From: Matt Fleming <matt@codeblueprint.co.uk>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
kernel-hardening@lists.openwall.com, will.deacon@arm.com,
catalin.marinas@arm.com, mark.rutland@arm.com,
leif.lindholm@linaro.org, keescook@chromium.org,
linux-kernel@vger.kernel.org, stuart.yoder@freescale.com,
bhupesh.sharma@freescale.com, arnd@arndb.de,
marc.zyngier@arm.com, christoffer.dall@linaro.org
Subject: Re: [PATCH v3 21/21] arm64: efi: invoke EFI_RNG_PROTOCOL to supply KASLR randomness
Date: Thu, 21 Jan 2016 16:31:49 +0000 [thread overview]
Message-ID: <20160121163149.GH2510@codeblueprint.co.uk> (raw)
In-Reply-To: <1452518355-4606-23-git-send-email-ard.biesheuvel@linaro.org>
On Mon, 11 Jan, at 02:19:15PM, Ard Biesheuvel wrote:
> Since arm64 does not use a decompressor that supplies an execution
> environment where it is feasible to some extent to provide a source of
> randomness, the arm64 KASLR kernel depends on the bootloader to supply
> some random bits in register x1 upon kernel entry.
>
> On UEFI systems, we can use the EFI_RNG_PROTOCOL, if supplied, to obtain
> some random bits. At the same time, use it to randomize the offset of the
> kernel Image in physical memory.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/arm64/Kconfig | 5 ++
> arch/arm64/kernel/efi-entry.S | 7 +-
> drivers/firmware/efi/libstub/arm-stub.c | 17 ++---
> drivers/firmware/efi/libstub/arm64-stub.c | 67 +++++++++++++++-----
> drivers/firmware/efi/libstub/efi-stub-helper.c | 10 +++
> drivers/firmware/efi/libstub/efistub.h | 2 +
> 6 files changed, 82 insertions(+), 26 deletions(-)
[...]
> diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
> index 2a7a3015d7e0..e8a3b8cd53cc 100644
> --- a/drivers/firmware/efi/libstub/efi-stub-helper.c
> +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
> @@ -32,6 +32,10 @@
>
> static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
>
> +#ifdef CONFIG_RANDOMIZE_BASE
> +bool __nokaslr;
> +#endif
> +
> /*
> * Allow the platform to override the allocation granularity: this allows
> * systems that have the capability to run with a larger page size to deal
> @@ -317,6 +321,12 @@ efi_status_t efi_parse_options(char *cmdline)
> {
> char *str;
>
> +#ifdef CONFIG_RANDOMIZE_BASE
> + str = strstr(cmdline, "nokaslr");
> + if (str && (str == cmdline || *(str - 1) == ' '))
> + __nokaslr = true;
> +#endif
> +
> /*
> * If no EFI parameters were specified on the cmdline we've got
> * nothing to do.
Could we not keep the "nokaslr" parsing inside of arm-stub.c? It's not
really specific to EFI and doesn't make use of any of the code in
efi_parse_options() anyhow.
As an added bonus, __nokaslr could then become static.
