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From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	David Howells <dhowells@redhat.com>,
	Matthew Garrett <mjg59@google.com>,
	Kees Cook <keescook@chromium.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: [PATCH V37 24/29] Lock down perf when in confidentiality mode
Date: Wed, 31 Jul 2019 15:16:12 -0700	[thread overview]
Message-ID: <20190731221617.234725-25-matthewgarrett@google.com> (raw)
In-Reply-To: <20190731221617.234725-1-matthewgarrett@google.com>

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>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
---
 include/linux/security.h     | 1 +
 kernel/events/core.c         | 7 +++++++
 security/lockdown/lockdown.c | 1 +
 3 files changed, 9 insertions(+)

diff --git a/include/linux/security.h b/include/linux/security.h
index 8dd1741a52cd..8ef366de70b0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -119,6 +119,7 @@ enum lockdown_reason {
 	LOCKDOWN_KCORE,
 	LOCKDOWN_KPROBES,
 	LOCKDOWN_BPF_READ,
+	LOCKDOWN_PERF,
 	LOCKDOWN_CONFIDENTIALITY_MAX,
 };
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c1f52a749db2..5c520b60163a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10826,6 +10826,13 @@ SYSCALL_DEFINE5(perf_event_open,
 	    perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
 		return -EACCES;
 
+	err = security_locked_down(LOCKDOWN_PERF);
+	if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
+		/* REGS_INTR can leak data, lockdown must prevent this */
+		return err;
+
+	err = 0;
+
 	/*
 	 * In cgroup mode, the pid argument is used to pass the fd
 	 * opened to the cgroup directory in cgroupfs. The cpu argument
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 1b89d3e8e54d..fb437a7ef5f2 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -34,6 +34,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
 	[LOCKDOWN_KCORE] = "/proc/kcore access",
 	[LOCKDOWN_KPROBES] = "use of kprobes",
 	[LOCKDOWN_BPF_READ] = "use of bpf to read kernel RAM",
+	[LOCKDOWN_PERF] = "unsafe use of perf",
 	[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };
 
-- 
2.22.0.770.g0f2c4a37fd-goog


  parent reply	other threads:[~2019-07-31 22:18 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-31 22:15 [PATCH V37 00/29] security: Add support for locking down the kernel Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 01/29] security: Support early LSMs Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 02/29] security: Add a "locked down" LSM hook Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 03/29] security: Add a static lockdown policy LSM Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 04/29] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-08-01 14:21   ` Jessica Yu
2019-08-01 20:42     ` Matthew Garrett
2019-08-08 10:01       ` Jessica Yu
2019-08-08 18:31         ` Matthew Garrett
2019-08-08 22:43           ` James Morris
2019-08-09 20:59         ` [PATCH V39] " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 05/29] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 06/29] kexec_load: Disable at runtime if " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 07/29] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 08/29] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 09/29] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 10/29] hibernate: Disable when " Matthew Garrett
2019-07-31 22:15 ` [PATCH V37 11/29] PCI: Lock down BAR access " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 12/29] x86: Lock down IO port " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 13/29] x86/msr: Restrict MSR " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 14/29] ACPI: Limit access to custom_method " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 15/29] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 16/29] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 17/29] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 18/29] Lock down TIOCSSERIAL Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 19/29] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-08-01 16:19   ` Jessica Yu
2019-08-01 20:44     ` Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 20/29] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 21/29] Lock down /proc/kcore Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 22/29] Lock down tracing and perf kprobes when in confidentiality mode Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 23/29] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-07-31 22:16 ` Matthew Garrett [this message]
2019-07-31 22:16 ` [PATCH V37 25/29] kexec: Allow kexec_file() with appropriate IMA policy when locked down Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 26/29] debugfs: Restrict debugfs when the kernel is " Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 27/29] tracefs: Restrict tracefs " Matthew Garrett
     [not found]   ` <CGME20190813061053eucas1p1b6945259d9663b743e7cb32521d041e7@eucas1p1.samsung.com>
2019-08-13  6:10     ` Marek Szyprowski
     [not found]       ` <CGME20190813072111eucas1p2b87f3f8d16c22a0a3d024bc5ebcc8bcc@eucas1p2.samsung.com>
2019-08-13  7:21         ` Marek Szyprowski
     [not found]           ` <CGME20190814061246eucas1p128cae99a14f27bc79fa2aa72084a0413@eucas1p1.samsung.com>
2019-08-14  6:12             ` [PATCH] tracefs: Fix NULL pointer dereference when no lockdown is used Marek Szyprowski
2019-07-31 22:16 ` [PATCH V37 28/29] efi: Restrict efivar_ssdt_load when the kernel is locked down Matthew Garrett
2019-07-31 22:16 ` [PATCH V37 29/29] lockdown: Print current->comm in restriction messages Matthew Garrett

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