From c7d2361f7524f365c1ae42f47880e3fa9efb2c2a Mon Sep 17 00:00:00 2001 From: Thomas Garnier Date: Tue, 9 Aug 2016 10:11:04 -0700 Subject: [PATCH] x86/mm/KASLR: Fix physical memory calculation on KASLR memory randomization Initialize KASLR memory randomization after max_pfn is initialized. Also ensure the size is rounded up. It could create problems on machines with more than 1Tb of memory on certain random addresses. Signed-off-by: Thomas Garnier Cc: Aleksey Makarov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Christian Borntraeger Cc: Dan Williams Cc: Dave Hansen Cc: Dave Young Cc: Denys Vlasenko Cc: Fabian Frederick Cc: H. Peter Anvin Cc: Joerg Roedel Cc: Josh Poimboeuf Cc: Kees Cook Cc: Linus Torvalds Cc: Lv Zheng Cc: Mark Salter Cc: Peter Zijlstra Cc: Rafael J . Wysocki Cc: Thomas Gleixner Cc: Toshi Kani Cc: kernel-hardening@lists.openwall.com Fixes: 021182e52fe0 ("Enable KASLR for physical mapping memory regions") Link: http://lkml.kernel.org/r/1470762665-88032-1-git-send-email-thgarnie@google.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/setup.c | 8 ++++++-- arch/x86/mm/kaslr.c | 2 +- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 991b77986d57..95cf31c9f4ec 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -936,8 +936,6 @@ void __init setup_arch(char **cmdline_p) x86_init.oem.arch_setup(); - kernel_randomize_memory(); - iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; setup_memory_map(); parse_setup_data(); @@ -1055,6 +1053,12 @@ void __init setup_arch(char **cmdline_p) max_possible_pfn = max_pfn; + /* + * Define random base addresses for memory sections after max_pfn is + * defined and before each memory section base is used. + */ + kernel_randomize_memory(); + #ifdef CONFIG_X86_32 /* max_low_pfn get updated here */ find_low_pfn_range(); diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c index 26dccd6c0df1..ec8654f117d8 100644 --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -97,7 +97,7 @@ void __init kernel_randomize_memory(void) * add padding if needed (especially for memory hotplug support). */ BUG_ON(kaslr_regions[0].base != &page_offset_base); - memory_tb = ((max_pfn << PAGE_SHIFT) >> TB_SHIFT) + + memory_tb = DIV_ROUND_UP(max_pfn << PAGE_SHIFT, 1UL << TB_SHIFT) + CONFIG_RANDOMIZE_MEMORY_PHYSICAL_PADDING; /* Adapt phyiscal memory region size based on available memory */ -- 2.20.1