libsmb/common/smb_util.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 (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
 */

#include <ctype.h>
#include <stdio.h>
#include <stdarg.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <pthread.h>
#include <sys/varargs.h>
#include <sys/types.h>
#include <sys/mnttab.h>
#include <tiuser.h>
#include <netconfig.h>
#include <netdir.h>
#include <sys/systeminfo.h>
#include <sys/utsname.h>
#include <libzfs.h>
#include <dlfcn.h>
#include <time.h>
#include <syslog.h>
#include <smbsrv/string.h>
#include <smbsrv/libsmb.h>

#define SMB_LIB_ALT "/usr/lib/smbsrv/libsmbex.so"

static boolean_t smb_netgroup_match(struct nd_hostservlist *, char *, int);

extern int __multi_innetgr();
extern int __netdir_getbyaddr_nosrv(struct netconfig *,
    struct nd_hostservlist **, struct netbuf *);

#define C2H(c)      "0123456789ABCDEF"[(c)]
#define H2C(c)    (((c) >= '0' && (c) <= '9') ? ((c) - '0') :     \
    ((c) >= 'a' && (c) <= 'f') ? ((c) - 'a' + 10) :         \
    ((c) >= 'A' && (c) <= 'F') ? ((c) - 'A' + 10) :         \
    '\0')
#define DEFAULT_SBOX_SIZE       256

/*
 *
 * hexdump
 *
 * Simple hex dump display function. Displays nbytes of buffer in hex and
 * printable format. Non-printing characters are shown as '.'. It is safe
 * to pass a null pointer. Each line begins with the offset. If nbytes is
 * 0, the line will be blank except for the offset. Example output:
 *
 * 00000000  54 68 69 73 20 69 73 20 61 20 70 72 6F 67 72 61  This is a progra
 * 00000010  6D 20 74 65 73 74 2E 00                          m test..
 *
 */
void
hexdump_offset(unsigned char *buffer, int nbytes, unsigned long *start)
{
    static char *hex = "0123456789ABCDEF";
    int i, count;
    int offset;
    unsigned char *p;
    char ascbuf[64];
    char hexbuf[64];
    char *ap = ascbuf;
    char *hp = hexbuf;

    if ((p = buffer) == NULL)
        return;

    offset = *start;

    *ap = '\0';
    *hp = '\0';
    count = 0;

    for (i = 0; i < nbytes; ++i) {
        if (i && (i % 16) == 0) {
            smb_tracef("%06X %s  %s", offset, hexbuf, ascbuf);
            ap = ascbuf;
            hp = hexbuf;
            count = 0;
            offset += 16;
        }

        ap += sprintf(ap, "%c",
            (*p >= 0x20 && *p < 0x7F) ? *p : '.');
        hp += sprintf(hp, " %c%c",
            hex[(*p >> 4) & 0x0F], hex[(*p & 0x0F)]);
        ++p;
        ++count;
    }

    if (count) {
        smb_tracef("%06X %-48s  %s", offset, hexbuf, ascbuf);
        offset += count;
    }

    *start = offset;
}

void
hexdump(unsigned char *buffer, int nbytes)
{
    unsigned long start = 0;

    hexdump_offset(buffer, nbytes, &start);
}

/*
 * bintohex
 *
 * Converts the given binary data (srcbuf) to
 * its equivalent hex chars (hexbuf).
 *
 * hexlen should be at least twice as srclen.
 * if hexbuf is not big enough returns 0.
 * otherwise returns number of valid chars in
 * hexbuf which is srclen * 2.
 */
size_t
bintohex(const char *srcbuf, size_t srclen,
    char *hexbuf, size_t hexlen)
{
    size_t outlen;
    char c;

    outlen = srclen << 1;

    if (hexlen < outlen)
        return (0);

    while (srclen-- > 0) {
        c = *srcbuf++;
        *hexbuf++ = C2H(c & 0xF);
        *hexbuf++ = C2H((c >> 4) & 0xF);
    }

