From: Namjae Jeon <namjae.jeon@samsung.com>
Date: Wed, 26 May 2021 06:31:37 +0000 (+0900)
Subject: cifsd: add the check if nvec is zero
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=41a7848a01b3f4401b8b87815e643584b86895f2;p=linux.git

cifsd: add the check if nvec is zero

Dan Carpenter pointed out that memory can be corrupted when nvec is zero.
This patch add the check to prevent it.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/cifsd/auth.c b/fs/cifsd/auth.c
index 7e56966f87d41..9f957c8c123c5 100644
--- a/fs/cifsd/auth.c
+++ b/fs/cifsd/auth.c
@@ -1172,6 +1172,9 @@ static struct scatterlist *ksmbd_init_sg(struct kvec *iov, unsigned int nvec,
 	unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 24;
 	int i, nr_entries[3] = {0}, total_entries = 0, sg_idx = 0;
 
+	if (!nvec)
+		return NULL;
+
 	for (i = 0; i < nvec - 1; i++) {
 		unsigned long kaddr = (unsigned long)iov[i + 1].iov_base;