/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 * 

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 * 

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 * 

 * Except as contained in this notice, the names of the authors or their

 * institutions shall not be used in advertising or otherwise to promote the

 * sale, use or other dealings in this Software without prior written

 * authorization from the authors.

 */

/* Authorization systems for the X protocol. */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <assert.h>

#include <X11/Xauth.h>

#include <sys/param.h>

#include <unistd.h>

#include <stdlib.h>

#ifdef __INTERIX

/* _don't_ ask. interix has INADDR_LOOPBACK in here. */

#include <rpc/types.h>

#endif

#ifdef _WIN32

#ifdef HASXDMAUTH

/* We must include the wrapped windows.h before any system header which includes

   it unwrapped, to avoid conflicts with types defined in X headers */

#include <X11/Xwindows.h>

#endif

#include "xcb_windefs.h"

#else

#include <arpa/inet.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <sys/un.h>

#endif /* _WIN32 */

#include "xcb.h"

#include "xcbint.h"

#ifdef HASXDMAUTH

#include <X11/Xdmcp.h>

#endif

enum auth_protos {

#ifdef HASXDMAUTH

    AUTH_XA1,

#endif

    AUTH_MC1,

    N_AUTH_PROTOS

};

#define AUTH_PROTO_XDM_AUTHORIZATION "XDM-AUTHORIZATION-1"

#define AUTH_PROTO_MIT_MAGIC_COOKIE "MIT-MAGIC-COOKIE-1"

static char *authnames[N_AUTH_PROTOS] = {

#ifdef HASXDMAUTH

    AUTH_PROTO_XDM_AUTHORIZATION,

#endif

    AUTH_PROTO_MIT_MAGIC_COOKIE,

};

static int authnameslen[N_AUTH_PROTOS] = {

#ifdef HASXDMAUTH

    sizeof(AUTH_PROTO_XDM_AUTHORIZATION) - 1,

#endif

    sizeof(AUTH_PROTO_MIT_MAGIC_COOKIE) - 1,

};

static size_t memdup(char **dst, void *src, size_t len)

{

    if(len)

        *dst = malloc(len);

    else

        *dst = 0;

    if(!*dst)

        return 0;

    memcpy(*dst, src, len);

    return len;

}

static int authname_match(enum auth_protos kind, char *name, size_t namelen)

{

    if(authnameslen[kind] != namelen)

        return 0;

    if(memcmp(authnames[kind], name, namelen))

        return 0;

    return 1;

}

#define SIN6_ADDR(s) (&((struct sockaddr_in6 *)s)->sin6_addr)

static Xauth *get_authptr(struct sockaddr *sockname, int display)

{

    char *addr = 0;

    int addrlen = 0;

    unsigned short family;

    char hostnamebuf[256];   /* big enough for max hostname */

    char dispbuf[40];   /* big enough to hold more than 2^64 base 10 */

    int dispbuflen;

    family = FamilyLocal; /* 256 */

    switch(sockname->sa_family)

    {

#ifdef AF_INET6

    case AF_INET6:

        addr = (char *) SIN6_ADDR(sockname);

        addrlen = sizeof(*SIN6_ADDR(sockname));

        if(!IN6_IS_ADDR_V4MAPPED(SIN6_ADDR(sockname)))

        {

            if(!IN6_IS_ADDR_LOOPBACK(SIN6_ADDR(sockname)))

                family = XCB_FAMILY_INTERNET_6;

            break;

        }

        addr += 12;

        /* if v4-mapped, fall through. */

#endif

    case AF_INET:

        if(!addr)

            addr = (char *) &((struct sockaddr_in *)sockname)->sin_addr;

        addrlen = sizeof(((struct sockaddr_in *)sockname)->sin_addr);

        if(*(in_addr_t *) addr != htonl(INADDR_LOOPBACK))

            family = XCB_FAMILY_INTERNET;

        break;

    case AF_UNIX:

        break;

    default:

        return 0;   /* cannot authenticate this family */

    }

    dispbuflen = snprintf(dispbuf, sizeof(dispbuf), "%d", display);

    if(dispbuflen < 0)

        return 0;

    /* snprintf may have truncate our text */

    dispbuflen = MIN(dispbuflen, sizeof(dispbuf) - 1);

    if (family == FamilyLocal) {

        if (gethostname(hostnamebuf, sizeof(hostnamebuf)) == -1)

            return 0;   /* do not know own hostname */

        addr = hostnamebuf;

        addrlen = strlen(addr);

    }

    return XauGetBestAuthByAddr (family,

                                 (unsigned short) addrlen, addr,

                                 (unsigned short) dispbuflen, dispbuf,

                                 N_AUTH_PROTOS, authnames, authnameslen);

}

#ifdef HASXDMAUTH

static int next_nonce(void)

{

    static int nonce = 0;

    static pthread_mutex_t nonce_mutex = PTHREAD_MUTEX_INITIALIZER;

    int ret;

    pthread_mutex_lock(&nonce_mutex);

    ret = nonce++;

    pthread_mutex_unlock(&nonce_mutex);

    return ret;

}

static void do_append(char *buf, int *idxp, void *val, size_t valsize) {

    memcpy(buf + *idxp, val, valsize);

    *idxp += valsize;

}

#endif

static int compute_auth(xcb_auth_info_t *info, Xauth *authptr, struct sockaddr *sockname)

{

    if (authname_match(AUTH_MC1, authptr->name, authptr->name_length)) {

        info->datalen = memdup(&info->data, authptr->data, authptr->data_length);

        if(!info->datalen)

            return 0;

        return 1;

