+ break;
+
+ case 'x':
+ if (! ((n > 2) && isxdigit(p[1]) && isxdigit(p[2])))
+ {
+ *erroff = p - buffer;
+ /* Invalid hex value. */
+ err = GPG_ERR_SEXP_BAD_QUOTATION;
+ //return gcry_error (GPG_ERR_SEXP_BAD_QUOTATION);
+ }
+ p += 2;
+ n -= 2;
+ quoted_esc = 0;
+ break;
+
+ case '\r':
+ /* ignore CR[,LF] */
+ if (n && (p[1] == '\n'))
+ {
+ p++;
+ n--;
+ }
+ quoted_esc = 0;
+ break;
+
+ case '\n':
+ /* ignore LF[,CR] */
+ if (n && (p[1] == '\r'))
+ {
+ p++;
+ n--;
+ }
+ quoted_esc = 0;
+ break;
+
+ default:
+ *erroff = p - buffer;
+ /* Invalid quoted string escape. */
+ err = GPG_ERR_SEXP_BAD_QUOTATION;
+ }
+ }
+ else if (*p == '\\')
+ quoted_esc = 1;
+ else if (*p == '\"')
+ {
+ /* Keep it easy - we know that the unquoted string will
+ never be larger. */
+ char *save;
+ size_t len;
+
+ quoted++; /* Skip leading quote. */
+ MAKE_SPACE (p - quoted);
+ *c.pos++ = ST_DATA;
+ save = c.pos;
+ STORE_LEN (c.pos, 0); /* Will be fixed up later. */
+ len = unquote_string (quoted, p - quoted, c.pos);
+ c.pos += len;
+ STORE_LEN (save, len);
+ quoted = NULL;
+ }
+ }
+ else if (hexfmt)
+ {
+ if (isxdigit (*p))
+ hexcount++;
+ else if (*p == '#')
+ {
+ if ((hexcount & 1))
+ {
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_ODD_HEX_NUMBERS;
+ }
+
+ datalen = hexcount / 2;
+ MAKE_SPACE (datalen);
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, datalen);
+ for (hexfmt++; hexfmt < p; hexfmt++)
+ {
+ if (isspace (*hexfmt))
+ continue;
+ *c.pos++ = hextobyte (hexfmt);
+ hexfmt++;
+ }
+ hexfmt = NULL;
+ }
+ else if (! isspace (*p))
+ {
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_BAD_HEX_CHAR;
+ }
+ }
+ else if (base64)
+ {
+ if (*p == '|')
+ base64 = NULL;
+ }
+ else if (digptr)
+ {
+ if (isdigit (*p))
+ ;
+ else if (*p == ':')
+ {
+ datalen = atoi (digptr); /* FIXME: check for overflow. */
+ digptr = NULL;
+ if (datalen > n - 1)
+ {
+ *erroff = p - buffer;
+ /* Buffer too short. */
+ err = GPG_ERR_SEXP_STRING_TOO_LONG;
+ }
+ /* Make a new list entry. */
+ MAKE_SPACE (datalen);
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, datalen);
+ memcpy (c.pos, p + 1, datalen);
+ c.pos += datalen;
+ n -= datalen;
+ p += datalen;
+ }
+ else if (*p == '\"')
+ {
+ digptr = NULL; /* We ignore the optional length. */
+ quoted = p;
+ quoted_esc = 0;
+ }
+ else if (*p == '#')
+ {
+ digptr = NULL; /* We ignore the optional length. */
+ hexfmt = p;
+ hexcount = 0;
+ }
+ else if (*p == '|')
+ {
+ digptr = NULL; /* We ignore the optional length. */
+ base64 = p;
+ }
+ else
+ {
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_INV_LEN_SPEC;
+ }
+ }
+ else if (percent)
+ {
+ if (*p == 'm')
+ {
+ /* Insert an MPI. */
+ gcry_mpi_t m;
+ size_t nm = 0;
+
+ ARG_NEXT (m, gcry_mpi_t);
+
+ if (gcry_mpi_print (GCRYMPI_FMT_STD, NULL, 0, &nm, m))
+ BUG ();
+
+ MAKE_SPACE (nm);
