From: Igor Lubashev <ilubashe@akamai.com>
To: <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Igor Lubashev <ilubashe@akamai.com>,
James Morris <jmorris@namei.org>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] perf: Use CAP_SYSLOG with kptr_restrict checks
Date: Tue, 2 Jul 2019 20:10:05 -0400 [thread overview]
Message-ID: <1562112605-6235-4-git-send-email-ilubashe@akamai.com> (raw)
In-Reply-To: <1562112605-6235-1-git-send-email-ilubashe@akamai.com>
Kernel is using CAP_SYSLOG capcbility 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 5cbad55cd99d..fd68dae3f58e 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"
@@ -889,7 +892,11 @@ 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) {
@@ -2100,9 +2107,9 @@ 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
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next prev parent reply other threads:[~2019-07-03 0:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-03 0:10 [PATCH 0/3] perf: Use capabilities instead of uid and euid Igor Lubashev
2019-07-03 0:10 ` [PATCH 1/3] perf: Add capability-related utilities Igor Lubashev
2019-07-16 8:46 ` Jiri Olsa
2019-07-17 21:05 ` Arnaldo Carvalho de Melo
2019-07-17 23:46 ` Arnaldo Carvalho de Melo
2019-07-17 23:48 ` Arnaldo Carvalho de Melo
2019-07-18 21:00 ` Lubashev, Igor
2019-08-07 3:58 ` Lubashev, Igor
2019-07-03 0:10 ` [PATCH 2/3] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks Igor Lubashev
2019-07-16 8:47 ` Jiri Olsa
2019-07-16 17:01 ` Lubashev, Igor
2019-07-17 7:10 ` Jiri Olsa
2019-07-17 18:33 ` Lubashev, Igor
2019-07-03 0:10 ` Igor Lubashev [this message]
2019-07-16 10:51 ` [PATCH 0/3] perf: Use capabilities instead of uid and euid Alexey Budankov
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