lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20220418161145.hj3ahxqjdgqd3qn2@treble>
Date:   Mon, 18 Apr 2022 09:11:45 -0700
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Chen Zhongjin <chenzhongjin@...wei.com>
Cc:     "Madhavan T. Venkataraman" <madvenka@...ux.microsoft.com>,
        mark.rutland@....com, broonie@...nel.org, ardb@...nel.org,
        nobuta.keiya@...itsu.com, sjitindarsingh@...il.com,
        catalin.marinas@....com, will@...nel.org, jmorris@...ei.org,
        linux-arm-kernel@...ts.infradead.org,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v1 0/9] arm64: livepatch: Use DWARF Call Frame
 Information for frame pointer validation

On Mon, Apr 18, 2022 at 08:28:33PM +0800, Chen Zhongjin wrote:
> Hi Josh,
> 
> IIUC, ORC on x86 can make reliable stack unwind for this scenario
> because objtool validates BP state.
> 
> I'm thinking that on arm64 there's no guarantee that LR will be pushed
> onto stack. When we meet similar scenario on arm64, we should recover
> (LR, FP) on pt_regs and continue to unwind the stack. And this is
> reliable only after we validate (LR, FP).
> 
> So should we track LR on arm64 additionally as track BP on x86? Or can
> we just treat (LR, FP) as a pair? because as I know they are always set
> up together.

Does the arm64 unwinder have a way to detect kernel pt_regs on the
stack?  If so, the simplest solution is to mark all stacks with kernel
regs as unreliable.  That's what the x86 FP unwinder does.

-- 
Josh

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