[PATCH 4.19 052/287] selinux: Add boundary check in put_entry()

[Greg Kroah-Hartman]

From: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>

[ Upstream commit 15ec76fb29be31df2bccb30fc09875274cba2776 ]

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

Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@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 215f8f30ac5a..2a479785ebd4 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -360,6 +360,8 @@ 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;
-- 
2.35.1