next prev parent reply other threads:[~2016-01-21 16:31 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-11 13:18 [PATCH v3 00/21] arm64: implement support for KASLR Ard Biesheuvel
2016-01-11 13:18 ` [PATCH v3 01/21] of/fdt: make memblock minimum physical address arch configurable Ard Biesheuvel
2016-01-11 13:18 ` [PATCH v3 02/21] arm64: introduce KIMAGE_VADDR as the virtual base of the kernel region Ard Biesheuvel
2016-01-11 16:31 ` Mark Rutland
2016-01-11 13:18 ` [PATCH v3 03/21] arm64: pgtable: add dummy pud_index() and pmd_index() definitions Ard Biesheuvel
2016-01-11 17:40 ` Mark Rutland
2016-01-12 17:25 ` Ard Biesheuvel
2016-01-11 13:18 ` [PATCH v3 04/21] arm64: decouple early fixmap init from linear mapping Ard Biesheuvel
2016-01-11 16:09 ` Mark Rutland
2016-01-11 16:15 ` Ard Biesheuvel
2016-01-11 16:27 ` Mark Rutland
2016-01-11 16:51 ` Mark Rutland
2016-01-11 17:08 ` Ard Biesheuvel
2016-01-11 17:15 ` Ard Biesheuvel
2016-01-11 17:21 ` Mark Rutland
2016-01-11 13:18 ` [PATCH v3 05/21] arm64: kvm: deal with kernel symbols outside of " Ard Biesheuvel
2016-01-12 12:36 ` Mark Rutland
2016-01-12 13:23 ` Ard Biesheuvel
2016-01-11 13:18 ` [PATCH v3 06/21] arm64: pgtable: implement static [pte|pmd|pud]_offset variants Ard Biesheuvel
2016-01-11 16:24 ` Mark Rutland
2016-01-11 17:28 ` Ard Biesheuvel
2016-01-11 17:31 ` Mark Rutland
2016-01-11 13:19 ` [PATCH v3 07/21] arm64: move kernel image to base of vmalloc area Ard Biesheuvel
2016-01-12 18:14 ` Mark Rutland
2016-01-13 8:39 ` Ard Biesheuvel
2016-01-13 9:58 ` Ard Biesheuvel
2016-01-13 11:11 ` Mark Rutland
2016-01-13 11:14 ` Ard Biesheuvel
2016-01-13 13:51 ` Mark Rutland
2016-01-13 15:50 ` Ard Biesheuvel
2016-01-13 16:26 ` Mark Rutland
2016-01-14 18:57 ` Mark Rutland
2016-01-15 9:54 ` Ard Biesheuvel
2016-01-15 11:23 ` Mark Rutland
2016-01-27 14:31 ` Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 08/21] arm64: add support for module PLTs Ard Biesheuvel
2016-01-22 16:55 ` Mark Rutland
2016-01-22 17:06 ` Ard Biesheuvel
2016-01-22 17:19 ` Mark Rutland
2016-01-11 13:19 ` [PATCH v3 09/21] extable: add support for relative extables to search and sort routines Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 10/21] arm64: switch to relative exception tables Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 11/21] arm64: avoid R_AARCH64_ABS64 relocations for Image header fields Ard Biesheuvel
2016-01-13 18:12 ` Mark Rutland
2016-01-13 18:48 ` Ard Biesheuvel
2016-01-14 8:51 ` Ard Biesheuvel
2016-01-14 9:05 ` Ard Biesheuvel
2016-01-14 10:46 ` Mark Rutland
2016-01-14 11:22 ` Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 12/21] arm64: avoid dynamic relocations in early boot code Ard Biesheuvel
2016-01-14 17:09 ` Mark Rutland
2016-01-11 13:19 ` [PATCH v3 13/21] arm64: allow kernel Image to be loaded anywhere in physical memory Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 14/21] arm64: redefine SWAPPER_TABLE_SHIFT for use in asm code Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 14/21] arm64: [re]define SWAPPER_TABLE_[SHIFT|SIZE] " Ard Biesheuvel
2016-01-11 13:26 ` Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 15/21] arm64: split elf relocs into a separate header Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 16/21] scripts/sortextable: add support for ET_DYN binaries Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 17/21] arm64: add support for a relocatable kernel and KASLR Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 18/21] efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL Ard Biesheuvel
2016-01-21 15:42 ` Matt Fleming
2016-01-21 16:12 ` Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 19/21] efi: stub: add implementation of efi_random_alloc() Ard Biesheuvel
2016-01-21 16:10 ` Matt Fleming
2016-01-21 16:16 ` Ard Biesheuvel
2016-01-11 13:19 ` [PATCH v3 20/21] efi: stub: use high allocation for converted command line Ard Biesheuvel
2016-01-21 16:20 ` Matt Fleming
2016-01-11 13:19 ` [PATCH v3 21/21] arm64: efi: invoke EFI_RNG_PROTOCOL to supply KASLR randomness Ard Biesheuvel
2016-01-21 16:31 ` Matt Fleming [this message]
2016-01-11 22:07 ` [PATCH v3 00/21] arm64: implement support for KASLR Kees Cook
2016-01-12 7:17 ` Ard Biesheuvel
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