https://github.com/torvalds/linux
Revision 4f74d72aa7067e75af92fbab077e6d7d0210be66 authored by Mark Rutland on 18 May 2018, 14:08:41 UTC, committed by Ingo Molnar on 19 May 2018, 06:07:56 UTC
When CONFIG_RANDOMIZE_TEXT_OFFSET=y, TEXT_OFFSET is an arbitrary multiple of PAGE_SIZE in the interval [0, 2MB). The EFI stub does not account for the potential misalignment of TEXT_OFFSET relative to EFI_KIMG_ALIGN, and produces a randomized physical offset which is always a round multiple of EFI_KIMG_ALIGN. This may result in statically allocated objects whose alignment exceeds PAGE_SIZE to appear misaligned in memory. This has been observed to result in spurious stack overflow reports and failure to make use of the IRQ stacks, and theoretically could result in a number of other issues. We can OR in the low bits of TEXT_OFFSET to ensure that we have the necessary offset (and hence preserve the misalignment of TEXT_OFFSET relative to EFI_KIMG_ALIGN), so let's do that. Reported-by: Kim Phillips <kim.phillips@arm.com> Tested-by: Kim Phillips <kim.phillips@arm.com> [ardb: clarify comment and commit log, drop unneeded parens] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes: 6f26b3671184c36d ("arm64: kaslr: increase randomization granularity") Link: http://lkml.kernel.org/r/20180518140841.9731-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 0b3225a
Tip revision: 4f74d72aa7067e75af92fbab077e6d7d0210be66 authored by Mark Rutland on 18 May 2018, 14:08:41 UTC
efi/libstub/arm64: Handle randomized TEXT_OFFSET
efi/libstub/arm64: Handle randomized TEXT_OFFSET
Tip revision: 4f74d72
trans_common.c
/*
* Copyright IBM Corporation, 2010
* Author Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <linux/mm.h>
#include <linux/module.h>
/**
* p9_release_pages - Release pages after the transaction.
*/
void p9_release_pages(struct page **pages, int nr_pages)
{
int i;
for (i = 0; i < nr_pages; i++)
if (pages[i])
put_page(pages[i]);
}
EXPORT_SYMBOL(p9_release_pages);
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