From: Benjamin Gray <bgray@linux.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: linux-hardening@vger.kernel.org, ajd@linux.ibm.com,
cmr@bluescreens.de, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection
Date: Tue, 07 Mar 2023 16:37:47 +1100 [thread overview]
Message-ID: <eb19afda911f4868ec6ff194738afcfe7050d5c1.camel@linux.ibm.com> (raw)
In-Reply-To: <CQZW0SBFI6QM.3FW6O6LJ0PVS1@bobo>
On Tue, 2023-03-07 at 15:05 +1000, Nicholas Piggin wrote:
> I think it is not quite per-process? I don't actually know how the
> user
> toolchain side is put together, but I'm thinking we can not give it a
> new
> salt on fork(), but we could on exec(). I think we could actually
> give
> each thread their own salt within a process too, right?
Yeah, the error case is we return further than we called in a given
execution context. A forked child may return after the fork, meaning it
needs the same key as the parent for the hashchk to work. Exec can get
a new key because we can't return with any existing hashes. I haven't
seen enough of kernel thread support to know if/how we can give threads
their own key. I believe they go through the fork() call that copies
the parent key currently.
next prev parent reply other threads:[~2023-03-07 5:39 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-28 2:44 [RFC PATCH 00/13] Add DEXCR support Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 01/13] powerpc/book3s: Add missing <linux/sched.h> include Benjamin Gray
2023-03-07 4:28 ` Nicholas Piggin
2022-11-28 2:44 ` [RFC PATCH 02/13] powerpc: Add initial Dynamic Execution Control Register (DEXCR) support Benjamin Gray
2023-03-07 4:45 ` Nicholas Piggin
2023-03-09 23:46 ` Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 03/13] powerpc/dexcr: Handle hashchk exception Benjamin Gray
2022-11-29 10:39 ` Nicholas Piggin
2022-11-29 22:04 ` Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 04/13] powerpc/dexcr: Support userspace ROP protection Benjamin Gray
2023-03-07 5:05 ` Nicholas Piggin
2023-03-07 5:37 ` Benjamin Gray [this message]
2023-03-21 4:51 ` Nicholas Piggin
2022-11-28 2:44 ` [RFC PATCH 05/13] prctl: Define PowerPC DEXCR interface Benjamin Gray
2023-03-07 5:07 ` Nicholas Piggin
2022-11-28 2:44 ` [RFC PATCH 06/13] powerpc/dexcr: Add prctl implementation Benjamin Gray
2023-03-07 5:12 ` Nicholas Piggin
2022-11-28 2:44 ` [RFC PATCH 07/13] powerpc/dexcr: Add sysctl entry for SBHE system override Benjamin Gray
2023-03-07 5:30 ` Nicholas Piggin
2023-03-07 5:58 ` Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 08/13] powerpc/dexcr: Add enforced userspace ROP protection config Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 09/13] selftests/powerpc: Add more utility macros Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 10/13] selftests/powerpc: Add hashst/hashchk test Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 11/13] selftests/powerpc: Add DEXCR prctl, sysctl interface test Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 12/13] selftests/powerpc: Add DEXCR status utility lsdexcr Benjamin Gray
2022-11-28 2:44 ` [RFC PATCH 13/13] Documentation: Document PowerPC kernel DEXCR interface Benjamin Gray
2023-03-07 5:40 ` Nicholas Piggin
2023-03-07 5:52 ` Benjamin Gray
2022-11-28 4:05 ` [RFC PATCH 00/13] Add DEXCR support Russell Currey
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