APPLIED: [SRU][Xenial][PATCH 0/5] Prevent speculation on user controlled pointer (LP #1775137)

[Khaled Elmously]

Juerg

I applied this patchset to Xenial, but the bug also affects trusty.

Was this supposed to have been applied to Trusty too? Is there another patchset for trusty coming?



On 2018-06-07 18:06:42 , Khaled Elmously wrote:
> Applied to xenial
> 
> 
> On 2018-06-06 16:20:47 , 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(-)
> > 
> > -- 
> > 2.17.1
> > 
> > 
> > -- 
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