297 lines
6.4 KiB
C
297 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/types.h>
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#include <sched.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syscall.h>
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#include <sys/wait.h>
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#include "pidfd.h"
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#include "../kselftest.h"
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struct error {
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int code;
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char msg[512];
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};
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static int error_set(struct error *err, int code, const char *fmt, ...)
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{
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va_list args;
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int r;
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if (code == PIDFD_PASS || !err || err->code != PIDFD_PASS)
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return code;
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err->code = code;
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va_start(args, fmt);
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r = vsnprintf(err->msg, sizeof(err->msg), fmt, args);
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assert((size_t)r < sizeof(err->msg));
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va_end(args);
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return code;
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}
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static void error_report(struct error *err, const char *test_name)
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{
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switch (err->code) {
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case PIDFD_ERROR:
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ksft_exit_fail_msg("%s test: Fatal: %s\n", test_name, err->msg);
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break;
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case PIDFD_FAIL:
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/* will be: not ok %d # error %s test: %s */
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ksft_test_result_error("%s test: %s\n", test_name, err->msg);
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break;
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case PIDFD_SKIP:
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/* will be: not ok %d # SKIP %s test: %s */
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ksft_test_result_skip("%s test: %s\n", test_name, err->msg);
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break;
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case PIDFD_XFAIL:
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ksft_test_result_pass("%s test: Expected failure: %s\n",
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test_name, err->msg);
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break;
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case PIDFD_PASS:
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ksft_test_result_pass("%s test: Passed\n");
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break;
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default:
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ksft_exit_fail_msg("%s test: Unknown code: %d %s\n",
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test_name, err->code, err->msg);
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break;
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}
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}
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static inline int error_check(struct error *err, const char *test_name)
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{
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/* In case of error we bail out and terminate the test program */
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if (err->code == PIDFD_ERROR)
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error_report(err, test_name);
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return err->code;
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}
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struct child {
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pid_t pid;
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int fd;
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};
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static struct child clone_newns(int (*fn)(void *), void *args,
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struct error *err)
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{
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static int flags = CLONE_PIDFD | CLONE_NEWPID | CLONE_NEWNS | SIGCHLD;
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size_t stack_size = 1024;
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char *stack[1024] = { 0 };
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struct child ret;
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if (!(flags & CLONE_NEWUSER) && geteuid() != 0)
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flags |= CLONE_NEWUSER;
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#ifdef __ia64__
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ret.pid = __clone2(fn, stack, stack_size, flags, args, &ret.fd);
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#else
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ret.pid = clone(fn, stack + stack_size, flags, args, &ret.fd);
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#endif
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if (ret.pid < 0) {
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error_set(err, PIDFD_ERROR, "clone failed (ret %d, errno %d)",
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ret.fd, errno);
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return ret;
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}
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ksft_print_msg("New child: %d, fd: %d\n", ret.pid, ret.fd);
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return ret;
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}
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static inline void child_close(struct child *child)
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{
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close(child->fd);
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}
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static inline int child_join(struct child *child, struct error *err)
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{
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int r;
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r = wait_for_pid(child->pid);
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if (r < 0)
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error_set(err, PIDFD_ERROR, "waitpid failed (ret %d, errno %d)",
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r, errno);
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else if (r > 0)
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error_set(err, r, "child %d reported: %d", child->pid, r);
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return r;
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}
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static inline int child_join_close(struct child *child, struct error *err)
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{
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child_close(child);
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return child_join(child, err);
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}
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static inline void trim_newline(char *str)
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{
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char *pos = strrchr(str, '\n');
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if (pos)
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*pos = '\0';
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}
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static int verify_fdinfo(int pidfd, struct error *err, const char *prefix,
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size_t prefix_len, const char *expect, ...)
