Check whether files are zero length before parsing them [rt17757]

RELNOTES

@@ -50,6 +50,8 @@ work on other platforms. Please report any problems and suggested fixes to
 
 			Changes since 4.1.0a1
 
+- Check whether files are zero length before trying to parse them.
+
 - Ari Edelkind's PARANOIA patch has been included and may be compiled in
   via two ./configure parameters, --enable-paranoia and
   --enable-early-chroot.

client/clparse.c

@@ -59,6 +59,7 @@ isc_result_t read_client_conf ()
 {
 	struct client_config *config;
 	struct interface_info *ip;
+	struct parse *parse;
 	isc_result_t status;
 	unsigned code;
 
@@ -147,24 +148,25 @@ isc_result_t read_client_conf ()
 	status = read_client_conf_file (path_dhclient_conf,
 					(struct interface_info *)0,
 					&top_level_config);
+
+	parse = NULL;
 	if (status != ISC_R_SUCCESS) {
 		;
 #ifdef LATER
 		/* Set up the standard name service updater routine. */
-		parse = (struct parse *)0;
 		status = new_parse(&parse, -1, default_client_config,
-				    (sizeof default_client_config) - 1,
+				   sizeof(default_client_config) - 1,
 				   "default client configuration", 0);
 		if (status != ISC_R_SUCCESS)
 			log_fatal ("can't begin default client config!");
+	}
 
+	if (parse != NULL) {
 		do {
-			token = peek_token (&val, (unsigned *)0, cfile);
+			token = peek_token(&val, NULL, cfile);
 			if (token == END_OF_FILE)
 				break;
-			parse_client_statement (cfile,
+			parse_client_statement(cfile, NULL, &top_level_config);
-						(struct interface_info *)0,
-						&top_level_config);
 		} while (1);
 		end_parse(&parse);
 #endif
@@ -211,8 +213,10 @@ int read_client_conf_file (const char *name, struct interface_info *ip,
 	if ((file = open (name, O_RDONLY)) < 0)
 		return uerr2isc (errno);
 
-	cfile = (struct parse *)0;
+	cfile = NULL;
-	new_parse (&cfile, file, (char *)0, 0, path_dhclient_conf, 0);
+	status = new_parse(&cfile, file, NULL, 0, path_dhclient_conf, 0);
+	if (status != ISC_R_SUCCESS || cfile == NULL)
+		return status;
 
 	do {
 		token = peek_token (&val, (unsigned *)0, cfile);
@@ -236,6 +240,7 @@ int read_client_conf_file (const char *name, struct interface_info *ip,
 void read_client_leases ()
 {
 	int file;
+	isc_result_t status;
 	struct parse *cfile;
 	const char *val;
 	int token;
@@ -244,10 +249,10 @@ void read_client_leases ()
 	   we can safely trust the server to remember our state. */
 	if ((file = open (path_dhclient_db, O_RDONLY)) < 0)
 		return;
-	cfile = (struct parse *)0;
+
-	/* new_parse() may fail if the file is of zero length. */
+	cfile = NULL;
-	if (new_parse(&cfile, file, (char *)0, 0,
+	status = new_parse(&cfile, file, NULL, 0, path_dhclient_db, 0);
-		      path_dhclient_db, 0) != ISC_R_SUCCESS)
+	if (status != ISC_R_SUCCESS || cfile == NULL)
 		return;
 
 	do {

common/comapi.c

@@ -174,12 +174,12 @@ isc_result_t dhcp_group_set_value  (omapi_object_t *h,
 		    value -> type == omapi_datatype_string) {
 			struct parse *parse;
 			int lose = 0;
-			parse = (struct parse *)0;
+			parse = NULL;
 			status = new_parse(&parse, -1,
 					    (char *) value->u.buffer.value,
 					    value->u.buffer.len,
 					    "network client", 0);
-			if (status != ISC_R_SUCCESS)
+			if (status != ISC_R_SUCCESS || parse == NULL)
 				return status;
 			if (!(parse_executable_statements
 			      (&group -> group -> statements, parse, &lose,

common/conflex.c

@@ -52,21 +52,18 @@ isc_result_t new_parse (cfile, file, inbuf, buflen, name, eolp)
 	const char *name;
 	int eolp;
 {
+	isc_result_t status = ISC_R_SUCCESS;
 	struct parse *tmp;
 
 	tmp = dmalloc(sizeof(struct parse), MDL);
 	if (tmp == NULL) {
-		return ISC_R_NOMEMORY;
+		return (ISC_R_NOMEMORY);
 	}
 
 	/*
 	 * We don't need to initialize things to zero here, since 
 	 * dmalloc() returns memory that is set to zero.
 	 */
-	/* tmp->token = 0; */ 
-	/* tmp->warnings_occurred = 0; */
-	/* tmp->bufix = 0; */
-	/* tmp->saved_state = NULL; */
 	tmp->tlname = name;
 	tmp->lpos = tmp -> line = 1;
 	tmp->cur_line = tmp->line1;
@@ -83,20 +80,30 @@ isc_result_t new_parse (cfile, file, inbuf, buflen, name, eolp)
 	} else {
 		struct stat sb;
 
-		if (fstat(file, &sb) < 0)
+		if (fstat(file, &sb) < 0) {
-			return ISC_R_IOERROR;
+			status = ISC_R_IOERROR;
+			goto cleanup;
+		}
+
+		if (sb.st_size == 0)
+			goto cleanup;
 
 		tmp->bufsiz = tmp->buflen = (size_t) sb.st_size;
 		tmp->inbuf = mmap(NULL, tmp->bufsiz, PROT_READ, MAP_SHARED,
 				  file, 0);
 
 		if (tmp->inbuf == MAP_FAILED) {
-			return ISC_R_IOERROR;
+			status = ISC_R_IOERROR;
+			goto cleanup;
 		}
 	}
 