+ if ((! gcry_is_secure (c.sexp->d))
+ && gcry_mpi_get_flag ( m, GCRYMPI_FLAG_SECURE))
+ {
+ /* We have to switch to secure allocation. */
+ gcry_sexp_t newsexp;
+ byte *newhead;
+
+ newsexp = gcry_xmalloc_secure (sizeof *newsexp
+ + c.allocated - 1);
+ newhead = newsexp->d;
+ memcpy (newhead, c.sexp->d, (c.pos - c.sexp->d));
+ c.pos = newhead + (c.pos - c.sexp->d);
+ gcry_free (c.sexp);
+ c.sexp = newsexp;
+ }
+
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, nm);
+ if (gcry_mpi_print (GCRYMPI_FMT_STD, c.pos, nm, &nm, m))
+ BUG ();
+ c.pos += nm;
+ }
+ else if (*p == 's')
+ {
+ /* Insert an string. */
+ const char *astr;
+ size_t alen;
+
+ ARG_NEXT (astr, const char *);
+ alen = strlen (astr);
+
+ MAKE_SPACE (alen);
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, alen);
+ memcpy (c.pos, astr, alen);
+ c.pos += alen;
+ }
+ else if (*p == 'b')
+ {
+ /* Insert a memory buffer. */
+ const char *astr;
+ int alen;
+
+ ARG_NEXT (alen, int);
+ ARG_NEXT (astr, const char *);
+
+ MAKE_SPACE (alen);
+ if (alen
+ && !gcry_is_secure (c.sexp->d)
+ && gcry_is_secure (astr))
+ {
+ /* We have to switch to secure allocation. */
+ gcry_sexp_t newsexp;
+ byte *newhead;
+
+ newsexp = gcry_xmalloc_secure (sizeof *newsexp
+ + c.allocated - 1);
+ newhead = newsexp->d;
+ memcpy (newhead, c.sexp->d, (c.pos - c.sexp->d));
+ c.pos = newhead + (c.pos - c.sexp->d);
+ gcry_free (c.sexp);
+ c.sexp = newsexp;
+ }
+
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, alen);
+ memcpy (c.pos, astr, alen);
+ c.pos += alen;
+ }
+ else if (*p == 'd')
+ {
+ /* Insert an integer as string. */
+ int aint;
+ size_t alen;
+ char buf[20];
+
+ ARG_NEXT (aint, int);
+ sprintf (buf, "%d", aint);
+ alen = strlen (buf);
+ MAKE_SPACE (alen);
+ *c.pos++ = ST_DATA;
+ STORE_LEN (c.pos, alen);
+ memcpy (c.pos, buf, alen);
+ c.pos += alen;
+ }
+ else
+ {
+ *erroff = p - buffer;
+ /* Invalid format specifier. */
+ err = GPG_ERR_SEXP_INV_LEN_SPEC;
+ }
+ percent = NULL;
+ }
+ else if (*p == '(')
+ {
+ if (disphint)
+ {
+ *erroff = p - buffer;
+ /* Open display hint. */
+ err = GPG_ERR_SEXP_UNMATCHED_DH;
+ }
+ MAKE_SPACE (0);
+ *c.pos++ = ST_OPEN;
+ level++;
+ }
+ else if (*p == ')')
+ {
+ /* Walk up. */
+ if (disphint)
+ {
+ *erroff = p - buffer;
+ /* Open display hint. */
+ err = GPG_ERR_SEXP_UNMATCHED_DH;
+ }
+ MAKE_SPACE (0);
+ *c.pos++ = ST_CLOSE;
+ level--;
+ }
+ else if (*p == '\"')
+ {
+ quoted = p;
+ quoted_esc = 0;
+ }
+ else if (*p == '#')
+ {
+ hexfmt = p;
+ hexcount = 0;
+ }
+ else if (*p == '|')
+ base64 = p;
+ else if (*p == '[')
+ {
+ if (disphint)
+ {
+ *erroff = p - buffer;
+ /* Open display hint. */
+ err = GPG_ERR_SEXP_NESTED_DH;
+ }
+ disphint = p;
+ }
+ else if (*p == ']')
+ {
+ if (! disphint)
+ {
+ *erroff = p - buffer;
+ /* Open display hint. */
+ err = GPG_ERR_SEXP_UNMATCHED_DH;
