[PATCH 13/14] tile/ptrace: run seccomp after ptrace

Kees Cook keescook at chromium.org
Fri Jun 10 07:02:03 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: Chris Metcalf <cmetcalf at mellanox.com>
---
 arch/tile/kernel/ptrace.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c
index 8c6d2f2fefa3..d89b7011667c 100644
--- a/arch/tile/kernel/ptrace.c
+++ b/arch/tile/kernel/ptrace.c
@@ -255,14 +255,15 @@ int do_syscall_trace_enter(struct pt_regs *regs)
 {
 	u32 work = ACCESS_ONCE(current_thread_info()->flags);
 
-	if (secure_computing(NULL) == -1)
+	if ((work & _TIF_SYSCALL_TRACE) &&
+	    tracehook_report_syscall_entry(regs)) {
+		regs->regs[TREG_SYSCALL_NR] = -1;
 		return -1;
-
-	if (work & _TIF_SYSCALL_TRACE) {
-		if (tracehook_report_syscall_entry(regs))
-			regs->regs[TREG_SYSCALL_NR] = -1;
 	}
 
+	if (secure_computing(NULL) == -1)
+		return -1;
+
 	if (work & _TIF_SYSCALL_TRACEPOINT)
 		trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
 
-- 
2.7.4



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