    }

#ifdef HASXDMAUTH

#define APPEND(buf,idx,val) do_append((buf),&(idx),&(val),sizeof(val))

    if (authname_match(AUTH_XA1, authptr->name, authptr->name_length)) {

        int j;

        info->data = malloc(192 / 8);

        if(!info->data)

            return 0;

        for (j = 0; j < 8; j++)

            info->data[j] = authptr->data[j];

        switch(sockname->sa_family) {

        case AF_INET:

            /*block*/ {

            struct sockaddr_in *si = (struct sockaddr_in *) sockname;

            APPEND(info->data, j, si->sin_addr.s_addr);

            APPEND(info->data, j, si->sin_port);

        }

        break;

#ifdef AF_INET6

        case AF_INET6:

            /*block*/ {

            struct sockaddr_in6 *si6 = (struct sockaddr_in6 *) sockname;

            if(IN6_IS_ADDR_V4MAPPED(SIN6_ADDR(sockname)))

            {

                do_append(info->data, &j, &si6->sin6_addr.s6_addr[12], 4);

                APPEND(info->data, j, si6->sin6_port);

            }

            else

            {

                /* XDM-AUTHORIZATION-1 does not handle IPv6 correctly.  Do the

                   same thing Xlib does: use all zeroes for the 4-byte address

                   and 2-byte port number. */

                uint32_t fakeaddr = 0;

                uint16_t fakeport = 0;

                APPEND(info->data, j, fakeaddr);

                APPEND(info->data, j, fakeport);

            }

        }

        break;

#endif

        case AF_UNIX:

            /*block*/ {

            uint32_t fakeaddr = htonl(0xffffffff - next_nonce());

            uint16_t fakeport = htons(getpid());

            APPEND(info->data, j, fakeaddr);

            APPEND(info->data, j, fakeport);

        }

        break;

        default:

            free(info->data);

            return 0;   /* do not know how to build this */

        }

        {

            uint32_t now = htonl(time(0));

            APPEND(info->data, j, now);

        }

        assert(j <= 192 / 8);

        while (j < 192 / 8)

            info->data[j++] = 0;

        info->datalen = j;

        XdmcpWrap ((unsigned char *) info->data, (unsigned char *) authptr->data + 8, (unsigned char *) info->data, info->datalen);

        return 1;

    }

#undef APPEND

#endif

    return 0;   /* Unknown authorization type */

}

/* `sockaddr_un.sun_path' typical size usually ranges between 92 and 108 */

#define INITIAL_SOCKNAME_SLACK 108

/* Return a dynamically allocated socket address structure according

   to the value returned by either getpeername() or getsockname()

   (according to POSIX, applications should not assume a particular

   length for `sockaddr_un.sun_path') */

static struct sockaddr *get_peer_sock_name(int (*socket_func)(int,

                                                              struct sockaddr *,

                                                              socklen_t *),

                                           int fd)

{

    socklen_t socknamelen = sizeof(struct sockaddr) + INITIAL_SOCKNAME_SLACK;

    socklen_t actual_socknamelen = socknamelen;

    struct sockaddr *sockname = malloc(socknamelen);

    if (sockname == NULL)

        return NULL;

    /* Both getpeername() and getsockname() truncates sockname if

       there is not enough space and set the required length in

       actual_socknamelen */

    if (socket_func(fd, sockname, &actual_socknamelen) == -1)

        goto sock_or_realloc_error;

    if (actual_socknamelen > socknamelen)

    {

        struct sockaddr *new_sockname = NULL;

        socknamelen = actual_socknamelen;

        if ((new_sockname = realloc(sockname, actual_socknamelen)) == NULL)

            goto sock_or_realloc_error;

        sockname = new_sockname;

        if (socket_func(fd, sockname, &actual_socknamelen) == -1 ||

            actual_socknamelen > socknamelen)

            goto sock_or_realloc_error;

    }

    return sockname;

 sock_or_realloc_error:

    free(sockname);

    return NULL;

}

int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display)

{

    /* code adapted from Xlib/ConnDis.c, xtrans/Xtranssocket.c,

       xtrans/Xtransutils.c */

    struct sockaddr *sockname = NULL;

    int gotsockname = 0;

    Xauth *authptr = 0;

    int ret = 1;

    /* Some systems like hpux or Hurd do not expose peer names

     * for UNIX Domain Sockets, but this is irrelevant,

     * since compute_auth() ignores the peer name in this

     * case anyway.*/

    if ((sockname = get_peer_sock_name(getpeername, fd)) == NULL)

    {

        if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL)

            return 0;   /* can only authenticate sockets */

        if (sockname->sa_family != AF_UNIX)

        {

            free(sockname);

            return 0;   /* except for AF_UNIX, sockets should have peernames */

        }

        gotsockname = 1;

    }

    authptr = get_authptr(sockname, display);

    if (authptr == 0)

    {

        free(sockname);

        return 0;   /* cannot find good auth data */

    }

    info->namelen = memdup(&info->name, authptr->name, authptr->name_length);

    if (!info->namelen)

        goto no_auth;   /* out of memory */

    if (!gotsockname)

    {

        free(sockname);

        if ((sockname = get_peer_sock_name(getsockname, fd)) == NULL)

        {

            free(info->name);

            goto no_auth;   /* can only authenticate sockets */

        }

    }

    ret = compute_auth(info, authptr, sockname);

    if(!ret)

    {

        free(info->name);

        goto no_auth;   /* cannot build auth record */

    }

    free(sockname);

    sockname = NULL;

    XauDisposeAuth(authptr);

    return ret;

 no_auth:

    free(sockname);

    info->name = 0;

    info->namelen = 0;

    XauDisposeAuth(authptr);

    return 0;

}