312 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#define _GNU_SOURCE4#include <assert.h>5#include <errno.h>6#include <fcntl.h>7#include <linux/types.h>8#include <sched.h>9#include <signal.h>10#include <stdio.h>11#include <stdlib.h>12#include <string.h>13#include <syscall.h>14#include <sys/wait.h>15#include <sys/mman.h>16 17#include "pidfd.h"18#include "../kselftest.h"19 20struct error {21 int code;22 char msg[512];23};24 25static int error_set(struct error *err, int code, const char *fmt, ...)26{27 va_list args;28 int r;29 30 if (code == PIDFD_PASS || !err || err->code != PIDFD_PASS)31 return code;32 33 err->code = code;34 va_start(args, fmt);35 r = vsnprintf(err->msg, sizeof(err->msg), fmt, args);36 assert((size_t)r < sizeof(err->msg));37 va_end(args);38 39 return code;40}41 42static void error_report(struct error *err, const char *test_name)43{44 switch (err->code) {45 case PIDFD_ERROR:46 ksft_exit_fail_msg("%s test: Fatal: %s\n", test_name, err->msg);47 break;48 49 case PIDFD_FAIL:50 /* will be: not ok %d # error %s test: %s */51 ksft_test_result_error("%s test: %s\n", test_name, err->msg);52 break;53 54 case PIDFD_SKIP:55 /* will be: not ok %d # SKIP %s test: %s */56 ksft_test_result_skip("%s test: %s\n", test_name, err->msg);57 break;58 59 case PIDFD_XFAIL:60 ksft_test_result_pass("%s test: Expected failure: %s\n",61 test_name, err->msg);62 break;63 64 case PIDFD_PASS:65 ksft_test_result_pass("%s test: Passed\n", test_name);66 break;67 68 default:69 ksft_exit_fail_msg("%s test: Unknown code: %d %s\n",70 test_name, err->code, err->msg);71 break;72 }73}74 75static inline int error_check(struct error *err, const char *test_name)76{77 /* In case of error we bail out and terminate the test program */78 if (err->code == PIDFD_ERROR)79 error_report(err, test_name);80 81 return err->code;82}83 84#define CHILD_STACK_SIZE 819285 86struct child {87 char *stack;88 pid_t pid;89 int fd;90};91 92static struct child clone_newns(int (*fn)(void *), void *args,93 struct error *err)94{95 static int flags = CLONE_PIDFD | CLONE_NEWPID | CLONE_NEWNS | SIGCHLD;96 struct child ret;97 98 if (!(flags & CLONE_NEWUSER) && geteuid() != 0)99 flags |= CLONE_NEWUSER;100 101 ret.stack = mmap(NULL, CHILD_STACK_SIZE, PROT_READ | PROT_WRITE,102 MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);103 if (ret.stack == MAP_FAILED) {104 error_set(err, -1, "mmap of stack failed (errno %d)", errno);105 return ret;106 }107 108#ifdef __ia64__109 ret.pid = __clone2(fn, ret.stack, CHILD_STACK_SIZE, flags, args, &ret.fd);110#else111 ret.pid = clone(fn, ret.stack + CHILD_STACK_SIZE, flags, args, &ret.fd);112#endif113 114 if (ret.pid < 0) {115 error_set(err, PIDFD_ERROR, "clone failed (ret %d, errno %d)",116 ret.fd, errno);117 return ret;118 }119 120 ksft_print_msg("New child: %d, fd: %d\n", ret.pid, ret.fd);121 122 return ret;123}124 125static inline void child_close(struct child *child)126{127 close(child->fd);128}129 130static inline int child_join(struct child *child, struct error *err)131{132 int r;133 134 r = wait_for_pid(child->pid);135 if (r < 0)136 error_set(err, PIDFD_ERROR, "waitpid failed (ret %d, errno %d)",137 r, errno);138 else if (r > 0)139 error_set(err, r, "child %d reported: %d", child->pid, r);140 141 if (munmap(child->stack, CHILD_STACK_SIZE)) {142 error_set(err, -1, "munmap of child stack failed (errno %d)", errno);143 r = -1;144 }145 146 ksft_print_msg("waitpid WEXITSTATUS=%d\n", r);147 return r;148}149 150static inline int child_join_close(struct child *child, struct error *err)151{152 child_close(child);153 return child_join(child, err);154}155 156static inline void trim_newline(char *str)157{158 char *pos = strrchr(str, '\n');159 160 if (pos)161 *pos = '\0';162}163 164static int verify_fdinfo(int pidfd, struct error *err, const