From ec78cb6f7b5934c952ee08b27c628d94ba9995b0 Mon Sep 17 00:00:00 2001
From: Jordy Zomer <jordyzomer@google.com>
Date: Wed, 12 Mar 2025 22:51:00 +0900
Subject: [PATCH] ksmbd: fix Out-of-Bounds Write in ksmbd_vfs_stream_write

BugLink: https://bugs.launchpad.net/bugs/2102118

commit 313dab082289e460391c82d855430ec8a28ddf81 upstream.

An offset from client could be a negative value, It could allows
to write data outside the bounds of the allocated buffer.
Note that this issue is coming when setting
'vfs objects = streams_xattr parameter' in ksmbd.conf.

Cc: stable@vger.kernel.org # v5.15+
Reported-by: Jordy Zomer <jordyzomer@google.com>
Signed-off-by: Jordy Zomer <jordyzomer@google.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CVE-2024-56626
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
---
 fs/smb/server/smb2pdu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index bff2e17aa0ba..1b78a73255f6 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -6637,6 +6637,8 @@ int smb2_write(struct ksmbd_work *work)
 	}
 
 	offset = le64_to_cpu(req->Offset);
+	if (offset < 0)
+		return -EINVAL;
 	length = le32_to_cpu(req->Length);
 
 	if (req->Channel == SMB2_CHANNEL_RDMA_V1 ||