From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x236.google.com (mail-pf0-x236.google.com [IPv6:2607:f8b0:400e:c00::236]) (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 3rQd6c5f39zDqPF for ; Fri, 10 Jun 2016 07:02:32 +1000 (AEST) Received: by mail-pf0-x236.google.com with SMTP id y124so16392465pfy.0 for ; Thu, 09 Jun 2016 14:02:32 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Jeff Dike , Richard Weinberger , user-mode-linux-devel@lists.sourceforge.net, Andy Lutomirski , Benjamin Herrenschmidt , Catalin Marinas , Chris Metcalf , Heiko Carstens , Helge Deller , "James E.J. Bottomley" , James Hogan , 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, linux-s390@vger.kernel.org, "Maciej W. Rozycki" , Mark Rutland , Martin Schwidefsky , Michael Ellerman , Paul Mackerras , Ralf Baechle , Russell King , Will Deacon , x86@kernel.org Subject: [PATCH 14/14] um/ptrace: run seccomp after ptrace Date: Thu, 9 Jun 2016 14:02:04 -0700 Message-Id: <1465506124-21866-15-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: Jeff Dike Cc: Richard Weinberger Cc: user-mode-linux-devel@lists.sourceforge.net --- arch/um/kernel/skas/syscall.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index 9c5570f0f397..ef4b8f949b51 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -20,12 +20,12 @@ void handle_syscall(struct uml_pt_regs *r) UPT_SYSCALL_NR(r) = PT_SYSCALL_NR(r->gp); PT_REGS_SET_SYSCALL_RETURN(regs, -ENOSYS); - /* Do the secure computing check first; failures should be fast. */ - if (secure_computing(NULL) == -1) + if (syscall_trace_enter(regs)) return; - if (syscall_trace_enter(regs)) - goto out; + /* Do the seccomp check after ptrace; failures should be fast. */ + if (secure_computing(NULL) == -1) + return; /* Update the syscall number after orig_ax has potentially been updated * with ptrace. @@ -37,6 +37,5 @@ void handle_syscall(struct uml_pt_regs *r) PT_REGS_SET_SYSCALL_RETURN(regs, EXECUTE_SYSCALL(syscall, regs)); -out: syscall_trace_leave(regs); } -- 2.7.4