[PATCH] net: qrtr: fix another OOB Read in qrtr_endpoint_post

From: butt3rflyh4ck
Date: Thu Aug 19 2021 - 14:15:28 EST


From: butt3rflyh4ck <butterflyhhuangxx@xxxxxxxxx>

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@xxxxxxxxx>
---
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