The following commit has been merged into the perf/core branch of tip: Commit-ID: cea7d0d4a59b4efd0e1fe067130b4c06ab4d412f Gitweb: https://git.kernel.org/tip/cea7d0d4a59b4efd0e1fe067130b4c06ab4d412f Author: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx> AuthorDate: Thu, 02 Apr 2020 11:51:21 +03:00 Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> CommitterDate: Thu, 16 Apr 2020 12:19:09 -03:00 drivers/perf: Open access for CAP_PERFMON privileged process 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 principle 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@xxxxxxxxxxxxxxx> Reviewed-by: James Morris <jamorris@xxxxxxxxxxxxxxxxxxx> Acked-by: Will Deacon <will@xxxxxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> Cc: Igor Lubashev <ilubashe@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Serge Hallyn <serge@xxxxxxxxxx> Cc: Song Liu <songliubraving@xxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-man@xxxxxxxxxxxxxxx Cc: linux-security-module@xxxxxxxxxxxxxxx Cc: selinux@xxxxxxxxxxxxxxx Link: http://lore.kernel.org/lkml/4ec1d6f7-548c-8d1c-f84a-cebeb9674e4e@xxxxxxxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> --- 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 b72c048..0e0961a 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))))
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