The Tor Browser / file revision

 /*	$NetBSD: ns_parse.c,v 1.2 2004/05/20 20:35:05 christos Exp $	*/

 /*

  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")

  * Copyright (c) 1996,1999 by Internet Software Consortium.

  *

  * Permission to use, copy, modify, and distribute this software for any

  * purpose with or without fee is hereby granted, provided that the above

  * copyright notice and this permission notice appear in all copies.

  *

  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES

  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR

  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT

  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

  */

 /*

  * This version of this file is derived from Android 2.3 "Gingerbread",

  * which contains uncredited changes by Android/Google developers.  It has

  * been modified in 2011 for use in the Android build of Mozilla Firefox by

  * Mozilla contributors (including Michael Edwards <m.k.edwards@gmail.com>,

  * and Steve Workman <sjhworkman@gmail.com>).

  * These changes are offered under the same license as the original NetBSD

  * file, whose copyright and license are unchanged above.

  */

 #define ANDROID_CHANGES 1

 #define MOZILLA_NECKO_EXCLUDE_CODE 1

 #include <sys/cdefs.h>

 #ifndef lint

 #ifdef notdef

 static const char rcsid[] = "Id: ns_parse.c,v 1.3.2.1.4.1 2004/03/09 08:33:44 marka Exp";

 #else

 __RCSID("$NetBSD: ns_parse.c,v 1.2 2004/05/20 20:35:05 christos Exp $");

 #endif

 #endif

 /* Import. */

 #include <sys/types.h>

 #include <netinet/in.h>

 #include "arpa_nameser.h"

 #include <errno.h>

 #ifdef ANDROID_CHANGES

 #include "resolv_private.h"

 #else

 #include <resolv.h>

 #endif

 #include <string.h>

 /* Forward. */

 static void	setsection(ns_msg *msg, ns_sect sect);

 /* Macros. */

 #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)

 /* Public. */

 /* These need to be in the same order as the nres.h:ns_flag enum. */

 const struct _ns_flagdata _ns_flagdata[16] = {

 	{ 0x8000, 15 },		/* qr. */

 	{ 0x7800, 11 },		/* opcode. */

 	{ 0x0400, 10 },		/* aa. */

 	{ 0x0200, 9 },		/* tc. */

 	{ 0x0100, 8 },		/* rd. */

 	{ 0x0080, 7 },		/* ra. */

 	{ 0x0040, 6 },		/* z. */

 	{ 0x0020, 5 },		/* ad. */

 	{ 0x0010, 4 },		/* cd. */

 	{ 0x000f, 0 },		/* rcode. */

 	{ 0x0000, 0 },		/* expansion (1/6). */

 	{ 0x0000, 0 },		/* expansion (2/6). */

 	{ 0x0000, 0 },		/* expansion (3/6). */

 	{ 0x0000, 0 },		/* expansion (4/6). */

 	{ 0x0000, 0 },		/* expansion (5/6). */

 	{ 0x0000, 0 },		/* expansion (6/6). */

 };

 int ns_msg_getflag(ns_msg handle, int flag) {

 	return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);

 }

 int

 ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {

 	const u_char *optr = ptr;

 	for (; count > 0; count--) {

 		int b, rdlength;

 		b = dn_skipname(ptr, eom);

 		if (b < 0)

 			RETERR(EMSGSIZE);

 		ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;

 		if (section != ns_s_qd) {

 			if (ptr + NS_INT32SZ + NS_INT16SZ > eom)

 				RETERR(EMSGSIZE);

 			ptr += NS_INT32SZ/*TTL*/;

 			NS_GET16(rdlength, ptr);

 			ptr += rdlength/*RData*/;

 		}

 	}

 	if (ptr > eom)

 		RETERR(EMSGSIZE);

 	return (ptr - optr);

 }

 int

 ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {

 	const u_char *eom = msg + msglen;

 	int i;

 	memset(handle, 0x5e, sizeof *handle);

 	handle->_msg = msg;

 	handle->_eom = eom;

 	if (msg + NS_INT16SZ > eom)

 		RETERR(EMSGSIZE);

 	NS_GET16(handle->_id, msg);

 	if (msg + NS_INT16SZ > eom)

 		RETERR(EMSGSIZE);

 	NS_GET16(handle->_flags, msg);

 	for (i = 0; i < ns_s_max; i++) {

 		if (msg + NS_INT16SZ > eom)

 			RETERR(EMSGSIZE);

 		NS_GET16(handle->_counts[i], msg);

 	}

 	for (i = 0; i < ns_s_max; i++)

 		if (handle->_counts[i] == 0)

 			handle->_sections[i] = NULL;

 		else {

 			int b = ns_skiprr(msg, eom, (ns_sect)i,

 					  handle->_counts[i]);

 			if (b < 0)

 				return (-1);

 			handle->_sections[i] = msg;

 			msg += b;

 		}

 	if (msg != eom)

 		RETERR(EMSGSIZE);

 	setsection(handle, ns_s_max);

 	return (0);

 }

 int

 ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {

 	int b;

 	/* Make section right. */

 	if ((unsigned)section >= (unsigned)ns_s_max)

 		RETERR(ENODEV);

 	if (section != handle->_sect)

 		setsection(handle, section);

 	/* Make rrnum right. */

 	if (rrnum == -1)

 		rrnum = handle->_rrnum;

 	if (rrnum < 0 || rrnum >= handle->_counts[(int)section])

 		RETERR(ENODEV);

 	if (rrnum < handle->_rrnum)

 		setsection(handle, section);

 	if (rrnum > handle->_rrnum) {

 		b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,

 			      rrnum - handle->_rrnum);

 		if (b < 0)

 			return (-1);

 		handle->_msg_ptr += b;

 		handle->_rrnum = rrnum;

 	}

 	/* Do the parse. */

 	b = dn_expand(handle->_msg, handle->_eom,

 		      handle->_msg_ptr, rr->name, NS_MAXDNAME);

 	if (b < 0)

 		return (-1);

 	handle->_msg_ptr += b;

 	if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)

 		RETERR(EMSGSIZE);

 	NS_GET16(rr->type, handle->_msg_ptr);

 	NS_GET16(rr->rr_class, handle->_msg_ptr);

 	if (section == ns_s_qd) {

 		rr->ttl = 0;

 		rr->rdlength = 0;

 		rr->rdata = NULL;

 	} else {

 		if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)

 			RETERR(EMSGSIZE);

 		NS_GET32(rr->ttl, handle->_msg_ptr);

 		NS_GET16(rr->rdlength, handle->_msg_ptr);

 		if (handle->_msg_ptr + rr->rdlength > handle->_eom)

 			RETERR(EMSGSIZE);

 		rr->rdata = handle->_msg_ptr;

 		handle->_msg_ptr += rr->rdlength;

 	}

 	if (++handle->_rrnum > handle->_counts[(int)section])

 		setsection(handle, (ns_sect)((int)section + 1));

 	/* All done. */

 	return (0);

 }

 /* Private. */

 static void

 setsection(ns_msg *msg, ns_sect sect) {

 	msg->_sect = sect;

 	if (sect == ns_s_max) {

 		msg->_rrnum = -1;

 		msg->_msg_ptr = NULL;

 	} else {

 		msg->_rrnum = 0;

 		msg->_msg_ptr = msg->_sections[(int)sect];

 	}

 }