From: Mark Brown <broonie@kernel.org>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: "dalias@libc.org" <dalias@libc.org>,
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Subject: Re: [musl] Re: [PATCH v8 00/38] arm64/gcs: Provide support for GCS in userspace
Date: Wed, 21 Feb 2024 00:44:43 +0000 [thread overview]
Message-ID: <cffc9c7e-ba1c-4894-a455-8b2d687182cd@sirena.org.uk> (raw)
In-Reply-To: <a57d6c7eada4b9a7c35addbc8556f5b53a0c3e6f.camel@intel.com>
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On Wed, Feb 21, 2024 at 12:35:48AM +0000, Edgecombe, Rick P wrote:
> doing. But those threads might be using shadow stack instructions
> (INCSSP, RSTORSSP, etc). These are a collection of instructions that
> allow limited control of the SSP. When shadow stack gets disabled,
> these suddenly turn into #UD generating instructions. So any other
> threads executing those instructions when shadow stack got disabled
> would be in for a nasty surprise.
> Glibc's permissive mode (that disables shadow stack when dlopen()ing a
> DSO that doesn't support shadow stack) is quite limited because of
> this. There was a POC for working around it, but I'll stop there for
> now, to not spam you with the details. I'm not sure of arm and risc-v
> details on this specific corner, but for x86.
We have the same issue with disabling GCS causing GCS instructions to
become undefined.
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next prev parent reply other threads:[~2024-02-21 0:51 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240203-arm64-gcs-v8-0-c9fec77673ef@kernel.org>
2024-02-20 16:36 ` Stefan O'Rear
2024-02-20 18:41 ` Edgecombe, Rick P
2024-02-20 18:57 ` Rich Felker
2024-02-20 23:30 ` Edgecombe, Rick P
2024-02-20 23:54 ` dalias
2024-02-21 0:35 ` Edgecombe, Rick P
2024-02-21 0:44 ` Mark Brown [this message]
2024-02-21 1:27 ` dalias
2024-02-21 2:11 ` Edgecombe, Rick P
2024-02-21 4:18 ` Edgecombe, Rick P
2024-02-21 13:53 ` Mark Brown
2024-02-21 14:58 ` dalias
2024-02-21 17:36 ` Mark Brown
2024-02-21 17:57 ` dalias
2024-02-21 18:12 ` Edgecombe, Rick P
2024-02-21 18:30 ` dalias
2024-02-21 18:53 ` Edgecombe, Rick P
2024-02-21 19:06 ` dalias
2024-02-21 19:22 ` Edgecombe, Rick P
2024-02-21 20:18 ` H.J. Lu
2024-02-21 20:25 ` H.J. Lu
2024-02-21 21:12 ` H.J. Lu
2024-02-21 20:18 ` dalias
2024-02-22 13:57 ` Mark Brown
2024-02-21 18:32 ` Mark Brown
2024-02-21 19:10 ` dalias
2024-03-02 14:57 ` Szabolcs Nagy
2024-03-02 15:05 ` H.J. Lu
2024-03-14 14:03 ` Mark Brown
2024-02-20 23:59 ` Stefan O'Rear
2024-02-21 0:40 ` Mark Brown
2024-02-21 4:30 ` Edgecombe, Rick P
2024-02-20 20:14 ` Mark Brown
2024-02-20 23:30 ` Edgecombe, Rick P
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