ctrl_iface_unix.c

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/*
 * WPA Supplicant / UNIX domain socket -based control interface
 * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <sys/un.h>
#include <sys/stat.h>
#include <grp.h>
#include <stddef.h>

#include "utils/common.h"
#include "utils/eloop.h"
#include "utils/list.h"
#include "eapol_supp/eapol_supp_sm.h"
#include "config.h"
#include "wpa_supplicant_i.h"
#include "ctrl_iface.h"

/* Per-interface ctrl_iface */

struct wpa_ctrl_dst {
        struct dl_list list;
        struct sockaddr_un addr;
        socklen_t addrlen;
        int debug_level;
        int errors;
};


struct ctrl_iface_priv {
        struct wpa_supplicant *wpa_s;
        int sock;
        struct dl_list ctrl_dst;
};


static void wpa_supplicant_ctrl_iface_send(struct ctrl_iface_priv *priv,
                                           int level, const char *buf,
                                           size_t len);


static int wpa_supplicant_ctrl_iface_attach(struct ctrl_iface_priv *priv,
                                            struct sockaddr_un *from,
                                            socklen_t fromlen)
{
        struct wpa_ctrl_dst *dst;

        dst = os_zalloc(sizeof(*dst));
        if (dst == NULL)
                return -1;
        os_memcpy(&dst->addr, from, sizeof(struct sockaddr_un));
        dst->addrlen = fromlen;
        dst->debug_level = MSG_INFO;
        dl_list_add(&priv->ctrl_dst, &dst->list);
        wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor attached",
                    (u8 *) from->sun_path,
                    fromlen - offsetof(struct sockaddr_un, sun_path));
        return 0;
}


static int wpa_supplicant_ctrl_iface_detach(struct ctrl_iface_priv *priv,
                                            struct sockaddr_un *from,
                                            socklen_t fromlen)
{
        struct wpa_ctrl_dst *dst;

        dl_list_for_each(dst, &priv->ctrl_dst, struct wpa_ctrl_dst, list) {
                if (fromlen == dst->addrlen &&
                    os_memcmp(from->sun_path, dst->addr.sun_path,
                              fromlen - offsetof(struct sockaddr_un, sun_path))
                    == 0) {
                        dl_list_del(&dst->list);
                        os_free(dst);
                        wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor detached",
                                    (u8 *) from->sun_path,
                                    fromlen -
                                    offsetof(struct sockaddr_un, sun_path));
                        return 0;
                }
        }
        return -1;
}


static int wpa_supplicant_ctrl_iface_level(struct ctrl_iface_priv *priv,
                                           struct sockaddr_un *from,
                                           socklen_t fromlen,
                                           char *level)
{
        struct wpa_ctrl_dst *dst;

        wpa_printf(MSG_DEBUG, "CTRL_IFACE LEVEL %s", level);

        dl_list_for_each(dst, &priv->ctrl_dst, struct wpa_ctrl_dst, list) {
                if (fromlen == dst->addrlen &&
                    os_memcmp(from->sun_path, dst->addr.sun_path,
                              fromlen - offsetof(struct sockaddr_un, sun_path))
                    == 0) {
                        wpa_hexdump(MSG_DEBUG, "CTRL_IFACE changed monitor "
                                    "level", (u8 *) from->sun_path,
                                    fromlen -
                                    offsetof(struct sockaddr_un, sun_path));
                        dst->debug_level = atoi(level);
                        return 0;
                }
        }

        return -1;
}


static void wpa_supplicant_ctrl_iface_receive(int sock, void *eloop_ctx,
                                              void *sock_ctx)
{
        struct wpa_supplicant *wpa_s = eloop_ctx;
        struct ctrl_iface_priv *priv = sock_ctx;
        char buf[256];
        int res;
        struct sockaddr_un from;
        socklen_t fromlen = sizeof(from);
        char *reply = NULL;
        size_t reply_len = 0;
        int new_attached = 0;

        res = recvfrom(sock, buf, sizeof(buf) - 1, 0,
                       (struct sockaddr *) &from, &fromlen);
        if (res < 0) {
                perror("recvfrom(ctrl_iface)");
                return;
        }
        buf[res] = '\0';

