ACK: [SRU][Xenial][PATCH 0/5] Prevent speculation on user controlled pointer (LP #1775137)
Kleber Souza
kleber.souza at canonical.com
Wed Jun 6 22:51:11 UTC 2018
On 06/06/18 07:20, Juerg Haefliger wrote:
> BugLink: https://bugs.launchpad.net/bugs/1775137
>
> This patchset adds the missing Spectre v1 mitigation for speculating on user controlled pointers.
>
> == SRU Justification ==
> Upstream's Spectre v1 mitigation prevents speculation on a user controlled pointer. This part of the Spectre v1 patchset was never backported to 4.4 (for unknown reasons) so Xenial/Trusty/Precise are lacking it as well. All the other stable upstream kernels include it, so add it to our older kernels.
>
> == Fix ==
> Backport the following patches:
> x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec
> x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}
> x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec
>
> == Regression Potential ==
> Low. Patches have been in upstream (and other distro kernels) for quite a while now and the changes only introduce a barrier on copy_from_user operations.
>
> == Test Case ==
> TBD.
>
> Signed-off-by: Juerg Haefliger <juergh at canonical.com>
>
>
> Dan Williams (3):
> x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec
> x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end}
> x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec
>
> Linus Torvalds (2):
> x86: reorganize SMAP handling in user space accesses
> x86: fix SMAP in 32-bit environments
>
> arch/x86/include/asm/uaccess.h | 64 ++++++++++++++-------
> arch/x86/include/asm/uaccess_32.h | 26 +++++++++
> arch/x86/include/asm/uaccess_64.h | 94 ++++++++++++++++++++++---------
> arch/x86/lib/usercopy_32.c | 20 +++----
> 4 files changed, 147 insertions(+), 57 deletions(-)
>
Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>
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