samples/seccomp: improve label helper
Fixes a potential corruption with uninitialized stack memory in the
seccomp BPF sample program.
[akpm@linux-foundation.org: coding-style fixlet]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Robert Swiecki <swiecki@google.com>
Tested-by: Robert Swiecki <swiecki@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/samples/seccomp/bpf-helper.c b/samples/seccomp/bpf-helper.c
index 579cfe3..05cb4d5 100644
--- a/samples/seccomp/bpf-helper.c
+++ b/samples/seccomp/bpf-helper.c
@@ -10,6 +10,7 @@
*/
#include <stdio.h>
+#include <stdlib.h>
#include <string.h>
#include "bpf-helper.h"
@@ -63,6 +64,11 @@
{
struct __bpf_label *begin = labels->labels, *end;
int id;
+
+ if (labels->count == BPF_LABELS_MAX) {
+ fprintf(stderr, "Too many labels\n");
+ exit(1);
+ }
if (labels->count == 0) {
begin->label = label;
begin->location = 0xffffffff;