lkml.org 
[lkml]   [2019]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: perf/core] perf symbols: Use CAP_SYSLOG with kptr_restrict checks
The following commit has been merged into the perf/core branch of tip:

Commit-ID: 8859aedefefe7eeea5e67968b7fe39c828d589a0
Gitweb: https://git.kernel.org/tip/8859aedefefe7eeea5e67968b7fe39c828d589a0
Author: Igor Lubashev <ilubashe@akamai.com>
AuthorDate: Mon, 26 Aug 2019 21:39:15 -04:00
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitterDate: Wed, 28 Aug 2019 17:19:19 -03:00

perf symbols: Use CAP_SYSLOG with kptr_restrict checks

The 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>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1566869956-7154-5-git-send-email-ilubashe@akamai.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 4efde78..035f2e7 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"
@@ -2195,13 +2198,19 @@ 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);
}

+ /* Per kernel/kallsyms.c:
+ * we also restrict when perf_event_paranoid > 1 w/o CAP_SYSLOG
+ */
+ if (perf_event_paranoid() > 1 && !perf_cap__capable(CAP_SYSLOG))
+ value = true;
+
return value;
}

\
 
 \ /
  Last update: 2019-08-29 21:03    [W:0.099 / U:8.644 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site