basic_smb_auth.cc

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
/*
 *  basic_smb_auth - SMB proxy authentication module
 *  Copyright (C) 1998  Richard Huveneers <richard@hekkihek.hacom.nl>
 *
 *  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 2 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, write to the Free Software
 */
 
#include "squid.h"
#include "helper/protocol_defines.h"
#include "rfc1738.h"
#include "util.h"
 
#include <cstring>
 
#define NMB_UNICAST     1
#define NMB_BROADCAST   2
 
struct SMBDOMAIN {
    const char *name;       /* domain name */
    const char *sname;      /* match this with user input */
    const char *passthrough;    /* pass-through authentication */
    const char *nmbaddr;    /* name service address */
    int nmbcast;        /* broadcast or unicast */
    char *authshare;        /* share name of auth file */
    const char *authfile;   /* pathname of auth file */
    struct SMBDOMAIN *next; /* linked list */
};
 
struct SMBDOMAIN *firstdom = nullptr;
struct SMBDOMAIN *lastdom = nullptr;
 
/*
 * escape the backslash character, since it has a special meaning
 * to the read command of the bourne shell.
 */
 
static void
print_esc(FILE * p, char *s)
{
    char buf[HELPER_INPUT_BUFFER];
    char *t;
    int i = 0;
 
    for (t = s; *t != '\0'; ++t) {
        /*
         * NP: The shell escaping permits 'i' to jump up to 2 octets per loop,
         *     so ensure we have at least 3 free.
         */
        if (i > HELPER_INPUT_BUFFER-3) {
            buf[i] = '\0';
            (void) fputs(buf, p);
            i = 0;
        }
        if (*t == '\\')
            buf[i++] = '\\';
 
        buf[i] = *t;
        ++i;
    }
 
    if (i > 0) {
        buf[i] = '\0';
        (void) fputs(buf, p);
    }
}
 
int
main(int argc, char *argv[])
{
    int i;
    char buf[HELPER_INPUT_BUFFER];
    struct SMBDOMAIN *dom;
    char *s;
    char *user;
    char *pass;
    char *domname;
    FILE *p;
    const char *shcmd;
 
    /* make standard output line buffered */
    if (setvbuf(stdout, nullptr, _IOLBF, 0) != 0)
        exit(EXIT_FAILURE);
 
    /* parse command line arguments */
    for (i = 1; i < argc; ++i) {
        if (strcmp(argv[i], "-d") == 0) {
            debug_enabled = 1;
            continue;
        }
        /* the next options require an argument */
        if (i + 1 == argc)
            break;
 
        if (strcmp(argv[i], "-W") == 0) {
            dom = static_cast<struct SMBDOMAIN *>(xmalloc(sizeof(struct SMBDOMAIN)));
 
            dom->name = dom->sname = argv[++i];
            dom->passthrough = "";
            dom->nmbaddr = "";
            dom->nmbcast = NMB_BROADCAST;
            dom->authshare = (char *)"NETLOGON";
            dom->authfile = "proxyauth";
            dom->next = nullptr;
 
            /* append to linked list */
            if (lastdom != nullptr)
                lastdom->next = dom;
            else
                firstdom = dom;
 
            lastdom = dom;
            continue;
        }
        if (strcmp(argv[i], "-w") == 0) {
            if (lastdom != nullptr)
                lastdom->sname = argv[++i];
            continue;
        }
        if (strcmp(argv[i], "-P") == 0) {
            if (lastdom != nullptr)
                lastdom->passthrough = argv[++i];
            continue;
        }
        if (strcmp(argv[i], "-B") == 0) {
            if (lastdom != nullptr) {
                lastdom->nmbaddr = argv[++i];
                lastdom->nmbcast = NMB_BROADCAST;
            }
            continue;
        }
        if (strcmp(argv[i], "-U") == 0) {
            if (lastdom != nullptr) {
                lastdom->nmbaddr = argv[++i];
                lastdom->nmbcast = NMB_UNICAST;
            }
            continue;
        }
        if (strcmp(argv[i], "-S") == 0) {
            if (lastdom != nullptr) {
                if ((lastdom->authshare = xstrdup(argv[++i])) == nullptr)
                    exit(EXIT_FAILURE);
 
                /* convert backslashes to forward slashes */
                for (s = lastdom->authshare; *s != '\0'; ++s)
                    if (*s == '\\')
                        *s = '/';
 
                /* strip leading forward slash from share name */
                if (*lastdom->authshare == '/')
                    ++lastdom->authshare;
 
                if ((s = strchr(lastdom->authshare, '/')) != nullptr) {
                    *s = '\0';
                    lastdom->authfile = s + 1;
                }
            }
            continue;
        }
    }
 
    shcmd = debug_enabled ? HELPERSCRIPT : HELPERSCRIPT " > /dev/null 2>&1";
 
    while (fgets(buf, HELPER_INPUT_BUFFER, stdin) != nullptr) {
 
        if ((s = strchr(buf, '\n')) == nullptr)
            continue;
        *s = '\0';
 
        if ((s = strchr(buf, ' ')) == nullptr) {
            SEND_ERR("");
            continue;
        }
        *s = '\0';
 
        user = buf;
        pass = s + 1;
        domname = nullptr;
 
        rfc1738_unescape(user);
        rfc1738_unescape(pass);
 
        if ((s = strchr(user, '\\')) != nullptr) {
            *s = '\0';
            domname = user;
            user = s + 1;
        }
        /* match domname with linked list */
        if (domname != nullptr && strlen(domname) > 0) {
            for (dom = firstdom; dom != nullptr; dom = dom->next)
                if (strcasecmp(dom->sname, domname) == 0)
                    break;
        } else
            dom = firstdom;
 
        if (dom == nullptr) {
            SEND_ERR("");
            continue;
        }
        if ((p = popen(shcmd, "w")) == nullptr) {
            SEND_ERR("");
            continue;
        }
        (void) fprintf(p, "%s\n", dom->name);
        (void) fprintf(p, "%s\n", dom->passthrough);
        (void) fprintf(p, "%s\n", dom->nmbaddr);
        (void) fprintf(p, "%d\n", dom->nmbcast);
        (void) fprintf(p, "%s\n", dom->authshare);
        (void) fprintf(p, "%s\n", dom->authfile);
        (void) fprintf(p, "%s\n", user);
        /* the password can contain special characters */
        print_esc(p, pass);
        (void) fputc('\n', p);
        (void) fflush(p);
 
        if (pclose(p) == 0)
            SEND_OK("");
        else
            SEND_ERR("");
    }               /* while (1) */
 
    return EXIT_SUCCESS;
}