diff options
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/selftests/mount/unprivileged-remount-test.c | 172 |
1 files changed, 142 insertions, 30 deletions
diff --git a/tools/testing/selftests/mount/unprivileged-remount-test.c b/tools/testing/selftests/mount/unprivileged-remount-test.c index 1b3ff2fda4d0..9669d375625a 100644 --- a/tools/testing/selftests/mount/unprivileged-remount-test.c +++ b/tools/testing/selftests/mount/unprivileged-remount-test.c @@ -6,6 +6,8 @@ #include <sys/types.h> #include <sys/mount.h> #include <sys/wait.h> +#include <sys/vfs.h> +#include <sys/statvfs.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> @@ -32,11 +34,14 @@ # define CLONE_NEWPID 0x20000000 #endif +#ifndef MS_REC +# define MS_REC 16384 +#endif #ifndef MS_RELATIME -#define MS_RELATIME (1 << 21) +# define MS_RELATIME (1 << 21) #endif #ifndef MS_STRICTATIME -#define MS_STRICTATIME (1 << 24) +# define MS_STRICTATIME (1 << 24) #endif static void die(char *fmt, ...) @@ -87,6 +92,45 @@ static void write_file(char *filename, char *fmt, ...) } } +static int read_mnt_flags(const char *path) +{ + int ret; + struct statvfs stat; + int mnt_flags; + + ret = statvfs(path, &stat); + if (ret != 0) { + die("statvfs of %s failed: %s\n", + path, strerror(errno)); + } + if (stat.f_flag & ~(ST_RDONLY | ST_NOSUID | ST_NODEV | \ + ST_NOEXEC | ST_NOATIME | ST_NODIRATIME | ST_RELATIME | \ + ST_SYNCHRONOUS | ST_MANDLOCK)) { + die("Unrecognized mount flags\n"); + } + mnt_flags = 0; + if (stat.f_flag & ST_RDONLY) + mnt_flags |= MS_RDONLY; + if (stat.f_flag & ST_NOSUID) + mnt_flags |= MS_NOSUID; + if (stat.f_flag & ST_NODEV) + mnt_flags |= MS_NODEV; + if (stat.f_flag & ST_NOEXEC) + mnt_flags |= MS_NOEXEC; + if (stat.f_flag & ST_NOATIME) + mnt_flags |= MS_NOATIME; + if (stat.f_flag & ST_NODIRATIME) + mnt_flags |= MS_NODIRATIME; + if (stat.f_flag & ST_RELATIME) + mnt_flags |= MS_RELATIME; + if (stat.f_flag & ST_SYNCHRONOUS) + mnt_flags |= MS_SYNCHRONOUS; + if (stat.f_flag & ST_MANDLOCK) + mnt_flags |= ST_MANDLOCK; + + return mnt_flags; +} + static void create_and_enter_userns(void) { uid_t uid; @@ -118,7 +162,8 @@ static void create_and_enter_userns(void) } static -bool test_unpriv_remount(int mount_flags, int remount_flags, int invalid_flags) +bool test_unpriv_remount(const char *fstype, const char *mount_options, + int mount_flags, int remount_flags, int invalid_flags) { pid_t child; @@ -151,9 +196,11 @@ bool test_unpriv_remount(int mount_flags, int remount_flags, int invalid_flags) strerror(errno)); } - if (mount("testing", "/tmp", "ramfs", mount_flags, NULL) != 0) { - die("mount of /tmp failed: %s\n", - strerror(errno)); + if (mount("testing", "/tmp", fstype, mount_flags, mount_options) != 0) { + die("mount of %s with options '%s' on /tmp failed: %s\n", + fstype, + mount_options? mount_options : "", + strerror(errno)); } create_and_enter_userns(); @@ -181,62 +228,127 @@ bool test_unpriv_remount(int mount_flags, int remount_flags, int invalid_flags) static bool test_unpriv_remount_simple(int mount_flags) { - return test_unpriv_remount(mount_flags, mount_flags, 0); + return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags, 0); } static bool test_unpriv_remount_atime(int mount_flags, int invalid_flags) { - return test_unpriv_remount(mount_flags, mount_flags, invalid_flags); + return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags, + invalid_flags); +} + +static