Unverified Commit 6d225089 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
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!3475 kaslr: ppc64: Introduce KASLR for PPC64 

Merge Pull Request from: @ci-robot 
 
PR sync from: GUO Zihua <guozihua@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/XBDTRKAJR4UKNYN7ABWJOI5YLPUM6DSH/ 
This patchset introduces KASLR for PowerPC64 chips.

v3:
  Fixed one more commit message.
v2:
  Replaced bugzilla in commit messages.

GUO Zihua (2):
  powerpc/fsl_booke/kaslr: Provide correct r5 value for relocated kernel
  powerpc/fsl_booke/kaslr: Fix preserved memory size for int-vectors
    issue

Jason Yan (6):
  powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and
    kaslr_early_init()
  powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper
  powerpc/fsl_booke/64: implement KASLR for fsl_booke64
  powerpc/fsl_booke/64: do not clear the BSS for the second pass
  powerpc/fsl_booke/64: clear the original kernel if randomized
  powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst
    and add 64bit part

 rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%)

-- 
2.34.1
 
https://gitee.com/openeuler/kernel/issues/I8OHAZ 
 
Link:https://gitee.com/openeuler/kernel/pulls/3475

 

Reviewed-by: default avatarZhang Jianhua <chris.zjh@huawei.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parents c9e132d6 d1dda26f

Documentation/powerpc/index.rst

+1 −1
Original line number Diff line number Diff line
@@ -24,7 +24,7 @@ powerpc 
    hvcs

    imc

    isa-versions

    kaslr-booke32

    kaslr-booke

    mpc52xx

    papr_hcalls

    pci_iov_resource_on_powernv

Documentation/powerpc/kaslr-booke32.rst→Documentation/powerpc/kaslr-booke.rst

+31 −4
Original line number Diff line number Diff line 
.. SPDX-License-Identifier: GPL-2.0



===========================

KASLR for Freescale BookE32

===========================

=========================

KASLR for Freescale BookE

=========================



The word KASLR stands for Kernel Address Space Layout Randomization.



This document tries to explain the implementation of the KASLR for

Freescale BookE32. KASLR is a security feature that deters exploit

Freescale BookE. KASLR is a security feature that deters exploit

attempts relying on knowledge of the location of kernel internals.



KASLR for Freescale BookE32

-------------------------



Since CONFIG_RELOCATABLE has already supported, what we need to do is

map or copy kernel to a proper place and relocate. Freescale Book-E

parts expect lowmem to be mapped by fixed TLB entries(TLB1). The TLB1
@@ -38,5 +41,29 @@ bit of the entropy to decide the index of the 64M zone. Then we chose a 


                              kernstart_virt_addr





KASLR for Freescale BookE64

---------------------------



The implementation for Freescale BookE64 is similar to BookE32. One

difference is that Freescale BookE64 set up a TLB mapping of 1G during

booting. Another difference is that ppc64 needs the kernel to be

64K-aligned. So we can randomize the kernel in this 1G mapping and make

it 64K-aligned. This can save some code to creat another TLB map at early

boot. The disadvantage is that we only have about 1G/64K = 16384 slots to

put the kernel in::



    KERNELBASE



          64K                     |--> kernel <--|

           |                      |              |

        +--+--+--+    +--+--+--+--+--+--+--+--+--+    +--+--+

        |  |  |  |....|  |  |  |  |  |  |  |  |  |....|  |  |

        +--+--+--+    +--+--+--+--+--+--+--+--+--+    +--+--+

        |                         |                        1G

        |----->   offset    <-----|



                              kernstart_virt_addr



To enable KASLR, set CONFIG_RANDOMIZE_BASE = y. If KASLR is enabled and you

want to disable it at runtime, add "nokaslr" to the kernel cmdline.

arch/powerpc/Kconfig

+3 −2
Original line number Diff line number Diff line
@@ -660,14 +660,15 @@ config RELOCATABLE 


config RANDOMIZE_BASE

	bool "Randomize the address of the kernel image"

	depends on PPC_85xx && FLATMEM

	depends on PPC_E500 && FLATMEM

	depends on RELOCATABLE

	default n

	help

	  Randomizes the virtual address at which the kernel image is

	  loaded, as a security feature that deters exploit attempts

	  relying on knowledge of the location of kernel internals.



	  If unsure, say Y.