        if (os_strcmp(buf, "ATTACH") == 0) {
                if (wpa_supplicant_ctrl_iface_attach(priv, &from, fromlen))
                        reply_len = 1;
                else {
                        new_attached = 1;
                        reply_len = 2;
                }
        } else if (os_strcmp(buf, "DETACH") == 0) {
                if (wpa_supplicant_ctrl_iface_detach(priv, &from, fromlen))
                        reply_len = 1;
                else
                        reply_len = 2;
        } else if (os_strncmp(buf, "LEVEL ", 6) == 0) {
                if (wpa_supplicant_ctrl_iface_level(priv, &from, fromlen,
                                                    buf + 6))
                        reply_len = 1;
                else
                        reply_len = 2;
        } else {
                reply = wpa_supplicant_ctrl_iface_process(wpa_s, buf,
                                                          &reply_len);
        }

        if (reply) {
                sendto(sock, reply, reply_len, 0, (struct sockaddr *) &from,
                       fromlen);
                os_free(reply);
        } else if (reply_len == 1) {
                sendto(sock, "FAIL\n", 5, 0, (struct sockaddr *) &from,
                       fromlen);
        } else if (reply_len == 2) {
                sendto(sock, "OK\n", 3, 0, (struct sockaddr *) &from,
                       fromlen);
        }

        if (new_attached)
                eapol_sm_notify_ctrl_attached(wpa_s->eapol);
}


static char * wpa_supplicant_ctrl_iface_path(struct wpa_supplicant *wpa_s)
{
        char *buf;
        size_t len;
        char *pbuf, *dir = NULL, *gid_str = NULL;
        int res;

        if (wpa_s->conf->ctrl_interface == NULL)
                return NULL;

        pbuf = os_strdup(wpa_s->conf->ctrl_interface);
        if (pbuf == NULL)
                return NULL;
        if (os_strncmp(pbuf, "DIR=", 4) == 0) {
                dir = pbuf + 4;
                gid_str = os_strstr(dir, " GROUP=");
                if (gid_str) {
                        *gid_str = '\0';
                        gid_str += 7;
                }
        } else
                dir = pbuf;

        len = os_strlen(dir) + os_strlen(wpa_s->ifname) + 2;
        buf = os_malloc(len);
        if (buf == NULL) {
                os_free(pbuf);
                return NULL;
        }

        res = os_snprintf(buf, len, "%s/%s", dir, wpa_s->ifname);
        if (res < 0 || (size_t) res >= len) {
                os_free(pbuf);
                os_free(buf);
                return NULL;
        }
#ifdef __CYGWIN__
        {
                /* Windows/WinPcap uses interface names that are not suitable
                 * as a file name - convert invalid chars to underscores */
                char *pos = buf;
                while (*pos) {
                        if (*pos == '\\')
                                *pos = '_';
                        pos++;
                }
        }
#endif /* __CYGWIN__ */
        os_free(pbuf);
        return buf;
}


static void wpa_supplicant_ctrl_iface_msg_cb(void *ctx, int level,
                                             const char *txt, size_t len)
{
        struct wpa_supplicant *wpa_s = ctx;
        if (wpa_s == NULL || wpa_s->ctrl_iface == NULL)
                return;
        wpa_supplicant_ctrl_iface_send(wpa_s->ctrl_iface, level, txt, len);
}


struct ctrl_iface_priv *
wpa_supplicant_ctrl_iface_init(struct wpa_supplicant *wpa_s)
{
        struct ctrl_iface_priv *priv;
        struct sockaddr_un addr;
        char *fname = NULL;
        gid_t gid = 0;
        int gid_set = 0;
        char *buf, *dir = NULL, *gid_str = NULL;
        struct group *grp;
        char *endp;

        priv = os_zalloc(sizeof(*priv));
        if (priv == NULL)
                return NULL;
        dl_list_init(&priv->ctrl_dst);
        priv->wpa_s = wpa_s;
        priv->sock = -1;

        if (wpa_s->conf->ctrl_interface == NULL)
                return priv;

        buf = os_strdup(wpa_s->conf->ctrl_interface);
        if (buf == NULL)
                goto fail;
        if (os_strncmp(buf, "DIR=", 4) == 0) {
                dir = buf + 4;
                gid_str = os_strstr(dir, " GROUP=");
                if (gid_str) {
                        *gid_str = '\0';
                        gid_str += 7;
                }
        } else {
                dir = buf;
                gid_str = wpa_s->conf->ctrl_interface_group;
        }

        if (mkdir(dir, S_IRWXU | S_IRWXG) < 0) {
                if (errno == EEXIST) {
                        wpa_printf(MSG_DEBUG, "Using existing control "
                                   "interface directory.");
                } else {
                        perror("mkdir[ctrl_interface]");
                        goto fail;
                }
        }