    return (outlen);
}

/*
 * hextobin
 *
 * Converts hex to binary.
 *
 * Assuming hexbuf only contains hex digits (chars)
 * this function convert every two bytes of hexbuf
 * to one byte and put it in dstbuf.
 *
 * hexlen should be an even number.
 * dstlen should be at least half of hexlen.
 *
 * Returns 0 if sizes are not correct, otherwise
 * returns the number of converted bytes in dstbuf
 * which is half of hexlen.
 */
size_t
hextobin(const char *hexbuf, size_t hexlen,
    char *dstbuf, size_t dstlen)
{
    size_t outlen;

    if ((hexlen % 2) != 0)
        return (0);

    outlen = hexlen >> 1;
    if (dstlen < outlen)
        return (0);

    while (hexlen > 0) {
        *dstbuf = H2C(*hexbuf) & 0x0F;
        hexbuf++;
        *dstbuf++ |= (H2C(*hexbuf) << 4) & 0xF0;
        hexbuf++;

        hexlen -= 2;
    }

    return (outlen);
}

/*
 * Trim leading and trailing characters in the set defined by class
 * from a buffer containing a null-terminated string.
 * For example, if the input buffer contained "ABtext23" and class
 * contains "ABC123", the buffer will contain "text" on return.
 *
 * This function modifies the contents of buf in place and returns
 * a pointer to buf.
 */
char *
strtrim(char *buf, const char *class)
{
    char *p = buf;
    char *q = buf;

    if (buf == NULL)
        return (NULL);

    p += strspn(p, class);

    if (p != buf) {
        while ((*q = *p++) != '\0')
            ++q;
    }

    while (q != buf) {
        --q;
        if (strspn(q, class) == 0)
            return (buf);
        *q = '\0';
    }

    return (buf);
}

/*
 * Strip the characters in the set defined by class from a buffer
 * containing a null-terminated string.
 * For example, if the input buffer contained "XYA 1textZ string3"
 * and class contains "123XYZ", the buffer will contain "A text string"
 * on return.
 *
 * This function modifies the contents of buf in place and returns
 * a pointer to buf.
 */
char *
strstrip(char *buf, const char *class)
{
    char *p = buf;
    char *q = buf;

    if (buf == NULL)
        return (NULL);

    while (*p) {
        p += strspn(p, class);
        *q++ = *p++;
    }

    *q = '\0';
    return (buf);
}

/*
 * trim_whitespace
 *
 * Trim leading and trailing whitespace chars (as defined by isspace)
 * from a buffer. Example; if the input buffer contained "  text  ",
 * it will contain "text", when we return. We assume that the buffer
 * contains a null terminated string. A pointer to the buffer is
 * returned.
 */
char *
trim_whitespace(char *buf)
{
    char *p = buf;
    char *q = buf;

    if (buf == NULL)
        return (NULL);

    while (*p && isspace(*p))
        ++p;

    while ((*q = *p++) != 0)
        ++q;

    if (q != buf) {
        while ((--q, isspace(*q)) != 0)
            *q = '\0';
    }

    return (buf);
}

/*
 * This is the hash mechanism used to encrypt passwords for commands like
 * SamrSetUserInformation. It uses a 256 byte s-box.
 */
void
rand_hash(
    unsigned char *data,
    size_t datalen,
    unsigned char *key,
    size_t keylen)
{
    unsigned char sbox[DEFAULT_SBOX_SIZE];
    unsigned char tmp;
    unsigned char index_i = 0;
    unsigned char index_j = 0;
    unsigned char j = 0;
    int i;

    for (i = 0; i < DEFAULT_SBOX_SIZE; ++i)
        sbox[i] = (unsigned char)i;

    for (i = 0; i < DEFAULT_SBOX_SIZE; ++i) {
        j += (sbox[i] + key[i % keylen]);

        tmp = sbox[i];
        sbox[i] = sbox[j];
        sbox[j] = tmp;
    }

    for (i = 0; i < datalen; ++i) {
        index_i++;
        index_j += sbox[index_i];

        tmp = sbox[index_i];
        sbox[index_i] = sbox[index_j];
        sbox[index_j] = tmp;

        tmp = sbox[index_i] + sbox[index_j];
        data[i] = data[i] ^ sbox[tmp];
    }
}

