smbd: Protect ea-reading on symlinks

[Samba.git] / source3 / lib / util_sock.c

/*
   Unix SMB/CIFS implementation.
   Samba utility functions
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Tim Potter      2000-2001
   Copyright (C) Jeremy Allison  1992-2007

   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "system/filesys.h"
#include "../lib/util/memcache.h"
#include "../lib/async_req/async_sock.h"
#include "../lib/util/select.h"
#include "lib/socket/interfaces.h"
#include "../lib/util/tevent_unix.h"
#include "../lib/util/tevent_ntstatus.h"
#include "../lib/tsocket/tsocket.h"
#include "lib/util/sys_rw.h"
#include "lib/util/sys_rw_data.h"
#include "source3/lib/util_tsock.h"

/****************************************************************************
 Determine if a file descriptor is in fact a socket.
****************************************************************************/

bool is_a_socket(int fd)
{
        int v;
        socklen_t l;
        l = sizeof(int);
        return(getsockopt(fd, SOL_SOCKET, SO_TYPE, (char *)&v, &l) == 0);
}

/****************************************************************************
 Read data from a file descriptor with a timeout in msec.
 mincount = if timeout, minimum to read before returning
 maxcount = number to be read.
 time_out = timeout in milliseconds
 NB. This can be called with a non-socket fd, don't change
 sys_read() to sys_recv() or other socket call.
****************************************************************************/

NTSTATUS read_fd_with_timeout(int fd, char *buf,
                                  size_t mincnt, size_t maxcnt,
                                  unsigned int time_out,
                                  size_t *size_ret)
{
        int pollrtn;
        ssize_t readret;
        size_t nread = 0;

        /* just checking .... */
        if (maxcnt <= 0)
                return NT_STATUS_OK;

        /* Blocking read */
        if (time_out == 0) {
                if (mincnt == 0) {
                        mincnt = maxcnt;
                }

                while (nread < mincnt) {
                        readret = sys_read(fd, buf + nread, maxcnt - nread);

                        if (readret == 0) {
                                DEBUG(5,("read_fd_with_timeout: "
                                        "blocking read. EOF from client.\n"));
                                return NT_STATUS_END_OF_FILE;
                        }

                        if (readret == -1) {
                                return map_nt_error_from_unix(errno);
                        }
                        nread += readret;
                }
                goto done;
        }

        /* Most difficult - timeout read */
        /* If this is ever called on a disk file and
           mincnt is greater then the filesize then
           system performance will suffer severely as
           select always returns true on disk files */

        for (nread=0; nread < mincnt; ) {
                int revents;

                pollrtn = poll_intr_one_fd(fd, POLLIN|POLLHUP, time_out,
                                           &revents);

                /* Check if error */
                if (pollrtn == -1) {
                        return map_nt_error_from_unix(errno);
                }

                /* Did we timeout ? */
                if ((pollrtn == 0) ||
                    ((revents & (POLLIN|POLLHUP|POLLERR)) == 0)) {
                        DEBUG(10,("read_fd_with_timeout: timeout read. "
                                "select timed out.\n"));
                        return NT_STATUS_IO_TIMEOUT;
                }

                readret = sys_read(fd, buf+nread, maxcnt-nread);

                if (readret == 0) {
                        /* we got EOF on the file descriptor */
                        DEBUG(5,("read_fd_with_timeout: timeout read. "
                                "EOF from client.\n"));
                        return NT_STATUS_END_OF_FILE;
                }

                if (readret == -1) {
                        return map_nt_error_from_unix(errno);
                }

                nread += readret;
        }

 done:
        /* Return the number we got */
        if (size_ret) {
                *size_ret = nread;
        }
        return NT_STATUS_OK;
}

/****************************************************************************
 Read data from an fd, reading exactly N bytes.
 NB. This can be called with a non-socket fd, don't add dependencies
 on socket calls.
****************************************************************************/

NTSTATUS read_data_ntstatus(int fd, char *buffer, size_t N)
{
        return read_fd_with_timeout(fd, buffer, N, N, 0, NULL);
}

/****************************************************************************
 Read 4 bytes of a smb packet and return the smb length of the packet.
 Store the result in the buffer.
 This version of the function will return a length of zero on receiving
 a keepalive packet.
 Timeout is in milliseconds.
****************************************************************************/

