Commit 0da28919 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Stefan Bader

bitops: avoid integer overflow in GENMASK(_ULL)

GENMASK(_ULL) performs a left-shift of ~0UL(L), which technically
results in an integer overflow.  clang raises a warning if the overflow
occurs in a preprocessor expression.  Clear the low-order bits through a
substraction instead of the left-shift to avoid the overflow.

(akpm: no change in .text size in my testing)

Link: http://lkml.kernel.org/r/20170803212020.24939-1-mka@chromium.orgSigned-off-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>

CVE-2018-12126
CVE-2018-12127
CVE-2018-12130

(cherry picked from commit c32ee3d9)
Signed-off-by: default avatarJuerg Haefliger <juergh@canonical.com>
Acked-by: default avatarTyler Hicks <tyhicks@canonical.com>
Acked-by: default avatarStefan Bader <stefan.bader@canonical.com>
Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
parent 383bc2d3
......@@ -19,10 +19,11 @@
* GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
*/
#define GENMASK(h, l) \
(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
#define GENMASK_ULL(h, l) \
(((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
(((~0ULL) - (1ULL << (l)) + 1) & \
(~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
extern unsigned int __sw_hweight8(unsigned int w);
extern unsigned int __sw_hweight16(unsigned int w);
......
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