subr.c revision 221898
1/*- 2 * Copyright (c) 2010 The FreeBSD Foundation 3 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net> 4 * All rights reserved. 5 * 6 * This software was developed by Pawel Jakub Dawidek under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31#include <sys/cdefs.h> 32__FBSDID("$FreeBSD: head/sbin/hastd/subr.c 221898 2011-05-14 16:55:24Z pjd $"); 33 34#include <sys/capability.h> 35#include <sys/types.h> 36#include <sys/disk.h> 37#include <sys/ioctl.h> 38#include <sys/stat.h> 39 40#include <errno.h> 41#include <fcntl.h> 42#include <pwd.h> 43#include <stdarg.h> 44#include <stdbool.h> 45#include <stdio.h> 46#include <string.h> 47#include <unistd.h> 48 49#include <pjdlog.h> 50 51#include "hast.h" 52#include "subr.h" 53 54int 55vsnprlcat(char *str, size_t size, const char *fmt, va_list ap) 56{ 57 size_t len; 58 59 len = strlen(str); 60 return (vsnprintf(str + len, size - len, fmt, ap)); 61} 62 63int 64snprlcat(char *str, size_t size, const char *fmt, ...) 65{ 66 va_list ap; 67 int result; 68 69 va_start(ap, fmt); 70 result = vsnprlcat(str, size, fmt, ap); 71 va_end(ap); 72 return (result); 73} 74 75int 76provinfo(struct hast_resource *res, bool dowrite) 77{ 78 struct stat sb; 79 80 PJDLOG_ASSERT(res->hr_localpath != NULL && 81 res->hr_localpath[0] != '\0'); 82 83 if (res->hr_localfd == -1) { 84 res->hr_localfd = open(res->hr_localpath, 85 dowrite ? O_RDWR : O_RDONLY); 86 if (res->hr_localfd < 0) { 87 KEEP_ERRNO(pjdlog_errno(LOG_ERR, "Unable to open %s", 88 res->hr_localpath)); 89 return (-1); 90 } 91 } 92 if (fstat(res->hr_localfd, &sb) < 0) { 93 KEEP_ERRNO(pjdlog_errno(LOG_ERR, "Unable to stat %s", 94 res->hr_localpath)); 95 return (-1); 96 } 97 if (S_ISCHR(sb.st_mode)) { 98 /* 99 * If this is character device, it is most likely GEOM provider. 100 */ 101 if (ioctl(res->hr_localfd, DIOCGMEDIASIZE, 102 &res->hr_local_mediasize) < 0) { 103 KEEP_ERRNO(pjdlog_errno(LOG_ERR, 104 "Unable obtain provider %s mediasize", 105 res->hr_localpath)); 106 return (-1); 107 } 108 if (ioctl(res->hr_localfd, DIOCGSECTORSIZE, 109 &res->hr_local_sectorsize) < 0) { 110 KEEP_ERRNO(pjdlog_errno(LOG_ERR, 111 "Unable obtain provider %s sectorsize", 112 res->hr_localpath)); 113 return (-1); 114 } 115 } else if (S_ISREG(sb.st_mode)) { 116 /* 117 * We also support regular files for which we hardcode 118 * sector size of 512 bytes. 119 */ 120 res->hr_local_mediasize = sb.st_size; 121 res->hr_local_sectorsize = 512; 122 } else { 123 /* 124 * We support no other file types. 125 */ 126 pjdlog_error("%s is neither GEOM provider nor regular file.", 127 res->hr_localpath); 128 errno = EFTYPE; 129 return (-1); 130 } 131 return (0); 132} 133 134const char * 135role2str(int role) 136{ 137 138 switch (role) { 139 case HAST_ROLE_INIT: 140 return ("init"); 141 case HAST_ROLE_PRIMARY: 142 return ("primary"); 143 case HAST_ROLE_SECONDARY: 144 return ("secondary"); 145 } 146 return ("unknown"); 147} 148 149int 150drop_privs(bool usecapsicum) 151{ 152 struct passwd *pw; 153 uid_t ruid, euid, suid; 154 gid_t rgid, egid, sgid; 155 gid_t gidset[1]; 156 bool capsicum; 157 158 /* 159 * According to getpwnam(3) we have to clear errno before calling the 160 * function to be able to distinguish between an error and missing 161 * entry (with is not treated as error by getpwnam(3)). 162 */ 163 errno = 0; 164 pw = getpwnam(HAST_USER); 165 if (pw == NULL) { 166 if (errno != 0) { 167 KEEP_ERRNO(pjdlog_errno(LOG_ERR, 168 "Unable to find info about '%s' user", HAST_USER)); 169 return (-1); 170 } else { 171 pjdlog_error("'%s' user doesn't exist.", HAST_USER); 172 errno = ENOENT; 173 return (-1); 174 } 175 } 176 if (chroot(pw->pw_dir) == -1) { 177 KEEP_ERRNO(pjdlog_errno(LOG_ERR, 178 "Unable to change root directory to %s", pw->pw_dir)); 179 return (-1); 180 } 181 PJDLOG_VERIFY(chdir("/") == 0); 182 gidset[0] = pw->pw_gid; 183 if (setgroups(1, gidset) == -1) { 184 KEEP_ERRNO(pjdlog_errno(LOG_ERR, 185 "Unable to set groups to gid %u", 186 (unsigned int)pw->pw_gid)); 187 return (-1); 188 } 189 if (setgid(pw->pw_gid) == -1) { 190 KEEP_ERRNO(pjdlog_errno(LOG_ERR, "Unable to set gid to %u", 191 (unsigned int)pw->pw_gid)); 192 return (-1); 193 } 194 if (setuid(pw->pw_uid) == -1) { 195 KEEP_ERRNO(pjdlog_errno(LOG_ERR, "Unable to set uid to %u", 196 (unsigned int)pw->pw_uid)); 197 return (-1); 198 } 199 200 capsicum = false; 201 if (usecapsicum) { 202 if (cap_enter() == 0) { 203 capsicum = true; 204 } else { 205 pjdlog_errno(LOG_WARNING, 206 "Unable to sandbox using capsicum"); 207 } 208 } 209 210 /* 211 * Better be sure that everything succeeded. 212 */ 213 PJDLOG_VERIFY(getresuid(&ruid, &euid, &suid) == 0); 214 PJDLOG_VERIFY(ruid == pw->pw_uid); 215 PJDLOG_VERIFY(euid == pw->pw_uid); 216 PJDLOG_VERIFY(suid == pw->pw_uid); 217 PJDLOG_VERIFY(getresgid(&rgid, &egid, &sgid) == 0); 218 PJDLOG_VERIFY(rgid == pw->pw_gid); 219 PJDLOG_VERIFY(egid == pw->pw_gid); 220 PJDLOG_VERIFY(sgid == pw->pw_gid); 221 PJDLOG_VERIFY(getgroups(0, NULL) == 1); 222 PJDLOG_VERIFY(getgroups(1, gidset) == 1); 223 PJDLOG_VERIFY(gidset[0] == pw->pw_gid); 224 225 pjdlog_debug(1, 226 "Privileges successfully dropped using %schroot+setgid+setuid.", 227 capsicum ? "capsicum+" : ""); 228 229 return (0); 230} 231