1 /*- 2 * Copyright 2018 Aniket Pandey 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #include <sys/types.h> 29 #include <sys/extattr.h> 30 #include <sys/ioctl.h> 31 32 #include <bsm/libbsm.h> 33 #include <bsm/auditd_lib.h> 34 #include <security/audit/audit_ioctl.h> 35 36 #include <atf-c.h> 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <time.h> 42 #include <unistd.h> 43 44 #include "utils.h" 45 46 /* 47 * Checks the presence of "auditregex" in auditpipe(4) after the 48 * corresponding system call has been triggered. 49 */ 50 static bool 51 get_records(const char *auditregex, FILE *pipestream) 52 { 53 uint8_t *buff; 54 tokenstr_t token; 55 ssize_t size = 1024; 56 char membuff[size]; 57 char del[] = ","; 58 int reclen, bytes = 0; 59 FILE *memstream; 60 61 /* 62 * Open a stream on 'membuff' (address to memory buffer) for storing 63 * the audit records in the default mode.'reclen' is the length of the 64 * available records from auditpipe which is passed to the functions 65 * au_fetch_tok(3) and au_print_flags_tok(3) for further use. 66 */ 67 ATF_REQUIRE((memstream = fmemopen(membuff, size, "w")) != NULL); 68 ATF_REQUIRE((reclen = au_read_rec(pipestream, &buff)) != -1); 69 70 /* 71 * Iterate through each BSM token, extracting the bits that are 72 * required to start processing the token sequences. 73 */ 74 while (bytes < reclen) { 75 if (au_fetch_tok(&token, buff + bytes, reclen - bytes) == -1) { 76 perror("au_read_rec"); 77 atf_tc_fail("Incomplete Audit Record"); 78 } 79 80 /* Print the tokens as they are obtained, in the default form */ 81 au_print_flags_tok(memstream, &token, del, AU_OFLAG_NONE); 82 bytes += token.len; 83 } 84 85 free(buff); 86 ATF_REQUIRE_EQ(0, fclose(memstream)); 87 return (atf_utils_grep_string("%s", membuff, auditregex)); 88 } 89 90 /* 91 * Override the system-wide audit mask settings in /etc/security/audit_control 92 * and set the auditpipe's maximum allowed queue length limit 93 */ 94 static void 95 set_preselect_mode(int filedesc, au_mask_t *fmask) 96 { 97 int qlimit_max; 98 int fmode = AUDITPIPE_PRESELECT_MODE_LOCAL; 99 100 /* Set local preselection mode for auditing */ 101 if (ioctl(filedesc, AUDITPIPE_SET_PRESELECT_MODE, &fmode) < 0) 102 atf_tc_fail("Preselection mode: %s", strerror(errno)); 103 104 /* Set local preselection flag corresponding to the audit_event */ 105 if (ioctl(filedesc, AUDITPIPE_SET_PRESELECT_FLAGS, fmask) < 0) 106 atf_tc_fail("Preselection flag: %s", strerror(errno)); 107 108 /* Set local preselection flag for non-attributable audit_events */ 109 if (ioctl(filedesc, AUDITPIPE_SET_PRESELECT_NAFLAGS, fmask) < 0) 110 atf_tc_fail("Preselection naflag: %s", strerror(errno)); 111 112 /* Query the maximum possible queue length limit for auditpipe */ 113 if (ioctl(filedesc, AUDITPIPE_GET_QLIMIT_MAX, &qlimit_max) < 0) 114 atf_tc_fail("Query max-limit: %s", strerror(errno)); 115 116 /* Set the queue length limit as obtained from previous step */ 117 if (ioctl(filedesc, AUDITPIPE_SET_QLIMIT, &qlimit_max) < 0) 118 atf_tc_fail("Set max-qlimit: %s", strerror(errno)); 119 120 /* This removes any outstanding record on the auditpipe */ 121 if (ioctl(filedesc, AUDITPIPE_FLUSH) < 0) 122 atf_tc_fail("Auditpipe flush: %s", strerror(errno)); 123 } 124 125 /* 126 * Get the corresponding audit_mask for class-name "name" then