300 lines
7.8 KiB
C
300 lines
7.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2010 The FreeBSD Foundation
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* Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>
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* All rights reserved.
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*
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* This software was developed by Pawel Jakub Dawidek under sponsorship from
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* the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/disk.h>
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#include <sys/ioctl.h>
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#include <sys/jail.h>
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#include <sys/stat.h>
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#ifdef HAVE_CAPSICUM
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#include <sys/capsicum.h>
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#include <geom/gate/g_gate.h>
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#endif
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#include <errno.h>
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#include <fcntl.h>
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#include <pwd.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <pjdlog.h>
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#include "hast.h"
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#include "subr.h"
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int
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vsnprlcat(char *str, size_t size, const char *fmt, va_list ap)
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{
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size_t len;
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len = strlen(str);
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return (vsnprintf(str + len, size - len, fmt, ap));
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}
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int
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snprlcat(char *str, size_t size, const char *fmt, ...)
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{
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va_list ap;
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int result;
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va_start(ap, fmt);
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result = vsnprlcat(str, size, fmt, ap);
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va_end(ap);
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return (result);
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}
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int
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provinfo(struct hast_resource *res, bool dowrite)
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{
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struct stat sb;
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PJDLOG_ASSERT(res->hr_localpath != NULL &&
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res->hr_localpath[0] != '\0');
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if (res->hr_localfd == -1) {
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res->hr_localfd = open(res->hr_localpath,
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dowrite ? O_RDWR : O_RDONLY);
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if (res->hr_localfd == -1) {
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pjdlog_errno(LOG_ERR, "Unable to open %s",
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res->hr_localpath);
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return (-1);
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}
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}
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if (fstat(res->hr_localfd, &sb) == -1) {
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pjdlog_errno(LOG_ERR, "Unable to stat %s", res->hr_localpath);
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return (-1);
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}
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if (S_ISCHR(sb.st_mode)) {
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/*
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* If this is character device, it is most likely GEOM provider.
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*/
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if (ioctl(res->hr_localfd, DIOCGMEDIASIZE,
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&res->hr_local_mediasize) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable obtain provider %s mediasize",
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res->hr_localpath);
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return (-1);
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}
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if (ioctl(res->hr_localfd, DIOCGSECTORSIZE,
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&res->hr_local_sectorsize) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable obtain provider %s sectorsize",
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res->hr_localpath);
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return (-1);
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}
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} else if (S_ISREG(sb.st_mode)) {
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/*
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* We also support regular files for which we hardcode
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* sector size of 512 bytes.
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*/
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res->hr_local_mediasize = sb.st_size;
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res->hr_local_sectorsize = 512;
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} else {
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/*
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* We support no other file types.
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*/
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pjdlog_error("%s is neither GEOM provider nor regular file.",
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res->hr_localpath);
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errno = EFTYPE;
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return (-1);
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}
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return (0);
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}
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const char *
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role2str(int role)
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{
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switch (role) {
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case HAST_ROLE_INIT:
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return ("init");
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case HAST_ROLE_PRIMARY:
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return ("primary");
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case HAST_ROLE_SECONDARY:
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return ("secondary");
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}
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return ("unknown");
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}
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int
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drop_privs(const struct hast_resource *res)
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{
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char jailhost[sizeof(res->hr_name) * 2];
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struct jail jailst;
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struct passwd *pw;
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uid_t ruid, euid, suid;
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gid_t rgid, egid, sgid;
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gid_t gidset[1];
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bool capsicum, jailed;
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/*
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* According to getpwnam(3) we have to clear errno before calling the
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* function to be able to distinguish between an error and missing
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* entry (with is not treated as error by getpwnam(3)).
