[PATCH v10 3/3] arm64/syscalls: Check address limit on user-mode return

[Thomas Garnier]

On Wed, Jun 21, 2017 at 1:16 AM, Catalin Marinas
<catalin.marinas at arm.com> wrote:
> On Wed, Jun 14, 2017 at 06:12:03PM -0700, Thomas Garnier wrote:
>> Ensure the address limit is a user-mode segment before returning to
>> user-mode. Otherwise a process can corrupt kernel-mode memory and
>> elevate privileges [1].
>>
>> The set_fs function sets the TIF_SETFS flag to force a slow path on
>> return. In the slow path, the address limit is checked to be USER_DS if
>> needed.
>>
>> [1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990
>>
>> Signed-off-by: Thomas Garnier <thgarnie at google.com>
>> ---
>> v10 redesigns the change to use work flags on set_fs as recommended by
>> Linus and agreed by others.
>>
>> Based on next-20170609
>> ---
>>  arch/arm64/include/asm/thread_info.h | 4 +++-
>>  arch/arm64/include/asm/uaccess.h     | 3 +++
>>  arch/arm64/kernel/signal.c           | 5 +++++
>>  3 files changed, 11 insertions(+), 1 deletion(-)
>
> For arm64:
>
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>

Thanks Catalin

-- 
Thomas