From 8859aedefefe7eeea5e67968b7fe39c828d589a0 Mon Sep 17 00:00:00 2001 From: Igor Lubashev Date: Mon, 26 Aug 2019 21:39:15 -0400 Subject: [PATCH] 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 Tested-by: Mathieu Poirier Cc: Alexander Shishkin Cc: Alexey Budankov Cc: James Morris Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse 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 --- 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 4efde7879474..035f2e75728c 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -4,6 +4,7 @@ #include #include #include +#include #include #include #include @@ -15,8 +16,10 @@ #include #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; }