NTSTATUS read_smb_length_return_keepalive(int fd, char *inbuf,
                                          unsigned int timeout,
                                          size_t *len)
{
        int msg_type;
        NTSTATUS status;

        status = read_fd_with_timeout(fd, inbuf, 4, 4, timeout, NULL);

        if (!NT_STATUS_IS_OK(status)) {
                return status;
        }

        *len = smb_len(inbuf);
        msg_type = CVAL(inbuf,0);

        if (msg_type == NBSSkeepalive) {
                DEBUG(5,("Got keepalive packet\n"));
        }

        DEBUG(10,("got smb length of %lu\n",(unsigned long)(*len)));

        return NT_STATUS_OK;
}

/****************************************************************************
 Read an smb from a fd.
 The timeout is in milliseconds.
 This function will return on receipt of a session keepalive packet.
 maxlen is the max number of bytes to return, not including the 4 byte
 length. If zero it means buflen limit.
 Doesn't check the MAC on signed packets.
****************************************************************************/

NTSTATUS receive_smb_raw(int fd, char *buffer, size_t buflen, unsigned int timeout,
                         size_t maxlen, size_t *p_len)
{
        size_t len;
        NTSTATUS status;

        status = read_smb_length_return_keepalive(fd,buffer,timeout,&len);

        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0, ("read_fd_with_timeout failed, read "
                          "error = %s.\n", nt_errstr(status)));
                return status;
        }

        if (len > buflen) {
                DEBUG(0,("Invalid packet length! (%lu bytes).\n",
                                        (unsigned long)len));
                return NT_STATUS_INVALID_PARAMETER;
        }

        if(len > 0) {
                if (maxlen) {
                        len = MIN(len,maxlen);
                }

                status = read_fd_with_timeout(
                        fd, buffer+4, len, len, timeout, &len);

                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("read_fd_with_timeout failed, read error = "
                                  "%s.\n", nt_errstr(status)));
                        return status;
                }

                /* not all of samba3 properly checks for packet-termination
                 * of strings. This ensures that we don't run off into
                 * empty space. */
                SSVAL(buffer+4,len, 0);
        }

        *p_len = len;
        return NT_STATUS_OK;
}

/*
 * Open a socket of the specified type, port, and address for incoming data.
 *
 * Return sock or -errno
 */

int open_socket_in(
        int type,
        const struct sockaddr_storage *paddr,
        uint16_t port,
        bool rebind)
{
        struct samba_sockaddr addr = {
                .sa_socklen = sizeof(struct sockaddr_storage),
                .u.ss = *paddr,
        };
        int ret, sock = -1;
        int val = rebind ? 1 : 0;
        bool ok;

        switch (addr.u.sa.sa_family) {
        case AF_INET6:
                addr.sa_socklen = sizeof(struct sockaddr_in6);
                break;
        case AF_INET:
                addr.sa_socklen = sizeof(struct sockaddr_in);
                break;
        }

        ok = samba_sockaddr_set_port(&addr, port);
        if (!ok) {
                ret = -EINVAL;
                DBG_DEBUG("samba_sockaddr_set_port failed\n");
                goto fail;
        }

        sock = socket(addr.u.ss.ss_family, type, 0 );
        if (sock == -1) {
                ret = -errno;
                DBG_DEBUG("socket() failed: %s\n", strerror(errno));
                goto fail;
        }

        ret = setsockopt(
                sock, SOL_SOCKET, SO_REUSEADDR, (char *)&val, sizeof(val));
        if (ret == -1) {
                ret = -errno;
                DBG_DEBUG("setsockopt(SO_REUSEADDR) failed: %s\n",
                          strerror(errno));
                goto fail;
        }

#ifdef SO_REUSEPORT
        ret = setsockopt(
                sock, SOL_SOCKET, SO_REUSEPORT, (char *)&val, sizeof(val));
        if (ret == -1) {
                ret = -errno;
                DBG_DEBUG("setsockopt(SO_REUSEPORT) failed: %s\n",
                          strerror(errno));
                goto fail;
        }
#endif /* SO_REUSEPORT */