        if (gid_str) {
                grp = getgrnam(gid_str);
                if (grp) {
                        gid = grp->gr_gid;
                        gid_set = 1;
                        wpa_printf(MSG_DEBUG, "ctrl_interface_group=%d"
                                   " (from group name '%s')",
                                   (int) gid, gid_str);
                } else {
                        /* Group name not found - try to parse this as gid */
                        gid = strtol(gid_str, &endp, 10);
                        if (*gid_str == '\0' || *endp != '\0') {
                                wpa_printf(MSG_ERROR, "CTRL: Invalid group "
                                           "'%s'", gid_str);
                                goto fail;
                        }
                        gid_set = 1;
                        wpa_printf(MSG_DEBUG, "ctrl_interface_group=%d",
                                   (int) gid);
                }
        }

        if (gid_set && chown(dir, -1, gid) < 0) {
                perror("chown[ctrl_interface]");
                goto fail;
        }

        /* Make sure the group can enter and read the directory */
        if (gid_set &&
            chmod(dir, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP) < 0) {
                wpa_printf(MSG_ERROR, "CTRL: chmod[ctrl_interface]: %s",
                           strerror(errno));
                goto fail;
        }

        if (os_strlen(dir) + 1 + os_strlen(wpa_s->ifname) >=
            sizeof(addr.sun_path)) {
                wpa_printf(MSG_ERROR, "ctrl_iface path limit exceeded");
                goto fail;
        }

        priv->sock = socket(PF_UNIX, SOCK_DGRAM, 0);
        if (priv->sock < 0) {
                perror("socket(PF_UNIX)");
                goto fail;
        }

        os_memset(&addr, 0, sizeof(addr));
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
        addr.sun_len = sizeof(addr);
#endif /* __FreeBSD__ */
        addr.sun_family = AF_UNIX;
        fname = wpa_supplicant_ctrl_iface_path(wpa_s);
        if (fname == NULL)
                goto fail;
        os_strlcpy(addr.sun_path, fname, sizeof(addr.sun_path));
        if (bind(priv->sock, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
                wpa_printf(MSG_DEBUG, "ctrl_iface bind(PF_UNIX) failed: %s",
                           strerror(errno));
                if (connect(priv->sock, (struct sockaddr *) &addr,
                            sizeof(addr)) < 0) {
                        wpa_printf(MSG_DEBUG, "ctrl_iface exists, but does not"
                                   " allow connections - assuming it was left"
                                   "over from forced program termination");
                        if (unlink(fname) < 0) {
                                perror("unlink[ctrl_iface]");
                                wpa_printf(MSG_ERROR, "Could not unlink "
                                           "existing ctrl_iface socket '%s'",
                                           fname);
                                goto fail;
                        }
                        if (bind(priv->sock, (struct sockaddr *) &addr,
                                 sizeof(addr)) < 0) {
                                perror("bind(PF_UNIX)");
                                goto fail;
                        }
                        wpa_printf(MSG_DEBUG, "Successfully replaced leftover "
                                   "ctrl_iface socket '%s'", fname);
                } else {
                        wpa_printf(MSG_INFO, "ctrl_iface exists and seems to "
                                   "be in use - cannot override it");
                        wpa_printf(MSG_INFO, "Delete '%s' manually if it is "
                                   "not used anymore", fname);
                        os_free(fname);
                        fname = NULL;
                        goto fail;
                }
        }

        if (gid_set && chown(fname, -1, gid) < 0) {
                perror("chown[ctrl_interface/ifname]");
                goto fail;
        }

        if (chmod(fname, S_IRWXU | S_IRWXG) < 0) {
                perror("chmod[ctrl_interface/ifname]");
                goto fail;
        }
        os_free(fname);

        eloop_register_read_sock(priv->sock, wpa_supplicant_ctrl_iface_receive,
                                 wpa_s, priv);
        wpa_msg_register_cb(wpa_supplicant_ctrl_iface_msg_cb);

        os_free(buf);
        return priv;

fail:
        if (priv->sock >= 0)
                close(priv->sock);
        os_free(priv);
        if (fname) {
                unlink(fname);
                os_free(fname);
        }
        os_free(buf);
        return NULL;
}


void wpa_supplicant_ctrl_iface_deinit(struct ctrl_iface_priv *priv)
{
        struct wpa_ctrl_dst *dst, *prev;

