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 <[email protected]> --- 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
