From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x22d.google.com (mail-pf0-x22d.google.com [IPv6:2607:f8b0:400e:c00::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rQd6b6YmQzDqHQ for ; Fri, 10 Jun 2016 07:02:31 +1000 (AEST) Received: by mail-pf0-x22d.google.com with SMTP id 62so16361730pfd.1 for ; Thu, 09 Jun 2016 14:02:31 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Heiko Carstens , Martin Schwidefsky , linux-s390@vger.kernel.org, Andy Lutomirski , Benjamin Herrenschmidt , Catalin Marinas , Chris Metcalf , Helge Deller , "James E.J. Bottomley" , James Hogan , Jeff Dike , linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "Maciej W. Rozycki" , Mark Rutland , Michael Ellerman , Paul Mackerras , Ralf Baechle , Richard Weinberger , Russell King , user-mode-linux-devel@lists.sourceforge.net, Will Deacon , x86@kernel.org Subject: [PATCH 11/14] s390/ptrace: run seccomp after ptrace Date: Thu, 9 Jun 2016 14:02:01 -0700 Message-Id: <1465506124-21866-12-git-send-email-keescook@chromium.org> In-Reply-To: <1465506124-21866-1-git-send-email-keescook@chromium.org> References: <1465506124-21866-1-git-send-email-keescook@chromium.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Close the hole where ptrace can change a syscall out from under seccomp. Signed-off-by: Kees Cook Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: linux-s390@vger.kernel.org --- arch/s390/kernel/ptrace.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c index c238e9958c2a..cea17010448f 100644 --- a/arch/s390/kernel/ptrace.c +++ b/arch/s390/kernel/ptrace.c @@ -821,15 +821,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) { - long ret = 0; - - /* Do the secure computing check first. */ - if (secure_computing(NULL)) { - /* seccomp failures shouldn't expose any additional code. */ - ret = -1; - goto out; - } - /* * The sysc_tracesys code in entry.S stored the system * call number to gprs[2]. @@ -843,7 +834,13 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) * the system call and the system call restart handling. */ clear_pt_regs_flag(regs, PIF_SYSCALL); - ret = -1; + return -1; + } + + /* Do the secure computing check after ptrace. */ + if (secure_computing(NULL)) { + /* seccomp failures shouldn't expose any additional code. */ + return -1; } if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) @@ -852,8 +849,8 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) audit_syscall_entry(regs->gprs[2], regs->orig_gpr2, regs->gprs[3], regs->gprs[4], regs->gprs[5]); -out: - return ret ?: regs->gprs[2]; + + return regs->gprs[2]; } asmlinkage void do_syscall_trace_exit(struct pt_regs *regs) -- 2.7.4