[PATCH -next] selinux: Add boundary check in put_entry()

[Xiu Jianfeng]

Just like next_entry(), boundary check is necessary to prevent memory
out-of-bound access.

Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
---
 security/selinux/ss/policydb.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index c24d4e1063ea..ffc4e7bad205 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -370,6 +370,8 @@ static inline int put_entry(const void *buf, size_t bytes, int num, struct polic
 {
 	size_t len = bytes * num;
 
+	if (len > fp->len)
+		return -EINVAL;
 	memcpy(fp->data, buf, len);
 	fp->data += len;
 	fp->len -= len;
-- 
2.17.1