x86: make sure IDT is page aligned
authorKees Cook <keescook@chromium.org>
Mon, 15 Jul 2013 18:50:45 +0000 (11:50 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 4 Aug 2013 08:50:53 +0000 (16:50 +0800)
commit943741e352f8b0c524f542b93e8b62978dc0a9b0
tree23c4c741d4d2c4a65167c1f98be8faf9a1ad40b4
parent6d7d28443969512be95873d2fb155f4be9261ca5
x86: make sure IDT is page aligned

based on 4df05f361937ee86e5a8c9ead8aeb6a19ea9b7d7 upstream.

Since the IDT is referenced from a fixmap, make sure it is page aligned.
This avoids the risk of the IDT ever being moved in the bss and having
the mapping be offset, resulting in calling incorrect handlers. In the
current upstream kernel this is not a manifested bug, but heavily patched
kernels (such as those using the PaX patch series) did encounter this bug.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: PaX Team <pageexec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/head_64.S