Le 17/07/2019 à 10:06, Jason Yan a écrit :
The original kernel still exists in the memory, clear it now.
Signed-off-by: Jason Yan <yanai...@huawei.com>
Cc: Diana Craciun <diana.crac...@nxp.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Christophe Leroy <christophe.le...@c-s.fr>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Kees Cook <keesc...@chromium.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);
Why are we clearing ? Is that just to tidy up or is it of security
importance ?
If so, maybe memzero_explicit() should be used instead ?
+ }
+}
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);
No new 'extern' please.
#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;
}
Christophe
