perf symbols: Check kptr_restrict for root

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 <[email protected]> Tested-by: Arnaldo Carvalho de Melo <[email protected]> Cc: Zefan Li <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
zhenyw · May 27, 2016 · 38272dc · 38272dc
1 parent 275ae41
commit 38272dc
Showing 1 changed file with 8 additions and 8 deletions.
diff --git 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;