From ad9d24c9429e2159d1e279dc3a83191ccb4daf1d Mon Sep 17 00:00:00 2001
From: Pavel Skripkin <paskripkin@gmail.com>
Date: Mon, 14 Jun 2021 15:06:50 +0300
Subject: [PATCH] net: qrtr: fix OOB Read in qrtr_endpoint_post
Git-commit: ad9d24c9429e2159d1e279dc3a83191ccb4daf1d
Patch-mainline: v5.13-rc7
References: CVE-2021-3743 bsc#1189883

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>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/qrtr/qrtr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -255,7 +255,7 @@ int qrtr_endpoint_post(struct qrtr_endpo
 	const struct qrtr_hdr_v2 *v2;
 	struct sk_buff *skb;
 	struct qrtr_cb *cb;
-	unsigned int size;
+	size_t size;
 	unsigned int ver;
 	size_t hdrlen;