Commit 8859aede authored by Igor Lubashev's avatar Igor Lubashev Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarIgor Lubashev <ilubashe@akamai.com>
Tested-by: default avatarMathieu 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent aa97293f

tools/perf/util/symbol.c

+12 −3
Original line number Original line Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <stdlib.h>

#include <stdlib.h>

#include <stdio.h>

#include <stdio.h>

#include <string.h>

#include <string.h>

#include <linux/capability.h>

#include <linux/kernel.h>

#include <linux/kernel.h>

#include <linux/mman.h>

#include <linux/mman.h>

#include <linux/time64.h>

#include <linux/time64.h>
@@ -15,8 +16,10 @@ 
#include <inttypes.h>

#include <inttypes.h>

#include "annotate.h"

#include "annotate.h"

#include "build-id.h"

#include "build-id.h"

#include "cap.h"

#include "util.h"

#include "util.h"

#include "debug.h"

#include "debug.h"

#include "event.h"

#include "machine.h"

#include "machine.h"

#include "map.h"

#include "map.h"

#include "symbol.h"

#include "symbol.h"
@@ -2195,13 +2198,19 @@ static bool symbol__read_kptr_restrict(void) 
		char line[8];

		char line[8];





		if (fgets(line, sizeof(line), fp) != NULL)

		if (fgets(line, sizeof(line), fp) != NULL)

			value = ((geteuid() != 0) || (getuid() != 0)) ?

			value = perf_cap__capable(CAP_SYSLOG) ?

					(atoi(line) != 0) :

					(atoi(line) >= 2) :

					(atoi(line) == 2);

					(atoi(line) != 0);





		fclose(fp);

		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;

	return value;

}

}