net: qrtr: fix OOB Read in qrtr_endpoint_post

net: qrtr: fix OOB Read in qrtr_endpoint_post

BugLink: https://bugs.launchpad.net/bugs/1936688
[ Upstream commit ad9d24c9429e2159d1e279dc3a83191ccb4daf1d ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>