/*
 * smb_chk_hostaccess
 *
 * Determines whether the specified host is in the given access list.
 *
 * We match on aliases of the hostname as well as on the canonical name.
 * Names in the access list may be either hosts or netgroups;  they're
 * not distinguished syntactically.  We check for hosts first because
 * it's cheaper (just M*N strcmp()s), then try netgroups.
 *
 * Function returns:
 *  -1 for "all" (list is empty "" or "*")
 *  0 not found  (host is not in the list or list is NULL)
 *  1 found
 *
 */
int
smb_chk_hostaccess(smb_inaddr_t *ipaddr, char *access_list)
{
    char addr[INET_ADDRSTRLEN];
    char buff[256];
    char *cstr = access_list, *gr = access_list;
    char *host;
    int clres;
    int i;
    int nentries = 0;
    int off;
    int response;
    int sbr = 0;
    struct nd_hostservlist *clnames;
    struct in_addr inaddr;
    struct sockaddr_in sa;
    struct sockaddr_in6 sa6;
    struct netbuf buf;
    struct netconfig *config;
    struct netent n, *np;

    if (access_list == NULL)
        return (0);

    /* If access list is empty or "*" - then it's "all" */
    if (*access_list == '\0' || strcmp(access_list, "*") == 0)
        return (-1);

    switch (ipaddr->a_family) {
    case AF_INET:
        inaddr.s_addr = ipaddr->a_ipv4;
        sa.sin_family = AF_INET;
        sa.sin_port = 0;
        sa.sin_addr = inaddr;
        buf.len = buf.maxlen = sizeof (sa);
        buf.buf = (char *)&sa;
        config = getnetconfigent("tcp");
        break;
    case AF_INET6:
        sa6.sin6_family = AF_INET6;
        sa6.sin6_port = 0;
        sa6.sin6_addr = ipaddr->a_ipv6;
        buf.len = buf.maxlen = sizeof (sa6);
        buf.buf = (char *)&sa6;
        config = getnetconfigent("tcp6");
        break;
    default:
        return (1);
    }

    if (config == NULL)
        return (1);

    /* Try to lookup client hostname */
    clres = __netdir_getbyaddr_nosrv(config, &clnames, &buf);
    freenetconfigent(config);

    for (;;) {
        if ((cstr = strpbrk(cstr, "[]:")) != NULL) {
            switch (*cstr) {
            case '[':
            case ']':
                sbr = !sbr;
                cstr++;
                continue;
            case ':':
                if (sbr) {
                    cstr++;
                    continue;
                }
                *cstr = '\0';
            }
        }

        /*
         * If the list name has a '-' prepended then a match of
         * the following name implies failure instead of success.
         */
        if (*gr == '-') {
            response = 0;
            gr++;
        } else {
            response = 1;
        }

        /*
         * First check if we have '@' entry, as it doesn't
         * require client hostname.
         */
        if (*gr == '@') {
            gr++;

            if (!isdigit(*gr) && *gr != '[') {
                /* Netname support */
                if ((np = getnetbyname_r(gr, &n, buff,
                    sizeof (buff))) != NULL &&
                    np->n_net != 0) {
                    while ((np->n_net & 0xFF000000u) == 0)
                        np->n_net <<= 8;
                    np->n_net = htonl(np->n_net);
                    if (inet_ntop(AF_INET, &np->n_net, addr,
                        INET_ADDRSTRLEN) == NULL)
                        break;
                    if (inet_matchaddr(buf.buf, addr) == 1)
                        return (response);
                }
            } else {
                if (inet_matchaddr(buf.buf, gr) == 1)
                    return (response);
            }

            if (cstr == NULL)
                break;

            gr = ++cstr;

            continue;
        }

        /*
         * No other checks can be performed if client address
         * can't be resolved.
         */
        if (clres) {
            if (cstr == NULL)
                break;

            gr = ++cstr;

