1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2010 The FreeBSD Foundation 5 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net> 6 * All rights reserved. 7 * 8 * This software was developed by Pawel Jakub Dawidek under sponsorship from 9 * the FreeBSD Foundation. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/param.h> 34 #include <sys/disk.h> 35 #include <sys/ioctl.h> 36 #include <sys/jail.h> 37 #include <sys/stat.h> 38 #ifdef HAVE_CAPSICUM 39 #include <sys/capsicum.h> 40 #include <geom/gate/g_gate.h> 41 #endif 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <pwd.h> 46 #include <stdarg.h> 47 #include <stdbool.h> 48 #include <stdio.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 #include <pjdlog.h> 53 54 #include "hast.h" 55 #include "subr.h" 56 57 int 58 vsnprlcat(char *str, size_t size, const char *fmt, va_list ap) 59 { 60 size_t len; 61 62 len = strlen(str); 63 return (vsnprintf(str + len, size - len, fmt, ap)); 64 } 65 66 int 67 snprlcat(char *str, size_t size, const char *fmt, ...) 68 { 69 va_list ap; 70 int result; 71 72 va_start(ap, fmt); 73 result = vsnprlcat(str, size, fmt, ap); 74 va_end(ap); 75 return (result); 76 } 77 78 int 79 provinfo(struct hast_resource *res, bool dowrite) 80 { 81 struct stat sb; 82 83 PJDLOG_ASSERT(res->hr_localpath != NULL && 84 res->hr_localpath[0] != '\0'); 85 86 if (res->hr_localfd == -1) { 87 res->hr_localfd = open(res->hr_localpath, 88 dowrite ? O_RDWR : O_RDONLY); 89 if (res->hr_localfd == -1) { 90 pjdlog_errno(LOG_ERR, "Unable to open %s", 91 res->hr_localpath); 92 return (-1); 93 } 94 } 95 if (fstat(res->hr_localfd, &sb) == -1) { 96 pjdlog_errno(LOG_ERR, "Unable to stat %s", res->hr_localpath); 97 return (-1); 98 } 99 if (S_ISCHR(sb.st_mode)) { 100 /* 101 * If this is character device, it is most likely GEOM provider. 102 */ 103 if (ioctl(res->hr_localfd, DIOCGMEDIASIZE, 104 &res->hr_local_mediasize) == -1) { 105 pjdlog_errno(LOG_ERR, 106 "Unable obtain provider %s mediasize", 107 res->hr_localpath); 108 return (-1); 109 } 110 if (ioctl(res->hr_localfd, DIOCGSECTORSIZE, 111 &res->hr_local_sectorsize) == -1) { 112 pjdlog_errno(LOG_ERR, 113 "Unable obtain provider %s sectorsize", 114 res->hr_localpath); 115 return (-1); 116 } 117 } else if (S_ISREG(sb.st_mode)) { 118 /* 119 * We also support regular files for which we hardcode 120 * sector size of 512 bytes. 121 */ 122 res->hr_local_mediasize = sb.st_size; 123 res->hr_local_sectorsize = 512; 124 } else { 125 /* 126 * We support no other file types. 127 */ 128 pjdlog_error("%s is neither GEOM provider nor regular file.", 129 res->hr_localpath); 130 errno = EFTYPE; 131 return (-1); 132 } 133 return (0); 134 } 135 136 const char * 137 role2str(int role) 138 { 139 140 switch (role) { 141 case HAST_ROLE_INIT: 142 return ("init"); 143 case HAST_ROLE_PRIMARY: 144 return ("primary"); 145 case HAST_ROLE_SECONDARY: 146 return ("secondary"); 147 } 148 return ("unknown"); 149 } 150 151 int 152 drop_privs(const struct hast_resource *res) 153 { 154 char jailhost[sizeof(res->hr_name) * 2]; 155 struct jail jailst; 156 struct passwd *pw; 157 uid_t ruid, euid, suid; 158 gid_t rgid, egid, sgid; 159 gid_t gidset[1]; 160 bool capsicum, jailed; 161 162 /* 163 * According to getpwnam(3) we have to clear errno before calling the 164 * function to be able to distinguish between an error and missing 165 * entry (with is not treated as error by getpwnam(3)). 