#ifdef HAVE_IPV6
        /*
         * As IPV6_V6ONLY is the default on some systems,
         * we better try to be consistent and always use it.
         *
         * This also avoids using IPv4 via AF_INET6 sockets
         * and makes sure %I never resolves to a '::ffff:192.168.0.1'
         * string.
         */
        if (addr.u.ss.ss_family == AF_INET6) {

                val = 1;

                ret = setsockopt(
                        sock,
                        IPPROTO_IPV6,
                        IPV6_V6ONLY,
                        (const void *)&val,
                        sizeof(val));
                if (ret == -1) {
                        ret = -errno;
                        DBG_DEBUG("setsockopt(IPV6_V6ONLY) failed: %s\n",
                                  strerror(errno));
                        goto fail;
                }
        }
#endif

        /* now we've got a socket - we need to bind it */
        ret = bind(sock, &addr.u.sa, addr.sa_socklen);
        if (ret == -1) {
                char addrstr[INET6_ADDRSTRLEN];

                ret = -errno;

                print_sockaddr(addrstr, sizeof(addrstr), &addr.u.ss);
                DBG_DEBUG("bind for %s port %"PRIu16" failed: %s\n",
                          addrstr,
                          port,
                          strerror(-ret));
                goto fail;
        }

        DBG_DEBUG("bind succeeded on port %"PRIu16"\n", port);

        return sock;

fail:
        if (sock != -1) {
                close(sock);
                sock = -1;
        }
        return ret;
 }

struct open_socket_out_state {
        int fd;
        struct tevent_context *ev;
        struct sockaddr_storage ss;
        socklen_t salen;
        uint16_t port;
        struct tevent_req *connect_subreq;
};

static void open_socket_out_connected(struct tevent_req *subreq);

static void open_socket_out_cleanup(struct tevent_req *req,
                                    enum tevent_req_state req_state)
{
        struct open_socket_out_state *state =
                tevent_req_data(req, struct open_socket_out_state);

        /*
         * Make sure that the async_connect_send subreq has a chance to reset
         * fcntl before the socket goes away.
         */
        TALLOC_FREE(state->connect_subreq);

        if (req_state == TEVENT_REQ_DONE) {
                /*
                 * we keep the socket open for the caller to use
                 */
                return;
        }

        if (state->fd != -1) {
                close(state->fd);
                state->fd = -1;
        }
}

/****************************************************************************
 Create an outgoing socket. timeout is in milliseconds.
**************************************************************************/

struct tevent_req *open_socket_out_send(TALLOC_CTX *mem_ctx,
                                        struct tevent_context *ev,
                                        const struct sockaddr_storage *pss,
                                        uint16_t port,
                                        int timeout)
{
        char addr[INET6_ADDRSTRLEN];
        struct tevent_req *req;
        struct open_socket_out_state *state;
        NTSTATUS status;

        req = tevent_req_create(mem_ctx, &state,
                                struct open_socket_out_state);
        if (req == NULL) {
                return NULL;
        }
        state->ev = ev;
        state->ss = *pss;
        state->port = port;
        state->salen = -1;

        state->fd = socket(state->ss.ss_family, SOCK_STREAM, 0);
        if (state->fd == -1) {
                status = map_nt_error_from_unix(errno);
                tevent_req_nterror(req, status);
                return tevent_req_post(req, ev);
        }

        tevent_req_set_cleanup_fn(req, open_socket_out_cleanup);

        if ((timeout != 0) &&
            !tevent_req_set_endtime(
                    req, ev, timeval_current_ofs_msec(timeout))) {
                tevent_req_oom(req);
                return tevent_req_post(req, ev);
        }

#if defined(HAVE_IPV6)
        if (pss->ss_family == AF_INET6) {
                struct sockaddr_in6 *psa6;
                psa6 = (struct sockaddr_in6 *)&state->ss;
                psa6->sin6_port = htons(port);
                if (psa6->sin6_scope_id == 0
                    && IN6_IS_ADDR_LINKLOCAL(&psa6->sin6_addr)) {
                        setup_linklocal_scope_id(
                                (struct sockaddr *)&(state->ss));
                }
                state->salen = sizeof(struct sockaddr_in6);
        }
#endif
        if (pss->ss_family == AF_INET) {
                struct sockaddr_in *psa;
                psa = (struct sockaddr_in *)&state->ss;
                psa->sin_port = htons(port);
                state->salen = sizeof(struct sockaddr_in);
        }

        if (pss->ss_family == AF_UNIX) {
                state->salen = sizeof(struct sockaddr_un);
        }

        print_sockaddr(addr, sizeof(addr), &state->ss);
        DEBUG(3,("Connecting to %s at port %u\n", addr, (unsigned int)port));

