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From: Thomas Garnier <thgarnie@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: kristen@linux.intel.com, Thomas Garnier <thgarnie@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v7 05/12] x86/entry/64: Adapt assembly for PIE support
Date: Mon, 20 May 2019 16:19:30 -0700	[thread overview]
Message-ID: <20190520231948.49693-6-thgarnie@chromium.org> (raw)
In-Reply-To: <20190520231948.49693-1-thgarnie@chromium.org>

From: Thomas Garnier <thgarnie@google.com>

Change the assembly code to use only relative references of symbols for the
kernel to be PIE compatible.

Position Independent Executable (PIE) support will allow to extend the
KASLR randomization range below 0xffffffff80000000.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
---
 arch/x86/entry/entry_64.S | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 20e45d9b4e15..e99b3438aa9b 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1268,7 +1268,8 @@ ENTRY(error_entry)
 	movl	%ecx, %eax			/* zero extend */
 	cmpq	%rax, RIP+8(%rsp)
 	je	.Lbstep_iret
-	cmpq	$.Lgs_change, RIP+8(%rsp)
+	leaq	.Lgs_change(%rip), %rcx
+	cmpq	%rcx, RIP+8(%rsp)
 	jne	.Lerror_entry_done
 
 	/*
@@ -1465,10 +1466,10 @@ ENTRY(nmi)
 	 * resume the outer NMI.
 	 */
 
-	movq	$repeat_nmi, %rdx
+	leaq	repeat_nmi(%rip), %rdx
 	cmpq	8(%rsp), %rdx
 	ja	1f
-	movq	$end_repeat_nmi, %rdx
+	leaq	end_repeat_nmi(%rip), %rdx
 	cmpq	8(%rsp), %rdx
 	ja	nested_nmi_out
 1:
@@ -1522,7 +1523,8 @@ nested_nmi:
 	pushq	%rdx
 	pushfq
 	pushq	$__KERNEL_CS
-	pushq	$repeat_nmi
+	leaq	repeat_nmi(%rip), %rdx
+	pushq	%rdx
 
 	/* Put stack back */
 	addq	$(6*8), %rsp
@@ -1561,7 +1563,11 @@ first_nmi:
 	addq	$8, (%rsp)	/* Fix up RSP */
 	pushfq			/* RFLAGS */
 	pushq	$__KERNEL_CS	/* CS */
-	pushq	$1f		/* RIP */
+	pushq	$0		/* Futur return address */
+	pushq	%rax		/* Save RAX */
+	leaq	1f(%rip), %rax	/* RIP */
+	movq    %rax, 8(%rsp)   /* Put 1f on return address */
+	popq	%rax		/* Restore RAX */
 	iretq			/* continues at repeat_nmi below */
 	UNWIND_HINT_IRET_REGS
 1:
-- 
2.21.0.1020.gf2820cf01a-goog


  parent reply	other threads:[~2019-05-20 23:20 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20 23:19 [PATCH v7 00/12] x86: PIE support to extend KASLR randomization Thomas Garnier
2019-05-20 23:19 ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 01/12] x86/crypto: Adapt assembly for PIE support Thomas Garnier
2019-05-21  4:06   ` Eric Biggers
2019-05-22 20:47     ` Thomas Garnier
2019-05-22 20:55       ` Eric Biggers
2019-05-29 15:48         ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 02/12] x86: Use symbol name in jump table " Thomas Garnier
2019-05-20 23:23   ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 03/12] x86: Add macro to get symbol address " Thomas Garnier
2019-05-21  3:12   ` hpa
2019-05-22 15:57     ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 04/12] x86: relocate_kernel - Adapt assembly " Thomas Garnier
2019-06-10 21:33   ` Kees Cook
2019-05-20 23:19 ` Thomas Garnier [this message]
2019-06-10 21:34   ` [PATCH v7 05/12] x86/entry/64: " Kees Cook
2019-05-20 23:19 ` [PATCH v7 06/12] x86: pm-trace - " Thomas Garnier
2019-06-10 21:34   ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 07/12] x86/CPU: " Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 08/12] x86/acpi: " Thomas Garnier
2019-06-10 23:52   ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 09/12] x86/boot/64: " Thomas Garnier
2019-06-10 22:26   ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 10/12] x86/power/64: " Thomas Garnier
2019-06-10 23:52   ` Kees Cook
2019-05-20 23:19 ` [PATCH v7 11/12] x86/paravirt: " Thomas Garnier
2019-05-20 23:19   ` Thomas Garnier
2019-05-27  5:47   ` Juergen Gross
2019-05-27  5:47   ` Juergen Gross
2019-05-29 15:48     ` Thomas Garnier
2019-05-29 15:48     ` Thomas Garnier
2019-05-20 23:19 ` [PATCH v7 12/12] x86/alternatives: " Thomas Garnier
2019-06-10 21:32 ` [PATCH v7 00/12] x86: PIE support to extend KASLR randomization Kees Cook
2019-06-10 21:32 ` Kees Cook

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