diff mbox series

[1/4] seccomp/mips: change syscall_trace_enter() to use secure_computing()

Message ID 20250120134445.GA21268@redhat.com (mailing list archive)
State New
Headers show
Series seccomp: remove the 'sd' argument from __secure_computing() | expand

Commit Message

Oleg Nesterov Jan. 20, 2025, 1:44 p.m. UTC
arch/mips/Kconfig selects HAVE_ARCH_SECCOMP_FILTER so syscall_trace_enter()
can just use __secure_computing(NULL) and rely on populate_seccomp_data(sd)
and "sd == NULL" checks in __secure_computing(sd) paths.

With the change above syscall_trace_enter() can just use secure_computing()
and avoid #ifdef + test_thread_flag(TIF_SECCOMP). CONFIG_GENERIC_ENTRY is
not defined, so test_syscall_work(SECCOMP) will check TIF_SECCOMP.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 arch/mips/kernel/ptrace.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

Comments

Kees Cook Jan. 20, 2025, 9:48 p.m. UTC | #1
On Mon, Jan 20, 2025 at 02:44:45PM +0100, Oleg Nesterov wrote:
> arch/mips/Kconfig selects HAVE_ARCH_SECCOMP_FILTER so syscall_trace_enter()
> can just use __secure_computing(NULL) and rely on populate_seccomp_data(sd)
> and "sd == NULL" checks in __secure_computing(sd) paths.
> 
> With the change above syscall_trace_enter() can just use secure_computing()
> and avoid #ifdef + test_thread_flag(TIF_SECCOMP). CONFIG_GENERIC_ENTRY is
> not defined, so test_syscall_work(SECCOMP) will check TIF_SECCOMP.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---
>  arch/mips/kernel/ptrace.c | 20 ++------------------
>  1 file changed, 2 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
> index 61503a36067e..f7107479c7fa 100644
> --- a/arch/mips/kernel/ptrace.c
> +++ b/arch/mips/kernel/ptrace.c
> @@ -1326,24 +1326,8 @@ asmlinkage long syscall_trace_enter(struct pt_regs *regs)
>  			return -1;
>  	}
>  
> -#ifdef CONFIG_SECCOMP
> -	if (unlikely(test_thread_flag(TIF_SECCOMP))) {

Yup, this test works out the same as what secure_computing() does.

> -		int ret, i;
> -		struct seccomp_data sd;
> -		unsigned long args[6];
> -
> -		sd.nr = current_thread_info()->syscall;

This matches MIPS's syscall_get_nr() in populate_seccomp_data().

> -		sd.arch = syscall_get_arch(current);
> -		syscall_get_arguments(current, regs, args);
> -		for (i = 0; i < 6; i++)
> -			sd.args[i] = args[i];
> -		sd.instruction_pointer = KSTK_EIP(current);

Rest matches the rest of populate_seccomp_data().

> -
> -		ret = __secure_computing(&sd);
> -		if (ret == -1)
> -			return ret;
> -	}
> -#endif
> +	if (secure_computing())
> +		return -1;
>  
>  	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
>  		trace_sys_enter(regs, regs->regs[2]);
> -- 

So this check out logically from what I can see. I can build test it,
but I don't have MIPS emulation set up. I'd love an Ack from a MIPS
maintainer...

Reviewed-by: Kees Cook <kees@kernel.org>
diff mbox series

Patch

diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 61503a36067e..f7107479c7fa 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -1326,24 +1326,8 @@  asmlinkage long syscall_trace_enter(struct pt_regs *regs)
 			return -1;
 	}
 
-#ifdef CONFIG_SECCOMP
-	if (unlikely(test_thread_flag(TIF_SECCOMP))) {
-		int ret, i;
-		struct seccomp_data sd;
-		unsigned long args[6];
-
-		sd.nr = current_thread_info()->syscall;
-		sd.arch = syscall_get_arch(current);
-		syscall_get_arguments(current, regs, args);
-		for (i = 0; i < 6; i++)
-			sd.args[i] = args[i];
-		sd.instruction_pointer = KSTK_EIP(current);
-
-		ret = __secure_computing(&sd);
-		if (ret == -1)
-			return ret;
-	}
-#endif
+	if (secure_computing())
+		return -1;
 
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_enter(regs, regs->regs[2]);