[PATCH 07/14] arm/ptrace: run seccomp after ptrace
From: Kees Cook <hidden>
Date: 2016-06-09 21:03:54
Also in:
linux-arch, linux-mips, linux-s390, linux-um, linuxppc-dev, lkml
Subsystem:
arm port, ptrace support, the rest · Maintainers:
Russell King, Oleg Nesterov, Linus Torvalds
Close the hole where ptrace can change a syscall out from under seccomp. Signed-off-by: Kees Cook <redacted> Cc: Russell King <linux@armlinux.org.uk> Cc: linux-arm-kernel at 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 ad5e90ab165c..dc7b372872ff 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))
--
2.7.4