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Message-Id: <e36e964567beed0a2769d84c8d4144870e922655.1539798901.git.tim.c.chen@linux.intel.com>
Date: Wed, 17 Oct 2018 10:59:40 -0700
From: Tim Chen <tim.c.chen@...ux.intel.com>
To: Jiri Kosina <jikos@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>,
Tom Lendacky <thomas.lendacky@....com>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Andrea Arcangeli <aarcange@...hat.com>,
David Woodhouse <dwmw@...zon.co.uk>,
Andi Kleen <ak@...ux.intel.com>,
Dave Hansen <dave.hansen@...el.com>,
Casey Schaufler <casey.schaufler@...el.com>,
Asit Mallick <asit.k.mallick@...el.com>,
Arjan van de Ven <arjan@...ux.intel.com>,
Jon Masters <jcm@...hat.com>, linux-kernel@...r.kernel.org,
x86@...nel.org
Subject: [Patch v3 12/13] x86/speculation: Protect non-dumpable processes against Spectre v2 attack
Mark the non-dumpable processes with TIF_STIBP flag so they will
use STIBP and IBPB defenses against Spectre v2 attack from
processes in user space.
Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>
---
arch/x86/kernel/cpu/bugs.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 1d317f2..cc77b9e 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/nospec.h>
#include <linux/prctl.h>
+#include <linux/sched/coredump.h>
#include <asm/spec-ctrl.h>
#include <asm/cmdline.h>
@@ -773,6 +774,26 @@ int arch_prctl_spec_ctrl_set(struct task_struct *task, unsigned long which,
}
}
+void arch_set_dumpable(struct task_struct *tsk, unsigned int value)
+{
+ bool update;
+
+ if (!static_branch_unlikely(&spectre_v2_app_lite))
+ return;
+ if (!static_cpu_has(X86_FEATURE_STIBP))
+ return;
+ if (spectre_v2_app2app_enabled == SPECTRE_V2_APP2APP_NONE)
+ return;
+
+ if (tsk->mm && value != SUID_DUMP_USER)
+ update = !test_and_set_tsk_thread_flag(tsk, TIF_STIBP);
+ else
+ update = test_and_clear_tsk_thread_flag(tsk, TIF_STIBP);
+
+ if (tsk == current && update)
+ speculation_ctrl_update_current();
+}
+
#ifdef CONFIG_SECCOMP
void arch_seccomp_spec_mitigate(struct task_struct *task)
{
--
2.9.4
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