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 <iluba...@akamai.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Alexey Budankov <alexey.budan...@linux.intel.com> Cc: James Morris <jmor...@namei.org> Cc: Mathieu Poirier <mathieu.poir...@linaro.org> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Suzuki Poulouse <suzuki.poul...@arm.com> Cc: linux-arm-ker...@lists.infradead.org Link: http://lkml.kernel.org/r/291d2cda6ee75b4cd4c9ce717c177db18bf03a31.1565188228.git.iluba...@akamai.com Cc: Arnaldo Carvalho de Melo <a...@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 4efde7879474..035f2e75728c 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; } -- 2.7.4
