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Date: Fri, 11 Mar 2016 17:10:20 -0500
From: Chris Metcalf <cmetcalf@...lanox.com>
To: Gilad Ben Yossef <giladb@...hip.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"Rik van Riel" <riel@...hat.com>, Tejun Heo <tj@...nel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Christoph Lameter <cl@...ux.com>,
Viresh Kumar <viresh.kumar@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Andy Lutomirski <luto@...capital.net>,
"H. Peter Anvin" <hpa@...or.com>, <x86@...nel.org>,
<linux-kernel@...r.kernel.org>
CC: Chris Metcalf <cmetcalf@...lanox.com>
Subject: [PATCH v11 10/13] arch/x86: enable task isolation functionality
In prepare_exit_to_usermode(), call task_isolation_ready() for
TIF_TASK_ISOLATION tasks when we are checking the thread-info flags,
and after we've handled the other work, call task_isolation_enter()
for such tasks.
In syscall_trace_enter_phase1(), we add the necessary support for
strict-mode detection of syscalls.
We add strict reporting for the kernel exception types that do
not result in signals, namely non-signalling page faults and
non-signalling MPX fixups.
Signed-off-by: Chris Metcalf <cmetcalf@...lanox.com>
---
arch/x86/entry/common.c | 18 +++++++++++++++++-
arch/x86/include/asm/thread_info.h | 2 ++
arch/x86/kernel/traps.c | 2 ++
arch/x86/mm/fault.c | 2 ++
4 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 03663740c866..62e1e34cffc5 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
#include <linux/context_tracking.h>
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
+#include <linux/isolation.h>
#include <asm/desc.h>
#include <asm/traps.h>
@@ -95,6 +96,13 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
}
#endif
+ /* In isolation mode, we may prevent the syscall from running. */
+ if (work & _TIF_TASK_ISOLATION) {
+ if (task_isolation_syscall(regs->orig_ax) == -1)
+ return -1;
+ work &= ~_TIF_TASK_ISOLATION;
+ }
+
#ifdef CONFIG_SECCOMP
/*
* Do seccomp first -- it should minimize exposure of other
@@ -220,7 +228,7 @@ long syscall_trace_enter(struct pt_regs *regs)
#define EXIT_TO_USERMODE_LOOP_FLAGS \
(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
- _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY)
+ _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_TASK_ISOLATION)
static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
{
@@ -254,11 +262,19 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
if (cached_flags & _TIF_USER_RETURN_NOTIFY)
fire_user_return_notifiers();
+ if (cached_flags & _TIF_TASK_ISOLATION)
+ task_isolation_enter();
+
/* Disable IRQs and retry */
local_irq_disable();
cached_flags = READ_ONCE(pt_regs_to_thread_info(regs)->flags);
+ /* Clear task isolation from cached_flags manually. */
+ if ((cached_flags & _TIF_TASK_ISOLATION) &&
+ task_isolation_ready())
+ cached_flags &= ~_TIF_TASK_ISOLATION;
+
if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
break;
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index c7b551028740..5280b92bdc3b 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -97,6 +97,7 @@ struct thread_info {
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
#define TIF_UPROBE 12 /* breakpointed or singlestepping */
+#define TIF_TASK_ISOLATION 13 /* task isolation enabled for task */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* IA32 compatibility process */
#define TIF_FORK 18 /* ret_from_fork */
@@ -121,6 +122,7 @@ struct thread_info {
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_TASK_ISOLATION (1 << TIF_TASK_ISOLATION)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
#define _TIF_FORK (1 << TIF_FORK)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ade185a46b1d..bc50c275bb9b 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -36,6 +36,7 @@
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/io.h>
+#include <linux/isolation.h>
#ifdef CONFIG_EISA
#include <linux/ioport.h>
@@ -398,6 +399,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
case 2: /* Bound directory has invalid entry. */
if (mpx_handle_bd_fault())
goto exit_trap;
+ task_isolation_exception("bounds check");
break; /* Success, it was handled */
case 1: /* Bound violation. */
info = mpx_generate_siginfo(regs);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e830c71a1323..86def02ff9a0 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -14,6 +14,7 @@
#include <linux/prefetch.h> /* prefetchw */
#include <linux/context_tracking.h> /* exception_enter(), ... */
#include <linux/uaccess.h> /* faulthandler_disabled() */
+#include <linux/isolation.h> /* task_isolation_exception */
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
@@ -1155,6 +1156,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
local_irq_enable();
error_code |= PF_USER;
flags |= FAULT_FLAG_USER;
+ task_isolation_exception("page fault at %#lx", address);
} else {
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
--
2.7.2
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