libpapi-lpd/common/lpd-port.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 */

/* $Id: lpd-port.c 155 2006-04-26 02:34:54Z ktou $ */

#include <config-site.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <signal.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <syslog.h>
#include <values.h>
#include <stropts.h>    /* for sendfd */
#include <sys/uio.h>    /* for sendmsg stuff */
#include <pwd.h>
#include <sys/sendfile.h>
#include <ctype.h>
#ifdef HAVE_PRIV_H
#include <priv.h>
#endif

#ifndef JOB_ID_FILE
#define JOB_ID_FILE "/var/run/rfc-1179.seq"
#endif  /* JOB_ID_FILE */

static int
sendfd(int sockfd, int fd)
{
    syslog(LOG_DEBUG, "sendfd(%d, %d)", sockfd, fd);

#if defined(sun) && defined(unix) && defined(I_SENDFD)
    return (ioctl(sockfd, I_SENDFD, fd));
#else
    struct iovec    iov[1];
    struct msghdr   msg;
#ifdef CMSG_DATA
    struct cmsghdr cmp[1];
    char buf[2];    /* send/recv 2 byte protocol */

    iov[0].iov_base = buf;
    iov[0].iov_len = 2;

    cmp[0].cmsg_level = SOL_SOCKET;
    cmp[0].cmsg_type = SCM_RIGHTS;
    cmp[0].cmsg_len = sizeof (struct cmsghdr) + sizeof (int);
    * (int *)CMSG_DATA(cmp) = fd;

    buf[1] = 0;
    buf[0] = 0;
    msg.msg_control = cmp;
    msg.msg_controllen = sizeof (struct cmsghdr) + sizeof (int);
#else
    iov[0].iov_base = NULL;
    iov[0].iov_len = 0;
    msg.msg_accrights = (caddr_t)&fd;
    msg.msg_accrights = sizeof (fd);
#endif
    msg.msg_iov = iov;
    msg.msg_iovlen = 1;
    msg.msg_name = NULL;
    msg.msg_namelen = 0;

    return (sendmsg(sockfd, &msg, 0));
#endif
}

static void
null(int i)
{
}

static int
sock_connect(int sock, char *host, int timeout)
{
    struct hostent *hp;
    struct servent *sp;
#if defined(HAVE_GETIPNODEBYNAME) && defined(HAVE_RRESVPORT_AF)
    struct sockaddr_in6 sin;
#else
    struct sockaddr_in sin;
#endif
    static void (*old_handler)();
    int err, error_num;
    unsigned timo = 1;

    /*
     * Get the host address and port number to connect to.
     */
    if (host == NULL) {
        return (-1);
    }

    /* linux style NULL usage */
    (void) memset((char *)&sin, (int)NULL, sizeof (sin));

#if defined(HAVE_GETIPNODEBYNAME) && defined(HAVE_RRESVPORT_AF)
    if ((hp = getipnodebyname(host, AF_INET6, AI_DEFAULT,
        &error_num)) == NULL) {
        errno = ENOENT;
        return (-1);
    }
    (void) memcpy((caddr_t)&sin.sin6_addr, hp->h_addr, hp->h_length);
    sin.sin6_family = hp->h_addrtype;
#else
    if ((hp = gethostbyname(host)) == NULL) {
        errno = ENOENT;
        return (-1);
    }

    (void) memcpy((caddr_t)&sin.sin_addr, hp->h_addr, hp->h_length);
    sin.sin_family = hp->h_addrtype;
#endif

    if ((sp = getservbyname("printer", "tcp")) == NULL) {
        errno = ENOENT;
        return (-1);
    }

#if defined(HAVE_GETIPNODEBYNAME) && defined(HAVE_RRESVPORT_AF)
    sin.sin6_port = sp->s_port;
#else
    sin.sin_port = sp->s_port;
#endif

retry:
    old_handler = signal(SIGALRM, null);
    (void) alarm(timeout);

    if (connect(sock, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
        (void) alarm(0);
        (void) signal(SIGALRM, old_handler);

        if (errno == ECONNREFUSED && timo <= 16) {
            (void) sleep(timo);
            timo *= 2;
            goto retry;
        }

        return (-1);
    }

    (void) alarm(0);
    (void) signal(SIGALRM, old_handler);
    return (sock);
}

static int
next_job_id()
{
    int fd, result = getpid() % 1000;

