From: Borislav Petkov <bp@alien8.de>
To: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, hmh@hmh.eng.br
Subject: Re: [PATCH v2] x86/microcode: Change checksum to u32
Date: Tue, 1 Mar 2016 15:29:18 +0100 [thread overview]
Message-ID: <20160301142918.GB22677@pd.tnic> (raw)
In-Reply-To: <1456834359-5132-1-git-send-email-chris.bainbridge@gmail.com>
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.
next prev parent reply other threads:[~2016-03-01 14:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-01 12:12 Chris Bainbridge
2016-03-01 14:29 ` Borislav Petkov [this message]
2016-03-08 8:12 ` [tip:x86/microcode] x86/microcode/intel: Change checksum variables " tip-bot for Chris Bainbridge
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