Messages in this thread | | | Date | Tue, 1 Mar 2016 15:29:18 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v2] x86/microcode: Change checksum to u32 |
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On Tue, Mar 01, 2016 at 12:12:39PM +0000, Chris Bainbridge wrote: > Checksum should be unsigned 32-bit otherwise the calculation overflow > results in undefined behaviour: > > [ 0.000000] ================================================================================ > [ 0.000000] UBSAN: Undefined behaviour in arch/x86/kernel/cpu/microcode/intel_lib.c:105:12 > [ 0.000000] signed integer overflow: > [ 0.000000] -1500151068 + -2125470173 cannot be represented in type 'int' > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.5.0-rc5+ #495 > [ 0.000000] 0000000000000086 0000000000000086 0000000000000000 ffffffff83203968 > [ 0.000000] ffffffff81b30952 ffffffff834c43b8 ffffffff83203998 ffffffff814fe623 > [ 0.000000] ffffffff83203980 ffffffff81bcdf2d ffffffff8339a448 ffffffff83203a08 > [ 0.000000] Call Trace: > [ 0.000000] [<ffffffff81b30952>] dump_stack+0x4e/0x6c > [ 0.000000] [<ffffffff814fe623>] ? inotify_ioctl+0x43/0x1c0 > [ 0.000000] [<ffffffff81bcdf2d>] ubsan_epilogue+0xd/0x40 > [ 0.000000] [<ffffffff81bce2fd>] handle_overflow+0xbd/0xe0 > [ 0.000000] [<ffffffff81bce32e>] __ubsan_handle_add_overflow+0xe/0x10 > [ 0.000000] [<ffffffff81148e45>] microcode_sanity_check+0x405/0x590 > [ 0.000000] [<ffffffff8549b01b>] get_matching_model_microcode.isra.2.constprop.8+0xa5/0x345 > [ 0.000000] [<ffffffff8548615d>] ? early_idt_handler_common+0x3d/0xae > [ 0.000000] [<ffffffff81b50962>] ? strlcpy+0x52/0xa0 > [ 0.000000] [<ffffffff81b30ce1>] ? find_cpio_data+0x371/0x510 > [ 0.000000] [<ffffffff8549b461>] load_ucode_intel_bsp+0xa1/0xe5 > [ 0.000000] [<ffffffff8549aea8>] load_ucode_bsp+0xdf/0xf3 > [ 0.000000] [<ffffffff8549aea8>] ? load_ucode_bsp+0xdf/0xf3 > [ 0.000000] [<ffffffff8548671c>] x86_64_start_kernel+0xd1/0xee > [ 0.000000] ================================================================================ > > Link: https://lkml.org/lkml/2016/2/27/79 > Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com> > --- > arch/x86/kernel/cpu/microcode/intel_lib.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-)
Applied, thanks.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
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