Re: Another out-of-bound Read in qrtr_endpoint_post in net/qrtr/qrtr.c

Ok, no problem, I will send the fix later.

Regards,
 butt3rflyh4ck.

On Fri, Aug 20, 2021 at 12:57 AM Manivannan Sadhasivam [off-list ref] wrote:

Hi,

On Wed, Aug 18, 2021 at 03:33:38PM +0800, butt3rflyh4ck wrote:

quoted

Here I make a patch for this issue.

[...]

quoted

From 18d9f83f17375785beadbe6a0d0ee59503f65925 Mon Sep 17 00:00:00 2001
From: butt3rflyh4ck <redacted>
Date: Wed, 18 Aug 2021 14:19:38 +0800
Subject: [PATCH] net: qrtr: fix another OOB Read in qrtr_endpoint_post

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 <redacted>

Thanks for the bug report and the fix. Could you please send the fix as a proper
patch as per: Documentation/process/submitting-patches.rst

Thanks,
Mani

quoted

---
 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

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