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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 19/24] acpi: Disable APEI error injection if the kernel is locked down From: David Howells To: linux-kernel@vger.kernel.org Cc: gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org, Linn Crosetto , matthew.garrett@nebula.com, gregkh@linuxfoundation.org, dhowells@redhat.com, linux-acpi@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Date: Wed, 05 Apr 2017 21:17:16 +0100 Message-ID: <149142343682.5101.14960696203158482012.stgit@warthog.procyon.org.uk> In-Reply-To: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> References: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 05 Apr 2017 20:17:20 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Linn Crosetto ACPI provides an error injection mechanism, EINJ, for debugging and testing the ACPI Platform Error Interface (APEI) and other RAS features. If supported by the firmware, ACPI specification 5.0 and later provide for a way to specify a physical memory address to which to inject the error. Injecting errors through EINJ can produce errors which to the platform are indistinguishable from real hardware errors. This can have undesirable side-effects, such as causing the platform to mark hardware as needing replacement. While it does not provide a method to load unauthenticated privileged code, the effect of these errors may persist across reboots and affect trust in the underlying hardware, so disable error injection through EINJ if the kernel is locked down. Signed-off-by: Linn Crosetto Signed-off-by: David Howells cc: linux-acpi@vger.kernel.org --- drivers/acpi/apei/einj.c | 3 +++ 1 file changed, 3 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c index ec50c32ea3da..e082718d01c2 100644 --- a/drivers/acpi/apei/einj.c +++ b/drivers/acpi/apei/einj.c @@ -518,6 +518,9 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, int rc; u64 base_addr, size; + if (kernel_is_locked_down()) + return -EPERM; + /* If user manually set "flags", make sure it is legal */ if (flags && (flags & ~(SETWA_FLAGS_APICID|SETWA_FLAGS_MEM|SETWA_FLAGS_PCIE_SBDF)))