    /* gain back enough privilege to open the id file */
#ifdef  PRIV_ALLSETS
    if ((priv_set(PRIV_ON, PRIV_EFFECTIVE,
        PRIV_FILE_DAC_READ, PRIV_FILE_DAC_WRITE, NULL)) < 0) {
        syslog(LOG_ERR, "lpd_port:next_job_id:priv_set fails: : %m");
        return (-1);
    }
#else
    seteuid(0);
#endif

    /* open the sequence file */
    if (((fd = open(JOB_ID_FILE, O_RDWR)) < 0) && (errno == ENOENT))
        fd = open(JOB_ID_FILE, O_CREAT|O_EXCL|O_RDWR, 0644);

    syslog(LOG_DEBUG, "sequence file fd: %d", fd);

    /* drop our privilege again */
#ifdef  PRIV_ALLSETS
    /* drop file access privilege */
    priv_set(PRIV_OFF, PRIV_PERMITTED,
        PRIV_FILE_DAC_READ, PRIV_FILE_DAC_WRITE, NULL);
#else
    seteuid(getuid());
#endif

    if (fd >= 0) {
        /* wait for a lock on the file */
        if (lockf(fd, F_LOCK, 0) == 0) {
            char buf[8];
            int next;

            /* get the current id */
            (void) memset(buf, 0, sizeof (buf));
            if (read(fd, buf, sizeof (buf)) > 0)
                result = atoi(buf);

            next = ((result < 999) ? (result + 1) : 0);

            /* store the next id in the file */
            snprintf(buf, sizeof (buf), "%.3d", next);
            if ((lseek(fd, 0, SEEK_SET) == 0) &&
                (ftruncate(fd, 0) == 0))
                write(fd, buf, strlen(buf));
        }
        close(fd);
    }
    syslog(LOG_DEBUG, "next_job_id() is %d", result);

    return (result);
}

static int
reserved_port()
{
    int result = -1;
    int port;

    /* gain back enough privilege to open a reserved port */
#ifdef  PRIV_ALLSETS
    if ((priv_set(
        PRIV_ON, PRIV_EFFECTIVE, PRIV_NET_PRIVADDR, NULL)) != 0) {
        syslog(LOG_ERR, "priv_set fails for net_privaddr %m");
        return (-1);
    }
#else
    seteuid(0);
#endif

#if defined(HAVE_GETIPNODEBYNAME) && defined(HAVE_RRESVPORT_AF)
    port = 0;   /* set to 0, rresvport_af() will find us one. */
    result = rresvport_af(&port, AF_INET6);
#else
    port = IPPORT_RESERVED - 1;
    while (((result = rresvport(&port)) < 0) && (port >= 0))
        port--;
#endif

    /* drop our privilege again */
#ifdef  PRIV_ALLSETS
    priv_set(PRIV_OFF, PRIV_PERMITTED, PRIV_NET_PRIVADDR, NULL);
#else
    seteuid(getuid());
#endif

    return (result);
}

static char *
get_user_name()
{
    static struct passwd *p = NULL;

    if ((p = getpwuid(getuid())) != NULL)
        return (p->pw_name);
    else
        return ("unknown");
}

static void
add_args(int ac, char **av, char *buf, size_t len)
{
    while (ac--) {
        strlcat(buf, " ", len);
        strlcat(buf, *(av++), len);
    }
}

static int
massage_control_data(char *data, int id)
{
    char *line, *iter = NULL;
    char *ptr, *mod_ptr, *datacpy;
    char host[BUFSIZ];
    int host_present = 0;

    if (gethostname(host, sizeof (host)) != 0)
        return (-1);

    if ((datacpy = strdup(data)) == NULL) {
        return (-1);
    }

    for (ptr = strtok_r(datacpy, "\n", &iter); ptr != NULL;
        ptr = strtok_r(NULL, "\n", &iter)) {

        if (ptr[0] == 'H') {
            if (strncmp(++ptr, host, strlen(host)) != 0) {
                free(datacpy);
                return (-1);
            }
            host_present = 1;
        } else if ((ptr[0] == 'P') || (ptr[0] == 'L')) {
            /* check the user name */
            uid_t uid = getuid();
            struct passwd *pw;
            int len;

            if (uid == 0) { /* let root do what they want */
                continue;
            }
            if ((pw = getpwuid(uid)) == NULL) {
                free(datacpy);
                return (-1);    /* failed */
            }
            len = strlen(pw->pw_name);
            if ((strncmp(++ptr, pw->pw_name, len) != 0)) {
                free(datacpy);
                return (-1);    /* failed */
            }
        } else if ((islower(ptr[0]) != 0) || (ptr[0] == 'U')) {
            /* check/fix df?XXXhostname */
            ptr++;

            if (strlen(ptr) < 6) {
                free(datacpy);
                return (-1);
            }

