ksmbd: validate request buffer size in smb2_allocate_rsp_buf()

commit 17cf0c2794bdb6f39671265aa18aea5c22ee8c4a upstream.

The response buffer should be allocated in smb2_allocate_rsp_buf
before validating request. But the fields in payload as well as smb2 header
is used in smb2_allocate_rsp_buf(). This patch add simple buffer size
validation to avoid potencial out-of-bounds in request buffer.

Cc: stable@vger.kernel.org
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>

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 924f08326eef420b3658f0473ed28eaa4d76a7a1..fb9eea631069e25d9f86be34a50a9295114a7889 100644 (file)
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -535,6 +535,10 @@ int smb2_allocate_rsp_buf(struct ksmbd_work *work)
        if (cmd == SMB2_QUERY_INFO_HE) {
                struct smb2_query_info_req *req;
 
+               if (get_rfc1002_len(work->request_buf) <
+                   offsetof(struct smb2_query_info_req, OutputBufferLength))
+                       return -EINVAL;
+
                req = smb2_get_msg(work->request_buf);
                if ((req->InfoType == SMB2_O_INFO_FILE &&
                     (req->FileInfoClass == FILE_FULL_EA_INFORMATION ||