From 0f3912fd934cdfd03d93f2dc6f064099795bf638 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 2 Jun 2016 12:16:31 -0700 Subject: [PATCH] arm/ptrace: run seccomp after ptrace Close the hole where ptrace can change a syscall out from under seccomp. Signed-off-by: Kees Cook Cc: Russell King Cc: linux-arm-kernel@lists.infradead.org --- arch/arm/kernel/ptrace.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 1027d3b54541..ce131ed5939d 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -932,18 +932,19 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) { current_thread_info()->syscall = scno; - /* Do the secure computing check first; failures should be fast. */ + if (test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); + + /* Do seccomp after ptrace; syscall may have changed. */ #ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER if (secure_computing(NULL) == -1) return -1; #else /* XXX: remove this once OABI gets fixed */ - secure_computing_strict(scno); + secure_computing_strict(current_thread_info()->syscall); #endif - if (test_thread_flag(TIF_SYSCALL_TRACE)) - tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); - + /* Tracer or seccomp may have changed syscall. */ scno = current_thread_info()->syscall; if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) -- 2.20.1