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// SPDX-License-Identifier: GPL-2.0
/* Test triggering of loading of firmware from different mount
* namespaces. Expect firmware to be always loaded from the mount
* namespace of PID 1. */
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
static char *fw_path = NULL;
static void die(char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
if (fw_path)
unlink(fw_path);
umount("/lib/firmware");
exit(EXIT_FAILURE);
}
static void trigger_fw(const char *fw_name, const char *sys_path)
{
int fd;
fd = open(sys_path, O_WRONLY);
if (fd < 0)
die("open failed: %s\n",
strerror(errno));
if (write(fd, fw_name, strlen(fw_name)) != strlen(fw_name))
exit(EXIT_FAILURE);
close(fd);
}
static void setup_fw(const char *fw_path)
{
int fd;
const char fw[] = "ABCD0123";
fd = open(fw_path, O_WRONLY | O_CREAT, 0600);
if (fd < 0)
die("open failed: %s\n",
strerror(errno));
if (write(fd, fw, sizeof(fw) -1) != sizeof(fw) -1)
die("write failed: %s\n",
strerror(errno));
close(fd);
}
static bool test_fw_in_ns(const char *fw_name, const char *sys_path, bool block_fw_in_parent_ns)
{
pid_t child;
if (block_fw_in_parent_ns)
if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
die("blocking firmware in parent ns failed\n");
child = fork();
if (child == -1) {
die("fork failed: %s\n",
strerror(errno));
}
if (child != 0) { /* parent */
pid_t pid;
int status;
pid = waitpid(child, &status, 0);
if (pid == -1) {
die("waitpid failed: %s\n",
strerror(errno));
}
if (pid != child) {
die("waited for %d got %d\n",
child, pid);
}
if (!WIFEXITED(status)) {
die("child did not terminate cleanly\n");
}
if (block_fw_in_parent_ns)
umount("/lib/firmware");
return WEXITSTATUS(status) == EXIT_SUCCESS;
}
if (unshare(CLONE_NEWNS) != 0) {
die("unshare(CLONE_NEWNS) failed: %s\n",
strerror(errno));
}
if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) == -1)
die("remount root in child ns failed\n");
if (!block_fw_in_parent_ns) {
if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
die("blocking firmware in child ns failed\n");
} else
umount("/lib/firmware");
trigger_fw(fw_name, sys_path);
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
const char *fw_name = "test-firmware.bin";
char *sys_path;
if (argc != 2)
die("usage: %s sys_path\n", argv[0]);
/* Mount tmpfs to /lib/firmware so we don't have to assume
that it is writable for us.*/
if (mount("test", "/lib/firmware", "tmpfs", 0, NULL) == -1)
die("mounting tmpfs to /lib/firmware failed\n");
sys_path = argv[1];
if (asprintf(&fw_path, "/lib/firmware/%s", fw_name) < 0)
die("error: failed to build full fw_path\n");
setup_fw(fw_path);
setvbuf(stdout, NULL, _IONBF, 0);
/* Positive case: firmware in PID1 mount namespace */
printf("Testing with firmware in parent namespace (assumed to be same file system as PID1)\n");
if (!test_fw_in_ns(fw_name, sys_path, false))
die("error: failed to access firmware\n");
/* Negative case: firmware in child mount namespace, expected to fail */
printf("Testing with firmware in child namespace\n");
if (test_fw_in_ns(fw_name, sys_path, true))
die("error: firmware access did not fail\n");
unlink(fw_path);
free(fw_path);
umount("/lib/firmware");
exit(EXIT_SUCCESS);
}
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