From 10452edd175fcc4fd0f5ac782ed2a002e3e5d65c Mon Sep 17 00:00:00 2001
From: Bui Quang Minh <minhquangbui99@gmail.com>
Date: Wed, 24 Apr 2024 21:44:22 +0700
Subject: [PATCH] s390/cio: Ensure the copied buf is NUL terminated
[ Upstream commit da7c622cddd4fe36be69ca61e8c42e43cde94784 ]
Currently, we allocate a lbuf-sized kernel buffer and copy lbuf from
userspace to that buffer. Later, we use scanf on this buffer but we don't
ensure that the string is terminated inside the buffer, this can lead to
OOB read when using scanf. Fix this issue by using memdup_user_nul instead.
Fixes: a4f17cc72671 ("s390/cio: add CRW inject functionality")
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240424-fix-oob-read-v2-5-f1f1b53a10f4@gmail.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/cio/cio_inject.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/s390/cio/cio_inject.c b/drivers/s390/cio/cio_inject.c
index 8613fa937237..a2e771ebae8e 100644
--- a/drivers/s390/cio/cio_inject.c
+++ b/drivers/s390/cio/cio_inject.c
@@ -95,7 +95,7 @@ static ssize_t crw_inject_write(struct file *file, const char __user *buf,
return -EINVAL;
}
- buffer = vmemdup_user(buf, lbuf);
+ buffer = memdup_user_nul(buf, lbuf);
if (IS_ERR(buffer))
return -ENOMEM;