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From: Pavel Skripkin <paskripkin@gmail.com>
To: mani@kernel.org, davem@davemloft.net, bjorn.andersson@linaro.org
Cc: linux-arm-msm@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Pavel Skripkin <paskripkin@gmail.com>,
	syzbot+1917d778024161609247@syzkaller.appspotmail.com
Subject: [PATCH] net: qrtr: fix OOB Read in qrtr_endpoint_post
Date: Mon, 14 Jun 2021 15:06:50 +0300	[thread overview]
Message-ID: <20210614120650.2731-1-paskripkin@gmail.com> (raw)

Syzbot reported slab-out-of-bounds Read in
qrtr_endpoint_post. The problem was in wrong
_size_ type:

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

If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of
ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293
in header this check won't fail and

	skb_put_data(skb, data + hdrlen, size);

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

Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
Reported-and-tested-by: syzbot+1917d778024161609247@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.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 c0477bec09bd..f2efaa4225f9 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -436,7 +436,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
 	struct qrtr_sock *ipc;
 	struct sk_buff *skb;
 	struct qrtr_cb *cb;
-	unsigned int size;
+	size_t size;
 	unsigned int ver;
 	size_t hdrlen;
 
-- 
2.32.0


             reply	other threads:[~2021-06-14 12:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 12:06 Pavel Skripkin [this message]
2021-06-14 15:57 ` [PATCH] net: qrtr: fix OOB Read in qrtr_endpoint_post Bjorn Andersson
2021-06-14 20:10 ` patchwork-bot+netdevbpf

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