 	*cfile = tmp;
-	return ISC_R_SUCCESS;
+	return (ISC_R_SUCCESS);
+
+cleanup:
+	dfree(tmp, MDL);
+	return (status);
 }
 
 isc_result_t end_parse (cfile)

common/resolv.c

@@ -47,14 +47,17 @@ void read_resolv_conf (parse_time)
 	int token;
 	struct name_server *sp, *sl, *ns;
 	struct domain_search_list *dp, *dl, *nd;
+	isc_result_t status;
 
 	if ((file = open (path_resolv_conf, O_RDONLY)) < 0) {
 		log_error ("Can't open %s: %m", path_resolv_conf);
 		return;
 	}
 
-	cfile = (struct parse *)0;
+	cfile = NULL;
-	new_parse (&cfile, file, (char *)0, 0, path_resolv_conf, 1);
+	status = new_parse(&cfile, file, NULL, 0, path_resolv_conf, 1);
+	if (status != ISC_R_SUCCESS || cfile == NULL)
+		return;
 
 	do {
 		token = next_token (&val, (unsigned *)0, cfile);

server/confpars.c

@@ -157,10 +157,13 @@ isc_result_t read_conf_file (const char *filename, struct group *group,
 	/* If we're recording, write out the filename and file contents. */
 	if (trace_record ())
 		trace_write_packet (ttype, ulen + tflen + 1, dbuf, MDL);
-	new_parse (&cfile, -1, fbuf, ulen, filename, 0); /* XXX */
+	status = new_parse(&cfile, -1, fbuf, ulen, filename, 0); /* XXX */
 #else
-	new_parse (&cfile, file, (char *)0, 0, filename, 0);
+	status = new_parse(&cfile, file, NULL, 0, filename, 0);
 #endif
+	if (status != ISC_R_SUCCESS || cfile == NULL)
+		return status;
+
 	if (leasep)
 		status = lease_file_subparse (cfile);
 	else
@@ -181,6 +184,7 @@ void trace_conf_input (trace_type_t *ttype, unsigned len, char *data)
 	struct parse *cfile = (struct parse *)0;
 	static int postconf_initialized;
 	static int leaseconf_initialized;
+	isc_result_t status;
 	
 	/* Do what's done above, except that we don't have to read in the
 	   data, because it's already been read for us. */
@@ -191,12 +195,15 @@ void trace_conf_input (trace_type_t *ttype, unsigned len, char *data)
 	/* If we're recording, write out the filename and file contents. */
 	if (trace_record ())
 		trace_write_packet (ttype, len, data, MDL);
-	new_parse (&cfile, -1, fbuf, flen, data, 0);
+
+	status = new_parse(&cfile, -1, fbuf, flen, data, 0);
+	if (status == ISC_R_SUCCESS || cfile != NULL) {
 		if (ttype == trace_readleases_type)
 			lease_file_subparse (cfile);
 		else
 			conf_file_subparse (cfile, root_group, ROOT_GROUP);
 		end_parse (&cfile);
+	}
 
 	/* Postconfiguration needs to be done after the config file
 	   has been loaded. */

server/dhcpd.c

@@ -612,20 +612,21 @@ main(int argc, char **argv) {
 
 #if defined (NSUPDATE)
 	/* Set up the standard name service updater routine. */
-	parse = (struct parse *)0;
+	parse = NULL;
-	status = new_parse (&parse, -1,
+	status = new_parse(&parse, -1, std_nsupdate, sizeof(std_nsupdate) - 1,
-			    std_nsupdate, (sizeof std_nsupdate) - 1,
 			    "standard name service update routine", 0);
 	if (status != ISC_R_SUCCESS)
 		log_fatal ("can't begin parsing name service updater!");
 
+	if (parse != NULL) {
 		lose = 0;
-	if (!(parse_executable_statements
+		if (!(parse_executable_statements(&root_group->statements,
-	      (&root_group -> statements, parse, &lose, context_any))) {
+						  parse, &lose, context_any))) {
 			end_parse(&parse);
 			log_fatal("can't parse standard name service updater!");
 		}
 		end_parse(&parse);
+	}
 #endif
 
 	/* Initialize icmp support... */
@@ -1129,19 +1130,21 @@ void postconf_initialization (int quiet)
 		}
 
 		/* Set up the standard name service updater routine. */
-		parse = (struct parse *)0;
+		parse = NULL;
-		result = new_parse (&parse, -1,
+		result = new_parse(&parse, -1, old_nsupdate,
-				 old_nsupdate, (sizeof old_nsupdate) - 1,
+				   sizeof(old_nsupdate) - 1,
 				   "old name service update routine", 0);
 		if (result != ISC_R_SUCCESS)
 			log_fatal ("can't begin parsing old ddns updater!");
 
+		if (parse != NULL) {
 			tmp = 0;
-		if (!(parse_executable_statements (e, parse,
+			if (!(parse_executable_statements(e, parse, &tmp,
-						   &tmp, context_any))) {
+							  context_any))) {
 				end_parse(&parse);
 				log_fatal("can't parse standard ddns updater!");
 			}
+		}
 		end_parse(&parse);
 	}
 #endif

server/omapi.c

@@ -1071,8 +1071,9 @@ isc_result_t dhcp_host_set_value  (omapi_object_t *h,
 					    (char *) value->u.buffer.value,
 					    value->u.buffer.len,
 					    "network client", 0);
-			if (status != ISC_R_SUCCESS)
+			if (status != ISC_R_SUCCESS || parse == NULL)
 				return status;
+
 			if (!(parse_executable_statements
 			      (&host -> group -> statements, parse, &lose,
 			       context_any))) {