x86: Don't leak 64-bit kernel register values to 32-bit processes
authorJan Beulich <JBeulich@novell.com>
Wed, 30 Sep 2009 10:22:11 +0000 (11:22 +0100)
committerIngo Molnar <mingo@elte.hu>
Thu, 1 Oct 2009 09:24:26 +0000 (11:24 +0200)
commit24e35800cdc4350fc34e2bed37b608a9e13ab3b6
tree0e592a3f097d101263c7da4fc529f86d03cf9f2a
parent4701472e441e41be2549a25228f703bc9cd13b5b
x86: Don't leak 64-bit kernel register values to 32-bit processes

While 32-bit processes can't directly access R8...R15, they can
gain access to these registers by temporarily switching themselves
into 64-bit mode.

Therefore, registers not preserved anyway by called C functions
(i.e. R8...R11) must be cleared prior to returning to user mode.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: <stable@kernel.org>
LKML-Reference: <4AC34D73020000780001744A@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/ia32/ia32entry.S