[PATCH 1/2] perf tools: Check kptr_restrict for root

From: Wang Nan
Date: Tue May 24 2016 - 05:23:40 EST


If kptr_restrict is set to 2, even root is not allowed to see pointers.
This patch checks kptr_restrict even if euid == 0. For root, report
error if kptr_restrict is 2.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
tools/perf/util/symbol.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 20f9cb3..54c4ff2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1933,17 +1933,17 @@ int setup_intlist(struct intlist **list, const char *list_str,
static bool symbol__read_kptr_restrict(void)
{
bool value = false;
+ FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");

- if (geteuid() != 0) {
- FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");
- if (fp != NULL) {
- char line[8];
+ if (fp != NULL) {
+ char line[8];

- if (fgets(line, sizeof(line), fp) != NULL)
- value = atoi(line) != 0;
+ if (fgets(line, sizeof(line), fp) != NULL)
+ value = (geteuid() != 0) ?
+ (atoi(line) != 0) :
+ (atoi(line) == 2);

- fclose(fp);
- }
+ fclose(fp);
}

return value;
--
1.8.3.4