net: qrtr: fix OOB Read in qrtr_endpoint_post

[ 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: 194ccc8829 ("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>
This commit is contained in:
Pavel Skripkin 2021-06-14 15:06:50 +03:00 committed by Greg Kroah-Hartman
parent 0239c439ce
commit 960b08dd36

View File

@ -429,7 +429,7 @@ 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;