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From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Andy Lutomirski <luto@kernel.org>,
	Balbir Singh <bsingharora@gmail.com>,
	Borislav Petkov <bp@alien8.de>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Eugene Syromiatnikov <esyr@redhat.com>,
	Florian Weimer <fweimer@redhat.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Nadav Amit <nadav.amit@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Weijiang Yang <weijiang.yang@intel.com>,
	Pengfei Xu <pengfei.xu@intel.com>,
	Haitao Huang <haitao.huang@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH v24 8/9] x86/vdso/32: Add ENDBR to __kernel_vsyscall entry point
Date: Thu,  1 Apr 2021 15:14:02 -0700	[thread overview]
Message-ID: <20210401221403.32253-9-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20210401221403.32253-1-yu-cheng.yu@intel.com>

From: "H.J. Lu" <hjl.tools@gmail.com>

ENDBR is a special new instruction for the Indirect Branch Tracking (IBT)
component of CET.  IBT prevents attacks by ensuring that (most) indirect
branches and function calls may only land at ENDBR instructions.  Branches
that don't follow the rules will result in control flow (#CF) exceptions.

ENDBR is a noop when IBT is unsupported or disabled.  Most ENDBR
instructions are inserted automatically by the compiler, but branch
targets written in assembly must have ENDBR added manually.

Add that to __kernel_vsyscall entry point.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/x86/entry/vdso/vdso32/system_call.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S
index de1fff7188aa..c962e7e4f7e3 100644
--- a/arch/x86/entry/vdso/vdso32/system_call.S
+++ b/arch/x86/entry/vdso/vdso32/system_call.S
@@ -7,6 +7,7 @@
 #include <asm/dwarf2.h>
 #include <asm/cpufeatures.h>
 #include <asm/alternative-asm.h>
+#include <asm/vdso.h>
 
 	.text
 	.globl __kernel_vsyscall
@@ -14,6 +15,7 @@
 	ALIGN
 __kernel_vsyscall:
 	CFI_STARTPROC
+	ENDBR
 	/*
 	 * Reshuffle regs so that all of any of the entry instructions
 	 * will preserve enough state.
-- 
2.21.0



  parent reply	other threads:[~2021-04-01 22:14 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01 22:13 [PATCH v24 0/9] Control-flow Enforcement: Indirect Branch Tracking Yu-cheng Yu
2021-04-01 22:13 ` [PATCH v24 1/9] x86/cet/ibt: Add Kconfig option for " Yu-cheng Yu
2021-04-01 22:13 ` [PATCH v24 2/9] x86/cet/ibt: Add user-mode Indirect Branch Tracking support Yu-cheng Yu
2021-04-01 22:13 ` [PATCH v24 3/9] x86/cet/ibt: Handle signals for Indirect Branch Tracking Yu-cheng Yu
2021-04-01 22:13 ` [PATCH v24 4/9] x86/cet/ibt: Update ELF header parsing " Yu-cheng Yu
2021-04-01 22:13 ` [PATCH v24 5/9] x86/cet/ibt: Update arch_prctl functions " Yu-cheng Yu
2021-04-01 22:14 ` [PATCH v24 6/9] x86/vdso: Insert endbr32/endbr64 to vDSO Yu-cheng Yu
2021-04-01 22:14 ` [PATCH v24 7/9] x86/vdso: Introduce ENDBR macro Yu-cheng Yu
2021-04-01 22:14 ` Yu-cheng Yu [this message]
2021-04-01 22:14 ` [PATCH v24 9/9] x86/vdso: Add ENDBR to __vdso_sgx_enter_enclave Yu-cheng Yu
2021-04-04 15:54   ` Jarkko Sakkinen
2021-05-24 18:51   ` Sean Christopherson
2021-05-24 19:01     ` Yu, Yu-cheng

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