        state->connect_subreq = async_connect_send(
                state, state->ev, state->fd, (struct sockaddr *)&state->ss,
                state->salen, NULL, NULL, NULL);
        if (tevent_req_nomem(state->connect_subreq, NULL)) {
                return tevent_req_post(req, ev);
        }
        tevent_req_set_callback(state->connect_subreq,
                                open_socket_out_connected, req);
        return req;
}

static void open_socket_out_connected(struct tevent_req *subreq)
{
        struct tevent_req *req =
                tevent_req_callback_data(subreq, struct tevent_req);
        struct open_socket_out_state *state =
                tevent_req_data(req, struct open_socket_out_state);
        int ret;
        int sys_errno;

        ret = async_connect_recv(subreq, &sys_errno);
        TALLOC_FREE(subreq);
        state->connect_subreq = NULL;
        if (ret == 0) {
                tevent_req_done(req);
                return;
        }

        tevent_req_nterror(req, map_nt_error_from_unix(sys_errno));
}

NTSTATUS open_socket_out_recv(struct tevent_req *req, int *pfd)
{
        struct open_socket_out_state *state =
                tevent_req_data(req, struct open_socket_out_state);
        NTSTATUS status;

        if (tevent_req_is_nterror(req, &status)) {
                tevent_req_received(req);
                return status;
        }
        *pfd = state->fd;
        state->fd = -1;
        tevent_req_received(req);
        return NT_STATUS_OK;
}

/**
* @brief open a socket
*
* @param pss a struct sockaddr_storage defining the address to connect to
* @param port to connect to
* @param timeout in MILLISECONDS
* @param pfd file descriptor returned
*
* @return NTSTATUS code
*/
NTSTATUS open_socket_out(const struct sockaddr_storage *pss, uint16_t port,
                         int timeout, int *pfd)
{
        TALLOC_CTX *frame = talloc_stackframe();
        struct tevent_context *ev;
        struct tevent_req *req;
        NTSTATUS status = NT_STATUS_NO_MEMORY;

        ev = samba_tevent_context_init(frame);
        if (ev == NULL) {
                goto fail;
        }

        req = open_socket_out_send(frame, ev, pss, port, timeout);
        if (req == NULL) {
                goto fail;
        }
        if (!tevent_req_poll(req, ev)) {
                status = NT_STATUS_INTERNAL_ERROR;
                goto fail;
        }
        status = open_socket_out_recv(req, pfd);
 fail:
        TALLOC_FREE(frame);
        return status;
}

struct open_socket_out_defer_state {
        struct tevent_context *ev;
        struct sockaddr_storage ss;
        uint16_t port;
        int timeout;
        int fd;
};

static void open_socket_out_defer_waited(struct tevent_req *subreq);
static void open_socket_out_defer_connected(struct tevent_req *subreq);

struct tevent_req *open_socket_out_defer_send(TALLOC_CTX *mem_ctx,
                                              struct tevent_context *ev,
                                              struct timeval wait_time,
                                              const struct sockaddr_storage *pss,
                                              uint16_t port,
                                              int timeout)
{
        struct tevent_req *req, *subreq;
        struct open_socket_out_defer_state *state;

        req = tevent_req_create(mem_ctx, &state,
                                struct open_socket_out_defer_state);
        if (req == NULL) {
                return NULL;
        }
        state->ev = ev;
        state->ss = *pss;
        state->port = port;
        state->timeout = timeout;

        subreq = tevent_wakeup_send(
                state, ev,
                timeval_current_ofs(wait_time.tv_sec, wait_time.tv_usec));
        if (subreq == NULL) {
                goto fail;
        }
        tevent_req_set_callback(subreq, open_socket_out_defer_waited, req);
        return req;
 fail:
        TALLOC_FREE(req);
        return NULL;
}

static void open_socket_out_defer_waited(struct tevent_req *subreq)
{
        struct tevent_req *req = tevent_req_callback_data(
                subreq, struct tevent_req);
        struct open_socket_out_defer_state *state = tevent_req_data(
                req, struct open_socket_out_defer_state);
        bool ret;

        ret = tevent_wakeup_recv(subreq);
        TALLOC_FREE(subreq);
        if (!ret) {
                tevent_req_nterror(req, NT_STATUS_INTERNAL_ERROR);
                return;
        }

