Merge tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull execve updates from Kees Cook:
 "Most are small refactorings and bug fixes, but three things stand out:
  switching timens (which got reverted before) looks solid now,
  FOLL_FORCE has been removed (no failures seen yet across several weeks
  in -next), and some whitespace cleanups (which are long overdue).

   - Add timens support (when switching mm). This version has survived
     in -next for the entire cycle (Andrei Vagin)

   - Various small bug fixes, refactoring, and readability improvements
     (Bernd Edlinger, Rolf Eike Beer, Bo Liu, Li Zetao Liu Shixin)

   - Remove FOLL_FORCE for stack setup (Kees Cook)

   - Whitespace cleanups (Rolf Eike Beer, Kees Cook)"

* tag 'execve-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  binfmt_misc: fix shift-out-of-bounds in check_special_flags
  binfmt: Fix error return code in load_elf_fdpic_binary()
  exec: Remove FOLL_FORCE for stack setup
  binfmt_elf: replace IS_ERR() with IS_ERR_VALUE()
  binfmt_elf: simplify error handling in load_elf_phdrs()
  binfmt_elf: fix documented return value for load_elf_phdrs()
  exec: simplify initial stack size expansion
  binfmt: Fix whitespace issues
  exec: Add comments on check_unsafe_exec() fs counting
  ELF uapi: add spaces before '{'
  selftests/timens: add a test for vfork+exit
  fs/exec: switch timens when a task gets a new mm

3 files changed, 141 insertions, 1 deletions

diff --git a/tools/testing/selftests/timens/.gitignore b/tools/testing/selftests/timens/.gitignore
index fe1eb8271b35..cae8dca0fbff 100644
--- a/tools/testing/selftests/timens/.gitignore
+++ b/tools/testing/selftests/timens/.gitignore
@@ -8,3 +8,4 @@ procfs
 timens
 timer
 timerfd
+vfork_exec
diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
index 3a5936cc10ab..f0d51d4d2c87 100644
--- a/tools/testing/selftests/timens/Makefile
+++ b/tools/testing/selftests/timens/Makefile
@@ -1,4 +1,4 @@
-TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec futex
+TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec futex vfork_exec
 TEST_GEN_PROGS_EXTENDED := gettime_perf
 
 CFLAGS := -Wall -Werror -pthread
diff --git a/tools/testing/selftests/timens/vfork_exec.c b/tools/testing/selftests/timens/vfork_exec.c
new file mode 100644
index 000000000000..beb7614941fb
--- /dev/null
+++ b/tools/testing/selftests/timens/vfork_exec.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "log.h"
+#include "timens.h"
+
+#define OFFSET (36000)
+
+struct thread_args {
+	char *tst_name;
+	struct timespec *now;
+};
+
+static void *tcheck(void *_args)
+{
+	struct thread_args *args = _args;
+	struct timespec *now = args->now, tst;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		_gettime(CLOCK_MONOTONIC, &tst, i);
+		if (abs(tst.tv_sec - now->tv_sec) > 5) {
+			pr_fail("%s: in-thread: unexpected value: %ld (%ld)\n",
+				args->tst_name, tst.tv_sec, now->tv_sec);
+			return (void *)1UL;
+		}
+	}
+	return NULL;
+}
+
+static int check_in_thread(char *tst_name, struct timespec *now)
+{
+	struct thread_args args = {
+		.tst_name = tst_name,
+		.now = now,
+	};
+	pthread_t th;
+	void *retval;
+
+	if (pthread_create(&th, NULL, tcheck, &args))
+		return pr_perror("thread");
+	if (pthread_join(th, &retval))
+		return pr_perror("pthread_join");
+	return !(retval == NULL);
+}
+
+static int check(char *tst_name, struct timespec *now)
+{
+	struct timespec tst;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		_gettime(CLOCK_MONOTONIC, &tst, i);
+		if (abs(tst.tv_sec - now->tv_sec) > 5)
+			return pr_fail("%s: unexpected value: %ld (%ld)\n",
+					tst_name, tst.tv_sec, now->tv_sec);
+	}
+	if (check_in_thread(tst_name, now))
+		return 1;
+	ksft_test_result_pass("%s\n", tst_name);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct timespec now;
+	int status;
+	pid_t pid;
+
+	if (argc > 1) {
+		char *endptr;
+
+		ksft_cnt.ksft_pass = 1;
+		now.tv_sec = strtoul(argv[1], &endptr, 0);
+		if (*endptr != 0)
+			return pr_perror("strtoul");
+
+		return check("child after exec", &now);
+	}
+
+	nscheck();
+
+	ksft_set_plan(4);
+
+	clock_gettime(CLOCK_MONOTONIC, &now);
+
+	if (unshare_timens())
+		return 1;
+
+	if (_settime(CLOCK_MONOTONIC, OFFSET))
+		return 1;
+
+	if (check("parent before vfork", &now))
+		return 1;
+
+	pid = vfork();
+	if (pid < 0)
+		return pr_perror("fork");
+
+	if (pid == 0) {
+		char now_str[64];
+		char *cargv[] = {"exec", now_str, NULL};
+		char *cenv[] = {NULL};
+
+		/* Check for proper vvar offsets after execve. */
+		snprintf(now_str, sizeof(now_str), "%ld", now.tv_sec + OFFSET);
+		execve("/proc/self/exe", cargv, cenv);
+		pr_perror("execve");
+		_exit(1);
+	}
+
+	if (waitpid(pid, &status, 0) != pid)
+		return pr_perror("waitpid");
+
+	if (status)
+		ksft_exit_fail();
+	ksft_inc_pass_cnt();
+	ksft_test_result_pass("wait for child\n");
+
+	/* Check that we are still in the source timens. */
+	if (check("parent after vfork", &now))
+		return 1;
+
+	ksft_exit_pass();
+	return 0;
+}