166 */ 167 errno = 0; 168 pw = getpwnam(HAST_USER); 169 if (pw == NULL) { 170 if (errno != 0) { 171 pjdlog_errno(LOG_ERR, 172 "Unable to find info about '%s' user", HAST_USER); 173 return (-1); 174 } else { 175 pjdlog_error("'%s' user doesn't exist.", HAST_USER); 176 errno = ENOENT; 177 return (-1); 178 } 179 } 180 181 bzero(&jailst, sizeof(jailst)); 182 jailst.version = JAIL_API_VERSION; 183 jailst.path = pw->pw_dir; 184 if (res == NULL) { 185 (void)snprintf(jailhost, sizeof(jailhost), "hastctl"); 186 } else { 187 (void)snprintf(jailhost, sizeof(jailhost), "hastd: %s (%s)", 188 res->hr_name, role2str(res->hr_role)); 189 } 190 jailst.hostname = jailhost; 191 jailst.jailname = NULL; 192 jailst.ip4s = 0; 193 jailst.ip4 = NULL; 194 jailst.ip6s = 0; 195 jailst.ip6 = NULL; 196 if (jail(&jailst) >= 0) { 197 jailed = true; 198 } else { 199 jailed = false; 200 pjdlog_errno(LOG_WARNING, 201 "Unable to jail to directory to %s", pw->pw_dir); 202 if (chroot(pw->pw_dir) == -1) { 203 pjdlog_errno(LOG_ERR, 204 "Unable to change root directory to %s", 205 pw->pw_dir); 206 return (-1); 207 } 208 } 209 PJDLOG_VERIFY(chdir("/") == 0); 210 gidset[0] = pw->pw_gid; 211 if (setgroups(1, gidset) == -1) { 212 pjdlog_errno(LOG_ERR, "Unable to set groups to gid %u", 213 (unsigned int)pw->pw_gid); 214 return (-1); 215 } 216 if (setgid(pw->pw_gid) == -1) { 217 pjdlog_errno(LOG_ERR, "Unable to set gid to %u", 218 (unsigned int)pw->pw_gid); 219 return (-1); 220 } 221 if (setuid(pw->pw_uid) == -1) { 222 pjdlog_errno(LOG_ERR, "Unable to set uid to %u", 223 (unsigned int)pw->pw_uid); 224 return (-1); 225 } 226 227 #ifdef HAVE_CAPSICUM 228 capsicum = (cap_enter() == 0); 229 if (!capsicum) { 230 pjdlog_common(LOG_DEBUG, 1, errno, 231 "Unable to sandbox using capsicum"); 232 } else if (res != NULL) { 233 cap_rights_t rights; 234 static const unsigned long geomcmds[] = { 235 DIOCGDELETE, 236 DIOCGFLUSH 237 }; 238 239 PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY || 240 res->hr_role == HAST_ROLE_SECONDARY); 241 242 cap_rights_init(&rights, CAP_FLOCK, CAP_IOCTL, CAP_PREAD, 243 CAP_PWRITE); 244 if (cap_rights_limit(res->hr_localfd, &rights) == -1) { 245 pjdlog_errno(LOG_ERR, 246 "Unable to limit capability rights on local descriptor"); 247 } 248 if (cap_ioctls_limit(res->hr_localfd, geomcmds, 249 nitems(geomcmds)) == -1) { 250 pjdlog_errno(LOG_ERR, 251 "Unable to limit allowed GEOM ioctls"); 252 } 253 254 if (res->hr_role == HAST_ROLE_PRIMARY) { 255 static const unsigned long ggatecmds[] = { 256 G_GATE_CMD_MODIFY, 257 G_GATE_CMD_START, 258 G_GATE_CMD_DONE, 259 G_GATE_CMD_DESTROY 260 }; 261 262 cap_rights_init(&rights, CAP_IOCTL); 263 if (cap_rights_limit(res->hr_ggatefd, &rights) == -1) { 264 pjdlog_errno(LOG_ERR, 265 "Unable to limit capability rights to CAP_IOCTL on ggate descriptor"); 266 } 267 if (cap_ioctls_limit(res->hr_ggatefd, ggatecmds, 268 nitems(ggatecmds)) == -1) { 269 pjdlog_errno(LOG_ERR, 270 "Unable to limit allowed ggate ioctls"); 271 } 272 } 273 } 274 #else 275 capsicum = false; 276 #endif 277 278 /* 279 * Better be sure that everything succeeded. 280 */ 281 PJDLOG_VERIFY(getresuid(&ruid, &euid, &suid) == 0); 282 PJDLOG_VERIFY(ruid == pw->pw_uid); 283 PJDLOG_VERIFY(euid == pw->pw_uid); 284 PJDLOG_VERIFY(suid == pw->pw_uid); 285 PJDLOG_VERIFY(getresgid(&rgid, &egid, &sgid) == 0); 286 PJDLOG_VERIFY(rgid == pw->pw_gid); 287 PJDLOG_VERIFY(egid == pw->pw_gid); 288 PJDLOG_VERIFY(sgid == pw->pw_gid); 289 PJDLOG_VERIFY(getgroups(0, NULL) == 1); 290 PJDLOG_VERIFY(getgroups(1, gidset) == 1); 291 PJDLOG_VERIFY(gidset[0] == pw->pw_gid); 292 293 pjdlog_debug(1, 294 "Privileges successfully dropped using %s%s+setgid+setuid.", 295 capsicum ? "capsicum+" : "", jailed ? "jail" : "chroot"); 296 297 return (0); 298 } 299