bool test_priv_mount_unpriv_remount(void) +{ + pid_t child; + int ret; + const char *orig_path = "/dev"; + const char *dest_path = "/tmp"; + int orig_mnt_flags, remount_mnt_flags; + + 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"); + } + return WEXITSTATUS(status) == EXIT_SUCCESS ? true : false; + } + + orig_mnt_flags = read_mnt_flags(orig_path); + + create_and_enter_userns(); + ret = unshare(CLONE_NEWNS); + if (ret != 0) { + die("unshare(CLONE_NEWNS) failed: %s\n", + strerror(errno)); + } + + ret = mount(orig_path, dest_path, "bind", MS_BIND | MS_REC, NULL); + if (ret != 0) { + die("recursive bind mount of %s onto %s failed: %s\n", + orig_path, dest_path, strerror(errno)); + } + + ret = mount(dest_path, dest_path, "none", + MS_REMOUNT | MS_BIND | orig_mnt_flags , NULL); + if (ret != 0) { + /* system("cat /proc/self/mounts"); */ + die("remount of /tmp failed: %s\n", + strerror(errno)); + } + + remount_mnt_flags = read_mnt_flags(dest_path); + if (orig_mnt_flags != remount_mnt_flags) { + die("Mount flags unexpectedly changed during remount of %s originally mounted on %s\n", + dest_path, orig_path); + } + exit(EXIT_SUCCESS); } int main(int argc, char **argv) { - if (!test_unpriv_remount_simple(MS_RDONLY|MS_NODEV)) { + if (!test_unpriv_remount_simple(MS_RDONLY)) { die("MS_RDONLY malfunctions\n"); } - if (!test_unpriv_remount_simple(MS_NODEV)) { + if (!test_unpriv_remount("devpts", "newinstance", MS_NODEV, MS_NODEV, 0)) { die("MS_NODEV malfunctions\n"); } - if (!test_unpriv_remount_simple(MS_NOSUID|MS_NODEV)) { + if (!test_unpriv_remount_simple(MS_NOSUID)) { die("MS_NOSUID malfunctions\n"); } - if (!test_unpriv_remount_simple(MS_NOEXEC|MS_NODEV)) { + if (!test_unpriv_remount_simple(MS_NOEXEC)) { die("MS_NOEXEC malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODEV, - MS_NOATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_RELATIME, + MS_NOATIME)) { die("MS_RELATIME malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODEV, - MS_NOATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_STRICTATIME, + MS_NOATIME)) { die("MS_STRICTATIME malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODEV, - MS_STRICTATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_NOATIME, + MS_STRICTATIME)) { - die("MS_RELATIME malfunctions\n"); + die("MS_NOATIME malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME|MS_NODEV, - MS_NOATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME, + MS_NOATIME)) { - die("MS_RELATIME malfunctions\n"); + die("MS_RELATIME|MS_NODIRATIME malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME|MS_NODEV, - MS_NOATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME, + MS_NOATIME)) { - die("MS_RELATIME malfunctions\n"); + die("MS_STRICTATIME|MS_NODIRATIME malfunctions\n"); } - if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME|MS_NODEV, - MS_STRICTATIME|MS_NODEV)) + if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME, + MS_STRICTATIME)) { - die("MS_RELATIME malfunctions\n"); + die("MS_NOATIME|MS_DIRATIME malfunctions\n"); } - if (!test_unpriv_remount(MS_STRICTATIME|MS_NODEV, MS_NODEV, - MS_NOATIME|MS_NODEV)) + if (!test_unpriv_remount("ramfs", NULL, MS_STRICTATIME, 0, MS_NOATIME)) { die("Default atime malfunctions\n"); } + if (!test_priv_mount_unpriv_remount()) { + die("Mount flags unexpectedly changed after remount\n"); + } return EXIT_SUCCESS; } |