From: Kees Cook <keescook@chromium.org>
Date: Thu, 2 Jun 2016 20:15:52 +0000 (-0700)
Subject: parisc/ptrace: run seccomp after ptrace
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=375f0183047109b98658d539db6ff22a6ac24abc;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

parisc/ptrace: run seccomp after ptrace

Close the hole where ptrace can change a syscall out from under seccomp.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
---

diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 8edc47c0b98e..e02d7b4d2b69 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -311,10 +311,6 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 long do_syscall_trace_enter(struct pt_regs *regs)
 {
-	/* Do the secure computing check first. */
-	if (secure_computing(NULL) == -1)
-		return -1;
-
 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 	    tracehook_report_syscall_entry(regs)) {
 		/*
@@ -325,6 +321,11 @@ long do_syscall_trace_enter(struct pt_regs *regs)
 		regs->gr[20] = -1UL;
 		goto out;
 	}
+
+	/* Do the secure computing check after ptrace. */
+	if (secure_computing(NULL) == -1)
+		return -1;
+
 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_enter(regs, regs->gr[20]);