+ }
+ disphint = NULL;
+ }
+ else if (isdigit (*p))
+ {
+ if (*p == '0')
+ {
+ /* A length may not begin with zero. */
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_ZERO_PREFIX;
+ }
+ digptr = p;
+ }
+ else if (strchr (tokenchars, *p))
+ tokenp = p;
+ else if (isspace (*p))
+ ;
+ else if (*p == '{')
+ {
+ /* fixme: handle rescanning: we can do this by saving our
+ current state and start over at p+1 -- Hmmm. At this
+ point here we are in a well defined state, so we don't
+ need to save it. Great. */
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_UNEXPECTED_PUNC;
+ }
+ else if (strchr ("&\\", *p))
+ {
+ /* Reserved punctuation. */
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_UNEXPECTED_PUNC;
+ }
+ else if (argflag && (*p == '%'))
+ percent = p;
+ else
+ {
+ /* Bad or unavailable. */
+ *erroff = p - buffer;
+ err = GPG_ERR_SEXP_BAD_CHARACTER;
+ }
+ }
+ MAKE_SPACE (0);
+ *c.pos++ = ST_STOP;
+
+ if (level)
+ err = GPG_ERR_SEXP_UNMATCHED_PAREN;
+
+ if (err)
+ {
+ /* Error -> deallocate. */
+ if (c.sexp)
+ {
+ /* Extra paranoid wipe on error. */
+ if (gcry_is_secure (c.sexp))
+ wipememory (c.sexp, sizeof (struct gcry_sexp) + c.allocated - 1);
+ gcry_free (c.sexp);
+ }
+ /* This might be expected by existing code... */
+ *retsexp = NULL;
+ }
+ else
+ *retsexp = normalize (c.sexp);
+
+ return gcry_error (err);
+#undef MAKE_SPACE
+#undef STORE_LEN
+}
+
+gcry_error_t
+gcry_sexp_build (gcry_sexp_t *retsexp, size_t *erroff, const char *format, ...)
+{
+ gcry_error_t rc;
+ va_list arg_ptr;
+
+ va_start (arg_ptr, format);
+ rc = sexp_sscan (retsexp, erroff, format, strlen(format), 1,
+ arg_ptr, NULL);
+ va_end (arg_ptr);
+
+ return rc;
+}
+
+/* Like gcry_sexp_build, but uses an array instead of variable
+ function arguments. */
+gcry_error_t
+gcry_sexp_build_array (gcry_sexp_t *retsexp, size_t *erroff,
+ const char *format, void **arg_list)
+{
+ /* We don't need the va_list because it is controlled by the
+ following flag, however we have to pass it but can't initialize
+ it as there is no portable way to do so. volatile is needed to
+ suppress the compiler warning */
+ volatile va_list dummy_arg_ptr;
+
+ gcry_error_t rc;
+
+ rc = sexp_sscan (retsexp, erroff, format, strlen(format), 1,
+ dummy_arg_ptr, arg_list);
+
+ return rc;
+}
+
+gcry_error_t
+gcry_sexp_sscan (gcry_sexp_t *retsexp, size_t *erroff,
+ const char *buffer, size_t length)
+{
+ /* We don't need the va_list because it is controlled by the
+ following flag, however we have to pass it but can't initialize
+ it as there is no portable way to do so. volatile is needed to
+ suppress the compiler warning */
+ volatile va_list dummy_arg_ptr;
+
+ return sexp_sscan (retsexp, erroff, buffer, length, 0,
+ dummy_arg_ptr, NULL);
+}
+
+
+/* Figure out a suitable encoding for BUFFER of LENGTH.
