From b39697a80ad388e2063c54e56333882f4307c1a1 Mon Sep 17 00:00:00 2001

From: Jan Synacek <jsynacek@redhat.com>

Date: Tue, 12 Nov 2019 13:27:49 +0100

Subject: [PATCH] test: add test case for restrict_suid_sgid()

(cherry picked from commit 167fc10cb352b04d442c9010dab4f8dc24219749)

Related: #1687512

---

 src/test/test-seccomp.c | 226 ++++++++++++++++++++++++++++++++++++++++

 1 file changed, 226 insertions(+)

diff --git a/src/test/test-seccomp.c b/src/test/test-seccomp.c

index d177515ac7..4021a06e0e 100644

--- a/src/test/test-seccomp.c

+++ b/src/test/test-seccomp.c

@@ -17,9 +17,11 @@

 #include "nsflags.h"

 #include "process-util.h"

 #include "raw-clone.h"

+#include "rm-rf.h"

 #include "seccomp-util.h"

 #include "set.h"

 #include "string-util.h"

+#include "umask-util.h"

 #include "util.h"

 #include "virt.h"

@@ -666,6 +668,229 @@ static void test_filter_sets_ordered(void) {

         }

 }

+static int mkostemp_safe(char *pattern) {

+        _unused_ _cleanup_umask_ mode_t u = umask(0077);

+        int fd;

+

+        assert(pattern);

+

+        fd = mkostemp(pattern, O_CLOEXEC);

+        if (fd < 0)

+                return -errno;

+

+        return fd;

+}

+

+static int real_open(const char *path, int flags, mode_t mode) {

+        /* glibc internally calls openat() when open() is requested. Let's hence define our own wrapper for

+         * testing purposes that calls the real syscall, on architectures where SYS_open is defined. On

+         * other architectures, let's just fall back to the glibc call. */

+

+#ifdef SYS_open

+        return (int) syscall(SYS_open, path, flags, mode);

+#else

+        return open(path, flags, mode);

+#endif

+}

+

+static void test_restrict_suid_sgid(void) {

+        pid_t pid;

+

+        log_info("/* %s */", __func__);

+

+        if (!is_seccomp_available()) {

+                log_notice("Seccomp not available, skipping %s", __func__);

+                return;

+        }

+        if (geteuid() != 0) {

+                log_notice("Not root, skipping %s", __func__);

+                return;

+        }

+

+        pid = fork();

+        assert_se(pid >= 0);

+

+        if (pid == 0) {

+                char path[] = "/tmp/suidsgidXXXXXX", dir[] = "/tmp/suidsgiddirXXXXXX";

+                int fd = -1, k = -1;

+                const char *z;

+

+                fd = mkostemp_safe(path);

+                assert_se(fd >= 0);

+

+                assert_se(mkdtemp(dir));

+                z = strjoina(dir, "/test");

+

+                assert_se(chmod(path, 0755 | S_ISUID) >= 0);

+                assert_se(chmod(path, 0755 | S_ISGID) >= 0);

+                assert_se(chmod(path, 0755 | S_ISGID | S_ISUID) >= 0);

+                assert_se(chmod(path, 0755) >= 0);

+

+                assert_se(fchmod(fd, 0755 | S_ISUID) >= 0);

+                assert_se(fchmod(fd, 0755 | S_ISGID) >= 0);

+                assert_se(fchmod(fd, 0755 | S_ISGID | S_ISUID) >= 0);

+                assert_se(fchmod(fd, 0755) >= 0);

+

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISUID, 0) >= 0);

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISGID, 0) >= 0);

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISGID | S_ISUID, 0) >= 0);

+                assert_se(fchmodat(AT_FDCWD, path, 0755, 0) >= 0);

+

+                k = real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = creat(z, 0644 | S_ISUID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = creat(z, 0644 | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = creat(z, 0644 | S_ISUID | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = creat(z, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID | S_ISGID);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                k = openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(mkdir(z, 0755 | S_ISUID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdir(z, 0755 | S_ISGID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdir(z, 0755 | S_ISUID | S_ISGID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdir(z, 0755) >= 0);

+                assert_se(rmdir(z) >= 0);

+

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISUID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISGID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISUID | S_ISGID) >= 0);

