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* [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64
@ 2019-11-15  9:32 Jason Yan
  2019-11-15  9:32 ` [PATCH 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

This is a try to implement KASLR for Freescale BookE64 which is based on
my earlier implementation for Freescale BookE32:
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718

The implementation for Freescale BookE64 is similar as 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

I'm not sure if the slot numbers is enough or the design has any
defects. If you have some better ideas, I would be happy to hear that.

Thank you all.

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

 .../{kaslr-booke32.rst => kaslr-booke.rst}    | 35 ++++++++--
 arch/powerpc/Kconfig                          |  2 +-
 arch/powerpc/kernel/exceptions-64e.S          | 13 ++++
 arch/powerpc/kernel/head_64.S                 |  7 ++
 arch/powerpc/kernel/setup_64.c                |  4 +-
 arch/powerpc/mm/mmu_decl.h                    |  3 +-
 arch/powerpc/mm/nohash/kaslr_booke.c          | 67 +++++++++++++------
 7 files changed, 104 insertions(+), 27 deletions(-)
 rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%)

-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init()
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-15  9:32 ` [PATCH 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper Jason Yan
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

Some code refactor in kaslr_legal_offset() and kaslr_early_init(). No
functional change. This is a preparation for KASLR fsl_booke64.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/mm/nohash/kaslr_booke.c | 40 ++++++++++++++--------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 4a75f2d9bf0e..07b036e98353 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -25,6 +25,7 @@ struct regions {
 	unsigned long pa_start;
 	unsigned long pa_end;
 	unsigned long kernel_size;
+	unsigned long linear_sz;
 	unsigned long dtb_start;
 	unsigned long dtb_end;
 	unsigned long initrd_start;
@@ -260,11 +261,23 @@ static __init void get_cell_sizes(const void *fdt, int node, int *addr_cells,
 		*size_cells = fdt32_to_cpu(*prop);
 }
 
-static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long index,
-					       unsigned long offset)
+static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long random)
 {
 	unsigned long koffset = 0;
 	unsigned long start;
+	unsigned long index;
+	unsigned long offset;
+
+	/*
+	 * Decide which 64M we want to start
+	 * Only use the low 8 bits of the random seed
+	 */
+	index = random & 0xFF;
+	index %= regions.linear_sz / SZ_64M;
+
+	/* Decide offset inside 64M */
+	offset = random % (SZ_64M - regions.kernel_size);
+	offset = round_down(offset, SZ_16K);
 
 	while ((long)index >= 0) {
 		offset = memstart_addr + index * SZ_64M + offset;
@@ -289,10 +302,9 @@ static inline __init bool kaslr_disabled(void)
 static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size,
 						  unsigned long kernel_sz)
 {
-	unsigned long offset, random;
+	unsigned long random;
 	unsigned long ram, linear_sz;
 	u64 seed;
-	unsigned long index;
 
 	kaslr_get_cmdline(dt_ptr);
 	if (kaslr_disabled())
@@ -333,22 +345,12 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	regions.dtb_start = __pa(dt_ptr);
 	regions.dtb_end = __pa(dt_ptr) + fdt_totalsize(dt_ptr);
 	regions.kernel_size = kernel_sz;
+	regions.linear_sz = linear_sz;
 
 	get_initrd_range(dt_ptr);
 	get_crash_kernel(dt_ptr, ram);
 
-	/*
-	 * Decide which 64M we want to start
-	 * Only use the low 8 bits of the random seed
-	 */
-	index = random & 0xFF;
-	index %= linear_sz / SZ_64M;
-
-	/* Decide offset inside 64M */
-	offset = random % (SZ_64M - kernel_sz);
-	offset = round_down(offset, SZ_16K);
-
-	return kaslr_legal_offset(dt_ptr, index, offset);
+	return kaslr_legal_offset(dt_ptr, random);
 }
 
 /*
@@ -358,8 +360,6 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
  */
 notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 {
-	unsigned long tlb_virt;
-	phys_addr_t tlb_phys;
 	unsigned long offset;
 	unsigned long kernel_sz;
 
@@ -375,8 +375,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 	is_second_reloc = 1;
 
 	if (offset >= SZ_64M) {
-		tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
-		tlb_phys = round_down(kernstart_addr, SZ_64M);
+		unsigned long tlb_virt = round_down(kernstart_virt_addr, SZ_64M);
+		phys_addr_t tlb_phys = round_down(kernstart_addr, SZ_64M);
 
 		/* Create kernel map to relocate in */
 		create_kaslr_tlb_entry(1, tlb_virt, tlb_phys);
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
  2019-11-15  9:32 ` [PATCH 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-15  9:32 ` [PATCH 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Jason Yan
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

