From: Catalin Marinas <catalin.marinas@arm.com>
To: Jeremy Linton <jeremy.linton@arm.com>
Cc: linux-trace-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org, mhiramat@kernel.org,
oleg@redhat.com, peterz@infradead.org, mingo@redhat.com,
acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, jolsa@kernel.org,
irogers@google.com, adrian.hunter@intel.com,
kan.liang@linux.intel.com, thiago.bauermann@linaro.org,
broonie@kernel.org, yury.khrustalev@arm.com,
kristina.martsenko@arm.com, liaochang1@huawei.com,
will@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/7] arm64: probes: Add GCS support to bl/blr/ret
Date: Fri, 15 Aug 2025 15:08:40 +0100 [thread overview]
Message-ID: <aJ8_aH7ncFfznl8S@arm.com> (raw)
In-Reply-To: <20250811141010.741989-5-jeremy.linton@arm.com>
On Mon, Aug 11, 2025 at 09:10:07AM -0500, Jeremy Linton wrote:
> The arm64 probe simulation doesn't currently have logic in place
> to deal with GCS and this results in core dumps if probes are inserted
> at control flow locations. Fix-up bl, blr and ret to manipulate the
> shadow stack as needed.
>
> While we manipulate and validate the shadow stack correctly, the
> hardware provides additional security by only allowing GCS operations
> against pages which are marked to support GCS. For writing there is
> gcssttr() which enforces this, but there isn't an equivalent for
> reading. This means that uprobe users should be aware that probing on
> control flow instructions which require reading the shadow stack (ex:
> ret) offers lower security guarantees than what is achieved without
> the uprobe active.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
next prev parent reply other threads:[~2025-08-15 16:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-11 14:10 [PATCH v5 0/7] arm64: Enable UPROBES with GCS Jeremy Linton
2025-08-11 14:10 ` [PATCH v5 1/7] arm64: probes: Break ret out from bl/blr Jeremy Linton
2025-08-11 14:10 ` [PATCH v5 2/7] arm64: uaccess: Move existing GCS accessors definitions to gcs.h Jeremy Linton
2025-08-11 14:10 ` [PATCH v5 3/7] arm64: uaccess: Add additional userspace GCS accessors Jeremy Linton
2025-08-11 14:40 ` Jeremy Linton
2025-08-11 14:10 ` [PATCH v5 4/7] arm64: probes: Add GCS support to bl/blr/ret Jeremy Linton
2025-08-15 14:08 ` Catalin Marinas [this message]
2025-08-11 14:10 ` [PATCH v5 5/7] arm64: uprobes: Add GCS support to uretprobes Jeremy Linton
2025-08-13 6:12 ` kernel test robot
2025-08-15 14:10 ` Catalin Marinas
2025-08-11 14:10 ` [PATCH v5 6/7] arm64: Kconfig: Remove GCS restrictions on UPROBES Jeremy Linton
2025-08-11 14:10 ` [PATCH v5 7/7] uprobes: uprobe_warn should use passed task Jeremy Linton
2025-08-15 14:09 ` Catalin Marinas
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