[PATCH 10/14] parisc/ptrace: run seccomp after ptrace

Kees Cook keescook at chromium.org
Fri Jun 10 07:02:00 AEST 2016


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

Signed-off-by: Kees Cook <keescook at chromium.org>
Cc: "James E.J. Bottomley" <jejb at parisc-linux.org>
Cc: Helge Deller <deller at gmx.de>
Cc: linux-parisc at vger.kernel.org
---
 arch/parisc/kernel/ptrace.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

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]);
-- 
2.7.4



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