	  If unsure, say N.



config RELOCATABLE_TEST

	bool "Test relocatable kernel"

arch/powerpc/kernel/exceptions-64e.S

+27 −0
Original line number Diff line number Diff line
@@ -1249,6 +1249,7 @@ skpinv: addi r6,r6,1 /* Increment */ 
1:	mflr	r6

	addi	r6,r6,(2f - 1b)

	tovirt(r6,r6)

	add	r6,r6,r19

	lis	r7,MSR_KERNEL@h

	ori	r7,r7,MSR_KERNEL@l

	mtspr	SPRN_SRR0,r6
@@ -1271,6 +1272,7 @@ skpinv: addi r6,r6,1 /* Increment */ 


	/* We translate LR and return */

	tovirt(r8,r8)

	add	r8,r8,r19

	mtlr	r8

	blr
@@ -1403,6 +1405,7 @@ a2_tlbinit_code_end: 
 */

_GLOBAL(start_initialization_book3e)

	mflr	r28

	li	r19, 0



	/* First, we need to setup some initial TLBs to map the kernel

	 * text, data and bss at PAGE_OFFSET. We don't have a real mode
@@ -1445,6 +1448,12 @@ _GLOBAL(book3e_secondary_core_init) 
	cmplwi	r4,0

	bne	2f



	li	r19, 0

#ifdef CONFIG_RANDOMIZE_BASE

	LOAD_REG_ADDR_PIC(r19, __kaslr_offset)

	ld	r19,0(r19)

	rlwinm  r19,r19,0,0,5

#endif

	/* Setup TLB for this core */

	bl	initial_tlb_book3e
@@ -1477,6 +1486,7 @@ _GLOBAL(book3e_secondary_core_init) 
	lis	r3,PAGE_OFFSET@highest

	sldi	r3,r3,32

	or	r28,r28,r3

	add	r28,r28,r19

1:	mtlr	r28

	blr
@@ -1554,3 +1564,20 @@ _GLOBAL(setup_ehv_ivors) 
_GLOBAL(setup_lrat_ivor)

	SET_IVOR(42, 0x340) /* LRAT Error */

	blr



/*

 * Return to the start of the relocated kernel and run again

 * r3 - virtual address of fdt

 * r4 - entry of the kernel

 */

_GLOBAL(reloc_kernel_entry)

	mfmsr	r7

	rlwinm	r7, r7, 0, ~(MSR_IS | MSR_DS)



	mtspr	SPRN_SRR0,r4

	mtspr	SPRN_SRR1,r7

#ifdef CONFIG_RANDOMIZE_BASE

	LOAD_REG_ADDR_PIC(r19, __is_prom)

	lwz	r5,0(r19)

#endif

	rfi

arch/powerpc/kernel/head_64.S

+22 −0
Original line number Diff line number Diff line
@@ -116,6 +116,15 @@ __secondary_hold_acknowledge: 
	.8byte	0x0



#ifdef CONFIG_RELOCATABLE

#ifdef CONFIG_RANDOMIZE_BASE

	.globl	__kaslr_offset

__kaslr_offset:

	.8byte	0x0

	.globl	__is_prom

__is_prom:

	.8byte	0x0

#endif



	/* This flag is set to 1 by a loader if the kernel should run

	 * at the loaded address instead of the linked address.  This

	 * is used by kexec-tools to keep the kdump kernel in the
@@ -535,6 +544,12 @@ __start_initialization_multiplatform: 
	/* Poison TOC */

	li	r2,-1



#ifdef CONFIG_RANDOMIZE_BASE

	/* Store value in r5 for relocation */

	LOAD_REG_ADDR_PIC(r19, __is_prom)

	stw r5,0(r19)

#endif



	/*

	 * Are we booted from a PROM Of-type client-interface ?

	 */
@@ -952,6 +967,13 @@ start_here_multiplatform: 
	/* Adjust TOC for moved kernel. Could adjust when moving it instead. */

	bl	relative_toc



	/* Do not clear the BSS for the second pass if randomized */

	LOAD_REG_ADDR(r3, kernstart_virt_addr)

	ld	r3,0(r3)

	LOAD_REG_IMMEDIATE(r4, KERNELBASE)

	cmpd	r3,r4

	bne	4f



	/* Clear out the BSS. It may have been done in prom_init,

	 * already but that's irrelevant since prom_init will soon

	 * be detached from the kernel completely. Besides, we need