        if (priv->sock > -1) {
                char *fname;
                char *buf, *dir = NULL, *gid_str = NULL;
                eloop_unregister_read_sock(priv->sock);
                if (!dl_list_empty(&priv->ctrl_dst)) {
                        /*
                         * Wait a second before closing the control socket if
                         * there are any attached monitors in order to allow
                         * them to receive any pending messages.
                         */
                        wpa_printf(MSG_DEBUG, "CTRL_IFACE wait for attached "
                                   "monitors to receive messages");
                        os_sleep(1, 0);
                }
                close(priv->sock);
                priv->sock = -1;
                fname = wpa_supplicant_ctrl_iface_path(priv->wpa_s);
                if (fname) {
                        unlink(fname);
                        os_free(fname);
                }

                buf = os_strdup(priv->wpa_s->conf->ctrl_interface);
                if (buf == NULL)
                        goto free_dst;
                if (os_strncmp(buf, "DIR=", 4) == 0) {
                        dir = buf + 4;
                        gid_str = os_strstr(dir, " GROUP=");
                        if (gid_str) {
                                *gid_str = '\0';
                                gid_str += 7;
                        }
                } else
                        dir = buf;

                if (rmdir(dir) < 0) {
                        if (errno == ENOTEMPTY) {
                                wpa_printf(MSG_DEBUG, "Control interface "
                                           "directory not empty - leaving it "
                                           "behind");
                        } else {
                                perror("rmdir[ctrl_interface]");
                        }
                }
                os_free(buf);
        }

free_dst:
        dl_list_for_each_safe(dst, prev, &priv->ctrl_dst, struct wpa_ctrl_dst,
                              list)
                os_free(dst);
        os_free(priv);
}


static void wpa_supplicant_ctrl_iface_send(struct ctrl_iface_priv *priv,
                                           int level, const char *buf,
                                           size_t len)
{
        struct wpa_ctrl_dst *dst, *next;
        char levelstr[10];
        int idx, res;
        struct msghdr msg;
        struct iovec io[2];

        if (priv->sock < 0 || dl_list_empty(&priv->ctrl_dst))
                return;

        res = os_snprintf(levelstr, sizeof(levelstr), "<%d>", level);
        if (res < 0 || (size_t) res >= sizeof(levelstr))
                return;
        io[0].iov_base = levelstr;
        io[0].iov_len = os_strlen(levelstr);
        io[1].iov_base = (char *) buf;
        io[1].iov_len = len;
        os_memset(&msg, 0, sizeof(msg));
        msg.msg_iov = io;
        msg.msg_iovlen = 2;

        idx = 0;
        dl_list_for_each_safe(dst, next, &priv->ctrl_dst, struct wpa_ctrl_dst,
                              list) {
                if (level >= dst->debug_level) {
                        wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor send",
                                    (u8 *) dst->addr.sun_path, dst->addrlen -
                                    offsetof(struct sockaddr_un, sun_path));
                        msg.msg_name = (void *) &dst->addr;
                        msg.msg_namelen = dst->addrlen;
                        if (sendmsg(priv->sock, &msg, 0) < 0) {
                                int _errno = errno;
                                wpa_printf(MSG_INFO, "CTRL_IFACE monitor[%d]: "
                                           "%d - %s",
                                           idx, errno, strerror(errno));
                                dst->errors++;
                                if (dst->errors > 1000 ||
                                    (_errno != ENOBUFS && dst->errors > 10) ||
                                    _errno == ENOENT) {
                                        wpa_supplicant_ctrl_iface_detach(
                                                priv, &dst->addr,
                                                dst->addrlen);
                                }
                        } else
                                dst->errors = 0;
                }
                idx++;
        }
}


void wpa_supplicant_ctrl_iface_wait(struct ctrl_iface_priv *priv)
{
        char buf[256];
        int res;
        struct sockaddr_un from;
        socklen_t fromlen = sizeof(from);

        for (;;) {
                wpa_printf(MSG_DEBUG, "CTRL_IFACE - %s - wait for monitor to "
                           "attach", priv->wpa_s->ifname);
                eloop_wait_for_read_sock(priv->sock);

                res = recvfrom(priv->sock, buf, sizeof(buf) - 1, 0,
                               (struct sockaddr *) &from, &fromlen);
                if (res < 0) {
                        perror("recvfrom(ctrl_iface)");
                        continue;
                }
                buf[res] = '\0';

                if (os_strcmp(buf, "ATTACH") == 0) {
                        /* handle ATTACH signal of first monitor interface */
                        if (!wpa_supplicant_ctrl_iface_attach(priv, &from,
                                                              fromlen)) {
                                sendto(priv->sock, "OK\n", 3, 0,
                                       (struct sockaddr *) &from, fromlen);
                                /* OK to continue */
                                return;
                        } else {
                                sendto(priv->sock, "FAIL\n", 5, 0,
                                       (struct sockaddr *) &from, fromlen);
                        }
                } else {
                        /* return FAIL for all other signals */
                        sendto(priv->sock, "FAIL\n", 5, 0,
                               (struct sockaddr *) &from, fromlen);
                }
        }
}