+ Returns: 0 = Binary
+ 1 = String possible
+ 2 = Token possible
+*/
+static int
+suitable_encoding (const unsigned char *buffer, size_t length)
+{
+ const unsigned char *s;
+ int maybe_token = 1;
+
+ if (!length)
+ return 1;
+
+ for (s=buffer; length; s++, length--)
+ {
+ if ( (*s < 0x20 || (*s >= 0x7f && *s <= 0xa0))
+ && !strchr ("\b\t\v\n\f\r\"\'\\", *s))
+ return 0; /*binary*/
+ if ( maybe_token
+ && !alphap (s) && !digitp (s) && !strchr (TOKEN_SPECIALS, *s))
+ maybe_token = 0;
+ }
+ s = buffer;
+ if ( maybe_token && !digitp (s) )
+ return 2;
+ return 1;
+}
+
+
+static int
+convert_to_hex (const unsigned char *src, size_t len, unsigned char *dest)
+{
+ int i;
+
+ if (dest)
+ {
+ *dest++ = '#';
+ for (i=0; i < len; i++, dest += 2 )
+ sprintf (dest, "%02X", src[i]);
+ *dest++ = '#';
+ }
+ return len*2+2;
+}
+
+static int
+convert_to_string (const unsigned char *s, size_t len, unsigned char *dest)
+{
+ if (dest)
+ {
+ unsigned char *p = dest;
+ *p++ = '\"';
+ for (; len; len--, s++ )
+ {
+ switch (*s)
+ {
+ case '\b': *p++ = '\\'; *p++ = 'b'; break;
+ case '\t': *p++ = '\\'; *p++ = 't'; break;
+ case '\v': *p++ = '\\'; *p++ = 'v'; break;
+ case '\n': *p++ = '\\'; *p++ = 'n'; break;
+ case '\f': *p++ = '\\'; *p++ = 'f'; break;
+ case '\r': *p++ = '\\'; *p++ = 'r'; break;
+ case '\"': *p++ = '\\'; *p++ = '\"'; break;
+ case '\'': *p++ = '\\'; *p++ = '\''; break;
+ case '\\': *p++ = '\\'; *p++ = '\\'; break;
+ default:
+ if ( (*s < 0x20 || (*s >= 0x7f && *s <= 0xa0)))
+ {
+ sprintf (p, "\\x%02x", *s);
+ p += 4;
+ }
+ else
+ *p++ = *s;
+ }
+ }
+ *p++ = '\"';
+ return p - dest;
+ }
+ else
+ {
+ int count = 2;
+ for (; len; len--, s++ )
+ {
+ switch (*s)
+ {
+ case '\b':
+ case '\t':
+ case '\v':
+ case '\n':
+ case '\f':
+ case '\r':
+ case '\"':
+ case '\'':
+ case '\\': count += 2; break;
+ default:
+ if ( (*s < 0x20 || (*s >= 0x7f && *s <= 0xa0)))
+ count += 4;
+ else
+ count++;
+ }
+ }
+ return count;
+ }
+}
+
+
+
+static int
+convert_to_token (const unsigned char *src, size_t len, unsigned char *dest)
+{
+ if (dest)
+ memcpy (dest, src, len);
+ return len;
+}
+
+
+/****************
+ * Print SEXP to buffer using the MODE. Returns the length of the
+ * SEXP in buffer or 0 if the buffer is too short (We have at least an
+ * empty list consisting of 2 bytes). If a buffer of NULL is provided,
+ * the required length is returned.
+ */
+size_t
+gcry_sexp_sprint( const gcry_sexp_t list, int mode,
+ char *buffer, size_t maxlength )
+{
+ static byte empty[3] = { ST_OPEN, ST_CLOSE, ST_STOP };
+ const byte *s;
+ char *d;
+ DATALEN n;
+ char numbuf[20];
+ size_t len = 0;
+ int i, indent = 0;
+
+ s = list? list->d : empty;
+ d = buffer;
+ while ( *s != ST_STOP )
+ {
+ switch ( *s )
+ {
+ case ST_OPEN:
+ s++;
+ if ( mode != GCRYSEXP_FMT_CANON )
+ {
+ if (indent)
+ len++;
+ len += indent;
+ }
+ len++;
+ if ( buffer )
+ {
+ if ( len >= maxlength )
+ return 0;
+ if ( mode != GCRYSEXP_FMT_CANON )
+ {
+ if (indent)
+ *d++ = '\n';
+ for (i=0; i < indent; i++)
+ *d++ = ' ';
+ }
+ *d++ = '(';
+ }
+ indent++;
+ break;
+ case ST_CLOSE:
+ s++;
+ len++;
+ if ( buffer )
+ {
+ if ( len >= maxlength )
+ return 0;
+ *d++ = ')';
+ }
+ indent--;
+ if (*s != ST_OPEN && *s != ST_STOP && mode != GCRYSEXP_FMT_CANON)
+ {
+ len++;
+ len += indent;
+ if (buffer)
+ {
+ if (len >= maxlength)
+ return 0;
+ *d++ = '\n';
+ for (i=0; i < indent; i++)
+ *d++ = ' ';
+ }
+ }
+ break;
+ case ST_DATA:
+ s++;
+ memcpy ( &n, s, sizeof n ); s += sizeof n;
+ if (mode == GCRYSEXP_FMT_ADVANCED)
+ {
+ int type;
+ size_t nn;
+
+ switch ( (type=suitable_encoding (s, n)))
+ {
+ case 1: nn = convert_to_string (s, n, NULL); break;