char *prefix,165 size_t prefix_len, const char *expect, ...)166{167 char buffer[512] = {0, };168 char path[512] = {0, };169 va_list args;170 FILE *f;171 char *line = NULL;172 size_t n = 0;173 int found = 0;174 int r;175 176 va_start(args, expect);177 r = vsnprintf(buffer, sizeof(buffer), expect, args);178 assert((size_t)r < sizeof(buffer));179 va_end(args);180 181 snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);182 f = fopen(path, "re");183 if (!f)184 return error_set(err, PIDFD_ERROR, "fdinfo open failed for %d",185 pidfd);186 187 while (getline(&line, &n, f) != -1) {188 char *val;189 190 if (strncmp(line, prefix, prefix_len))191 continue;192 193 found = 1;194 195 val = line + prefix_len;196 r = strcmp(val, buffer);197 if (r != 0) {198 trim_newline(line);199 trim_newline(buffer);200 error_set(err, PIDFD_FAIL, "%s '%s' != '%s'",201 prefix, val, buffer);202 }203 break;204 }205 206 free(line);207 fclose(f);208 209 if (found == 0)210 return error_set(err, PIDFD_FAIL, "%s not found for fd %d",211 prefix, pidfd);212 213 return PIDFD_PASS;214}215 216static int child_fdinfo_nspid_test(void *args)217{218 struct error err;219 int pidfd;220 int r;221 222 /* if we got no fd for the sibling, we are done */223 if (!args)224 return PIDFD_PASS;225 226 /* verify that we can not resolve the pidfd for a process227 * in a sibling pid namespace, i.e. a pid namespace it is228 * not in our or a descended namespace229 */230 r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);231 if (r < 0) {232 ksft_print_msg("Failed to remount / private\n");233 return PIDFD_ERROR;234 }235 236 (void)umount2("/proc", MNT_DETACH);237 r = mount("proc", "/proc", "proc", 0, NULL);238 if (r < 0) {239 ksft_print_msg("Failed to remount /proc\n");240 return PIDFD_ERROR;241 }242 243 pidfd = *(int *)args;244 r = verify_fdinfo(pidfd, &err, "NSpid:", 6, "\t0\n");245 246 if (r != PIDFD_PASS)247 ksft_print_msg("NSpid fdinfo check failed: %s\n", err.msg);248 249 return r;250}251 252static void test_pidfd_fdinfo_nspid(void)253{254 struct child a, b;255 struct error err = {0, };256 const char *test_name = "pidfd check for NSpid in fdinfo";257 258 /* Create a new child in a new pid and mount namespace */259 a = clone_newns(child_fdinfo_nspid_test, NULL, &err);260 error_check(&err, test_name);261 262 /* Pass the pidfd representing the first child to the263 * second child, which will be in a sibling pid namespace,264 * which means that the fdinfo NSpid entry for the pidfd265 * should only contain '0'.266 */267 b = clone_newns(child_fdinfo_nspid_test, &a.fd, &err);268 error_check(&err, test_name);269 270 /* The children will have pid 1 in the new pid namespace,271 * so the line must be 'NSPid:\t<pid>\t1'.272 */273 verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t%d\t%d\n", a.pid, 1);274 verify_fdinfo(b.fd, &err, "NSpid:", 6, "\t%d\t%d\n", b.pid, 1);275 276 /* wait for the process, check the exit status and set277 * 'err' accordingly, if it is not already set.278 */279 child_join_close(&a, &err);280 child_join_close(&b, &err);281 282 error_report(&err, test_name);283}284 285static void test_pidfd_dead_fdinfo(void)286{287 struct child a;288 struct error err = {0, };289 const char *test_name = "pidfd check fdinfo for dead process";290 291 /* Create a new child in a new pid and mount namespace */292 a = clone_newns(child_fdinfo_nspid_test, NULL, &err);293 error_check(&err, test_name);294 child_join(&a, &err);295 296 verify_fdinfo(a.fd, &err, "Pid:", 4, "\t-1\n");297 verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t-1\n");298 child_close(&a);299 error_report(&err, test_name);300}301 302int main(int argc, char **argv)303{304 ksft_print_header();305 ksft_set_plan(2);306 307 test_pidfd_fdinfo_nspid();308 test_pidfd_dead_fdinfo();309 310 ksft_exit_pass();311}312