Like the 32bit code, we introduce reloc_kernel_entry() helper to prepare
for the KASLR 64bit version. And move the C declaration of this function
out of CONFIG_PPC32 and use long instead of int for the parameter 'addr'.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/kernel/exceptions-64e.S | 13 +++++++++++++
 arch/powerpc/mm/mmu_decl.h           |  3 ++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index e4076e3c072d..1b9b174bee86 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -1679,3 +1679,16 @@ _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
+	rfi
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 8e99649c24fc..3e1c85c7d10b 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -140,9 +140,10 @@ extern void adjust_total_lowmem(void);
 extern int switch_to_as1(void);
 extern void restore_to_as0(int esel, int offset, void *dt_ptr, int bootcpu);
 void create_kaslr_tlb_entry(int entry, unsigned long virt, phys_addr_t phys);
-void reloc_kernel_entry(void *fdt, int addr);
 extern int is_second_reloc;
 #endif
+
+void reloc_kernel_entry(void *fdt, long addr);
 extern void loadcam_entry(unsigned int index);
 extern void loadcam_multi(int first_idx, int num, int tmp_idx);
 
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
  2019-11-15  9:32 ` [PATCH 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
  2019-11-15  9:32 ` [PATCH 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-15  9:32 ` [PATCH 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass Jason Yan
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

The implementation for Freescale BookE64 is similar as 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.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/Kconfig                 |  2 +-
 arch/powerpc/kernel/setup_64.c       |  4 +++-
 arch/powerpc/mm/nohash/kaslr_booke.c | 29 ++++++++++++++++++++++++++--
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 4c4a0fcd1674..3e563a07cb67 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -553,7 +553,7 @@ config RELOCATABLE
 
 config RANDOMIZE_BASE
 	bool "Randomize the address of the kernel image"
-	depends on (FSL_BOOKE && FLATMEM && PPC32)
+	depends on (PPC_FSL_BOOK3E && FLATMEM)
 	depends on RELOCATABLE
 	help
 	  Randomizes the virtual address at which the kernel image is
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index d2af4c228970..b7e4f1e92c7e 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -65,7 +65,7 @@
 #include <asm/hw_irq.h>
 #include <asm/feature-fixups.h>
 #include <asm/kup.h>
-
+#include <mm/mmu_decl.h>
 #include "setup.h"
 
 int spinning_secondaries;
@@ -299,6 +299,8 @@ void __init early_setup(unsigned long dt_ptr)
 	/* Enable early debugging if any specified (see udbg.h) */
 	udbg_early_init();
 
+	kaslr_early_init(__va(dt_ptr), 0);
+
 	udbg_printf(" -> %s(), dt_ptr: 0x%lx\n", __func__, dt_ptr);
 
 	/*
diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 07b036e98353..513f4616e92a 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -265,14 +265,14 @@ static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long rando
 {
 	unsigned long koffset = 0;
 	unsigned long start;
-	unsigned long index;
 	unsigned long offset;
 
+#ifdef CONFIG_PPC32
 	/*
 	 * Decide which 64M we want to start
 	 * Only use the low 8 bits of the random seed
 	 */
-	index = random & 0xFF;
+	unsigned long index = random & 0xFF;
 	index %= regions.linear_sz / SZ_64M;
 
 	/* Decide offset inside 64M */
@@ -287,6 +287,15 @@ static unsigned long __init kaslr_legal_offset(void *dt_ptr, unsigned long rando
 			break;
 		index--;
 	}
+#else
+	/* Decide kernel offset inside 1G */
+	offset = random % (SZ_1G - regions.kernel_size);
+	offset = round_down(offset, SZ_64K);
+
+	start = memstart_addr;
+	offset = memstart_addr + offset;
+	koffset = get_usable_address(dt_ptr, start, offset);
+#endif
 
 	if (koffset != 0)
 		koffset -= memstart_addr;
@@ -325,6 +334,7 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	else
 		pr_warn("KASLR: No safe seed for randomizing the kernel base.\n");
 
+#ifdef CONFIG_PPC32
 	ram = min_t(phys_addr_t, __max_low_memory, size);
 	ram = map_mem_in_cams(ram, CONFIG_LOWMEM_CAM_NUM, true);
 	linear_sz = min_t(unsigned long, ram, SZ_512M);
@@ -332,6 +342,7 @@ static unsigned long __init kaslr_choose_location(void *dt_ptr, phys_addr_t size
 	/* If the linear size is smaller than 64M, do not randmize */
 	if (linear_sz < SZ_64M)
 		return 0;
+#endif
 
 	/* check for a reserved-memory node and record its cell sizes */
 	regions.reserved_mem = fdt_path_offset(dt_ptr, "/reserved-memory");
@@ -363,6 +374,18 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 	unsigned long offset;
 	unsigned long kernel_sz;
 
+#ifdef CONFIG_PPC64
+	unsigned int *__run_at_load = (unsigned int *)(KERNELBASE + 0x5c);
+
+	if (*__run_at_load == 1)
+		return;
+
+	*__run_at_load = 1;
+
+	/* Setup flat device-tree pointer */
+	initial_boot_params = dt_ptr;
+#endif
+
 	kernel_sz = (unsigned long)_end - (unsigned long)_stext;
 
 	offset = kaslr_choose_location(dt_ptr, size, kernel_sz);
@@ -372,6 +395,7 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 	kernstart_virt_addr += offset;
 	kernstart_addr += offset;
 
