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From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: James Morris <jmorris@namei.org>, Serge Hallyn <serge@hallyn.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Peter Zijlstra <peterz@infradead.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	"joonas.lahtinen@linux.intel.com"
	<joonas.lahtinen@linux.intel.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Will Deacon <will@kernel.org>, Paul Mackerras <paulus@samba.org>,
	Helge Deller <deller@gmx.de>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>,
	Stephane Eranian <eranian@google.com>,
	Igor Lubashev <ilubashe@akamai.com>, Jiri Olsa <jolsa@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-parisc@vger.kernel.org" <linux-parisc@vger.kernel.org>,
	oprofile-list@lists.sf.net,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	linux-man@vger.kernel.org
Subject: [PATCH v7 09/12] drivers/perf: open access for CAP_PERFMON privileged process
Date: Mon, 17 Feb 2020 11:11:32 +0300
Message-ID: <48baecd5-a015-3dbf-f774-9f2caee13893@linux.intel.com> (raw)
In-Reply-To: <c8de937a-0b3a-7147-f5ef-69f467e87a13@linux.intel.com>


Open access to monitoring for CAP_PERFMON privileged process.
Providing the access under CAP_PERFMON capability singly, without
the rest of CAP_SYS_ADMIN credentials, excludes chances to misuse
the credentials and makes operation more secure.

CAP_PERFMON implements the principal of least privilege for performance
monitoring and observability operations (POSIX IEEE 1003.1e 2.2.2.39
principle of least privilege: A security design principle that states
that a process or program be granted only those privileges (e.g.,
capabilities) necessary to accomplish its legitimate function, and
only for the time that such privileges are actually required)

For backward compatibility reasons access to the monitoring remains
open for CAP_SYS_ADMIN privileged processes but CAP_SYS_ADMIN usage
for secure monitoring is discouraged with respect to CAP_PERFMON
capability.

Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
 drivers/perf/arm_spe_pmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index 4e4984a55cd1..5dff81bc3324 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c
@@ -274,7 +274,7 @@ static u64 arm_spe_event_to_pmscr(struct perf_event *event)
 	if (!attr->exclude_kernel)
 		reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
 
-	if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN))
+	if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && perfmon_capable())
 		reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
 
 	return reg;
@@ -700,7 +700,7 @@ static int arm_spe_pmu_event_init(struct perf_event *event)
 		return -EOPNOTSUPP;
 
 	reg = arm_spe_event_to_pmscr(event);
-	if (!capable(CAP_SYS_ADMIN) &&
+	if (!perfmon_capable() &&
 	    (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
 		    BIT(SYS_PMSCR_EL1_CX_SHIFT) |
 		    BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
-- 
2.20.1



  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-17  8:02 [PATCH v7 00/12] Introduce CAP_PERFMON to secure system performance monitoring and observability Alexey Budankov
2020-02-17  8:06 ` [PATCH v7 01/12] capabilities: introduce CAP_PERFMON to kernel and user space Alexey Budankov
2020-02-18 18:22   ` Stephen Smalley
2020-02-18 19:21   ` James Morris
2020-02-19  7:54     ` Alexey Budankov
2020-02-17  8:06 ` [PATCH v7 02/12] perf/core: open access to the core for CAP_PERFMON privileged process Alexey Budankov
2020-02-18 19:22   ` James Morris
2020-02-17  8:07 ` [PATCH v7 03/12] perf/core: open access to probes " Alexey Budankov
2020-02-18 19:22   ` James Morris
2020-02-17  8:08 ` [PATCH v7 04/12] perf tool: extend Perf tool with CAP_PERFMON capability support Alexey Budankov
2020-02-18 19:24   ` James Morris
2020-02-17  8:08 ` [PATCH v7 05/12] drm/i915/perf: open access for CAP_PERFMON privileged process Alexey Budankov
2020-02-18 19:25   ` James Morris
2020-02-17  8:09 ` [PATCH v7 06/12] trace/bpf_trace: " Alexey Budankov
2020-02-18 19:25   ` James Morris
2020-02-17  8:10 ` [PATCH v7 07/12] powerpc/perf: " Alexey Budankov
2020-02-18 19:28   ` James Morris
2020-02-17  8:10 ` [PATCH v7 08/12] parisc/perf: " Alexey Budankov
2020-02-18 19:29   ` James Morris
2020-02-17  8:11 ` Alexey Budankov [this message]
2020-02-18 19:43   ` [PATCH v7 09/12] drivers/perf: " James Morris
2020-02-17  8:12 ` [PATCH v7 10/12] drivers/oprofile: " Alexey Budankov
2020-02-18 19:44   ` James Morris
2020-02-17  8:12 ` [PATCH v7 11/12] doc/admin-guide: update perf-security.rst with CAP_PERFMON information Alexey Budankov
2020-02-17  8:13 ` [PATCH v7 12/12] doc/admin-guide: update kernel.rst " Alexey Budankov
2020-02-25  9:55 ` [PATCH v7 00/12] Introduce CAP_PERFMON to secure system performance monitoring and observability Alexey Budankov
2020-03-02  0:19   ` [Intel-gfx] " Serge Hallyn
2020-03-02 19:44     ` James Morris
2020-03-26 23:28     ` James Morris

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