net: qrtr: fix another OOB Read in qrtr_endpoint_post

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit?id=ad41706c771a038e9a334fa55216abd69b32bfdf
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2021-3743

commit 7e78c597c3ebfd0cb329aa09a838734147e4f117 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name net-qrtr-fix-another-OOB-Read-in-qrtr_endpoint_post.patch

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 0d9baddb9cd49f53cedccba11a1a66420e397f2f..fb5be151c7d1835469b15431f54af04a73fec562 100644 (file)
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -486,7 +486,7 @@ 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 &&