From 7e78c597c3ebfd0cb329aa09a838734147e4f117 Mon Sep 17 00:00:00 2001
From: Xiaolong Huang <butterflyhuangxx@gmail.com>
Date: Fri, 20 Aug 2021 03:50:34 +0800
Subject: [PATCH] net: qrtr: fix another OOB Read in qrtr_endpoint_post
Git-commit: 7e78c597c3ebfd0cb329aa09a838734147e4f117
Patch-mainline: v5.14
References: CVE-2021-3743 bsc#1189883

This check was incomplete, did not consider size is 0:

	if (len != ALIGN(size, 4) + hdrlen)
                    goto err;

if size from qrtr_hdr is 0, the result of ALIGN(size, 4)
will be 0, In case of len == hdrlen and size == 0
in header this check won't fail and

	if (cb->type == QRTR_TYPE_NEW_SERVER) {
                /* Remote node endpoint can bridge other distant nodes */
                const struct qrtr_ctrl_pkt *pkt = data + hdrlen;

                qrtr_node_assign(node, le32_to_cpu(pkt->server.node));
        }

will also read out of bound from data, which is hdrlen allocated block.

Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Fixes: ad9d24c9429e ("net: qrtr: fix OOB Read in qrtr_endpoint_post")
Signed-off-by: Xiaolong Huang <butterflyhuangxx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/qrtr/qrtr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -312,7 +312,7 @@ int qrtr_endpoint_post(struct qrtr_endpo
 		goto err;
 	}
 
-	if (len != ALIGN(size, 4) + hdrlen)
+	if (!size || len != ALIGN(size, 4) + hdrlen)
 		goto err;
 
 	if (cb->dst_port != QRTR_PORT_CTRL && cb->type != QRTR_TYPE_DATA)