http.c

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/* 
   Unix SMB/CIFS implementation.

   http handling code

   Copyright (C) Andrew Tridgell 2005
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "smbd/service_task.h"
#include "web_server/web_server.h"
#include "smbd/service_stream.h"
#include "smbd/service.h"
#include "lib/events/events.h"
#include "system/time.h"
#include "system/wait.h"
#include "lib/appweb/esp/esp.h"
#include "lib/appweb/ejs/ejsInternal.h"
#include "lib/util/dlinklist.h"
#include "lib/tls/tls.h"
#include "scripting/ejs/smbcalls.h"
#include "param/param.h"

#define SAMBA_SESSION_KEY "SambaSessionId"
#define HTTP_PREAUTH_URI  "/scripting/preauth.esp"

/* state of the esp subsystem for a specific request */
struct esp_state {
	struct websrv_context *web;
	struct EspRequest *req;
	struct MprVar variables[ESP_OBJ_MAX];
	struct session_data *session;
};

/*
  output the http headers
*/
static void http_output_headers(struct websrv_context *web)
{
	int i;
	char *s;
	DATA_BLOB b;
	uint32_t content_length = 0;
	const char *response_string = "Unknown Code";
	const struct {
		unsigned code;
		const char *response_string;
	} codes[] = {
		{ 200, "OK" },
		{ 301, "Moved" },
		{ 302, "Found" },
		{ 303, "Method" },
		{ 304, "Not Modified" },
		{ 400, "Bad request" },
		{ 401, "Unauthorized" },
		{ 403, "Forbidden" },
		{ 404, "Not Found" },
		{ 500, "Internal Server Error" },
		{ 501, "Not implemented" }
	};
	for (i=0;i<ARRAY_SIZE(codes);i++) {
		if (codes[i].code == web->output.response_code) {
			response_string = codes[i].response_string;
		}
	}

	if (web->output.headers == NULL) return;
	s = talloc_asprintf(web, "HTTP/1.0 %u %s\r\n", 
			    web->output.response_code, response_string);
	if (s == NULL) return;
	for (i=0;web->output.headers[i];i++) {
		s = talloc_asprintf_append_buffer(s, "%s\r\n", web->output.headers[i]);
	}

	/* work out the content length */
	content_length = web->output.content.length;
	if (web->output.fd != -1) {
		struct stat st;
		fstat(web->output.fd, &st);
		content_length += st.st_size;
	}
	s = talloc_asprintf_append_buffer(s, "Content-Length: %u\r\n\r\n", content_length);
	if (s == NULL) return;

	b = web->output.content;
	web->output.content = data_blob_string_const(s);
	data_blob_append(web, &web->output.content, b.data, b.length);
	data_blob_free(&b);
}

/*
  return the local path for a URL
*/
static const char *http_local_path(struct websrv_context *web,
                                   const char *url,
                                   const char *base_dir)
{
	int i;
	char *path;

	/* check that the url is OK */
	if (url[0] != '/') return NULL;

	for (i=0;url[i];i++) {
		if ((!isalnum((unsigned char)url[i]) && !strchr("./_-", url[i])) ||
		    (url[i] == '.' && strchr("/.", url[i+1]))) {
			return NULL;
		}
	}

	path = talloc_asprintf(web, "%s/%s", base_dir, url+1);
	if (path == NULL) return NULL;

	if (directory_exist(path)) {
		path = talloc_asprintf_append_buffer(path, "/index.esp");
	}
	return path;
}

/*
  called when esp wants to read a file to support include() calls
*/
static int http_readFile(EspHandle handle,
                         char **buf,
                         int *len,
                         const char *path,
                         const char *base_dir)
{
	struct websrv_context *web = talloc_get_type(handle, 
						     struct websrv_context);
	int fd = -1;
	struct stat st;
	*buf = NULL;

	path = http_local_path(web, path, base_dir);
	if (path == NULL) goto failed;

	fd = open(path, O_RDONLY);
	if (fd == -1 || fstat(fd, &st) != 0 || !S_ISREG(st.st_mode)) goto failed;