set the 127 * success and failure bits for fmask to be used as the ioctl argument 128 */ 129 static au_mask_t 130 get_audit_mask(const char *name) 131 { 132 au_mask_t fmask; 133 au_class_ent_t *class; 134 135 ATF_REQUIRE((class = getauclassnam(name)) != NULL); 136 fmask.am_success = class->ac_class; 137 fmask.am_failure = class->ac_class; 138 return (fmask); 139 } 140 141 /* 142 * Loop until the auditpipe returns something, check if it is what 143 * we want, else repeat the procedure until ppoll(2) times out. 144 */ 145 static void 146 check_auditpipe(struct pollfd fd[], const char *auditregex, FILE *pipestream) 147 { 148 struct timespec currtime, endtime, timeout; 149 150 /* Set the expire time for poll(2) while waiting for syscall audit */ 151 ATF_REQUIRE_EQ(0, clock_gettime(CLOCK_MONOTONIC, &endtime)); 152 /* Set limit to 30 seconds total and ~10s without an event. */ 153 endtime.tv_sec += 30; 154 155 for (;;) { 156 /* Update the time left for auditpipe to return any event */ 157 ATF_REQUIRE_EQ(0, clock_gettime(CLOCK_MONOTONIC, &currtime)); 158 timespecsub(&endtime, &currtime, &timeout); 159 timeout.tv_sec = MIN(timeout.tv_sec, 9); 160 if (timeout.tv_sec < 0) { 161 atf_tc_fail("%s not found in auditpipe within the " 162 "time limit", auditregex); 163 } 164 165 switch (ppoll(fd, 1, &timeout, NULL)) { 166 /* ppoll(2) returns, check if it's what we want */ 167 case 1: 168 if (fd[0].revents & POLLIN) { 169 if (get_records(auditregex, pipestream)) 170 return; 171 } else { 172 atf_tc_fail("Auditpipe returned an " 173 "unknown event %#x", fd[0].revents); 174 } 175 break; 176 177 /* poll(2) timed out */ 178 case 0: 179 atf_tc_fail("%s not found in auditpipe within the " 180 "time limit", auditregex); 181 break; 182 183 /* poll(2) standard error */ 184 case -1: 185 atf_tc_fail("Poll: %s", strerror(errno)); 186 break; 187 188 default: 189 atf_tc_fail("Poll returned too many file descriptors"); 190 } 191 } 192 } 193 194 /* 195 * Wrapper functions around static "check_auditpipe" 196 */ 197 static void 198 check_audit_startup(struct pollfd fd[], const char *auditrgx, FILE *pipestream){ 199 check_auditpipe(fd, auditrgx, pipestream); 200 } 201 202 void 203 check_audit(struct pollfd fd[], const char *auditrgx, FILE *pipestream) { 204 check_auditpipe(fd, auditrgx, pipestream); 205 206 /* Teardown: /dev/auditpipe's instance opened for this test-suite */ 207 ATF_REQUIRE_EQ(0, fclose(pipestream)); 208 } 209 210 void 211 skip_if_extattr_not_supported(const char *path) 212 { 213 ssize_t result; 214 215 /* 216 * Some file systems (e.g. tmpfs) do not support extattr, so we need 217 * skip tests that use extattrs. To detect this we can check whether 218 * the extattr_list_file returns EOPNOTSUPP. 219 */ 220 result = extattr_list_file(path, EXTATTR_NAMESPACE_USER, NULL, 0); 221 if (result == -1 && errno == EOPNOTSUPP) { 222 atf_tc_skip("File system does not support extattrs."); 223 } 224 } 225 226 static bool 227 is_auditd_running(void) 228 { 229 int trigger; 230 int err; 231 232 /* 233 * AUDIT_TRIGGER_INITIALIZE is a no-op message on FreeBSD and can 234 * therefore be used to check whether auditd has already been started. 235 * This is significantly cheaper than running `service auditd onestatus` 236 * for each test case. It is also slightly less racy since it will only 237 * return true once auditd() has opened the trigger file rather than 238 * just when the pidfile has been created. 