            continue;
        }

        /* Otherwise loop through all client hostname aliases */
        for (i = 0; i < clnames->h_cnt; i++) {
            host = clnames->h_hostservs[i].h_host;
            /*
             * If the list name begins with a dot then
             * do a domain name suffix comparison.
             * A single dot matches any name with no
             * suffix.
             */
            if (*gr == '.') {
                if (*(gr + 1) == '\0') {
                    if (strchr(host, '.') == NULL)
                        return (response);
                } else {
                    off = strlen(host) - strlen(gr);
                    if (off > 0 &&
                        strcasecmp(host + off, gr) == 0) {
                        return (response);
                    }
                }
            } else {
                /* Just do a hostname match */
                if (strcasecmp(gr, host) == 0)
                    return (response);
                }
            }

        nentries++;

        if (cstr == NULL)
            break;

        gr = ++cstr;
    }

    if (clres)
        return (0);

    return (smb_netgroup_match(clnames, access_list, nentries));
}

/*
 * smb_netgroup_match
 *
 * Check whether any of the hostnames in clnames are
 * members (or non-members) of the netgroups in glist.
 * Since the innetgr lookup is rather expensive, the
 * result is cached. The cached entry is valid only
 * for VALID_TIME seconds.  This works well because
 * typically these lookups occur in clusters when
 * a client is mounting.
 *
 * Note that this routine establishes a host membership
 * in a list of netgroups - we've no idea just which
 * netgroup in the list it is a member of.
 *
 * glist is a character array containing grc strings
 * representing netgroup names (optionally prefixed
 * with '-'). Each string is ended with '\0'  and
 * followed immediately by the next string.
 */
static boolean_t
smb_netgroup_match(struct nd_hostservlist *clnames, char  *glist, int grc)
{
    char **grl;
    char *gr;
    int nhosts = clnames->h_cnt;
    char *host;
    int i, j, n;
    boolean_t response;
    boolean_t belong = B_FALSE;
    static char *domain = NULL;

    if (domain == NULL) {
        int ssize;

        domain = malloc(SYS_NMLN);
        if (domain == NULL)
            return (B_FALSE);

        ssize = sysinfo(SI_SRPC_DOMAIN, domain, SYS_NMLN);
        if (ssize > SYS_NMLN) {
            free(domain);
            domain = malloc(ssize);
            if (domain == NULL)
                return (B_FALSE);
            ssize = sysinfo(SI_SRPC_DOMAIN, domain, ssize);
        }
        /* Check for error in syscall or NULL domain name */
        if (ssize <= 1)
            return (B_FALSE);
    }

    grl = calloc(grc, sizeof (char *));
    if (grl == NULL)
        return (B_FALSE);

    for (i = 0, gr = glist; i < grc && !belong; ) {
        /*
         * If the netgroup name has a '-' prepended
         * then a match of this name implies a failure
         * instead of success.
         */
        response = (*gr != '-') ? B_TRUE : B_FALSE;

        /*
         * Subsequent names with or without a '-' (but no mix)
         * can be grouped together for a single check.
         */
        for (n = 0; i < grc; i++, n++, gr += strlen(gr) + 1) {
            if ((response && *gr == '-') ||
                (!response && *gr != '-'))
                break;

            grl[n] = response ? gr : gr + 1;
        }

        /*
         * Check the netgroup for each
         * of the hosts names (usually just one).
         */
        for (j = 0; j < nhosts && !belong; j++) {
            host = clnames->h_hostservs[j].h_host;
            if (__multi_innetgr(n, grl, 1, &host, 0, NULL,
                1, &domain))
                belong = B_TRUE;
        }
    }

    free(grl);
    return (belong ? response : B_FALSE);
}

/*
 * Resolve the ZFS dataset from a path.
 * Returns,
 *  0  = On success.
 *  -1 = Failure to open /etc/mnttab file or to get ZFS dataset.
 */
int
smb_getdataset(const char *path, char *dataset, size_t len)
{
    char tmppath[MAXPATHLEN];
    char *cp;
    FILE *fp;
    struct mnttab mnttab;
    struct mnttab mntpref;
    int rc = -1;

    if ((fp = fopen(MNTTAB, "r")) == NULL)
        return (-1);

