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1// SPDX-License-Identifier: GPL-2.02/* Test triggering of loading of firmware from different mount3 * namespaces. Expect firmware to be always loaded from the mount4 * namespace of PID 1. */5#define _GNU_SOURCE6#include <errno.h>7#include <fcntl.h>8#include <sched.h>9#include <stdarg.h>10#include <stdbool.h>11#include <stdio.h>12#include <stdlib.h>13#include <string.h>14#include <sys/mount.h>15#include <sys/stat.h>16#include <sys/types.h>17#include <sys/wait.h>18#include <unistd.h>19 20static char *fw_path = NULL;21 22static void die(char *fmt, ...)23{24 va_list ap;25 26 va_start(ap, fmt);27 vfprintf(stderr, fmt, ap);28 va_end(ap);29 if (fw_path)30 unlink(fw_path);31 umount("/lib/firmware");32 exit(EXIT_FAILURE);33}34 35static void trigger_fw(const char *fw_name, const char *sys_path)36{37 int fd;38 39 fd = open(sys_path, O_WRONLY);40 if (fd < 0)41 die("open failed: %s\n",42 strerror(errno));43 if (write(fd, fw_name, strlen(fw_name)) != strlen(fw_name))44 exit(EXIT_FAILURE);45 close(fd);46}47 48static void setup_fw(const char *fw_path)49{50 int fd;51 const char fw[] = "ABCD0123";52 53 fd = open(fw_path, O_WRONLY | O_CREAT, 0600);54 if (fd < 0)55 die("open failed: %s\n",56 strerror(errno));57 if (write(fd, fw, sizeof(fw) -1) != sizeof(fw) -1)58 die("write failed: %s\n",59 strerror(errno));60 close(fd);61}62 63static bool test_fw_in_ns(const char *fw_name, const char *sys_path, bool block_fw_in_parent_ns)64{65 pid_t child;66 67 if (block_fw_in_parent_ns)68 if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)69 die("blocking firmware in parent ns failed\n");70 71 child = fork();72 if (child == -1) {73 die("fork failed: %s\n",74 strerror(errno));75 }76 if (child != 0) { /* parent */77 pid_t pid;78 int status;79 80 pid = waitpid(child, &status, 0);81 if (pid == -1) {82 die("waitpid failed: %s\n",83 strerror(errno));84 }85 if (pid != child) {86 die("waited for %d got %d\n",87 child, pid);88 }89 if (!WIFEXITED(status)) {90 die("child did not terminate cleanly\n");91 }92 if (block_fw_in_parent_ns)93 umount("/lib/firmware");94 return WEXITSTATUS(status) == EXIT_SUCCESS;95 }96 97 if (unshare(CLONE_NEWNS) != 0) {98 die("unshare(CLONE_NEWNS) failed: %s\n",99 strerror(errno));100 }101 if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) == -1)102 die("remount root in child ns failed\n");103 104 if (!block_fw_in_parent_ns) {105 if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)106 die("blocking firmware in child ns failed\n");107 } else108 umount("/lib/firmware");109 110 trigger_fw(fw_name, sys_path);111 112 exit(EXIT_SUCCESS);113}114 115int main(int argc, char **argv)116{117 const char *fw_name = "test-firmware.bin";118 char *sys_path;119 if (argc != 2)120 die("usage: %s sys_path\n", argv[0]);121 122 /* Mount tmpfs to /lib/firmware so we don't have to assume123 that it is writable for us.*/124 if (mount("test", "/lib/firmware", "tmpfs", 0, NULL) == -1)125 die("mounting tmpfs to /lib/firmware failed\n");126 127 sys_path = argv[1];128 if (asprintf(&fw_path, "/lib/firmware/%s", fw_name) < 0)129 die("error: failed to build full fw_path\n");130 131 setup_fw(fw_path);132 133 setvbuf(stdout, NULL, _IONBF, 0);134 /* Positive case: firmware in PID1 mount namespace */135 printf("Testing with firmware in parent namespace (assumed to be same file system as PID1)\n");136 if (!test_fw_in_ns(fw_name, sys_path, false))137 die("error: failed to access firmware\n");138 139 /* Negative case: firmware in child mount namespace, expected to fail */140 printf("Testing with firmware in child namespace\n");141 if (test_fw_in_ns(fw_name, sys_path, true))142 die("error: firmware access did not fail\n");143 144 unlink(fw_path);145 free(fw_path);146 umount("/lib/firmware");147 exit(EXIT_SUCCESS);148}149