+#ifdef CONFIG_PPC32
 	is_second_reloc = 1;
 
 	if (offset >= SZ_64M) {
@@ -381,6 +405,7 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 		/* Create kernel map to relocate in */
 		create_kaslr_tlb_entry(1, tlb_virt, tlb_phys);
 	}
+#endif
 
 	/* Copy the kernel to it's new location and run */
 	memcpy((void *)kernstart_virt_addr, (void *)_stext, kernel_sz);
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
                   ` (2 preceding siblings ...)
  2019-11-15  9:32 ` [PATCH 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-15  9:32 ` [PATCH 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized Jason Yan
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

The BSS section has already cleared out in the first pass. No need to
clear it again. This can save some time when booting with KASLR
enabled.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/kernel/head_64.S | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index ad79fddb974d..76d8cdeddc69 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -907,6 +907,13 @@ start_here_multiplatform:
 	bl      relative_toc
 	tovirt(r2,r2)
 
+	/* Do not clear the BSS for the second pass if randomized */
+	LOAD_REG_ADDR(r3, kernstart_virt_addr)
+	lwz     r3,0(r3)
+	LOAD_REG_IMMEDIATE(r4, KERNELBASE)
+	cmpw	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
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
                   ` (3 preceding siblings ...)
  2019-11-15  9:32 ` [PATCH 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-15  9:32 ` [PATCH 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part Jason Yan
  2019-11-20 18:51 ` [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Kees Cook
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

The original kernel still exists in the memory, clear it now.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 arch/powerpc/mm/nohash/kaslr_booke.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/nohash/kaslr_booke.c b/arch/powerpc/mm/nohash/kaslr_booke.c
index 513f4616e92a..323fe25e8e08 100644
--- a/arch/powerpc/mm/nohash/kaslr_booke.c
+++ b/arch/powerpc/mm/nohash/kaslr_booke.c
@@ -377,8 +377,10 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
 #ifdef CONFIG_PPC64
 	unsigned int *__run_at_load = (unsigned int *)(KERNELBASE + 0x5c);
 
-	if (*__run_at_load == 1)
+	if (*__run_at_load == 1) {
+		kaslr_late_init();
 		return;
+	}
 
 	*__run_at_load = 1;
 
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
                   ` (4 preceding siblings ...)
  2019-11-15  9:32 ` [PATCH 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized Jason Yan
@ 2019-11-15  9:32 ` Jason Yan
  2019-11-20 18:51 ` [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Kees Cook
  6 siblings, 0 replies; 8+ messages in thread
From: Jason Yan @ 2019-11-15  9:32 UTC (permalink / raw)
  To: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, keescook, kernel-hardening
  Cc: linux-kernel, oss, Jason Yan

Now we support both 32 and 64 bit KASLR for fsl booke. Add document for
64 bit part and rename kaslr-booke32.rst to kaslr-booke.rst.

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Cc: Scott Wood <oss@buserror.net>
Cc: Diana Craciun <diana.craciun@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
---
 .../{kaslr-booke32.rst => kaslr-booke.rst}    | 35 ++++++++++++++++---
 1 file changed, 31 insertions(+), 4 deletions(-)
 rename Documentation/powerpc/{kaslr-booke32.rst => kaslr-booke.rst} (59%)

diff --git a/Documentation/powerpc/kaslr-booke32.rst b/Documentation/powerpc/kaslr-booke.rst
similarity index 59%
rename from Documentation/powerpc/kaslr-booke32.rst
rename to Documentation/powerpc/kaslr-booke.rst
index 8b259fdfdf03..42121fed8249 100644
--- a/Documentation/powerpc/kaslr-booke32.rst
+++ b/Documentation/powerpc/kaslr-booke.rst
@@ -1,15 +1,18 @@
 .. 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 as 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 enable and you
 want to disable it at runtime, add "nokaslr" to the kernel cmdline.
-- 
2.17.2


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64
  2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
                   ` (5 preceding siblings ...)
  2019-11-15  9:32 ` [PATCH 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part Jason Yan
@ 2019-11-20 18:51 ` Kees Cook
  6 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2019-11-20 18:51 UTC (permalink / raw)
  To: Jason Yan
  Cc: mpe, linuxppc-dev, diana.craciun, christophe.leroy, benh, paulus,
	npiggin, kernel-hardening, linux-kernel, oss

On Fri, Nov 15, 2019 at 05:32:03PM +0800, Jason Yan wrote:
> This is a try to implement KASLR for Freescale BookE64 which is based on
> my earlier implementation for Freescale BookE32:
> https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=131718

Whee! :) I've updated https://github.com/KSPP/linux/issues/3 with a link
to this current series.

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 8+ messages in thread

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Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2019-11-15  9:32 [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
2019-11-15  9:32 ` [PATCH 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
2019-11-15  9:32 ` [PATCH 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper Jason Yan
2019-11-15  9:32 ` [PATCH 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Jason Yan
2019-11-15  9:32 ` [PATCH 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass Jason Yan
2019-11-15  9:32 ` [PATCH 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized Jason Yan
2019-11-15  9:32 ` [PATCH 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part Jason Yan
2019-11-20 18:51 ` [PATCH 0/6] implement KASLR for powerpc/fsl_booke/64 Kees Cook

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