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*/
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errno = 0;
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pw = getpwnam(HAST_USER);
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if (pw == NULL) {
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if (errno != 0) {
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pjdlog_errno(LOG_ERR,
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"Unable to find info about '%s' user", HAST_USER);
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return (-1);
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} else {
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pjdlog_error("'%s' user doesn't exist.", HAST_USER);
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errno = ENOENT;
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return (-1);
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}
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}
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bzero(&jailst, sizeof(jailst));
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jailst.version = JAIL_API_VERSION;
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jailst.path = pw->pw_dir;
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if (res == NULL) {
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(void)snprintf(jailhost, sizeof(jailhost), "hastctl");
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} else {
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(void)snprintf(jailhost, sizeof(jailhost), "hastd: %s (%s)",
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res->hr_name, role2str(res->hr_role));
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}
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jailst.hostname = jailhost;
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jailst.jailname = NULL;
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jailst.ip4s = 0;
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jailst.ip4 = NULL;
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jailst.ip6s = 0;
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jailst.ip6 = NULL;
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if (jail(&jailst) >= 0) {
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jailed = true;
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} else {
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jailed = false;
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pjdlog_errno(LOG_WARNING,
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"Unable to jail to directory to %s", pw->pw_dir);
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if (chroot(pw->pw_dir) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable to change root directory to %s",
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pw->pw_dir);
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return (-1);
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}
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}
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PJDLOG_VERIFY(chdir("/") == 0);
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gidset[0] = pw->pw_gid;
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if (setgroups(1, gidset) == -1) {
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pjdlog_errno(LOG_ERR, "Unable to set groups to gid %u",
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(unsigned int)pw->pw_gid);
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return (-1);
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}
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if (setgid(pw->pw_gid) == -1) {
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pjdlog_errno(LOG_ERR, "Unable to set gid to %u",
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(unsigned int)pw->pw_gid);
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return (-1);
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}
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if (setuid(pw->pw_uid) == -1) {
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pjdlog_errno(LOG_ERR, "Unable to set uid to %u",
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(unsigned int)pw->pw_uid);
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return (-1);
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}
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#ifdef HAVE_CAPSICUM
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capsicum = (cap_enter() == 0);
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if (!capsicum) {
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pjdlog_common(LOG_DEBUG, 1, errno,
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"Unable to sandbox using capsicum");
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} else if (res != NULL) {
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cap_rights_t rights;
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static const unsigned long geomcmds[] = {
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DIOCGDELETE,
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DIOCGFLUSH
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};
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PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY ||
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res->hr_role == HAST_ROLE_SECONDARY);
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cap_rights_init(&rights, CAP_FLOCK, CAP_IOCTL, CAP_PREAD,
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CAP_PWRITE);
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if (cap_rights_limit(res->hr_localfd, &rights) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable to limit capability rights on local descriptor");
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}
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if (cap_ioctls_limit(res->hr_localfd, geomcmds,
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nitems(geomcmds)) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable to limit allowed GEOM ioctls");
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}
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if (res->hr_role == HAST_ROLE_PRIMARY) {
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static const unsigned long ggatecmds[] = {
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G_GATE_CMD_MODIFY,
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G_GATE_CMD_START,
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G_GATE_CMD_DONE,
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G_GATE_CMD_DESTROY
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};
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cap_rights_init(&rights, CAP_IOCTL);
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if (cap_rights_limit(res->hr_ggatefd, &rights) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable to limit capability rights to CAP_IOCTL on ggate descriptor");
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}
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if (cap_ioctls_limit(res->hr_ggatefd, ggatecmds,
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nitems(ggatecmds)) == -1) {
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pjdlog_errno(LOG_ERR,
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"Unable to limit allowed ggate ioctls");
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}
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}
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}
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#else
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capsicum = false;
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#endif
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/*
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* Better be sure that everything succeeded.
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*/
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PJDLOG_VERIFY(getresuid(&ruid, &euid, &suid) == 0);
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PJDLOG_VERIFY(ruid == pw->pw_uid);
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PJDLOG_VERIFY(euid == pw->pw_uid);
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PJDLOG_VERIFY(suid == pw->pw_uid);
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PJDLOG_VERIFY(getresgid(&rgid, &egid, &sgid) == 0);
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PJDLOG_VERIFY(rgid == pw->pw_gid);
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PJDLOG_VERIFY(egid == pw->pw_gid);
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PJDLOG_VERIFY(sgid == pw->pw_gid);
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PJDLOG_VERIFY(getgroups(0, NULL) == 1);
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PJDLOG_VERIFY(getgroups(1, gidset) == 1);
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PJDLOG_VERIFY(gidset[0] == pw->pw_gid);
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pjdlog_debug(1,
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"Privileges successfully dropped using %s%s+setgid+setuid.",
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capsicum ? "capsicum+" : "", jailed ? "jail" : "chroot");
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return (0);
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}
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