	*buf = talloc_array(handle, char, st.st_size+1);
	if (*buf == NULL) goto failed;

	if (read(fd, *buf, st.st_size) != st.st_size) goto failed;

	(*buf)[st.st_size] = 0;

	close(fd);
	*len = st.st_size;
	return 0;

failed:
	DEBUG(0,("Failed to read file %s - %s\n", path, strerror(errno)));
	if (fd != -1) close(fd);
	talloc_free(*buf);
	*buf = NULL;
	return -1;
}

static int http_readFileFromSwatDir(EspHandle handle, char **buf, int *len,
                                       const char *path)
{
    return http_readFile(handle, buf, len, path, 
			 lp_swat_directory(global_loadparm));
}



/*
  called when esp wants to find the real path of a file
*/
static int http_mapToStorage(EspHandle handle, char *path, int len, const char *uri, int flags)
{
	if (uri == NULL || strlen(uri) >= len) return -1;
	strncpy(path, uri, len);
	return 0;
}

/*
  called when esp wants to output something
*/
static int http_writeBlock(EspHandle handle, const char *buf, int size)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	if (!data_blob_append(web, &web->output.content, buf, size))
		return -1;
	return size;
}


/*
  set a http header
*/
static void http_setHeader(EspHandle handle, const char *value, bool allowMultiple)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	char *p = strchr(value, ':');

	if (p && !allowMultiple && web->output.headers) {
		int i;
		for (i=0;web->output.headers[i];i++) {
			if (strncmp(web->output.headers[i], value, (p+1)-value) == 0) {
				web->output.headers[i] = talloc_strdup(web, value);
				return;
			}
		}
	}

	web->output.headers = str_list_add(web->output.headers, value);
	talloc_steal(web, web->output.headers);
}

/*
  set a http response code
*/
static void http_setResponseCode(EspHandle handle, int code)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	web->output.response_code = code;
}

/*
  redirect to another web page
 */
static void http_redirect(EspHandle handle, int code, char *url)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	const char *host = web->input.host;
	
	/* form the full url, unless it already looks like a url */
	if (strchr(url, ':') == NULL) {
		if (host == NULL) {
			struct socket_address *socket_address = socket_get_my_addr(web->conn->socket, web);
			if (socket_address == NULL) goto internal_error;
			host = talloc_asprintf(web, "%s:%u",
					       socket_address->addr, socket_address->port);
		}
		if (host == NULL) goto internal_error;
		if (url[0] != '/') {
			char *p = strrchr(web->input.url, '/');
			if (p == web->input.url) {
				url = talloc_asprintf(web, "http%s://%s/%s", 
						      tls_enabled(web->conn->socket)?"s":"",
						      host, url);
			} else {
				int dirlen = p - web->input.url;
				url = talloc_asprintf(web, "http%s://%s%*.*s/%s",
						      tls_enabled(web->conn->socket)?"s":"",
						      host, 
						      dirlen, dirlen, web->input.url,
						      url);
			}
			if (url == NULL) goto internal_error;
		}
	}

	http_setHeader(handle, talloc_asprintf(web, "Location: %s", url), 0);

	/* make sure we give a valid redirect code */
	if (code >= 300 && code < 400) {
		http_setResponseCode(handle, code);
	} else {
		http_setResponseCode(handle, 302);
	}
	return;

internal_error:
	http_error(web, 500, "Internal server error");
}


/*
  setup a cookie
*/
static void http_setCookie(EspHandle handle, const char *name, const char *value, 
			   int lifetime, const char *path, bool secure)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	char *buf;
	
	if (lifetime > 0) {
		buf = talloc_asprintf(web, "Set-Cookie: %s=%s; path=%s; Expires=%s; %s",
				      name, value, path?path:"/", 
				      http_timestring(web, time(NULL)+lifetime),
				      secure?"secure":"");
	} else {
		buf = talloc_asprintf(web, "Set-Cookie: %s=%s; path=%s; %s",
				      name, value, path?path:"/", 
				      secure?"secure":"");
	}
	http_setHeader(handle, "Cache-control: no-cache=\"set-cookie\"", 0);
	http_setHeader(handle, buf, 0);
	talloc_free(buf);
}

