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Message-ID: <75aa0324-d01c-59fa-f0f3-b49bf6c53ff3@linux.intel.com>
Date: Wed, 18 Dec 2019 12:26:33 +0300
From: Alexey Budankov <alexey.budankov@...ux.intel.com>
To: Peter Zijlstra <peterz@...radead.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Ingo Molnar <mingo@...hat.com>,
"jani.nikula@...ux.intel.com" <jani.nikula@...ux.intel.com>,
"joonas.lahtinen@...ux.intel.com" <joonas.lahtinen@...ux.intel.com>,
"rodrigo.vivi@...el.com" <rodrigo.vivi@...el.com>,
Alexei Starovoitov <ast@...nel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
"james.bottomley@...senpartnership.com"
<james.bottomley@...senpartnership.com>,
Serge Hallyn <serge@...lyn.com>,
James Morris <jmorris@...ei.org>,
Will Deacon <will.deacon@....com>,
Mark Rutland <mark.rutland@....com>,
Casey Schaufler <casey@...aufler-ca.com>,
Robert Richter <rric@...nel.org>
Cc: Jiri Olsa <jolsa@...hat.com>, Andi Kleen <ak@...ux.intel.com>,
Stephane Eranian <eranian@...gle.com>,
Igor Lubashev <ilubashe@...mai.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Namhyung Kim <namhyung@...nel.org>,
Kees Cook <keescook@...omium.org>,
Jann Horn <jannh@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
Lionel Landwerlin <lionel.g.landwerlin@...el.com>,
Song Liu <songliubraving@...com>,
linux-kernel <linux-kernel@...r.kernel.org>,
"linux-security-module@...r.kernel.org"
<linux-security-module@...r.kernel.org>,
"selinux@...r.kernel.org" <selinux@...r.kernel.org>,
"intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
"bpf@...r.kernel.org" <bpf@...r.kernel.org>,
"linux-parisc@...r.kernel.org" <linux-parisc@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
"linux-perf-users@...r.kernel.org" <linux-perf-users@...r.kernel.org>,
linux-arm-kernel@...ts.infradead.org, oprofile-list@...ts.sf.net
Subject: [PATCH v4 3/9] perf tool: extend Perf tool with CAP_SYS_PERFMON
capability support
Extend error messages to mention CAP_SYS_PERFMON capability as an option
to substitute CAP_SYS_ADMIN capability for secure system performance
monitoring and observability operations. Make perf_event_paranoid_check()
and __cmd_ftrace() to be aware of CAP_SYS_PERFMON capability.
Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
---
tools/perf/builtin-ftrace.c | 5 +++--
tools/perf/design.txt | 3 ++-
tools/perf/util/cap.h | 4 ++++
tools/perf/util/evsel.c | 10 +++++-----
tools/perf/util/util.c | 1 +
5 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index d5adc417a4ca..8096e9b5f4f9 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -284,10 +284,11 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
.events = POLLIN,
};
- if (!perf_cap__capable(CAP_SYS_ADMIN)) {
+ if (!(perf_cap__capable(CAP_SYS_PERFMON) ||
+ perf_cap__capable(CAP_SYS_ADMIN))) {
pr_err("ftrace only works for %s!\n",
#ifdef HAVE_LIBCAP_SUPPORT
- "users with the SYS_ADMIN capability"
+ "users with the CAP_SYS_PERFMON or CAP_SYS_ADMIN capability"
#else
"root"
#endif
diff --git a/tools/perf/design.txt b/tools/perf/design.txt
index 0453ba26cdbd..71755b3e1303 100644
--- a/tools/perf/design.txt
+++ b/tools/perf/design.txt
@@ -258,7 +258,8 @@ gets schedule to. Per task counters can be created by any user, for
their own tasks.
A 'pid == -1' and 'cpu == x' counter is a per CPU counter that counts
-all events on CPU-x. Per CPU counters need CAP_SYS_ADMIN privilege.
+all events on CPU-x. Per CPU counters need CAP_SYS_PERFMON or
+CAP_SYS_ADMIN privilege.
The 'flags' parameter is currently unused and must be zero.
diff --git a/tools/perf/util/cap.h b/tools/perf/util/cap.h
index 051dc590ceee..0f79fbf6638b 100644
--- a/tools/perf/util/cap.h
+++ b/tools/perf/util/cap.h
@@ -29,4 +29,8 @@ static inline bool perf_cap__capable(int cap __maybe_unused)
#define CAP_SYSLOG 34
#endif
+#ifndef CAP_SYS_PERFMON
+#define CAP_SYS_PERFMON 38
+#endif
+
#endif /* __PERF_CAP_H */
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index f4dea055b080..3a46325e3702 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2468,14 +2468,14 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target,
"You may not have permission to collect %sstats.\n\n"
"Consider tweaking /proc/sys/kernel/perf_event_paranoid,\n"
"which controls use of the performance events system by\n"
- "unprivileged users (without CAP_SYS_ADMIN).\n\n"
+ "unprivileged users (without CAP_SYS_PERFMON or CAP_SYS_ADMIN).\n\n"
"The current value is %d:\n\n"
" -1: Allow use of (almost) all events by all users\n"
" Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK\n"
- ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN\n"
- " Disallow raw tracepoint access by users without CAP_SYS_ADMIN\n"
- ">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n"
- ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n"
+ ">= 0: Disallow ftrace function tracepoint by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN\n"
+ " Disallow raw tracepoint access by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN\n"
+ ">= 1: Disallow CPU event access by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN\n"
+ ">= 2: Disallow kernel profiling by users without CAP_SYS_PERFMON or CAP_SYS_ADMIN\n\n"
"To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n"
" kernel.perf_event_paranoid = -1\n" ,
target->system_wide ? "system-wide " : "",
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 969ae560dad9..9981db0d8d09 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -272,6 +272,7 @@ int perf_event_paranoid(void)
bool perf_event_paranoid_check(int max_level)
{
return perf_cap__capable(CAP_SYS_ADMIN) ||
+ perf_cap__capable(CAP_SYS_PERFMON) ||
perf_event_paranoid() <= max_level;
}
--
2.20.1
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