[V31,23/25] Lock down perf when in confidentiality mode

Message ID	20190326182742.16950-24-matthewgarrett@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-security-module-owner@kernel.org> Date: Tue, 26 Mar 2019 11:27:39 -0700 In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com> Message-Id: <20190326182742.16950-24-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190326182742.16950-1-matthewgarrett@google.com> Subject: [PATCH V31 23/25] Lock down perf when in confidentiality mode From: Matthew Garrett <matthewgarrett@google.com> To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-api@vger.kernel.org, luto@kernel.org, Matthew Garrett <mjg59@google.com>, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org> Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk
Series	Add support for kernel lockdown \| expand [V31,00/25] Add support for kernel lockdown [V31,01/25] Add the ability to lock down access to the running kernel image [V31,02/25] Enforce module signatures if the kernel is locked down [V31,03/25] Restrict /dev/{mem,kmem,port} when the kernel is locked down [V31,04/25] kexec_load: Disable at runtime if the kernel is locked down [V31,05/25] Copy secure_boot flag in boot params across kexec reboot [V31,06/25] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE [V31,07/25] kexec_file: Restrict at runtime if the kernel is locked down [V31,08/25] hibernate: Disable when the kernel is locked down [V31,09/25] uswsusp: Disable when the kernel is locked down [V31,10/25] PCI: Lock down BAR access when the kernel is locked down [V31,11/25] x86: Lock down IO port access when the kernel is locked down [V31,12/25] x86/msr: Restrict MSR access when the kernel is locked down [V31,13/25] ACPI: Limit access to custom_method when the kernel is locked down [V31,14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down [V31,15/25] acpi: Disable ACPI table override if the kernel is locked down [V31,16/25] Prohibit PCMCIA CIS storage when the kernel is locked down [V31,17/25] Lock down TIOCSSERIAL [V31,18/25] Lock down module params that specify hardware parameters (eg. ioport) [V31,19/25] x86/mmiotrace: Lock down the testmmiotrace module [V31,20/25] Lock down /proc/kcore [V31,21/25] Lock down kprobes when in confidentiality mode [V31,22/25] bpf: Restrict bpf when kernel lockdown is in confidentiality mode [V31,23/25] Lock down perf when in confidentiality mode [V31,24/25] lockdown: Print current->comm in restriction messages [V31,25/25] debugfs: Disable open() when kernel is locked down

Message ID

20190326182742.16950-24-matthewgarrett@google.com (mailing list archive)

State

New, archived

Headers

Date: Tue, 26 Mar 2019 11:27:39 -0700
In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com>
Message-Id: <20190326182742.16950-24-matthewgarrett@google.com>
Mime-Version: 1.0
References: <20190326182742.16950-1-matthewgarrett@google.com>
Subject: [PATCH V31 23/25] Lock down perf when in confidentiality mode
From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, dhowells@redhat.com,
        linux-api@vger.kernel.org, luto@kernel.org,
        Matthew Garrett <mjg59@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: owner-linux-security-module@vger.kernel.org
Precedence: bulk

Series

Add support for kernel lockdown | expand

Commit Message

Matthew Garrett March 26, 2019, 6:27 p.m. UTC

From: David Howells <dhowells@redhat.com>

Disallow the use of certain perf facilities that might allow userspace to
access kernel data.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
---
 kernel/events/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3cd13a30f732..6ad3d83c091c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10461,6 +10461,12 @@  SYSCALL_DEFINE5(perf_event_open,
 			return -EINVAL;
 	}
 
+	if ((attr.sample_type & PERF_SAMPLE_REGS_INTR) &&
+	    kernel_is_locked_down("PERF_SAMPLE_REGS_INTR",
+				  LOCKDOWN_CONFIDENTIALITY))
+		/* REGS_INTR can leak data, lockdown must prevent this */
+		return -EPERM;
+
 	/* Only privileged users can get physical addresses */
 	if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
 	    perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))

[V31,23/25] Lock down perf when in confidentiality mode

Commit Message

Patch