239 */ 240 trigger = AUDIT_TRIGGER_INITIALIZE; 241 err = auditon(A_SENDTRIGGER, &trigger, sizeof(trigger)); 242 if (err == 0) { 243 fprintf(stderr, "auditd(8) is running.\n"); 244 return (true); 245 } else { 246 /* 247 * A_SENDTRIGGER returns ENODEV if auditd isn't listening, 248 * all other error codes indicate a fatal error. 249 */ 250 ATF_REQUIRE_MSG(errno == ENODEV, 251 "Unexpected error from auditon(2): %s", strerror(errno)); 252 return (false); 253 } 254 255 } 256 257 FILE * 258 setup(struct pollfd fd[], const char *name) 259 { 260 au_mask_t fmask, nomask; 261 FILE *pipestream; 262 fmask = get_audit_mask(name); 263 nomask = get_audit_mask("no"); 264 265 ATF_REQUIRE((fd[0].fd = open("/dev/auditpipe", O_RDONLY)) != -1); 266 ATF_REQUIRE((pipestream = fdopen(fd[0].fd, "r")) != NULL); 267 fd[0].events = POLLIN; 268 269 /* 270 * Disable stream buffering for read operations from /dev/auditpipe. 271 * Otherwise it is possible that fread(3), called via au_read_rec(3), 272 * can store buffered data in user-space unbeknown to ppoll(2), which 273 * as a result, reports that /dev/auditpipe is empty. 274 */ 275 ATF_REQUIRE_EQ(0, setvbuf(pipestream, NULL, _IONBF, 0)); 276 277 /* Set local preselection audit_class as "no" for audit startup */ 278 set_preselect_mode(fd[0].fd, &nomask); 279 if (!is_auditd_running()) { 280 fprintf(stderr, "Running audit_quick_start() for testing... "); 281 /* 282 * Previously, this test started auditd using 283 * `service auditd onestart`. However, there is a race condition 284 * there since service can return before auditd(8) has 285 * fully started (once the daemon parent process has forked) 286 * and this can cause check_audit_startup() to fail sometimes. 287 * 288 * In the CheriBSD CI this caused the first test executed by 289 * kyua (administrative:acct_failure) to fail every time, but 290 * subsequent ones would almost always succeed. 291 * 292 * To avoid this problem (and as a nice side-effect this speeds 293 * up the test quite a bit), we register this process as a 294 * "fake" auditd(8) using the audit_quick_start() function from 295 * libauditd. 296 */ 297 atf_utils_create_file("started_fake_auditd", "yes\n"); 298 ATF_REQUIRE(atf_utils_file_exists("started_fake_auditd")); 299 ATF_REQUIRE_EQ_MSG(0, audit_quick_start(), 300 "Failed to start fake auditd: %m"); 301 fprintf(stderr, "done.\n"); 302 /* audit_quick_start() should log an audit start event. */ 303 check_audit_startup(fd, "audit startup", pipestream); 304 /* 305 * If we exit cleanly shutdown audit_quick_start(), if not 306 * cleanup() will take care of it. 307 * This is not required, but makes it easier to run individual 308 * tests outside of kyua. 309 */ 310 atexit(cleanup); 311 } 312 313 /* Set local preselection parameters specific to "name" audit_class */ 314 set_preselect_mode(fd[0].fd, &fmask); 315 return (pipestream); 316 } 317 318 void 319 cleanup(void) 320 { 321 if (atf_utils_file_exists("started_fake_auditd")) { 322 fprintf(stderr, "Running audit_quick_stop()... "); 323 if (audit_quick_stop() != 0) { 324 fprintf(stderr, "Failed to stop fake auditd: %m\n"); 325 abort(); 326 } 327 fprintf(stderr, "done.\n"); 328 unlink("started_fake_auditd"); 329 } 330 } 331