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-rw-r--r--tools/testing/selftests/firmware/fw_namespace.c152
1 files changed, 152 insertions, 0 deletions
diff --git a/tools/testing/selftests/firmware/fw_namespace.c b/tools/testing/selftests/firmware/fw_namespace.c
new file mode 100644
index 000000000..4c6f0cd83
--- /dev/null
+++ b/tools/testing/selftests/firmware/fw_namespace.c
@@ -0,0 +1,152 @@
+// 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>
+
+#ifndef CLONE_NEWNS
+# define CLONE_NEWNS 0x00020000
+#endif
+
+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);
+}