+ case 2: nn = convert_to_token (s, n, NULL); break;
+ default: nn = convert_to_hex (s, n, NULL); break;
+ }
+ len += nn;
+ if (buffer)
+ {
+ if (len >= maxlength)
+ return 0;
+ switch (type)
+ {
+ case 1: convert_to_string (s, n, d); break;
+ case 2: convert_to_token (s, n, d); break;
+ default: convert_to_hex (s, n, d); break;
+ }
+ d += nn;
+ }
+ if (s[n] != ST_CLOSE)
+ {
+ len++;
+ if (buffer)
+ {
+ if (len >= maxlength)
+ return 0;
+ *d++ = ' ';
+ }
+ }
+ }
+ else
+ {
+ sprintf (numbuf, "%u:", (unsigned int)n );
+ len += strlen (numbuf) + n;
+ if ( buffer )
+ {
+ if ( len >= maxlength )
+ return 0;
+ d = stpcpy ( d, numbuf );
+ memcpy ( d, s, n ); d += n;
+ }
+ }
+ s += n;
+ break;
+ default:
+ BUG ();
+ }
+ }
+ if ( mode != GCRYSEXP_FMT_CANON )
+ {
+ len++;
+ if (buffer)
+ {
+ if ( len >= maxlength )
+ return 0;
+ *d++ = '\n';
+ }
+ }
+ if (buffer)
+ {
+ if ( len >= maxlength )
+ return 0;
+ *d++ = 0; /* for convenience we make a C string */
+ }
+ else
+ len++; /* we need one byte more for this */
+
+ return len;
+}
+
+
+/* Scan a cannocial encoded buffer with implicit length values and
+ return the actual length this S-expression uses. For a valid S-Exp
+ it should never return 0. If LENGTH is not zero, the maximum
+ length to scan is given - this can be used for syntax checks of
+ data passed from outside. errorcode and erroff may both be passed as
+ NULL. */
+size_t
+gcry_sexp_canon_len (const unsigned char *buffer, size_t length,
+ size_t *erroff, gcry_error_t *errcode)
+{
+ const unsigned char *p;
+ const char *disphint=NULL;
+ unsigned int datalen = 0;
+ size_t dummy_erroff;
+ gcry_error_t dummy_errcode;
+ size_t count = 0;
+ int level = 0;
+
+ if (!erroff)
+ erroff = &dummy_erroff;
+ if (!errcode)
+ errcode = &dummy_errcode;
+
+ *errcode = gcry_error (GPG_ERR_NO_ERROR);
+ *erroff = 0;
+ if (!buffer)
+ return 0;
+ if (*buffer != '(')
+ {
+ *errcode = gcry_error (GPG_ERR_SEXP_NOT_CANONICAL);
+ return 0;
+ }
+
+ for (p=buffer; ; p++, count++ )
+ {
+ if (length && count >= length)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_STRING_TOO_LONG);
+ return 0;
+ }
+
+ if (datalen)
+ {
+ if (*p == ':')
+ {
+ if (length && (count+datalen) >= length)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_STRING_TOO_LONG);
+ return 0;
+ }
+ count += datalen;
+ p += datalen;
+ datalen = 0;
+ }
+ else if (digitp(p))
+ datalen = datalen*10 + atoi_1(p);
+ else
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_INV_LEN_SPEC);
+ return 0;
+ }
+ }
+ else if (*p == '(')
+ {
+ if (disphint)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_UNMATCHED_DH);
+ return 0;
+ }
+ level++;
+ }
+ else if (*p == ')')
+ { /* walk up */
+ if (!level)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_UNMATCHED_PAREN);
+ return 0;
+ }
+ if (disphint)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_UNMATCHED_DH);
+ return 0;
+ }
+ if (!--level)
+ return ++count; /* ready */
+ }
+ else if (*p == '[')
+ {
+ if (disphint)
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_NESTED_DH);
+ return 0;
+ }
+ disphint = p;
+ }
+ else if (*p == ']')
+ {
+ if( !disphint )
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_UNMATCHED_DH);
+ return 0;
+ }
+ disphint = NULL;
+ }
+ else if (digitp (p) )
+ {
+ if (*p == '0')
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_ZERO_PREFIX);
+ return 0;
+ }
+ datalen = atoi_1 (p);
+ }
+ else if (*p == '&' || *p == '\\')
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_UNEXPECTED_PUNC);
+ return 0;
+ }
+ else
+ {
+ *erroff = count;
+ *errcode = gcry_error (GPG_ERR_SEXP_BAD_CHARACTER);
+ return 0;
+ }
+ }
+}