diff mbox series

[14/15] selftests/clone3: Avoid OS-defined clone_args

Message ID 20200912110820.597135-15-keescook@chromium.org
State New
Headers show
Series selftests/seccomp: Refactor change_syscall() | expand

Commit Message

Kees Cook Sept. 12, 2020, 11:08 a.m. UTC
As the UAPI headers start to appear in distros, we need to avoid
outdated versions of struct clone_args to be able to test modern
features. Additionally pull in the syscall numbers correctly.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
I needed to fix this to get MIPS to build the seccomp selftests.
---
 .../testing/selftests/clone3/clone3_selftests.h  | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

Comments

Christian Brauner Sept. 15, 2020, 4:25 p.m. UTC | #1
On Sat, Sep 12, 2020 at 04:08:19AM -0700, Kees Cook wrote:
> As the UAPI headers start to appear in distros, we need to avoid
> outdated versions of struct clone_args to be able to test modern
> features. Additionally pull in the syscall numbers correctly.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---

Hm, with this patch applied I'm getting:

gcc -g -I../../../../usr/include/    clone3_set_tid.c /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest_harness.h /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest.h -lcap -o /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid
In file included from clone3_set_tid.c:24:
clone3_selftests.h:37:8: error: redefinition of ‘struct clone_args’
   37 | struct clone_args {
      |        ^~~~~~~~~~
In file included from clone3_set_tid.c:12:
/usr/include/linux/sched.h:92:8: note: originally defined here
   92 | struct clone_args {
      |        ^~~~~~~~~~
make: *** [../lib.mk:140: /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid] Error 1

One trick to avoid this could be:

#ifndef CLONE_ARGS_SIZE_VER0
#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
#endif

#ifndef CLONE_ARGS_SIZE_VER1
#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
#endif

#ifndef CLONE_ARGS_SIZE_VER2
#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
#endif

struct __clone_args {
	__aligned_u64 flags;
	__aligned_u64 pidfd;
	__aligned_u64 child_tid;
	__aligned_u64 parent_tid;
	__aligned_u64 exit_signal;
	__aligned_u64 stack;
	__aligned_u64 stack_size;
	__aligned_u64 tls;
	__aligned_u64 set_tid;
	__aligned_u64 set_tid_size;
	__aligned_u64 cgroup;
};

static pid_t sys_clone3(struct __clone_args *args, size_t size)
{
	return syscall(__NR_clone3, args, size);
}

Christian
Kees Cook Sept. 18, 2020, 10 p.m. UTC | #2
On Tue, Sep 15, 2020 at 06:25:28PM +0200, Christian Brauner wrote:
> On Sat, Sep 12, 2020 at 04:08:19AM -0700, Kees Cook wrote:
> > As the UAPI headers start to appear in distros, we need to avoid
> > outdated versions of struct clone_args to be able to test modern
> > features. Additionally pull in the syscall numbers correctly.
> > 
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> 
> Hm, with this patch applied I'm getting:
> 
> gcc -g -I../../../../usr/include/    clone3_set_tid.c /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest_harness.h /home/brauner/src/git/linux/linux/tools/testing/selftests/kselftest.h -lcap -o /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid
> In file included from clone3_set_tid.c:24:
> clone3_selftests.h:37:8: error: redefinition of ‘struct clone_args’
>    37 | struct clone_args {
>       |        ^~~~~~~~~~
> In file included from clone3_set_tid.c:12:
> /usr/include/linux/sched.h:92:8: note: originally defined here
>    92 | struct clone_args {
>       |        ^~~~~~~~~~
> make: *** [../lib.mk:140: /home/brauner/src/git/linux/linux/tools/testing/selftests/clone3/clone3_set_tid] Error 1

Hm, weird.

> One trick to avoid this could be:
> 
> #ifndef CLONE_ARGS_SIZE_VER0
> #define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
> #endif
> 
> #ifndef CLONE_ARGS_SIZE_VER1
> #define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
> #endif
> 
> #ifndef CLONE_ARGS_SIZE_VER2
> #define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
> #endif
> 
> struct __clone_args {
> 	__aligned_u64 flags;
> 	__aligned_u64 pidfd;
> 	__aligned_u64 child_tid;
> 	__aligned_u64 parent_tid;
> 	__aligned_u64 exit_signal;
> 	__aligned_u64 stack;
> 	__aligned_u64 stack_size;
> 	__aligned_u64 tls;
> 	__aligned_u64 set_tid;
> 	__aligned_u64 set_tid_size;
> 	__aligned_u64 cgroup;
> };
> 
> static pid_t sys_clone3(struct __clone_args *args, size_t size)
> {
> 	return syscall(__NR_clone3, args, size);
> }

Yeah, that has fewer down sides. I'll rework it.
diff mbox series

Patch

diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h
index 91c1a78ddb39..bc0f34e37ae1 100644
--- a/tools/testing/selftests/clone3/clone3_selftests.h
+++ b/tools/testing/selftests/clone3/clone3_selftests.h
@@ -4,11 +4,19 @@ 
 #define _CLONE3_SELFTESTS_H
 
 #define _GNU_SOURCE
+
+/* Pull in syscall numbers. */
+#include <unistd.h>
+#include <sys/syscall.h>
+
+/* Avoid old OS versions of "struct clone_args". */
+#define clone_args old_clone_args
 #include <sched.h>
 #include <linux/sched.h>
+#undef clone_args
+
 #include <linux/types.h>
 #include <stdint.h>
-#include <syscall.h>
 #include <sys/wait.h>
 
 #include "../kselftest.h"
@@ -25,6 +33,7 @@ 
 
 #ifndef __NR_clone3
 #define __NR_clone3 -1
+#endif
 struct clone_args {
 	__aligned_u64 flags;
 	__aligned_u64 pidfd;
@@ -34,13 +43,16 @@  struct clone_args {
 	__aligned_u64 stack;
 	__aligned_u64 stack_size;
 	__aligned_u64 tls;
+#ifndef CLONE_ARGS_SIZE_VER1
 #define CLONE_ARGS_SIZE_VER1 80
+#endif
 	__aligned_u64 set_tid;
 	__aligned_u64 set_tid_size;
+#ifndef CLONE_ARGS_SIZE_VER2
 #define CLONE_ARGS_SIZE_VER2 88
+#endif
 	__aligned_u64 cgroup;
 };
-#endif /* __NR_clone3 */
 
 static pid_t sys_clone3(struct clone_args *args, size_t size)
 {