/*
  return the session id
*/
static const char *http_getSessionId(EspHandle handle)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	return web->session->id;
}

/*
  setup a session
*/
static void http_createSession(EspHandle handle, int timeout)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	if (web->session) {
		web->session->lifetime = timeout;
		http_setCookie(web, SAMBA_SESSION_KEY, web->session->id, 
			       web->session->lifetime, "/", 0);
	}
}

/*
  destroy a session
*/
static void http_destroySession(EspHandle handle)
{
	struct websrv_context *web = talloc_get_type(handle, struct websrv_context);
	talloc_free(web->session);
	web->session = NULL;
}


/*
  setup for a raw http level error
*/
void http_error(struct websrv_context *web, int code, const char *info)
{
	char *s;
	s = talloc_asprintf(web,"<HTML><HEAD><TITLE>Error %u</TITLE></HEAD><BODY><H1>Error %u</H1><pre>%s</pre><p></BODY></HTML>\r\n\r\n", 
			    code, code, info);
	if (s == NULL) {
		stream_terminate_connection(web->conn, "http_error: out of memory");
		return;
	}
	http_writeBlock(web, s, strlen(s));
	http_setResponseCode(web, code);
	http_output_headers(web);
	EVENT_FD_NOT_READABLE(web->conn->event.fde);
	EVENT_FD_WRITEABLE(web->conn->event.fde);
	web->output.output_pending = true;
}

/*
  map a unix error code to a http error
*/
void http_error_unix(struct websrv_context *web, const char *info)
{
	int code = 500;
	switch (errno) {
	case ENOENT:
	case EISDIR:
		code = 404;
		break;
	case EACCES:
		code = 403;
		break;
	}
	info = talloc_asprintf(web, "%s<p>%s<p>\n", info, strerror(errno));
	http_error(web, code, info);
}


/*
  a simple file request
*/
static void http_simple_request(struct websrv_context *web)
{
	const char *url = web->input.url;
	const char *path;
	struct stat st;

	path = http_local_path(web, url, lp_swat_directory(web->task->lp_ctx));
	if (path == NULL) goto invalid;

	/* looks ok */
	web->output.fd = open(path, O_RDONLY);
	if (web->output.fd == -1) {
		DEBUG(0,("Failed to read file %s - %s\n", path, strerror(errno)));
		http_error_unix(web, path);
		return;
	}

	if (fstat(web->output.fd, &st) != 0 || !S_ISREG(st.st_mode)) {
		close(web->output.fd);
		goto invalid;
	}

	return;

invalid:
	http_error(web, 400, "Malformed URL");
}

/*
  setup the standard ESP arrays
*/
static void http_setup_arrays(struct esp_state *esp)
{
	struct websrv_context *web = esp->web;
	struct esp_data *edata = talloc_get_type(web->task->private, struct esp_data);
	struct EspRequest *req = esp->req;
	struct socket_address *socket_address = socket_get_my_addr(web->conn->socket, esp);
	struct socket_address *peer_address = socket_get_peer_addr(web->conn->socket, esp);
	char *p;

#define SETVAR(type, name, value) do { \
		const char *v = value; \
		if (v) espSetStringVar(req, type, name, v); \
} while (0)