    (void) memset(&mnttab, '\0', sizeof (mnttab));
    (void) strlcpy(tmppath, path, MAXPATHLEN);
    cp = tmppath;

    while (*cp != '\0') {
        resetmnttab(fp);
        (void) memset(&mntpref, '\0', sizeof (mntpref));
        mntpref.mnt_mountp = tmppath;

        if (getmntany(fp, &mnttab, &mntpref) == 0) {
            if (mnttab.mnt_fstype == NULL)
                break;

            if (strcmp(mnttab.mnt_fstype, "zfs") != 0)
                break;
            /*
             * Ensure that there are no leading slashes
             * (required for zfs_open).
             */
            cp = mnttab.mnt_special;
            cp += strspn(cp, "/");
            (void) strlcpy(dataset, cp, len);
            rc = 0;
            break;
        }

        if (strcmp(tmppath, "/") == 0)
            break;

        if ((cp = strrchr(tmppath, '/')) == NULL)
            break;

        /*
         * The path has multiple components.
         * Remove the last component and try again.
         */
        *cp = '\0';
        if (tmppath[0] == '\0')
            (void) strcpy(tmppath, "/");

        cp = tmppath;
    }

    (void) fclose(fp);
    return (rc);
}

/*
 * smb_dlopen
 *
 * Check to see if an interposer library exists.  If it exists
 * and reports a valid version number and key (UUID), return
 * a handle to the library.  Otherwise, return NULL.
 */
void *
smb_dlopen(void)
{
    uuid_t uuid;
    void *interposer_hdl;
    typedef int (*smbex_versionfn_t)(smbex_version_t *);
    smbex_versionfn_t getversion;
    smbex_version_t *version;

    bzero(&uuid, sizeof (uuid_t));
    if (uuid_parse(SMBEX_KEY, uuid) < 0)
        return (NULL);

    interposer_hdl = dlopen(SMB_LIB_ALT, RTLD_NOW | RTLD_LOCAL);
    if (interposer_hdl == NULL)
        return (NULL);

    bzero(&getversion, sizeof (smbex_versionfn_t));
    getversion = (smbex_versionfn_t)dlsym(interposer_hdl,
        "smbex_get_version");
    if ((getversion == NULL) ||
        (version = malloc(sizeof (smbex_version_t))) == NULL) {
        (void) dlclose(interposer_hdl);
        return (NULL);
    }
    bzero(version, sizeof (smbex_version_t));

    if ((getversion(version) != 0) ||
        (version->v_version != SMBEX_VERSION) ||
        (uuid_compare(version->v_uuid, uuid) != 0)) {
        free(version);
        (void) dlclose(interposer_hdl);
        return (NULL);
    }

    free(version);
    return (interposer_hdl);
}

/*
 * smb_dlclose
 *
 * Closes handle to the interposed library.
 */
void
smb_dlclose(void *handle)
{
    if (handle)
        (void) dlclose(handle);
}

/*
 * This function is a wrapper for getnameinfo() to look up a hostname given an
 * IP address. The hostname returned by this function is used for constructing
 * the service principal name field of KRB AP-REQs. Hence, it should be
 * converted to lowercase for RFC 4120 section 6.2.1 conformance.
 */
int
smb_getnameinfo(smb_inaddr_t *ip, char *hostname, int hostlen, int flags)
{
    socklen_t salen;
    struct sockaddr_in6 sin6;
    struct sockaddr_in sin;
    void *sp;
    int rc;

    if (ip->a_family == AF_INET) {
        salen = sizeof (struct sockaddr_in);
        sin.sin_family = ip->a_family;
        sin.sin_port = 0;
        sin.sin_addr.s_addr = ip->a_ipv4;
        sp = &sin;
    } else {
        salen = sizeof (struct sockaddr_in6);
        sin6.sin6_family = ip->a_family;
        sin6.sin6_port = 0;
        (void) memcpy(&sin6.sin6_addr.s6_addr, &ip->a_ipv6,
            sizeof (sin6.sin6_addr.s6_addr));
        sp = &sin6;
    }

    if ((rc = (getnameinfo((struct sockaddr *)sp, salen,
        hostname, hostlen, NULL, 0, flags))) == 0)
        (void) smb_strlwr(hostname);