        subreq = open_socket_out_send(state, state->ev, &state->ss,
                                      state->port, state->timeout);
        if (tevent_req_nomem(subreq, req)) {
                return;
        }
        tevent_req_set_callback(subreq, open_socket_out_defer_connected, req);
}

static void open_socket_out_defer_connected(struct tevent_req *subreq)
{
        struct tevent_req *req = tevent_req_callback_data(
                subreq, struct tevent_req);
        struct open_socket_out_defer_state *state = tevent_req_data(
                req, struct open_socket_out_defer_state);
        NTSTATUS status;

        status = open_socket_out_recv(subreq, &state->fd);
        TALLOC_FREE(subreq);
        if (!NT_STATUS_IS_OK(status)) {
                tevent_req_nterror(req, status);
                return;
        }
        tevent_req_done(req);
}

NTSTATUS open_socket_out_defer_recv(struct tevent_req *req, int *pfd)
{
        struct open_socket_out_defer_state *state = tevent_req_data(
                req, struct open_socket_out_defer_state);
        NTSTATUS status;

        if (tevent_req_is_nterror(req, &status)) {
                return status;
        }
        *pfd = state->fd;
        state->fd = -1;
        return NT_STATUS_OK;
}

/*******************************************************************
 Return the IP addr of the remote end of a socket as a string.
 Optionally return the struct sockaddr_storage.
 ******************************************************************/

static const char *get_peer_addr_internal(int fd,
                                char *addr_buf,
                                size_t addr_buf_len,
                                struct sockaddr *pss,
                                socklen_t *plength)
{
        struct sockaddr_storage ss;
        socklen_t length = sizeof(ss);

        strlcpy(addr_buf,"0.0.0.0",addr_buf_len);

        if (fd == -1) {
                return addr_buf;
        }

        if (pss == NULL) {
                pss = (struct sockaddr *)&ss;
                plength = &length;
        }

        if (getpeername(fd, (struct sockaddr *)pss, plength) < 0) {
                int level = (errno == ENOTCONN) ? 2 : 0;
                DEBUG(level, ("getpeername failed. Error was %s\n",
                               strerror(errno)));
                return addr_buf;
        }

        print_sockaddr_len(addr_buf,
                        addr_buf_len,
                        pss,
                        *plength);
        return addr_buf;
}

/*******************************************************************
 Matchname - determine if host name matches IP address. Used to
 confirm a hostname lookup to prevent spoof attacks.
******************************************************************/

static bool matchname(const char *remotehost,
                const struct sockaddr *pss,
                socklen_t len)
{
        struct addrinfo *res = NULL;
        struct addrinfo *ailist = NULL;
        char addr_buf[INET6_ADDRSTRLEN];
        bool ret = interpret_string_addr_internal(&ailist,
                        remotehost,
                        AI_ADDRCONFIG|AI_CANONNAME);

        if (!ret || ailist == NULL) {
                DEBUG(3,("matchname: getaddrinfo failed for "
                        "name %s [%s]\n",
                        remotehost,
                        gai_strerror(ret) ));
                return false;
        }

        /*
         * Make sure that getaddrinfo() returns the "correct" host name.
         */

        if (ailist->ai_canonname == NULL ||
                (!strequal(remotehost, ailist->ai_canonname) &&
                 !strequal(remotehost, "localhost"))) {
                DEBUG(0,("matchname: host name/name mismatch: %s != %s\n",
                         remotehost,
                         ailist->ai_canonname ?
                                 ailist->ai_canonname : "(NULL)"));
                freeaddrinfo(ailist);
                return false;
        }

        /* Look up the host address in the address list we just got. */
        for (res = ailist; res; res = res->ai_next) {
                if (!res->ai_addr) {
                        continue;
                }
                if (sockaddr_equal((const struct sockaddr *)res->ai_addr,
                                        (const struct sockaddr *)pss)) {
                        freeaddrinfo(ailist);
                        return true;
                }
        }

        /*
         * The host name does not map to the original host address. Perhaps
         * someone has compromised a name server. More likely someone botched
         * it, but that could be dangerous, too.
         */

        DEBUG(0,("matchname: host name/address mismatch: %s != %s\n",
                print_sockaddr_len(addr_buf,
                        sizeof(addr_buf),
                        pss,
                        len),
                 ailist->ai_canonname ? ailist->ai_canonname : "(NULL)"));

        if (ailist) {
                freeaddrinfo(ailist);
        }
        return false;
}

