[v6,09/10] drivers/perf: open access for CAP_PERFMON privileged process
diff mbox series

Message ID 4fa7407f-0da8-fffa-dd79-2da0429055f6@linux.intel.com
State New
Headers show
Series
  • Introduce CAP_PERFMON to secure system performance monitoring and observability
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Commit Message

Alexey Budankov Feb. 5, 2020, 5:36 p.m. UTC
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(-)

Patch
diff mbox series

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))))