* [GIT PULL] EFI fixup for v4.12 queue
@ 2017-04-17 9:32 Ard Biesheuvel
2017-04-17 9:32 ` [PATCH] efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space Ard Biesheuvel
0 siblings, 1 reply; 3+ messages in thread
From: Ard Biesheuvel @ 2017-04-17 9:32 UTC (permalink / raw)
To: linux-arm-kernel, Ingo Molnar, Thomas Gleixner, H . Peter Anvin
Cc: Ard Biesheuvel, linux-kernel, linux-efi, Catalin Marinas,
James Morse, Mark Rutland, Matt Fleming
Hi all,
Please merge this onto the v4.12 EFI queue: it fixes an issue reported with
-next where arm64 machines fail to boot due to a premature dereference of the
'current' pointer.
The following changes since commit efc491b0f06f65ea588f6591f0bc31db779e0594:
ef/libstub: arm/arm64: Randomize the base of the UEFI rt services region (2017-04-02 16:36:29 +0100)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-next
for you to fetch changes up to d3e759649e1b057da72a8981aaafcd2f34f10681:
efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space (2017-04-17 08:16:25 +0100)
----------------------------------------------------------------
A single fix for a regression caused by changes that are queued for v4.12:
- don't use TASK_SIZE in the stub on arm64, as it depends on thread flags
----------------------------------------------------------------
Ard Biesheuvel (1):
efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space
drivers/firmware/efi/libstub/arm-stub.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH] efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space 2017-04-17 9:32 [GIT PULL] EFI fixup for v4.12 queue Ard Biesheuvel @ 2017-04-17 9:32 ` Ard Biesheuvel 2017-04-18 7:25 ` [tip:efi/core] efi/libstub/arm: Don't use TASK_SIZE when randomizing " tip-bot for Ard Biesheuvel 0 siblings, 1 reply; 3+ messages in thread From: Ard Biesheuvel @ 2017-04-17 9:32 UTC (permalink / raw) To: linux-arm-kernel, Ingo Molnar, Thomas Gleixner, H . Peter Anvin Cc: Ard Biesheuvel, linux-kernel, linux-efi, Matt Fleming As reported by James, Catalin and Mark, commit e69176d68d26 ("ef/libstub/arm/arm64: Randomize the base of the UEFI rt services region") results in a crash in the firmware regardless of whether KASLR is in effect or not, and whether the firmware implements EFI_RNG_PROTOCOL or not. Mark has identified the root cause to be the inappropriate use of TASK_SIZE in the stub, which arm64 defines as #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) and testing thread flags at this point results in the dereference of pointers in uninitialized structures. So instead, introduce a preprocessor symbol EFI_RT_VIRTUAL_LIMIT and define it to TASK_SIZE_64 on arm64 and TASK_SIZE on ARM, both of which are compile time constants. Also, change the 'headroom' variable to static const to force an error if this might change in the future. Cc: Matt Fleming <matt@codeblueprint.co.uk> Tested-by: Mark Rutland <mark.rutland@arm.com> Tested-by: James Morse <james.morse@arm.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- drivers/firmware/efi/libstub/arm-stub.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 1e45ec51b094..34010ff3b77e 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -32,6 +32,12 @@ #define EFI_RT_VIRTUAL_BASE SZ_512M #define EFI_RT_VIRTUAL_SIZE SZ_512M +#ifdef CONFIG_ARM64 +#define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64 +#else +#define EFI_RT_VIRTUAL_LIMIT TASK_SIZE +#endif + static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg, @@ -236,8 +242,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, * shift of 21 bit positions into account when scaling * the headroom value using a 32-bit random value. */ - u64 headroom = TASK_SIZE - EFI_RT_VIRTUAL_BASE - - EFI_RT_VIRTUAL_SIZE; + static const u64 headroom = EFI_RT_VIRTUAL_LIMIT - + EFI_RT_VIRTUAL_BASE - + EFI_RT_VIRTUAL_SIZE; u32 rnd; status = efi_get_random_bytes(sys_table, sizeof(rnd), -- 2.9.3 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* [tip:efi/core] efi/libstub/arm: Don't use TASK_SIZE when randomizing the RT space 2017-04-17 9:32 ` [PATCH] efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space Ard Biesheuvel @ 2017-04-18 7:25 ` tip-bot for Ard Biesheuvel 0 siblings, 0 replies; 3+ messages in thread From: tip-bot for Ard Biesheuvel @ 2017-04-18 7:25 UTC (permalink / raw) To: linux-tip-commits Cc: peterz, hpa, tglx, james.morse, matt, mingo, catalin.marinas, mark.rutland, linux-kernel, ard.biesheuvel, torvalds Commit-ID: 197decefdb79d6f1350ba0316ce26ba737372d0c Gitweb: http://git.kernel.org/tip/197decefdb79d6f1350ba0316ce26ba737372d0c Author: Ard Biesheuvel <ard.biesheuvel@linaro.org> AuthorDate: Mon, 17 Apr 2017 10:32:01 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 17 Apr 2017 12:35:33 +0200 efi/libstub/arm: Don't use TASK_SIZE when randomizing the RT space As reported by James, Catalin and Mark, commit: e69176d68d26 ("ef/libstub/arm/arm64: Randomize the base of the UEFI rt services region") ... results in a crash in the firmware, regardless of whether KASLR is in effect or not and whether the firmware implements EFI_RNG_PROTOCOL or not. Mark has identified the root cause to be the inappropriate use of TASK_SIZE in the stub, which arm64 defines as: #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) and testing thread flags at this point results in the dereference of pointers in uninitialized structures. So instead, introduce a preprocessor symbol EFI_RT_VIRTUAL_LIMIT and define it to TASK_SIZE_64 on arm64 and TASK_SIZE on ARM, both of which are compile time constants. Also, change the 'headroom' variable to static const to force an error if this might change in the future. Tested-by: Mark Rutland <mark.rutland@arm.com> Tested-by: James Morse <james.morse@arm.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20170417093201.10181-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- drivers/firmware/efi/libstub/arm-stub.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 1e45ec5..8181ac1 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -32,6 +32,12 @@ #define EFI_RT_VIRTUAL_BASE SZ_512M #define EFI_RT_VIRTUAL_SIZE SZ_512M +#ifdef CONFIG_ARM64 +# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE_64 +#else +# define EFI_RT_VIRTUAL_LIMIT TASK_SIZE +#endif + static u64 virtmap_base = EFI_RT_VIRTUAL_BASE; efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg, @@ -236,8 +242,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, * shift of 21 bit positions into account when scaling * the headroom value using a 32-bit random value. */ - u64 headroom = TASK_SIZE - EFI_RT_VIRTUAL_BASE - - EFI_RT_VIRTUAL_SIZE; + static const u64 headroom = EFI_RT_VIRTUAL_LIMIT - + EFI_RT_VIRTUAL_BASE - + EFI_RT_VIRTUAL_SIZE; u32 rnd; status = efi_get_random_bytes(sys_table, sizeof(rnd), ^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-04-18 7:31 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-04-17 9:32 [GIT PULL] EFI fixup for v4.12 queue Ard Biesheuvel 2017-04-17 9:32 ` [PATCH] efi/libstub/arm: Don't use TASK_SIZE when randomising the RT space Ard Biesheuvel 2017-04-18 7:25 ` [tip:efi/core] efi/libstub/arm: Don't use TASK_SIZE when randomizing " tip-bot for Ard Biesheuvel
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