            /*
             * As ptr is a copy of the string (df?XXX...) the code
             * needs to work on the original, hence the need for
             * mod_ptr. No need to check for a NULL mod_ptr
             * because the required string must already exist as
             * ptr is a copy of the original data.
             */

            mod_ptr = strstr(data, ptr);

            if ((mod_ptr[0] == 'd') && (mod_ptr[1] == 'f') &&
                (mod_ptr[3] == 'X') && (mod_ptr[4] == 'X') &&
                (mod_ptr[5] == 'X')) {
                mod_ptr[3] = '0' + (id / 100) % 10;
                mod_ptr[4] = '0' + (id / 10) % 10;
                mod_ptr[5] = '0' + id % 10;

                if (strncmp(&mod_ptr[6], host, strlen(host))
                    != 0) {
                    free(datacpy);
                    return (-1);
                }
            } else {
                free(datacpy);
                return (-1);
            }
        }

    }
    free(datacpy);

    if (!host_present) {
        return (-1);
    }

    return (1);
}

static int
send_lpd_message(int fd, char *fmt, ...)
{
    char buf[BUFSIZ];
    size_t size;
    va_list ap;

    va_start(ap, fmt);
    size = vsnprintf(buf, sizeof (buf), fmt, ap);
    va_end(ap);
    if (size == 0)
        size = 1;

    syslog(LOG_DEBUG, "lpd_messsage(%d, %s)", fd, buf);

    if (write(fd, buf, size) != size) {
        errno = EIO;
        return (-1);
    }

    if ((read(fd, buf, 1) != 1) || (buf[0] != 0))
        return (-1);

    return (0);
}

static int
send_data_file(int sock, char *dfname, char *name)
{
    size_t len;
    off_t off = 0;
    struct stat st;
    char buf[32];
    int fd = -1;

    if (strcmp(name, "standard input") != 0) {
        if ((fd = open(name, O_RDONLY)) < 0)
            return (-1);

        if (fstat(fd, &st) < 0)
            return (-1);
    } else
        st.st_size = MAXINT; /* should be 0 */

    /* request data file transfer, read ack/nack */
    errno = ENOSPC;
    if (send_lpd_message(sock, "\003%d %s\n", st.st_size, dfname) < 0)
        return (-1);

    if (fd != -1) {
        /* write the data */
        if (sendfile(sock, fd, &off, st.st_size) != st.st_size)
            return (-1);
        close(fd);

        /* request ack/nack after the data transfer */
        errno = EIO;
        if (send_lpd_message(sock, "") < 0)
            return (-1);
    }

    return (0);
}

static int
send_control_file(int sock, char *data, int id)
{
    int len;
    char buf[BUFSIZ];
    char *ptr, *iter = NULL;
    char *datacpy = NULL;
    char *host = NULL;

    len = strlen(data);

    if ((datacpy = strdup(data)) == NULL)
        return (-1);

    syslog(LOG_DEBUG, "cfA: %s\n", datacpy);

    for (ptr = strtok_r(datacpy, "\n", &iter); ptr != NULL;
        ptr = strtok_r(NULL, "\n", &iter)) {

        if (ptr[0] != 'H')
            continue;

        ptr++;
        host = ptr;
        syslog(LOG_DEBUG, "hostname: %s\n", host);
    }

    free(datacpy);

    /* request data file transfer, read ack/nack */
    errno = ENOSPC;
    if (send_lpd_message(sock, "\002%d cfA%.3d%s\n", len, id, host) < 0)
        return (-1);

    /* write the data */
    if (write(sock, data, len) != len)
        return (-1);

    /* request ack/nack after the data transfer */
    errno = EIO;
    if (send_lpd_message(sock, "") < 0)
        return (-1);

    return (0);
}


static int
submit_job(int sock, char *printer, int job_id, char *path)
{
    struct stat st;
    int current = 0;
    off_t off = 0;
    char *metadata = NULL;
    char *ptr, *iter = NULL;
    int fd, err;
    int sent_files = 0;
    char buf[BUFSIZ];
    size_t len;

    /* open the control file */
    if ((fd = open(path, O_RDONLY)) < 0) {
        syslog(LOG_ERR, "submit_job(%d, %s, %d, %s): open(): %m",
            sock, printer, job_id, path);
        return (-1);
    }

