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