From: Igor Lubashev <ilubashe@akamai.com>
To: <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@redhat.com>,
Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
<linux-arm-kernel@lists.infradead.org>,
James Morris <jmorris@namei.org>,
Igor Lubashev <ilubashe@akamai.com>
Subject: [PATCH v3 3/4] perf: Use CAP_SYSLOG with kptr_restrict checks
Date: Wed, 7 Aug 2019 10:44:16 -0400 [thread overview]
Message-ID: <291d2cda6ee75b4cd4c9ce717c177db18bf03a31.1565188228.git.ilubashe@akamai.com> (raw)
In-Reply-To: <cover.1565188228.git.ilubashe@akamai.com>
Kernel is using CAP_SYSLOG capability instead of uid==0 and euid==0 when
checking kptr_restrict. Make perf do the same.
Also, the kernel is a more restrictive than "no restrictions" in case of
kptr_restrict==0, so add the same logic to perf.
Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
---
tools/perf/util/symbol.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 173f3378aaa0..046271103499 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -4,6 +4,7 @@
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
+#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/mman.h>
#include <linux/time64.h>
@@ -15,8 +16,10 @@
#include <inttypes.h>
#include "annotate.h"
#include "build-id.h"
+#include "cap.h"
#include "util.h"
#include "debug.h"
+#include "event.h"
#include "machine.h"
#include "map.h"
#include "symbol.h"
@@ -890,7 +893,11 @@ bool symbol__restricted_filename(const char *filename,
{
bool restricted = false;
- if (symbol_conf.kptr_restrict) {
+ /* Per kernel/kallsyms.c:
+ * we also restrict when perf_event_paranoid > 1 w/o CAP_SYSLOG
+ */
+ if (symbol_conf.kptr_restrict ||
+ (perf_event_paranoid() > 1 && !perf_cap__capable(CAP_SYSLOG))) {
char *r = realpath(filename, NULL);
if (r != NULL) {
@@ -2190,9 +2197,9 @@ static bool symbol__read_kptr_restrict(void)
char line[8];
if (fgets(line, sizeof(line), fp) != NULL)
- value = ((geteuid() != 0) || (getuid() != 0)) ?
- (atoi(line) != 0) :
- (atoi(line) == 2);
+ value = perf_cap__capable(CAP_SYSLOG) ?
+ (atoi(line) >= 2) :
+ (atoi(line) != 0);
fclose(fp);
}
--
2.7.4
next prev parent reply other threads:[~2019-08-07 14:45 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 14:44 [PATCH v3 0/4] perf: Use capabilities instead of uid and euid Igor Lubashev
2019-08-07 14:44 ` [PATCH v3 1/4] perf: Add capability-related utilities Igor Lubashev
2019-08-12 19:43 ` Arnaldo Carvalho de Melo
2019-08-15 9:24 ` [tip:perf/core] tools build: Add capability-related feature detection tip-bot for Igor Lubashev
2019-08-15 9:25 ` [tip:perf/core] perf tools: Add helpers to use capabilities if present tip-bot for Igor Lubashev
2019-08-07 14:44 ` [PATCH v3 2/4] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks Igor Lubashev
2019-08-12 20:01 ` Arnaldo Carvalho de Melo
2019-08-12 20:15 ` Arnaldo Carvalho de Melo
2019-08-12 22:33 ` Lubashev, Igor
2019-08-13 13:20 ` Arnaldo Carvalho de Melo
2019-08-07 14:44 ` Igor Lubashev [this message]
2019-08-14 18:04 ` [PATCH v3 3/4] perf: Use CAP_SYSLOG with kptr_restrict checks Mathieu Poirier
2019-08-14 18:48 ` Arnaldo Carvalho de Melo
2019-08-14 18:52 ` Arnaldo Carvalho de Melo
2019-08-14 20:02 ` Lubashev, Igor
2019-08-15 15:01 ` Mathieu Poirier
2019-08-15 20:16 ` Mathieu Poirier
2019-08-15 21:42 ` Arnaldo Carvalho de Melo
2019-08-19 16:51 ` Mathieu Poirier
2019-08-19 22:22 ` Lubashev, Igor
2019-08-20 16:57 ` Mathieu Poirier
2019-08-20 17:13 ` Arnaldo Carvalho de Melo
2019-08-27 1:58 ` Lubashev, Igor
2019-08-15 22:27 ` Lubashev, Igor
2019-08-07 14:44 ` [PATCH v3 4/4] perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace Igor Lubashev
2019-08-12 20:22 ` Arnaldo Carvalho de Melo
2019-08-12 20:27 ` Arnaldo Carvalho de Melo
2019-08-12 20:29 ` Arnaldo Carvalho de Melo
2019-08-12 21:42 ` Mathieu Poirier
2019-08-13 13:23 ` Arnaldo Carvalho de Melo
2019-08-13 16:35 ` Mathieu Poirier
2019-08-15 9:27 ` [tip:perf/core] perf ftrace: Use CAP_SYS_ADMIN instead of euid==0 tip-bot for Igor Lubashev
2019-08-12 9:13 ` [PATCH v3 0/4] perf: Use capabilities instead of uid and euid Jiri Olsa
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