    /* get the size of the control file */
    if (fstat(fd, &st) < 0) {
        syslog(LOG_ERR, "submit_job(%d, %s, %d, %s): fstat(): %m",
            sock, printer, job_id, path);
        close(fd);
        return (-1);
    }

    /* allocate memory for the control file */
    if ((metadata = calloc(1, st.st_size + 1)) == NULL) {
        syslog(LOG_ERR, "submit_job(%d, %s, %d, %s): calloc(): %m",
            sock, printer, job_id, path);
        close(fd);
        return (-1);
    }

    /* read in the control file */
    if (read(fd, metadata, st.st_size) != st.st_size) {
        syslog(LOG_ERR, "submit_job(%d, %s, %d, %s): read(): %m",
            sock, printer, job_id, path);
        free(metadata);
        close(fd);
        return (-1);
    }

    /* massage the control file */
    if (massage_control_data(metadata, job_id) < 0) {
        /* bad control data, dump the job */
        syslog(LOG_ALERT,
            "bad control file, possible subversion attempt");
        free(metadata);
        errno = EINVAL;
        close(fd);
        return (-1);
    }

    /* request to transfer the job */
    if (send_lpd_message(sock, "\002%s\n", printer) < 0) {
        /* no such (or disabled) queue, got to love rfc-1179 */
        errno = ENOENT;
        return (-1);
    }

    /* send the control data */
    if (send_control_file(sock, metadata, job_id) < 0) {
        err = errno;
        write(sock, "\001\n", 2); /* abort */
        errno = err;
        return (-1);
    }

    /* walk the control file sending the data files */
    for (ptr = strtok_r(metadata, "\n", &iter); ptr != NULL;
        ptr = strtok_r(NULL, "\n", &iter)) {
        char *name = NULL;

        if (ptr[0] != 'U')
            continue;

        name = strtok_r(NULL, "\n", &iter);
        if (name[0] != 'N')
            continue;

        ptr++;
        name++;

        if (send_data_file(sock, ptr, name) < 0) {
            err = errno;
            write(sock, "\001\n", 2); /* abort */
            errno = err;
            return (-1);
        }
        if (strcmp(name, "standard input") != 0)
            sent_files++;
    }

    /* write back the job-id */
    err = errno;
    if ((fd = open(path, O_WRONLY)) >= 0) {
        ftruncate(fd, 0);
        write(fd, &job_id, sizeof (job_id));
        close(fd);
    }
    errno = err;

    if (sent_files != 0) {
        err = errno;
        close(sock);
        errno = err;
    }

    return (0);
}
static int
query(int fd, char *printer, int ac, char **av)
{
    char buf[BUFSIZ];
    int rc, len;

    /* build the request */
    snprintf(buf, sizeof (buf), "\04%s", printer);
    add_args(ac, av, buf, sizeof (buf));
    strlcat(buf, "\n", sizeof (buf));
    len = strlen(buf);

    if (((rc = write(fd, buf, len)) >= 0) && (rc != len)) {
        errno = EMSGSIZE;
        rc = -1;
    } else
        rc = 0;

    return (rc);
}

static int
cancel(int fd, char *printer, int ac, char **av)
{
    char buf[BUFSIZ];
    int rc, len;

    /* build the request */
    snprintf(buf, sizeof (buf), "\05%s %s", printer, get_user_name());
    add_args(ac, av, buf, sizeof (buf));
    strlcat(buf, "\n", sizeof (buf));
    len = strlen(buf);

    if (((rc = write(fd, buf, len)) >= 0) && (rc != len)) {
        errno = EMSGSIZE;
        rc = -1;
    } else
        rc = 0;

    return (rc);
}

static void
usage(char *program)
{
    char *name;

    setreuid(getuid(), getuid());

    if ((name = strrchr(program, '/')) == NULL)
        name = program;
    else
        name++;

    fprintf(stderr, "usage:\t%s -H host [-t timeout] -s queue control ]\n",
        name);
    fprintf(stderr, "\t%s -H host [-t timeout] -c queue [user|job ...]\n",
        name);
    fprintf(stderr, "\t%s -H host [-t timeout] -q queue [user|job ...]\n",
        name);
    exit(EINVAL);
}

