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    SubjectRe: [PATCH 0/4] kselftests/arm64: add PAuth tests
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    On 02/09/2020 17:48, Dave Martin wrote:
    > On Fri, Aug 28, 2020 at 02:16:02PM +0100, Boyan Karatotev wrote:
    >> Pointer Authentication (PAuth) is a security feature introduced in ARMv8.3.
    >> It introduces instructions to sign addresses and later check for potential
    >> corruption using a second modifier value and one of a set of keys. The
    >> signature, in the form of the Pointer Authentication Code (PAC), is stored
    >> in some of the top unused bits of the virtual address (e.g. [54: 49] if
    >> TBID0 is enabled and TnSZ is set to use a 48 bit VA space). A set of
    >> controls are present to enable/disable groups of instructions (which use
    >> certain keys) for compatibility with libraries that do not utilize the
    >> feature. PAuth is used to verify the integrity of return addresses on the
    >> stack with less memory than the stack canary.
    >>
    >> This patchset adds kselftests to verify the kernel's configuration of the
    >> feature and its runtime behaviour. There are 7 tests which verify that:
    >> * an authentication failure leads to a SIGSEGV
    >> * the data/instruction instruction groups are enabled
    >> * the generic instructions are enabled
    >> * all 5 keys are unique for a single thread
    >> * exec() changes all keys to new unique ones
    >> * context switching preserves the 4 data/instruction keys
    >> * context switching preserves the generic keys
    >>
    >> The tests have been verified to work on qemu without a working PAUTH
    >> Implementation and on ARM's FVP with a full or partial PAuth
    >> implementation.
    >>
    >> Note: This patchset is only verified for ARMv8.3 and there will be some
    >> changes required for ARMv8.6. More details can be found here [1]. Once
    >> ARMv8.6 PAuth is merged the first test in this series will required to be
    >> updated.
    >
    > Nit: is it worth running checkpatch over this series?
    >
    > Although this is not kernel code, there are a number of formatting
    > weirdnesses and surplus blank lines etc. that checkpatch would probably
    > warn about.
    >
    I ran it through checkpatch and it came out clean except for some
    MAINTAINERS warnings. I see that when I add --strict it does complain
    about multiple blank lines which I can fix for the next version. Are
    there any other flags I should be running checkpatch with?
    > [...]
    >
    > Cheers
    > ---Dave
    >


    --
    Regards,
    Boyan

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