ACK: [[SCRIPT=remove_re|Re: [B][SRU][PATCH 0/2] Provide ppc64el syscall for pkey_*]]

[Stefan Bader]

On 03.06.19 14:03, Dan Streetman wrote:
> From: Dan Streetman <ddstreet at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1821625
> 
> In bionic, all archs provided by Ubuntu either define __NR_pkey_mprotect
> (arm/x86) or define __IGNORE_pkey_mprotect (powerpc/s390).  This value was
> used, until libseccomp was updated via bug 1815415, to instead (if
> __NR_pkey_mprotect was not defined by the kernel headers) define it as a
> negative error value:
> 
> +#define __PNR_pkey_mprotect    -10201
> +#ifndef __NR_pkey_mprotect
> +#define __NR_pkey_mprotect     __PNR_pkey_mprotect
> +#endif /* __NR_pkey_mprotect */
> 
> systemd, the next time it was built against libseccomp, pulled that
> __NR_pkey_mprotect value and started using it for ppc64el, though it was
> a negative error value, so it would not actually work as a syscall number.
> This caused the systemd test-seccomp autopkgtest to start failing, as
> the systemd function it tested only issued the pkey_mprotect syscall if
> __NR_pkey_mprotect was defined.
> 
> After these patches are applied to bionic, both libseccomp and systemd will
> need to be rebuilt - libseccomp rebuilt against the kernel headers, and
> systemd against the libseccomp headers.
> 
> Note this is not only a fix to allow a test to pass, this actually
> provides the syscall number for the functionality on ppc64el on bionic,
> which would have failed before (on ppc64el on bionic, but not x86/arm
> on bionic); specifically one example is the systemd usage
> MemoryDenyWriteExecution as shown in bug 1725348.
> 
> Also note that s390x also defines __IGNORE_pkey_mprotect, but the systemd
> test only expects its test case to pass for select archs, and s390x is not
> one of them, so it has always expected a failure there.  It appears s390x
> still does not support pkey_mprotect (it defined pkey_* starting at
> commit b41c51c8e194c0bdfb4b1778a137aea8246c86cd, but appears to still
> not support them).
> 
> Ram Pai (2):
>   powerpc: sys_pkey_alloc() and sys_pkey_free() system calls
>   powerpc: sys_pkey_mprotect() system call
> 
>  arch/powerpc/include/asm/systbl.h      | 3 +++
>  arch/powerpc/include/asm/unistd.h      | 6 +-----
>  arch/powerpc/include/uapi/asm/unistd.h | 3 +++
>  3 files changed, 7 insertions(+), 5 deletions(-)
> 
Acked-by: Stefan Bader <stefan.bader at canonical.com>

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