/*
 * The main program temporarily loses privilege while searching the command
 * line arguments.  It then allocates any resources it need privilege for
 * job-id, reserved port.  Once it has the resources it needs, it perminently
 * drops all elevated privilege.  It ghen connects to the remote print service
 * based on destination hostname.  Doing it this way reduces the potenential
 * opportunity for a breakout with elevated privilege, breakout with an
 * unconnected reserved port, and exploitation of the remote print service
 * by a calling program.
 */
int
main(int ac, char *av[])
{
    enum { OP_NONE, OP_SUBMIT, OP_QUERY, OP_CANCEL } operation = OP_NONE;
    int fd, c, timeout = 0, exit_code = 0;
    char *host = NULL, *queue = NULL;
    uid_t uid = getuid();
#ifdef  PRIV_ALLSETS
    priv_set_t *saveset;
#endif

    openlog("lpd-port", LOG_PID, LOG_LPR);

#ifdef  PRIV_ALLSETS

    /* lose as much as we can perminently and temporarily drop the rest. */

    if ((saveset = priv_allocset()) == NULL) {
        syslog(LOG_ERR, "lpd_port: priv_allocset saveset failed: %m\n");
        return (-1);
    }

    priv_basicset(saveset);
    (void) priv_addset(saveset, PRIV_NET_PRIVADDR);
    (void) priv_addset(saveset, PRIV_FILE_DAC_READ);
    (void) priv_addset(saveset, PRIV_FILE_DAC_WRITE);

    if ((setppriv(PRIV_SET, PRIV_PERMITTED, saveset)) < 0) {
        syslog(LOG_ERR, "lpd_port:setppriv:priv_set failed: %m");
        return (-1);
    }

    priv_freeset(saveset);

    /*
     * These privileges permanently dropped in next_job_id() and
     * reserved_port()
     */

    if (priv_set(PRIV_OFF, PRIV_EFFECTIVE, PRIV_NET_PRIVADDR,
        PRIV_FILE_DAC_READ, PRIV_FILE_DAC_WRITE, (char *)NULL) < 0) {
        syslog(LOG_ERR, "lpd_port:priv_set:priv_off failed: %m");
        return (-1);
    }

    syslog(LOG_DEBUG, "using privs");
#else

    syslog(LOG_DEBUG, "no  privs");
    seteuid(uid);
#endif

    while ((c = getopt(ac, av, "H:t:c:q:s:")) != EOF) {
        switch (c) {
        case 'H':
            host = optarg;
            break;
        case 't':
            timeout = atoi(optarg);
            break;
        case 'c':
            if (operation != OP_NONE)
                usage(av[0]);
            operation = OP_CANCEL;
            queue = optarg;
            break;
        case 'q':
            if (operation != OP_NONE)
                usage(av[0]);
            operation = OP_QUERY;
            queue = optarg;
            break;
        case 's':
            if (operation != OP_NONE)
                usage(av[0]);
            operation = OP_SUBMIT;
            queue = optarg;
            break;
        default:
            usage(av[0]);
            /* does not return */
        }
    }

    if ((host == NULL) || (queue == NULL) || (timeout < 0) ||
        (operation == OP_NONE))
        usage(av[0]);

    if (operation == OP_SUBMIT) /* get a job-id if we need it */
        if ((c = next_job_id()) < 0) {
            syslog(LOG_ERR, "lpd_port:main:next_job_id fails");
            return (-1);
        }

    if ((fd = reserved_port()) < 0) {
        syslog(LOG_ERR, "reserved_port() failed %m");
        return (errno);
    }

    /*
     * we no longer want or need any elevated privilege, lose it all
     * permanently.
     */

    setreuid(uid, uid);

    /* connect to the print service */
    if ((fd = sock_connect(fd, host, timeout)) < 0)
        return (errno);

    /* perform the requested operation */
    switch (operation) {
    case OP_SUBMIT: /* transfer the job, close the fd */
        if (submit_job(fd, queue, c, av[optind]) < 0)
            exit_code = errno;
        break;
    case OP_QUERY:  /* send the query string, return the fd */
        if (query(fd, queue, ac - optind, &av[optind]) < 0)
            exit_code = errno;
        break;
    case OP_CANCEL: /* send the cancel string, return the fd */
        if (cancel(fd, queue, ac - optind, &av[optind]) < 0)
            exit_code = errno;
        break;
    default:    /* This should never happen */
        exit_code = EINVAL;
    }


    /* if the operation succeeded, send the fd to our parent */
    if ((exit_code == 0) && (sendfd(1, fd) < 0)) {
        char buf[BUFSIZ];

        exit_code = errno;

        /* sendfd() failed, dump the socket data for the heck of it */
        while ((c = read(fd, buf, sizeof (buf))) > 0)
            write(1, buf, c);
    }

    syslog(LOG_DEBUG, "exit code: %d", exit_code);
    return (exit_code);
}