[RESEND PATCH v4 2/2] arm64: Add seccomp support
From: Will Deacon <hidden>
Date: 2014-07-09 11:13:05
Also in:
lkml
Hi Akashi, On Fri, Jul 04, 2014 at 08:31:55AM +0100, AKASHI Takahiro wrote:
secure_computing() should always be called first in syscall_trace_enter(). If it returns non-zero, we should stop further handling. Then that system call may eventually fail, be trapped or the process itself be killed depending on loaded rules. In this case, syscall_trace_enter() returns a dedicated value in order to skip a normal syscall table lookup because a seccomp rule may have already overridden errno.
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 70526cf..baab5fc 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c@@ -21,12 +21,14 @@ #include <linux/audit.h> #include <linux/compat.h> +#include <linux/errno.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/ptrace.h> #include <linux/user.h> +#include <linux/seccomp.h> #include <linux/security.h> #include <linux/init.h> #include <linux/signal.h>@@ -1109,6 +1111,10 @@ static void tracehook_report_syscall(struct pt_regs *regs, asmlinkage int syscall_trace_enter(struct pt_regs *regs) { + if (secure_computing(regs->syscallno) == -1) + /* seccomp failures shouldn't expose any additional code. */ + return -EPERM; + if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
We return regs->syscallno immediately after this, so we have the same issue that Kees identified for arch/arm/. Did you follow the discussion I had with Andy? Will