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{
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char buffer[512] = {0, };
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char path[512] = {0, };
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va_list args;
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FILE *f;
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char *line = NULL;
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size_t n = 0;
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int found = 0;
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int r;
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va_start(args, expect);
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r = vsnprintf(buffer, sizeof(buffer), expect, args);
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assert((size_t)r < sizeof(buffer));
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va_end(args);
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snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
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f = fopen(path, "re");
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if (!f)
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return error_set(err, PIDFD_ERROR, "fdinfo open failed for %d",
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pidfd);
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while (getline(&line, &n, f) != -1) {
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char *val;
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if (strncmp(line, prefix, prefix_len))
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continue;
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found = 1;
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val = line + prefix_len;
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r = strcmp(val, buffer);
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if (r != 0) {
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trim_newline(line);
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trim_newline(buffer);
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error_set(err, PIDFD_FAIL, "%s '%s' != '%s'",
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prefix, val, buffer);
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}
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break;
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}
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free(line);
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fclose(f);
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if (found == 0)
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return error_set(err, PIDFD_FAIL, "%s not found for fd %d",
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prefix, pidfd);
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return PIDFD_PASS;
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}
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static int child_fdinfo_nspid_test(void *args)
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{
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struct error err;
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int pidfd;
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int r;
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/* if we got no fd for the sibling, we are done */
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if (!args)
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return PIDFD_PASS;
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/* verify that we can not resolve the pidfd for a process
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* in a sibling pid namespace, i.e. a pid namespace it is
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* not in our or a descended namespace
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*/
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r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
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if (r < 0) {
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ksft_print_msg("Failed to remount / private\n");
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return PIDFD_ERROR;
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}
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(void)umount2("/proc", MNT_DETACH);
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r = mount("proc", "/proc", "proc", 0, NULL);
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if (r < 0) {
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ksft_print_msg("Failed to remount /proc\n");
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return PIDFD_ERROR;
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}
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pidfd = *(int *)args;
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r = verify_fdinfo(pidfd, &err, "NSpid:", 6, "\t0\n");
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if (r != PIDFD_PASS)
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ksft_print_msg("NSpid fdinfo check failed: %s\n", err.msg);
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return r;
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}
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static void test_pidfd_fdinfo_nspid(void)
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{
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struct child a, b;
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struct error err = {0, };
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const char *test_name = "pidfd check for NSpid in fdinfo";
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/* Create a new child in a new pid and mount namespace */
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a = clone_newns(child_fdinfo_nspid_test, NULL, &err);
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error_check(&err, test_name);
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/* Pass the pidfd representing the first child to the
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* second child, which will be in a sibling pid namespace,
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* which means that the fdinfo NSpid entry for the pidfd
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* should only contain '0'.
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*/
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b = clone_newns(child_fdinfo_nspid_test, &a.fd, &err);
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error_check(&err, test_name);
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/* The children will have pid 1 in the new pid namespace,
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* so the line must be 'NSPid:\t<pid>\t1'.
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*/
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verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t%d\t%d\n", a.pid, 1);
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verify_fdinfo(b.fd, &err, "NSpid:", 6, "\t%d\t%d\n", b.pid, 1);
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/* wait for the process, check the exit status and set
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* 'err' accordingly, if it is not already set.
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*/
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child_join_close(&a, &err);
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child_join_close(&b, &err);
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error_report(&err, test_name);
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}
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static void test_pidfd_dead_fdinfo(void)
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{
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struct child a;
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struct error err = {0, };
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const char *test_name = "pidfd check fdinfo for dead process";
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/* Create a new child in a new pid and mount namespace */
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a = clone_newns(child_fdinfo_nspid_test, NULL, &err);
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error_check(&err, test_name);
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child_join(&a, &err);
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verify_fdinfo(a.fd, &err, "Pid:", 4, "\t-1\n");
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verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t-1\n");
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child_close(&a);
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error_report(&err, test_name);
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}
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int main(int argc, char **argv)
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{
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ksft_print_header();
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ksft_set_plan(2);
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test_pidfd_fdinfo_nspid();
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test_pidfd_dead_fdinfo();
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return ksft_exit_pass();
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}
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