Reimplement mod_headers as an output filter. mod_headers can now (788a3728) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

CHANGES

+5 −0

Original line number	Diff line number	Diff line
		Changes with Apache 2.0.18-dev
		*) Reimplement mod_headers as an output filter. mod_headers can now
		add custom headers to inbound requests using the HeaderIn directive
		and to responses using the HeaderOut directive. The Header
		directive has been deprecated in favor of the HeaderOut directive.
		[Graham Leggett]

		*) Fix command-line processing so that if a bad argument is specified
		Apache will exit. [Jeff Trawick]

modules/metadata/mod_headers.c

+114 −34

Original line number	Diff line number	Diff line
		@@ -60,12 +60,13 @@
		* mod_headers.c: Add/append/remove HTTP response headers
		* Written by Paul Sutton, paul@ukweb.com, 1 Oct 1996
		*
		* New directive, Header, can be used to add/replace/remove HTTP headers.
		* HeaderIn and HeaderOut can be used to add/replace/remove HTTP headers.
		* Valid in both per-server and per-dir configurations.
		*
		* Syntax is:
		*
		* Header action header value
		* HeaderIn action header value
		* HeaderOut action header value
		*
		* Where action is one of:
		* set - set this header, replacing any old value
		@@ -77,8 +78,8 @@
		* Where action is unset, the third argument (value) should not be given.
		* The header name can include the colon, or not.
		*
		* The Header directive can only be used where allowed by the FileInfo
		* override.
		* The Header(In\|Out) directive can only be used where allowed by the
		* FileInfo override.
		*
		* When the request is processed, the header directives are processed in
		* this order: firstly, the main server, then the virtual server handling
		@@ -89,21 +90,22 @@
		* the following two directives have different effect if applied in
		* the reverse order:
		*
		* Header append Author "John P. Doe"
		* Header unset Author
		* HeaderOut append Author "John P. Doe"
		* HeaderOut unset Author
		*
		* Examples:
		*
		* To set the "Author" header, use
		* Header add Author "John P. Doe"
		* HeaderOut add Author "John P. Doe"
		*
		* To remove a header:
		* Header unset Author
		* HeaderOut unset Author
		*
		*/

		#include "apr.h"
		#include "apr_strings.h"
		#include "apr_buckets.h"

		#define APR_WANT_STRFUNC
		#include "apr_want.h"
		@@ -111,7 +113,8 @@
		#include "httpd.h"
		#include "http_config.h"
		#include "http_request.h"

		#include "http_log.h"
		#include "util_filter.h"

		typedef enum {
		hdr_add = 'a', /* add header (could mean multiple hdrs) */
		@@ -120,6 +123,11 @@ typedef enum {
		hdr_unset = 'u' /* unset header */
		} hdr_actions;

		typedef enum {
		hdr_in = 0, /* HeaderIn */
		hdr_out = 1, /* HeaderOut */
		} hdr_inout;

		typedef struct {
		hdr_actions action;
		char *header;
		@@ -131,7 +139,8 @@ typedef struct {
		* a per-dir and per-server config
		*/
		typedef struct {
		apr_array_header_t *headers;
		apr_array_header_t *fixup_in;
		apr_array_header_t *fixup_out;
		} headers_conf;

		module AP_MODULE_DECLARE_DATA headers_module;
		@@ -140,7 +149,8 @@ static void create_headers_config(apr_pool_t p, server_rec *s)
		{
		headers_conf conf = apr_pcalloc(p, sizeof(conf));

		conf->headers = apr_array_make(p, 2, sizeof(header_entry));
		conf->fixup_in = apr_array_make(p, 2, sizeof(header_entry));
		conf->fixup_out = apr_array_make(p, 2, sizeof(header_entry));

		return conf;
		}
		@@ -156,13 +166,15 @@ static void merge_headers_config(apr_pool_t p, void basev, void overridesv)
		headers_conf *base = basev;
		headers_conf *overrides = overridesv;

		newconf->headers = apr_array_append(p, base->headers, overrides->headers);
		newconf->fixup_in = apr_array_append(p, base->fixup_in, overrides->fixup_in);
		newconf->fixup_out = apr_array_append(p, base->fixup_out, overrides->fixup_out);

		return newconf;
		}


		static const char header_cmd(cmd_parms cmd, void *indirconf,
		/* handle HeaderIn and HeaderOut directive */
		static const char header_inout_cmd(hdr_inout inout, cmd_parms cmd, void *indirconf,
		const char action, const char inhdr,
		const char *value)
		{
		@@ -175,10 +187,10 @@ static const char header_cmd(cmd_parms cmd, void *indirconf,
		char *colon;

		if (cmd->path) {
		new = (header_entry *) apr_array_push(dirconf->headers);
		new = (header_entry *) apr_array_push((hdr_in == inout) ? dirconf->fixup_in : dirconf->fixup_out);
		}
		else {
		new = (header_entry *) apr_array_push(serverconf->headers);
		new = (header_entry *) apr_array_push((hdr_in == inout) ? serverconf->fixup_in : serverconf->fixup_out);
		}

		if (!strcasecmp(action, "set"))
		@@ -194,10 +206,10 @@ static const char header_cmd(cmd_parms cmd, void *indirconf,

		if (new->action == hdr_unset) {
		if (value)
		return "Header unset takes two arguments";
		return "Header(In\|Out) unset takes two arguments";
		}
		else if (!value)
		return "Header requires three arguments";
		return "Header(In\|Out) requires three arguments";

