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Message-ID: <20190717080621.40424-9-yanaijie@huawei.com>
Date: Wed, 17 Jul 2019 16:06:19 +0800
From: Jason Yan <yanaijie@...wei.com>
To: <mpe@...erman.id.au>, <linuxppc-dev@...ts.ozlabs.org>,
<diana.craciun@....com>, <christophe.leroy@....fr>,
<benh@...nel.crashing.org>, <paulus@...ba.org>, <npiggin@...il.com>,
<keescook@...omium.org>, <kernel-hardening@...ts.openwall.com>
CC: <linux-kernel@...r.kernel.org>, <wangkefeng.wang@...wei.com>,
<yebin10@...wei.com>, <thunder.leizhen@...wei.com>,
<jingxiangfeng@...wei.com>, <fanchengyang@...wei.com>, Jason Yan
<yanaijie@...wei.com>
Subject: [RFC PATCH 08/10] powerpc/fsl_booke/kaslr: clear the original kernel if randomized
The original kernel still exists in the memory, clear it now.
Signed-off-by: Jason Yan <yanaijie@...wei.com>
Cc: Diana Craciun <diana.craciun@....com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Christophe Leroy <christophe.leroy@....fr>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Kees Cook <keescook@...omium.org>
---
arch/powerpc/kernel/kaslr_booke.c | 11 +++++++++++
arch/powerpc/mm/mmu_decl.h | 2 ++
arch/powerpc/mm/nohash/fsl_booke.c | 1 +
3 files changed, 14 insertions(+)
diff --git a/arch/powerpc/kernel/kaslr_booke.c b/arch/powerpc/kernel/kaslr_booke.c
index 90357f4bd313..00339c05879f 100644
--- a/arch/powerpc/kernel/kaslr_booke.c
+++ b/arch/powerpc/kernel/kaslr_booke.c
@@ -412,3 +412,14 @@ notrace void __init kaslr_early_init(void *dt_ptr, phys_addr_t size)
reloc_kernel_entry(dt_ptr, kimage_vaddr);
}
+
+void __init kaslr_second_init(void)
+{
+ /* If randomized, clear the original kernel */
+ if (kimage_vaddr != KERNELBASE) {
+ unsigned long kernel_sz;
+
+ kernel_sz = (unsigned long)_end - kimage_vaddr;
+ memset((void *)KERNELBASE, 0, kernel_sz);
+ }
+}
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 754ae1e69f92..9912ee598f9b 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -150,8 +150,10 @@ extern void loadcam_multi(int first_idx, int num, int tmp_idx);
#ifdef CONFIG_RANDOMIZE_BASE
extern void kaslr_early_init(void *dt_ptr, phys_addr_t size);
+extern void kaslr_second_init(void);
#else
static inline void kaslr_early_init(void *dt_ptr, phys_addr_t size) {}
+static inline void kaslr_second_init(void) {}
#endif
struct tlbcam {
diff --git a/arch/powerpc/mm/nohash/fsl_booke.c b/arch/powerpc/mm/nohash/fsl_booke.c
index 8d25a8dc965f..fa5a87f5c08e 100644
--- a/arch/powerpc/mm/nohash/fsl_booke.c
+++ b/arch/powerpc/mm/nohash/fsl_booke.c
@@ -269,6 +269,7 @@ notrace void __init relocate_init(u64 dt_ptr, phys_addr_t start)
kernstart_addr = start;
if (is_second_reloc) {
virt_phys_offset = PAGE_OFFSET - memstart_addr;
+ kaslr_second_init();
return;
}
--
2.17.2
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