linux-kernel - [PATCH] net: qrtr: fix another OOB Read in qrtr_endpoint

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Message-Id: <20210819181458.623832-1-butterflyhuangxx@gmail.com>
Date:   Fri, 20 Aug 2021 02:14:58 +0800
From:   butt3rflyh4ck <butterflyhuangxx@...il.com>
To:     mani@...nel.org, davem@...emloft.net, kuba@...nel.org
Cc:     linux-arm-msm@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        butt3rflyh4ck <butterflyhhuangxx@...il.com>
Subject: [PATCH] net: qrtr: fix another OOB Read in qrtr_endpoint_post

From: butt3rflyh4ck <butterflyhhuangxx@...il.com>

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: butt3rflyh4ck <butterflyhhuangxx@...il.com>
---
 net/qrtr/qrtr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 171b7f3be6ef..0c30908628ba 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -493,7 +493,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 		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 &&
-- 
2.25.1