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x86/KASLR: Drop CONFIG_RANDOMIZE_BASE_MAX_OFFSET

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Currently CONFIG_RANDOMIZE_BASE_MAX_OFFSET is used to limit the maximum
offset for kernel randomization. This limit doesn't need to be a CONFIG
since it is tied completely to KERNEL_IMAGE_SIZE, and will make no sense
once physical and virtual offsets are randomized separately. This patch
removes CONFIG_RANDOMIZE_BASE_MAX_OFFSET and consolidates the Kconfig
help text.

[kees: rewrote changelog, dropped KERNEL_IMAGE_SIZE_DEFAULT, rewrote help]
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: H.J. Lu <hjl.tools@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1461185746-8017-3-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Baoquan He
2016-04-20 13:55:43 -07:00
committed by Ingo Molnar
parent 4252db1055
commit e8581e3d67
4 changed files with 32 additions and 55 deletions
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12
arch/x86/boot/compressed/kaslr.c
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@@ -217,15 +217,13 @@ static bool mem_avoid_overlap(struct mem_vector *img)
return false;
}
static unsigned long slots[CONFIG_RANDOMIZE_BASE_MAX_OFFSET /
CONFIG_PHYSICAL_ALIGN];
static unsigned long slots[KERNEL_IMAGE_SIZE / CONFIG_PHYSICAL_ALIGN];
static unsigned long slot_max;
static void slots_append(unsigned long addr)
{
/* Overflowing the slots list should be impossible. */
if (slot_max >= CONFIG_RANDOMIZE_BASE_MAX_OFFSET /
CONFIG_PHYSICAL_ALIGN)
if (slot_max >= KERNEL_IMAGE_SIZE / CONFIG_PHYSICAL_ALIGN)
return;
slots[slot_max++] = addr;
@@ -251,7 +249,7 @@ static void process_e820_entry(struct e820entry *entry,
return;
/* Ignore entries entirely above our maximum. */
if (entry->addr >= CONFIG_RANDOMIZE_BASE_MAX_OFFSET)
if (entry->addr >= KERNEL_IMAGE_SIZE)
return;
/* Ignore entries entirely below our minimum. */
@@ -276,8 +274,8 @@ static void process_e820_entry(struct e820entry *entry,
region.size -= region.start - entry->addr;
/* Reduce maximum size to fit end of image within maximum limit. */
if (region.start + region.size > CONFIG_RANDOMIZE_BASE_MAX_OFFSET)
region.size = CONFIG_RANDOMIZE_BASE_MAX_OFFSET - region.start;
if (region.start + region.size > KERNEL_IMAGE_SIZE)
region.size = KERNEL_IMAGE_SIZE - region.start;
/* Walk each aligned slot and check for avoided areas. */
for (img.start = region.start, img.size = image_size ;