	SETVAR(ESP_REQUEST_OBJ, "CONTENT_LENGTH", 
	       talloc_asprintf(esp, "%u", web->input.content_length));
	SETVAR(ESP_REQUEST_OBJ, "QUERY_STRING", web->input.query_string);
	SETVAR(ESP_REQUEST_OBJ, "POST_DATA",
               talloc_strndup(esp,
                              web->input.partial.data,
                              web->input.partial.length));
	SETVAR(ESP_REQUEST_OBJ, "REQUEST_METHOD", web->input.post_request?"POST":"GET");
	SETVAR(ESP_REQUEST_OBJ, "REQUEST_URI", web->input.url);
	p = strrchr(web->input.url, '/');
	SETVAR(ESP_REQUEST_OBJ, "SCRIPT_NAME", p+1);
	SETVAR(ESP_REQUEST_OBJ, "SCRIPT_FILENAME", web->input.url);
	if (peer_address) {
		struct MprVar mpv = mprObject("socket_address");
		mprSetPtrChild(&mpv, "socket_address", peer_address);
		espSetVar(req, ESP_REQUEST_OBJ, "REMOTE_SOCKET_ADDRESS", mpv);
		SETVAR(ESP_REQUEST_OBJ, "REMOTE_ADDR", peer_address->addr);
	}
	p = socket_get_peer_name(web->conn->socket, esp);
	SETVAR(ESP_REQUEST_OBJ, "REMOTE_HOST", p);
	SETVAR(ESP_REQUEST_OBJ, "REMOTE_USER", "");
	SETVAR(ESP_REQUEST_OBJ, "CONTENT_TYPE", web->input.content_type);
	if (web->session) {
		SETVAR(ESP_REQUEST_OBJ, "SESSION_ID", web->session->id);
	}
	SETVAR(ESP_REQUEST_OBJ, "COOKIE_SUPPORT", web->input.cookie?"true":"false");

	SETVAR(ESP_HEADERS_OBJ, "HTTP_REFERER", web->input.referer);
	SETVAR(ESP_HEADERS_OBJ, "HOST", web->input.host);
	SETVAR(ESP_HEADERS_OBJ, "ACCEPT_ENCODING", web->input.accept_encoding);
	SETVAR(ESP_HEADERS_OBJ, "ACCEPT_LANGUAGE", web->input.accept_language);
	SETVAR(ESP_HEADERS_OBJ, "ACCEPT_CHARSET", web->input.accept_charset);
	SETVAR(ESP_HEADERS_OBJ, "COOKIE", web->input.cookie);
	SETVAR(ESP_HEADERS_OBJ, "USER_AGENT", web->input.user_agent);

	if (socket_address) {
		SETVAR(ESP_SERVER_OBJ, "SERVER_ADDR", socket_address->addr);
		SETVAR(ESP_SERVER_OBJ, "SERVER_NAME", socket_address->addr);
		SETVAR(ESP_SERVER_OBJ, "SERVER_HOST", socket_address->addr);
		SETVAR(ESP_SERVER_OBJ, "SERVER_PORT", 
		       talloc_asprintf(esp, "%u", socket_address->port));
	}

	SETVAR(ESP_SERVER_OBJ, "DOCUMENT_ROOT", lp_swat_directory(esp->web->task->lp_ctx));
	SETVAR(ESP_SERVER_OBJ, "SERVER_PROTOCOL", tls_enabled(web->conn->socket)?"https":"http");
	SETVAR(ESP_SERVER_OBJ, "SERVER_SOFTWARE", "SAMBA");
	SETVAR(ESP_SERVER_OBJ, "GATEWAY_INTERFACE", "CGI/1.1");
	SETVAR(ESP_SERVER_OBJ, "TLS_SUPPORT", tls_support(edata->tls_params)?"true":"false");
}

#if HAVE_SETJMP_H
/* the esp scripting lirary generates exceptions when
   it hits a major error. We need to catch these and
   report a internal server error via http
*/
static jmp_buf ejs_exception_buf;
static const char *exception_reason;

static void web_server_ejs_exception(const char *reason)
{
	Ejs *ep = ejsPtr(0);
	if (ep) {
		ejsSetErrorMsg(0, "%s", reason);
		exception_reason = ep->error;
	} else {
		exception_reason = reason;
	}
	DEBUG(0,("%s", exception_reason));
	longjmp(ejs_exception_buf, -1);
}
#else
static void web_server_ejs_exception(const char *reason)
{
	DEBUG(0,("%s", reason));
	smb_panic(reason);
}
#endif

/*
  process a esp request
*/
static void esp_request(struct esp_state *esp, const char *url)
{
	struct websrv_context *web = esp->web;
	int size;
	int res;
	char *emsg = NULL, *buf;