/*******************************************************************
 Deal with the singleton cache.
******************************************************************/

struct name_addr_pair {
        struct sockaddr_storage ss;
        const char *name;
};

/*******************************************************************
 Lookup a name/addr pair. Returns memory allocated from memcache.
******************************************************************/

static bool lookup_nc(struct name_addr_pair *nc)
{
        DATA_BLOB tmp;

        ZERO_STRUCTP(nc);

        if (!memcache_lookup(
                        NULL, SINGLETON_CACHE,
                        data_blob_string_const_null("get_peer_name"),
                        &tmp)) {
                return false;
        }

        memcpy(&nc->ss, tmp.data, sizeof(nc->ss));
        nc->name = (const char *)tmp.data + sizeof(nc->ss);
        return true;
}

/*******************************************************************
 Save a name/addr pair.
******************************************************************/

static void store_nc(const struct name_addr_pair *nc)
{
        DATA_BLOB tmp;
        size_t namelen = strlen(nc->name);

        tmp = data_blob(NULL, sizeof(nc->ss) + namelen + 1);
        if (!tmp.data) {
                return;
        }
        memcpy(tmp.data, &nc->ss, sizeof(nc->ss));
        memcpy(tmp.data+sizeof(nc->ss), nc->name, namelen+1);

        memcache_add(NULL, SINGLETON_CACHE,
                        data_blob_string_const_null("get_peer_name"),
                        tmp);
        data_blob_free(&tmp);
}

/*******************************************************************
 Return the IP addr of the remote end of a socket as a string.
 ******************************************************************/

const char *get_peer_addr(int fd, char *addr, size_t addr_len)
{
        return get_peer_addr_internal(fd, addr, addr_len, NULL, NULL);
}

int get_remote_hostname(const struct tsocket_address *remote_address,
                        char **name,
                        TALLOC_CTX *mem_ctx)
{
        char name_buf[MAX_DNS_NAME_LENGTH];
        char tmp_name[MAX_DNS_NAME_LENGTH];
        struct name_addr_pair nc;
        struct sockaddr_storage ss;
        ssize_t len;
        int rc;

        if (!lp_hostname_lookups()) {
                nc.name = tsocket_address_inet_addr_string(remote_address,
                                                           mem_ctx);
                if (nc.name == NULL) {
                        return -1;
                }

                len = tsocket_address_bsd_sockaddr(remote_address,
                                                   (struct sockaddr *) &nc.ss,
                                                   sizeof(struct sockaddr_storage));
                if (len < 0) {
                        return -1;
                }

                store_nc(&nc);
                lookup_nc(&nc);

                if (nc.name == NULL) {
                        *name = talloc_strdup(mem_ctx, "UNKNOWN");
                } else {
                        *name = talloc_strdup(mem_ctx, nc.name);
                }
                return 0;
        }

        lookup_nc(&nc);

        ZERO_STRUCT(ss);

        len = tsocket_address_bsd_sockaddr(remote_address,
                                           (struct sockaddr *) &ss,
                                           sizeof(struct sockaddr_storage));
        if (len < 0) {
                return -1;
        }

        /* it might be the same as the last one - save some DNS work */
        if (sockaddr_equal((struct sockaddr *)&ss, (struct sockaddr *)&nc.ss)) {
                if (nc.name == NULL) {
                        *name = talloc_strdup(mem_ctx, "UNKNOWN");
                } else {
                        *name = talloc_strdup(mem_ctx, nc.name);
                }
                return 0;
        }

        /* Look up the remote host name. */
        rc = sys_getnameinfo((struct sockaddr *) &ss,
                             len,
                             name_buf,
                             sizeof(name_buf),
                             NULL,
                             0,
                             0);
        if (rc < 0) {
                char *p;

                p = tsocket_address_inet_addr_string(remote_address, mem_ctx);
                if (p == NULL) {
                        return -1;
                }

                DEBUG(1,("getnameinfo failed for %s with error %s\n",
                         p,
                         gai_strerror(rc)));
                strlcpy(name_buf, p, sizeof(name_buf));