    return (rc);
}

/*
 * A share name is considered invalid if it contains control
 * characters or any of the following characters (MSDN 236388).
 *
 *  " / \ [ ] : | < > + ; , ? * =
 */
uint32_t
smb_name_validate_share(const char *sharename)
{
    const char *invalid = "\"/\\[]:|<>+;,?*=";
    const char *p;

    if (sharename == NULL)
        return (ERROR_INVALID_PARAMETER);

    if (strpbrk(sharename, invalid) != NULL)
        return (ERROR_INVALID_NAME);

    for (p = sharename; *p != '\0'; p++) {
        if (iscntrl(*p))
            return (ERROR_INVALID_NAME);
    }

    return (ERROR_SUCCESS);
}

/*
 * User and group names are limited to 256 characters, cannot be terminated
 * by '.' and must not contain control characters or any of the following
 * characters.
 *
 *  " / \ [ ] < > + ; , ? * = @
 */
uint32_t
smb_name_validate_account(const char *name)
{
    const char  *invalid = "\"/\\[]<>+;,?*=@";
    const char  *p;
    int     len;

    if ((name == NULL) || (*name == '\0'))
        return (ERROR_INVALID_PARAMETER);

    len = strlen(name);
    if ((len > MAXNAMELEN) || (name[len - 1] == '.'))
        return (ERROR_INVALID_NAME);

    if (strpbrk(name, invalid) != NULL)
        return (ERROR_INVALID_NAME);

    for (p = name; *p != '\0'; p++) {
        if (iscntrl(*p))
            return (ERROR_INVALID_NAME);
    }

    return (ERROR_SUCCESS);
}

/*
 * Check a domain name for RFC 1035 and 1123 compliance.  Domain names may
 * contain alphanumeric characters, hyphens and dots.  The first and last
 * character of a label must be alphanumeric.  Interior characters may be
 * alphanumeric or hypens.
 *
 * Domain names should not contain underscores but we allow them because
 * Windows names are often in non-compliance with this rule.
 */
uint32_t
smb_name_validate_domain(const char *domain)
{
    boolean_t new_label = B_TRUE;
    const char *p;
    char label_terminator;

    if (domain == NULL)
        return (ERROR_INVALID_PARAMETER);

    if (*domain == '\0')
        return (ERROR_INVALID_NAME);

    label_terminator = *domain;

    for (p = domain; *p != '\0'; ++p) {
        if (new_label) {
            if (!isalnum(*p))
                return (ERROR_INVALID_NAME);
            new_label = B_FALSE;
            label_terminator = *p;
            continue;
        }

        if (*p == '.') {
            if (!isalnum(label_terminator))
                return (ERROR_INVALID_NAME);
            new_label = B_TRUE;
            label_terminator = *p;
            continue;
        }

        label_terminator = *p;

        if (isalnum(*p) || *p == '-' || *p == '_')
            continue;

        return (ERROR_INVALID_NAME);
    }

    if (!isalnum(label_terminator))
        return (ERROR_INVALID_NAME);

    return (ERROR_SUCCESS);
}

/*
 * A NetBIOS domain name can contain letters (a-zA-Z), numbers (0-9) and
 * hyphens.
 *
 * It cannot:
 *  - be blank or longer than 15 chracters
 *  - contain all numbers
 *  - be the same as the computer name
 */
uint32_t
smb_name_validate_nbdomain(const char *name)
{
    char        netbiosname[NETBIOS_NAME_SZ];
    const char  *p;
    int     len;

    if (name == NULL)
        return (ERROR_INVALID_PARAMETER);

    len = strlen(name);
    if (len == 0 || len >= NETBIOS_NAME_SZ)
        return (ERROR_INVALID_NAME);

    if (strspn(name, "0123456789") == len)
        return (ERROR_INVALID_NAME);

    if (smb_getnetbiosname(netbiosname, NETBIOS_NAME_SZ) == 0) {
        if (smb_strcasecmp(name, netbiosname, 0) == 0)
            return (ERROR_INVALID_NAME);
    }

    for (p = name; *p != '\0'; ++p) {
        if (isalnum(*p) || *p == '-' || *p == '_')
            continue;

