Sun Java System Web Server 6.1 SP6 NSAPI Programmer's Guide

AuthTrans Example

This simple example of an AuthTrans function demonstrates how to use your own custom ways of verifying that the user name and password that a remote client provided is accurate. This program uses a hard-coded table of user names and passwords and checks a given user's password against the one in the static data array. The userdb parameter is not used in this function.

AuthTrans directives work in conjunction with PathCheck directives. Generally, an AuthTrans function checks if the user name and password associated with the request are acceptable, but it does not allow or deny access to the request; it leaves that to a PathCheck function.

AuthTrans functions get the user name and password from the headers associated with the request. When a client initially makes a request, the user name and password are unknown so the AuthTrans function and PathCheck function work together to reject the request, since they can not validate the user name and password. When the client receives the rejection, the usual response is for it to present a dialog box asking the user for their user name and password. The client submits the request again, this time including the user name and password in the headers.

In this example, the hardcoded-auth function, which is invoked during the AuthTrans step, checks if the user name and password correspond to an entry in the hard-coded table of users and passwords.

Installing the Example

To install the function on the Sun Java System Web Server, add the following Init directive to magnus.conf to load the compiled function:

Init fn=load-modules shlib=yourlibrary funcs=hardcoded-auth

Inside the default object in obj.conf, add the following AuthTrans directive:

AuthTrans fn=basic-auth auth-type="basic" userfn=hardcoded-auth

Note that this function does not actually enforce authorization requirements, it only takes given information and tells the server if it's correct or not. The PathCheck function require-auth performs the enforcement, so add the following PathCheck directive as well:

PathCheck fn=require-auth realm="test realm" auth-type="basic"

Source Code

The source code for this example is in the auth.c file in the nsapi/examples/ or plugins/nsapi/examples subdirectory of the server root directory.

#include "nsapi.h"
typedef struct {
    char *name;
    char *pw;
} user_s;

static user_s user_set[] = {
    {"joe", "shmoe"},
    {"suzy", "creamcheese"},
    {NULL, NULL}

#include "frame/log.h"

#ifdef __cplusplus
extern "C"
NSAPI_PUBLIC int hardcoded_auth(pblock *param, Session *sn, Request 
    /* Parameters given to us by auth-basic */
    char *pwfile = pblock_findval("userdb", param);
    char *user = pblock_findval("user", param);
    char *pw = pblock_findval("pw", param);

    /* Temp variables */
    register int x;

    for(x = 0; user_set[x].name != NULL; ++x) {
        /* If this isn't the user we want, keep going */
        if(strcmp(user, user_set[x].name) != 0) continue;

        /* Verify password */
        if(strcmp(pw, user_set[x].pw)) {
             log_error(LOG_SECURITY, "hardcoded-auth", sn, rq,
                    "user %s entered wrong password", user);
            /* This will cause the enforcement function to ask */
            /* user again */
            return REQ_NOACTION;
        /* If we return REQ_PROCEED, the username will be accepted */
        return REQ_PROCEED;
    /* No match, have it ask them again */
    log_error(LOG_SECURITY, "hardcoded-auth", sn, rq,
        "unknown user %s", user);
    return REQ_NOACTION;