ksmbd: fix slab-out-of-bounds in smb2_allocate_rsp_buf

If ->ProtocolId is SMB2_TRANSFORM_PROTO_NUM, smb2 request size
validation could be skipped. if request size is smaller than
sizeof(struct smb2_query_info_req), slab-out-of-bounds read can happen in
smb2_allocate_rsp_buf(). This patch allocate response buffer after
decrypting transform request. smb3_decrypt_req() will validate transform
request size and avoid slab-out-of-bound in smb2_allocate_rsp_buf().

Reported-by: Norbert Szetei <norbert@doyensec.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/server/server.c b/fs/smb/server/server.c
index c0788188aa82fa39211f0be694a13f925408580c..c67fbc8d6683ef957b2b39601031c0aa25d22ac7 100644 (file)
--- a/fs/smb/server/server.c
+++ b/fs/smb/server/server.c
@@ -167,20 +167,17 @@ static void __handle_ksmbd_work(struct ksmbd_work *work,
        int rc;
        bool is_chained = false;
 
-       if (conn->ops->allocate_rsp_buf(work))
-               return;
-
        if (conn->ops->is_transform_hdr &&
            conn->ops->is_transform_hdr(work->request_buf)) {
                rc = conn->ops->decrypt_req(work);
-               if (rc < 0) {
-                       conn->ops->set_rsp_status(work, STATUS_DATA_ERROR);
-                       goto send;
-               }
-
+               if (rc < 0)
+                       return;
                work->encrypted = true;
        }
 
+       if (conn->ops->allocate_rsp_buf(work))
+               return;
+
        rc = conn->ops->init_rsp_hdr(work);
        if (rc) {
                /* either uid or tid is not correct */