        return (ERROR_INVALID_NAME);
    }

    return (ERROR_SUCCESS);
}

/*
 * A workgroup name can contain 1 to 15 characters but cannot be the same
 * as the NetBIOS name.  The name must begin with a letter or number.
 *
 * The name cannot consist entirely of spaces or dots, which is covered
 * by the requirement that the name must begin with an alphanumeric
 * character.
 *
 * The name must not contain control characters or any of the following
 * characters.
 *
 *  " / \ [ ] : | < > + = ; , ?
 */
uint32_t
smb_name_validate_workgroup(const char *workgroup)
{
    char netbiosname[NETBIOS_NAME_SZ];
    const char *invalid = "\"/\\[]:|<>+=;,?";
    const char *p;

    if (workgroup == NULL)
        return (ERROR_INVALID_PARAMETER);

    if (*workgroup == '\0' || (!isalnum(*workgroup)))
        return (ERROR_INVALID_NAME);

    if (strlen(workgroup) >= NETBIOS_NAME_SZ)
        return (ERROR_INVALID_NAME);

    if (smb_getnetbiosname(netbiosname, NETBIOS_NAME_SZ) == 0) {
        if (smb_strcasecmp(workgroup, netbiosname, 0) == 0)
            return (ERROR_INVALID_NAME);
    }

    if (strpbrk(workgroup, invalid) != NULL)
        return (ERROR_INVALID_NAME);

    for (p = workgroup; *p != '\0'; p++) {
        if (iscntrl(*p))
            return (ERROR_INVALID_NAME);
    }

    return (ERROR_SUCCESS);
}

/*
 * Check for invalid characters in the given path.  The list of invalid
 * characters includes control characters and the following:
 *
 * " / \ [ ] : | < > + ; , ? * =
 *
 * Since this is checking a path not each component, '/' is accepted
 * as separator not an invalid character, except as the first character
 * since this is supposed to be a relative path.
 */
uint32_t
smb_name_validate_rpath(const char *relpath)
{
    char *invalid = "\"\\[]:|<>+;,?*=";
    char *cp;

    if ((relpath == NULL) || (*relpath == '\0') || (*relpath == '/'))
        return (ERROR_INVALID_NAME);

    if (strpbrk(relpath, invalid))
        return (ERROR_INVALID_NAME);

    for (cp = (char *)relpath; *cp != '\0'; cp++) {
        if (iscntrl(*cp))
            return (ERROR_INVALID_NAME);
    }

    return (ERROR_SUCCESS);
}

/*
 * Parse a string to obtain the account and domain names as separate strings.
 *
 * Names containing a backslash ('\') are known as qualified or composite
 * names.  The string preceding the backslash should be the domain name
 * and the string following the slash should be a name within that domain.
 *
 * Names that do not contain a backslash are known as isolated names.
 * An isolated name may be a single label, such as john, or may be in
 * user principal name (UPN) form, such as john@example.com.
 *
 *  domain\name
 *  domain/name
 *  name
 *  name@domain
 *
 * If we encounter any of the forms above in arg, the @, / or \ separator
 * is replaced by \0 and the name and domain pointers are set to point to
 * the appropriate components in arg.  Otherwise, name and domain pointers
 * will be set to NULL.
 */
void
smb_name_parse(char *arg, char **account, char **domain)
{
    char *p;

    *account = NULL;
    *domain = NULL;

    if ((p = strpbrk(arg, "/\\@")) != NULL) {
        if (*p == '@') {
            *p = '\0';
            ++p;
            *domain = p;
            *account = arg;
        } else {
            *p = '\0';
            ++p;
            *account = p;
            *domain = arg;
        }
    }
}

/*
 * The txid is an arbitrary transaction.  A new txid is returned on each call.
 *
 * 0 or -1 are not assigned so that they can be used to detect
 * invalid conditions.
 */
uint32_t
smb_get_txid(void)
{
    static mutex_t  txmutex;
    static uint32_t txid;
    uint32_t    txid_ret;

    (void) mutex_lock(&txmutex);

    if (txid == 0)
        txid = time(NULL);

    do {
        ++txid;
    } while (txid == 0 || txid == (uint32_t)-1);

    txid_ret = txid;
    (void) mutex_unlock(&txmutex);

    return (txid_ret);
}