Re: bin/58880: bozohttpd(8): set custom header field in responses

[Sunil Nimmagadda <sunil%nimmagadda.net@localhost>]

campbell+netbsd%mumble.net@localhost writes:

>>Number:         58880
>>Category:       bin
>>Synopsis:       bozohttpd(8): set custom header field in responses
>>Confidential:   no
>>Severity:       serious
>>Priority:       medium
>>Responsible:    bin-bug-people
>>State:          open
>>Class:          sw-bug
>>Submitter-Id:   net
>>Arrival-Date:   Fri Dec 06 03:50:00 +0000 2024
>>Originator:     Taylor R Campbell
>>Release:        10
>>Organization:
> The-NetBSD-Foundation: max-age=31556956
>>Environment:
>>Description:
> How do I set a custom header field in bozohttpd responses, such as `Strict-Transport-Security: max-age=31556956'?
>
> With Apache I would do:
>
> Header set Strict-Transport-Security "max-age=31556956"
>
> This is for serving any response, not just scripts, so while I can easily add the header field manually in a script that's not enough here.
>>How-To-Repeat:
> try to implement RFC 6797 or anything else that requires setting a header field on content, like X-Frame-Options or things like that
>>Fix:
> Yes, please!

This diff allows custom headers to be specified in a .bzcustomheaders file at
the root of the server. The lines from it are included verbatim as
headers in all of the responses...

diff --git a/libexec/httpd/bozohttpd.8 b/libexec/httpd/bozohttpd.8
index 196fcb52acc7..b37cfb50de6c 100644
--- a/libexec/httpd/bozohttpd.8
+++ b/libexec/httpd/bozohttpd.8
@@ -640,6 +640,11 @@ with a backslash
 .Pq Ql \e
 The right hand side of the colon is always used verbatim, no escape sequences
 are interpreted.
+.Ss CUSTOM RESPONSE HEADERS
+If a
+.Pa .bzcustomheaders
+file is found at the root of the server, it is expected to contain
+custom headers to be included verbatim in all of the responses.
 .Sh EXAMPLES
 To configure set of virtual hosts, one would use an
 .Xr inetd.conf 5
diff --git a/libexec/httpd/bozohttpd.c b/libexec/httpd/bozohttpd.c
index 656bdf073af3..cbdc5a6b96b0 100644
--- a/libexec/httpd/bozohttpd.c
+++ b/libexec/httpd/bozohttpd.c
@@ -181,6 +181,7 @@ struct {
 	{ ABSREDIRECT_FILE,   "rejected absredirect request" },
 	{ REMAP_FILE,         "rejected remap request" },
 	{ AUTH_FILE,          "rejected authfile request" },
+	{ CUSTOMHEADERS_FILE, "rejected customheaders request" },
 	{ NULL,               NULL },
 };
 
@@ -1974,12 +1975,17 @@ bozo_print_header(bozo_httpreq_t *request,
 	off_t len;
 	char	date[40];
 	bozoheaders_t *hdr;
+	bozocustomheaders_t *chdr;
 
 	SIMPLEQ_FOREACH(hdr, &request->hr_replheaders, h_next) {
 		bozo_printf(httpd, "%s: %s\r\n", hdr->h_header,
 				hdr->h_value);
 	}
 
+        SIMPLEQ_FOREACH(chdr, &httpd->customheaders, h_next) {
+		bozo_printf(httpd, "%s\r\n", chdr->h_header);
+        }
+
 	bozo_printf(httpd, "Date: %s\r\n", bozo_http_date(date, sizeof(date)));
 	bozo_printf(httpd, "Server: %s\r\n", httpd->server_software);
 	bozo_printf(httpd, "Accept-Ranges: bytes\r\n");
@@ -2524,6 +2530,8 @@ bozo_init_httpd(bozohttpd_t *httpd)
 #ifndef NO_LUA_SUPPORT
 	SIMPLEQ_INIT(&httpd->lua_states);
 #endif
+
+        SIMPLEQ_INIT(&httpd->customheaders);
 	return 1;
 }
 
@@ -2562,6 +2570,34 @@ bozo_set_defaults(bozohttpd_t *httpd, bozoprefs_t *prefs)
 	return bozo_init_httpd(httpd) && bozo_init_prefs(httpd, prefs);
 }
 
+static void
+bozo_setup_customheaders(bozohttpd_t *httpd)
+{
+	struct bozocustomheaders *hdr;
+	FILE *fp;
+	char *fn, *line = NULL;
+	size_t linecap = 0;
+	ssize_t linelen;
+
+	bozoasprintf(httpd, &fn, "%s/%s", httpd->slashdir, CUSTOMHEADERS_FILE);
+	fp = fopen(fn, "r");
+	if (fp == NULL) {
+		free(fn);
+		return;
+	}
+
+	bozowarn(httpd, "reading %s",  fn);
+	free(fn);
+	while ((linelen = getline(&line, &linecap, fp)) > 0) {
+		line[strcspn(line, "\n")] = '\0';
+		hdr = bozomalloc(httpd, sizeof *hdr);
+		hdr->h_header = bozostrdup(httpd, NULL, line);
+		SIMPLEQ_INSERT_TAIL(&httpd->customheaders, hdr, h_next);
+	}
+	free(line);
+	fclose(fp);
+}
+
 /* set the virtual host name, port and root */
 int
 bozo_setup(bozohttpd_t *httpd, bozoprefs_t *prefs, const char *vhost,
@@ -2674,6 +2710,7 @@ bozo_setup(bozohttpd_t *httpd, bozoprefs_t *prefs, const char *vhost,
 	 */
 	bozo_ssl_init(httpd);
 	bozo_daemon_init(httpd);
+	bozo_setup_customheaders(httpd);
 
 	username = bozo_get_pref(prefs, "username");
 	if (username != NULL) {
diff --git a/libexec/httpd/bozohttpd.h b/libexec/httpd/bozohttpd.h
index cdfec757793e..811b891215da 100644
--- a/libexec/httpd/bozohttpd.h
+++ b/libexec/httpd/bozohttpd.h
@@ -64,6 +64,12 @@ typedef struct bozoheaders {
 } bozoheaders_t;
 SIMPLEQ_HEAD(qheaders, bozoheaders);
 
+typedef struct bozocustomheaders {
+	const char *h_header;
+	SIMPLEQ_ENTRY(bozocustomheaders)	h_next;
+} bozocustomheaders_t;
+SIMPLEQ_HEAD(cheaders, bozocustomheaders);
+
 #ifndef NO_LUA_SUPPORT
 typedef struct lua_handler {
 	const char	*name;
@@ -144,6 +150,7 @@ typedef struct bozohttpd_t {
 	ssize_t		 getln_buflen;	/* length of allocated space */
 	char		*errorbuf;	/* no dynamic allocation allowed */
 	bozo_consts_t	 consts;	/* various constants */
+	struct cheaders	customheaders;	/* Headers read from .bzcustomheaders */
 } bozohttpd_t;
 
 /* bozo_httpreq_t */
@@ -280,6 +287,9 @@ void	debug__(bozohttpd_t *, int, const char *, ...) BOZO_PRINTFLIKE(3, 4);
 #ifndef AUTH_FILE
 #define AUTH_FILE		".htpasswd"
 #endif
+#ifndef CUSTOMHEADERS_FILE
+#define CUSTOMHEADERS_FILE	".bzcustomheaders"
+#endif
 
 /* be sure to always return this error up */
 int	bozo_http_error(bozohttpd_t *, int, bozo_httpreq_t *, const char *);