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

From: Kees Cook
Date: Thu Jun 09 2016 - 17:07:20 EST


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

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxxxx>
---
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