On Wed, Aug 1, 2018 at 9:28 AM, Randy Dunlap <rdun...@infradead.org> wrote: > On 07/31/2018 11:09 PM, Kees Cook wrote: >> From: Jason Gunthorpe <j...@mellanox.com> >> >> Add shift_overflow() helper to assist driver authors in ensuring that >> shift operations don't cause overflows or other odd conditions. >> >> Signed-off-by: Jason Gunthorpe <j...@mellanox.com> >> Signed-off-by: Leon Romanovsky <leo...@mellanox.com> >> [kees: tweaked comments and commit log, dropped unneeded assignment] >> Signed-off-by: Kees Cook <keesc...@chromium.org> >> --- >> include/linux/overflow.h | 31 +++++++++++++++++++++++++++++++ >> 1 file changed, 31 insertions(+) >> >> diff --git a/include/linux/overflow.h b/include/linux/overflow.h >> index 8712ff70995f..69fc366ce865 100644 >> --- a/include/linux/overflow.h >> +++ b/include/linux/overflow.h >> @@ -202,6 +202,37 @@ >> >> #endif /* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW */ >> >> +/** check_shift_overflow() - Calculate a left-shifted value and check >> overflow >> + * >> + * @a: Value to be shifted >> + * @b: How many bits left to shift >> + * @d: Pointer to where to store the result >> + * >> + * Computes *@d = (@a << @s) >> + * > > missed @b [again]
Heh, thanks. It's fixed on disk, but... I failed to merge it into the patch. Anyway, I'll spin this one more time with s/shift/shl/ and this fixed. -Kees -- Kees Cook Pixel Security
