• Jiri Slaby's avatar
    futex: Remove duplicated code and fix undefined behaviour · 81da9f87
    Jiri Slaby authored
    commit 30d6e0a4 upstream.
    
    There is code duplicated over all architecture's headers for
    futex_atomic_op_inuser. Namely op decoding, access_ok check for uaddr,
    and comparison of the result.
    
    Remove this duplication and leave up to the arches only the needed
    assembly which is now in arch_futex_atomic_op_inuser.
    
    This effectively distributes the Will Deacon's arm64 fix for undefined
    behaviour reported by UBSAN to all architectures. The fix was done in
    commit 5f16a046 (arm64: futex: Fix undefined behaviour with
    FUTEX_OP_OPARG_SHIFT usage). Look there for an example dump.
    
    And as suggested by Thomas, check for negative oparg too, because it was
    also reported to cause undefined behaviour report.
    
    Note that s390 removed access_ok check in d12a2970 ("s390/uaccess:
    remove pointless access_ok() checks") as access_ok there returns true.
    We introduce it back to the helper for the sake of simplicity (it gets
    optimized away anyway).
    Signed-off-by: 's avatarJiri Slaby <jslaby@suse.cz>
    Signed-off-by: 's avatarThomas Gleixner <tglx@linutronix.de>
    Acked-by: 's avatarRussell King <rmk+kernel@armlinux.org.uk>
    Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
    Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> [s390]
    Acked-by: Chris Metcalf <cmetcalf@mellanox.com> [for tile]
    Reviewed-by: 's avatarDarren Hart (VMware) <dvhart@infradead.org>
    Reviewed-by: Will Deacon <will.deacon@arm.com> [core/arm64]
    Cc: linux-mips@linux-mips.org
    Cc: Rich Felker <dalias@libc.org>
    Cc: linux-ia64@vger.kernel.org
    Cc: linux-sh@vger.kernel.org
    Cc: peterz@infradead.org
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Max Filippov <jcmvbkbc@gmail.com>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: sparclinux@vger.kernel.org
    Cc: Jonas Bonn <jonas@southpole.se>
    Cc: linux-s390@vger.kernel.org
    Cc: linux-arch@vger.kernel.org
    Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
    Cc: linux-hexagon@vger.kernel.org
    Cc: Helge Deller <deller@gmx.de>
    Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Matt Turner <mattst88@gmail.com>
    Cc: linux-snps-arc@lists.infradead.org
    Cc: Fenghua Yu <fenghua.yu@intel.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: linux-xtensa@linux-xtensa.org
    Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
    Cc: openrisc@lists.librecores.org
    Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
    Cc: Stafford Horne <shorne@gmail.com>
    Cc: linux-arm-kernel@lists.infradead.org
    Cc: Richard Henderson <rth@twiddle.net>
    Cc: Chris Zankel <chris@zankel.net>
    Cc: Michal Simek <monstr@monstr.eu>
    Cc: Tony Luck <tony.luck@intel.com>
    Cc: linux-parisc@vger.kernel.org
    Cc: Vineet Gupta <vgupta@synopsys.com>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: Richard Kuo <rkuo@codeaurora.org>
    Cc: linux-alpha@vger.kernel.org
    Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
    Cc: linuxppc-dev@lists.ozlabs.org
    Cc: "David S. Miller" <davem@davemloft.net>
    Link: http://lkml.kernel.org/r/20170824073105.3901-1-jslaby@suse.cz
    Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    81da9f87
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