+                assert_se(rmdir(z) >= 0);

+                assert_se(mkdirat(AT_FDCWD, z, 0755) >= 0);

+                assert_se(rmdir(z) >= 0);

+

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISUID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISGID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISUID | S_ISGID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknod(z, S_IFREG | 0755, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISUID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISGID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISUID | S_ISGID, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(seccomp_restrict_suid_sgid() >= 0);

+

+                assert_se(chmod(path, 0775 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(chmod(path, 0775 | S_ISGID) < 0  && errno == EPERM);

+                assert_se(chmod(path, 0775 | S_ISGID | S_ISUID) < 0  && errno == EPERM);

+                assert_se(chmod(path, 0775) >= 0);

+

+                assert_se(fchmod(fd, 0775 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(fchmod(fd, 0775 | S_ISGID) < 0  && errno == EPERM);

+                assert_se(fchmod(fd, 0775 | S_ISGID | S_ISUID) < 0  && errno == EPERM);

+                assert_se(fchmod(fd, 0775) >= 0);

+

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISUID, 0) < 0 && errno == EPERM);

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISGID, 0) < 0 && errno == EPERM);

+                assert_se(fchmodat(AT_FDCWD, path, 0755 | S_ISGID | S_ISUID, 0) < 0 && errno == EPERM);

+                assert_se(fchmodat(AT_FDCWD, path, 0755, 0) >= 0);

+

+                assert_se(real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISGID) < 0 && errno == EPERM);

+                assert_se(real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID | S_ISGID) < 0 && errno == EPERM);

+                k = real_open(z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(creat(z, 0644 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(creat(z, 0644 | S_ISGID) < 0 && errno == EPERM);

+                assert_se(creat(z, 0644 | S_ISUID | S_ISGID) < 0 && errno == EPERM);

+                k = creat(z, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISGID) < 0 && errno == EPERM);

+                assert_se(openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644 | S_ISUID | S_ISGID) < 0 && errno == EPERM);

+                k = openat(AT_FDCWD, z, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL, 0644);

+                k = safe_close(k);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(mkdir(z, 0755 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(mkdir(z, 0755 | S_ISGID) < 0 && errno == EPERM);

+                assert_se(mkdir(z, 0755 | S_ISUID | S_ISGID) < 0 && errno == EPERM);

+                assert_se(mkdir(z, 0755) >= 0);

+                assert_se(rmdir(z) >= 0);

+

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISUID) < 0 && errno == EPERM);

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISGID) < 0 && errno == EPERM);

+                assert_se(mkdirat(AT_FDCWD, z, 0755 | S_ISUID | S_ISGID) < 0 && errno == EPERM);

+                assert_se(mkdirat(AT_FDCWD, z, 0755) >= 0);

+                assert_se(rmdir(z) >= 0);

+

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISUID, 0) < 0 && errno == EPERM);

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISGID, 0) < 0 && errno == EPERM);

+                assert_se(mknod(z, S_IFREG | 0755 | S_ISUID | S_ISGID, 0) < 0 && errno == EPERM);

+                assert_se(mknod(z, S_IFREG | 0755, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISUID, 0) < 0 && errno == EPERM);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISGID, 0) < 0 && errno == EPERM);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755 | S_ISUID | S_ISGID, 0) < 0 && errno == EPERM);

+                assert_se(mknodat(AT_FDCWD, z, S_IFREG | 0755, 0) >= 0);

+                assert_se(unlink(z) >= 0);

+

+                assert_se(unlink(path) >= 0);

+                assert_se(rm_rf(dir, REMOVE_ROOT|REMOVE_PHYSICAL) >= 0);

+

+                _exit(EXIT_SUCCESS);

+        }

+

+        assert_se(wait_for_terminate_and_check("suidsgidseccomp", pid, WAIT_LOG) == EXIT_SUCCESS);

+}

+

 int main(int argc, char *argv[]) {

         log_set_max_level(LOG_DEBUG);

@@ -684,6 +909,7 @@ int main(int argc, char *argv[]) {

         test_load_syscall_filter_set_raw();

         test_lock_personality();

         test_filter_sets_ordered();

+        test_restrict_suid_sgid();

         return 0;

 }