                TALLOC_FREE(p);
        } else {
                if (!matchname(name_buf, (struct sockaddr *)&ss, len)) {
                        DEBUG(0,("matchname failed on %s\n", name_buf));
                        strlcpy(name_buf, "UNKNOWN", sizeof(name_buf));
                }
        }

        strlcpy(tmp_name, name_buf, sizeof(tmp_name));
        alpha_strcpy(name_buf, tmp_name, "_-.", sizeof(name_buf));
        if (strstr(name_buf,"..")) {
                strlcpy(name_buf, "UNKNOWN", sizeof(name_buf));
        }

        nc.name = name_buf;
        nc.ss = ss;

        store_nc(&nc);
        lookup_nc(&nc);

        if (nc.name == NULL) {
                *name = talloc_strdup(mem_ctx, "UNKNOWN");
        } else {
                *name = talloc_strdup(mem_ctx, nc.name);
        }

        return 0;
}

/*******************************************************************
 Create protected unix domain socket.

 Some unixes cannot set permissions on a ux-dom-sock, so we
 have to make sure that the directory contains the protection
 permissions instead.
 ******************************************************************/

int create_pipe_sock(const char *socket_dir,
                     const char *socket_name,
                     mode_t dir_perms)
{
#ifdef HAVE_UNIXSOCKET
        struct sockaddr_un sunaddr;
        bool ok;
        int sock = -1;
        mode_t old_umask;
        char *path = NULL;
        size_t path_len;

        old_umask = umask(0);

        ok = directory_create_or_exist_strict(socket_dir,
                                              sec_initial_uid(),
                                              dir_perms);
        if (!ok) {
                goto out_close;
        }

        /* Create the socket file */
        sock = socket(AF_UNIX, SOCK_STREAM, 0);

        if (sock == -1) {
                DEBUG(0, ("create_pipe_sock: socket error %s\n",
                        strerror(errno) ));
                goto out_close;
        }

        if (asprintf(&path, "%s/%s", socket_dir, socket_name) == -1) {
                goto out_close;
        }

        unlink(path);
        memset(&sunaddr, 0, sizeof(sunaddr));
        sunaddr.sun_family = AF_UNIX;

        path_len = strlcpy(sunaddr.sun_path, path, sizeof(sunaddr.sun_path));
        if (path_len > sizeof(sunaddr.sun_path)) {
                DBG_ERR("Refusing to attempt to create pipe socket "
                        "%s.  Path is longer than permitted for a "
                        "unix domain socket.  It would truncate to "
                        "%s\n",
                        path,
                        sunaddr.sun_path);
                goto out_close;
        }

        if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
                DEBUG(0, ("bind failed on pipe socket %s: %s\n", path,
                        strerror(errno)));
                goto out_close;
        }

        SAFE_FREE(path);

        umask(old_umask);
        return sock;

out_close:
        SAFE_FREE(path);
        if (sock != -1)
                close(sock);

        umask(old_umask);
        return -1;

#else
        DEBUG(0, ("create_pipe_sock: No Unix sockets on this system\n"));
        return -1;
#endif /* HAVE_UNIXSOCKET */
}

/****************************************************************************
 Get my own canonical name, including domain.
****************************************************************************/

const char *get_mydnsfullname(void)
{
        struct addrinfo *res = NULL;
        char my_hostname[HOST_NAME_MAX];
        bool ret;
        DATA_BLOB tmp;

        if (memcache_lookup(NULL, SINGLETON_CACHE,
                        data_blob_string_const_null("get_mydnsfullname"),
                        &tmp)) {
                SMB_ASSERT(tmp.length > 0);
                return (const char *)tmp.data;
        }

        /* get my host name */
        if (gethostname(my_hostname, sizeof(my_hostname)) == -1) {
                DEBUG(0,("get_mydnsfullname: gethostname failed\n"));
                return NULL;
        }

        /* Ensure null termination. */
        my_hostname[sizeof(my_hostname)-1] = '\0';

        ret = interpret_string_addr_internal(&res,
                                my_hostname,
                                AI_ADDRCONFIG|AI_CANONNAME);

        if (!ret || res == NULL) {
                DEBUG(3,("get_mydnsfullname: getaddrinfo failed for "
                        "name %s [%s]\n",
                        my_hostname,
                        gai_strerror(ret) ));
                return NULL;
        }

        /*
         * Make sure that getaddrinfo() returns the "correct" host name.
         */

        if (res->ai_canonname == NULL) {
                DEBUG(3,("get_mydnsfullname: failed to get "
                        "canonical name for %s\n",
                        my_hostname));
                freeaddrinfo(res);
                return NULL;
        }