		if ((colon = strchr(hdr, ':')))
		*colon = '\0';
		@@ -208,53 +220,121 @@ static const char header_cmd(cmd_parms cmd, void *indirconf,
		return NULL;
		}

		static const command_rec headers_cmds[] =
		/* handle deprecated Header directive */
		static const char header_cmd(cmd_parms cmd, void *indirconf,
		const char action, const char inhdr,
		const char *value)
		{
		AP_INIT_TAKE23("Header", header_cmd, NULL, OR_FILEINFO,
		"an action, header and value"),
		{NULL}
		};
		return "The Header directive has been deprecated. Use HeaderOut instead.";
		}

		static void do_headers_fixup(request_rec r, apr_array_header_t headers)
		/* handle HeaderOut directive */
		static const char header_out_cmd(cmd_parms cmd, void *indirconf,
		const char action, const char inhdr,
		const char *value)
		{
		return header_inout_cmd(hdr_out, cmd, indirconf, action, inhdr, value);
		}

		/* handle HeaderIn directive */
		static const char header_in_cmd(cmd_parms cmd, void *indirconf,
		const char action, const char inhdr,
		const char *value)
		{
		return header_inout_cmd(hdr_in, cmd, indirconf, action, inhdr, value);
		}


		static void do_headers_fixup(apr_table_t *headers,
		apr_array_header_t *fixup)
		{
		int i;

		for (i = 0; i < headers->nelts; ++i) {
		header_entry hdr = &((header_entry ) (headers->elts))[i];
		for (i = 0; i < fixup->nelts; ++i) {
		header_entry hdr = &((header_entry ) (fixup->elts))[i];
		switch (hdr->action) {
		case hdr_add:
		apr_table_addn(r->headers_out, hdr->header, hdr->value);
		apr_table_addn(headers, hdr->header, hdr->value);
		break;
		case hdr_append:
		apr_table_mergen(r->headers_out, hdr->header, hdr->value);
		apr_table_mergen(headers, hdr->header, hdr->value);
		break;
		case hdr_set:
		apr_table_setn(r->headers_out, hdr->header, hdr->value);
		apr_table_setn(headers, hdr->header, hdr->value);
		break;
		case hdr_unset:
		apr_table_unset(r->headers_out, hdr->header);
		apr_table_unset(headers, hdr->header);
		break;
		}
		}
		}

		static void ap_headers_insert_output_filter(request_rec *r)
		{
		headers_conf *serverconf = ap_get_module_config(r->server->module_config,
		&headers_module);
		headers_conf *dirconf = ap_get_module_config(r->per_dir_config,
		&headers_module);

		if (serverconf->fixup_out->nelts \|\| dirconf->fixup_out->nelts) {
		ap_add_output_filter("FIXUP_HEADERS_OUT", NULL, r, r->connection);
		}
		}

		static int fixup_headers(request_rec *r)
		static apr_status_t ap_headers_output_filter(ap_filter_t *f,
		apr_bucket_brigade *in)
		{
		headers_conf *serverconf = ap_get_module_config(f->r->server->module_config,
		&headers_module);
		headers_conf *dirconf = ap_get_module_config(f->r->per_dir_config,
		&headers_module);

		ap_log_error(APLOG_MARK, APLOG_DEBUG\|APLOG_NOERRNO, 0, f->r->server,
		"headers: ap_headers_output_filter()");

		/* do the fixup */
		do_headers_fixup(f->r->headers_out, serverconf->fixup_out);
		do_headers_fixup(f->r->headers_out, dirconf->fixup_out);

		/* remove ourselves from the filter chain */
		ap_remove_output_filter(f);

		/* send the data up the stack */
		return ap_pass_brigade(f->next,in);
		}

		static apr_status_t ap_headers_fixup(request_rec *r)
		{
		headers_conf *serverconf = ap_get_module_config(r->server->module_config,
		&headers_module);
		headers_conf *dirconf = ap_get_module_config(r->per_dir_config,
		&headers_module);

		do_headers_fixup(r, serverconf->headers);
		do_headers_fixup(r, dirconf->headers);
		/* do the fixup */
		if (serverconf->fixup_in->nelts \|\| dirconf->fixup_in->nelts) {
		do_headers_fixup(r->headers_in, serverconf->fixup_in);
		do_headers_fixup(r->headers_in, dirconf->fixup_in);
		}

		return DECLINED;
		}

		static const command_rec headers_cmds[] =
		{
		AP_INIT_TAKE23("Header", header_cmd, NULL, OR_FILEINFO,
		"deprecated, use HeaderOut instead"),
		AP_INIT_TAKE23("HeaderIn", header_in_cmd, NULL, OR_FILEINFO,
		"an action, header and value"),
		AP_INIT_TAKE23("HeaderOut", header_out_cmd, NULL, OR_FILEINFO,
		"an action, header and value"),
		{NULL}
		};

		static void register_hooks(apr_pool_t *p)
		{
		ap_hook_fixups(fixup_headers, NULL, NULL, APR_HOOK_MIDDLE);
		ap_hook_insert_filter(ap_headers_insert_output_filter, NULL, NULL, APR_HOOK_LAST);
		ap_hook_fixups(ap_headers_fixup, NULL, NULL, APR_HOOK_LAST);
		ap_register_output_filter("FIXUP_HEADERS_OUT", ap_headers_output_filter, AP_FTYPE_CONTENT);
		}

		module AP_MODULE_DECLARE_DATA headers_module =