/* Global ctrl_iface */

struct ctrl_iface_global_priv {
        struct wpa_global *global;
        int sock;
};


static void wpa_supplicant_global_ctrl_iface_receive(int sock, void *eloop_ctx,
                                                     void *sock_ctx)
{
        struct wpa_global *global = eloop_ctx;
        char buf[256];
        int res;
        struct sockaddr_un from;
        socklen_t fromlen = sizeof(from);
        char *reply;
        size_t reply_len;

        res = recvfrom(sock, buf, sizeof(buf) - 1, 0,
                       (struct sockaddr *) &from, &fromlen);
        if (res < 0) {
                perror("recvfrom(ctrl_iface)");
                return;
        }
        buf[res] = '\0';

        reply = wpa_supplicant_global_ctrl_iface_process(global, buf,
                                                         &reply_len);

        if (reply) {
                sendto(sock, reply, reply_len, 0, (struct sockaddr *) &from,
                       fromlen);
                os_free(reply);
        } else if (reply_len) {
                sendto(sock, "FAIL\n", 5, 0, (struct sockaddr *) &from,
                       fromlen);
        }
}


struct ctrl_iface_global_priv *
wpa_supplicant_global_ctrl_iface_init(struct wpa_global *global)
{
        struct ctrl_iface_global_priv *priv;
        struct sockaddr_un addr;

        priv = os_zalloc(sizeof(*priv));
        if (priv == NULL)
                return NULL;
        priv->global = global;
        priv->sock = -1;

        if (global->params.ctrl_interface == NULL)
                return priv;

        wpa_printf(MSG_DEBUG, "Global control interface '%s'",
                   global->params.ctrl_interface);

        priv->sock = socket(PF_UNIX, SOCK_DGRAM, 0);
        if (priv->sock < 0) {
                perror("socket(PF_UNIX)");
                goto fail;
        }

        os_memset(&addr, 0, sizeof(addr));
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
        addr.sun_len = sizeof(addr);
#endif /* __FreeBSD__ */
        addr.sun_family = AF_UNIX;
        os_strlcpy(addr.sun_path, global->params.ctrl_interface,
                   sizeof(addr.sun_path));
        if (bind(priv->sock, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
                perror("bind(PF_UNIX)");
                if (connect(priv->sock, (struct sockaddr *) &addr,
                            sizeof(addr)) < 0) {
                        wpa_printf(MSG_DEBUG, "ctrl_iface exists, but does not"
                                   " allow connections - assuming it was left"
                                   "over from forced program termination");
                        if (unlink(global->params.ctrl_interface) < 0) {
                                perror("unlink[ctrl_iface]");
                                wpa_printf(MSG_ERROR, "Could not unlink "
                                           "existing ctrl_iface socket '%s'",
                                           global->params.ctrl_interface);
                                goto fail;
                        }
                        if (bind(priv->sock, (struct sockaddr *) &addr,
                                 sizeof(addr)) < 0) {
                                perror("bind(PF_UNIX)");
                                goto fail;
                        }
                        wpa_printf(MSG_DEBUG, "Successfully replaced leftover "
                                   "ctrl_iface socket '%s'",
                                   global->params.ctrl_interface);
                } else {
                        wpa_printf(MSG_INFO, "ctrl_iface exists and seems to "
                                   "be in use - cannot override it");
                        wpa_printf(MSG_INFO, "Delete '%s' manually if it is "
                                   "not used anymore",
                                   global->params.ctrl_interface);
                        goto fail;
                }
        }

        eloop_register_read_sock(priv->sock,
                                 wpa_supplicant_global_ctrl_iface_receive,
                                 global, NULL);

        return priv;

fail:
        if (priv->sock >= 0)
                close(priv->sock);
        os_free(priv);
        return NULL;
}


void
wpa_supplicant_global_ctrl_iface_deinit(struct ctrl_iface_global_priv *priv)
{
        if (priv->sock >= 0) {
                eloop_unregister_read_sock(priv->sock);
                close(priv->sock);
        }
        if (priv->global->params.ctrl_interface)
                unlink(priv->global->params.ctrl_interface);
        os_free(priv);
}