        /* This copies the data, so we must do a lookup
         * afterwards to find the value to return.
         */

        memcache_add(NULL, SINGLETON_CACHE,
                        data_blob_string_const_null("get_mydnsfullname"),
                        data_blob_string_const_null(res->ai_canonname));

        if (!memcache_lookup(NULL, SINGLETON_CACHE,
                        data_blob_string_const_null("get_mydnsfullname"),
                        &tmp)) {
                tmp = data_blob_talloc(talloc_tos(), res->ai_canonname,
                                strlen(res->ai_canonname) + 1);
        }

        freeaddrinfo(res);

        return (const char *)tmp.data;
}

/************************************************************
 Is this my ip address ?
************************************************************/

static bool is_my_ipaddr(const char *ipaddr_str)
{
        struct sockaddr_storage ss;
        struct iface_struct *nics;
        int i, n;

        if (!interpret_string_addr(&ss, ipaddr_str, AI_NUMERICHOST)) {
                return false;
        }

        if (is_zero_addr(&ss)) {
                return false;
        }

        if (ismyaddr((struct sockaddr *)&ss) ||
                        is_loopback_addr((struct sockaddr *)&ss)) {
                return true;
        }

        n = get_interfaces(talloc_tos(), &nics);
        for (i=0; i<n; i++) {
                if (sockaddr_equal((struct sockaddr *)&nics[i].ip, (struct sockaddr *)&ss)) {
                        TALLOC_FREE(nics);
                        return true;
                }
        }
        TALLOC_FREE(nics);
        return false;
}

/************************************************************
 Is this my name ?
************************************************************/

bool is_myname_or_ipaddr(const char *s)
{
        TALLOC_CTX *ctx = talloc_tos();
        char *name = NULL;
        const char *dnsname;
        char *servername = NULL;

        if (!s) {
                return false;
        }

        /* Sanitize the string from '\\name' */
        name = talloc_strdup(ctx, s);
        if (!name) {
                return false;
        }

        servername = strrchr_m(name, '\\' );
        if (!servername) {
                servername = name;
        } else {
                servername++;
        }

        /* Optimize for the common case */
        if (strequal(servername, lp_netbios_name())) {
                return true;
        }

        /* Check for an alias */
        if (is_myname(servername)) {
                return true;
        }

        /* Check for loopback */
        if (strequal(servername, "127.0.0.1") ||
                        strequal(servername, "::1")) {
                return true;
        }

        if (strequal(servername, "localhost")) {
                return true;
        }

        /* Maybe it's my dns name */
        dnsname = get_mydnsfullname();
        if (dnsname && strequal(servername, dnsname)) {
                return true;
        }

        /* Maybe its an IP address? */
        if (is_ipaddress(servername)) {
                return is_my_ipaddr(servername);
        }

        /* Handle possible CNAME records - convert to an IP addr. list. */
        {
                /* Use DNS to resolve the name, check all addresses. */
                struct addrinfo *p = NULL;
                struct addrinfo *res = NULL;

                if (!interpret_string_addr_internal(&res,
                                servername,
                                AI_ADDRCONFIG)) {
                        return false;
                }

                for (p = res; p; p = p->ai_next) {
                        char addr[INET6_ADDRSTRLEN];
                        struct sockaddr_storage ss;

                        ZERO_STRUCT(ss);
                        memcpy(&ss, p->ai_addr, p->ai_addrlen);
                        print_sockaddr(addr,
                                        sizeof(addr),
                                        &ss);
                        if (is_my_ipaddr(addr)) {
                                freeaddrinfo(res);
                                return true;
                        }
                }
                freeaddrinfo(res);
        }

        /* No match */
        return false;
}

int poll_one_fd(int fd, int events, int timeout, int *revents)
{
        struct pollfd pfd;
        int ret;

        pfd.fd = fd;
        pfd.events = events;

        ret = poll(&pfd, 1, timeout);

        /*
         * Assign whatever poll did, even in the ret<=0 case.
         */
        *revents = pfd.revents;

        return ret;
}

int poll_intr_one_fd(int fd, int events, int timeout, int *revents)
{
        struct pollfd pfd;
        int ret;

        pfd.fd = fd;
        pfd.events = events;

        ret = sys_poll_intr(&pfd, 1, timeout);
        if (ret <= 0) {
                *revents = 0;
                return ret;
        }
        *revents = pfd.revents;
        return 1;
}