From: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
To: eric.dumazet@gmail.com
Cc: davem@davemloft.net, kuba@kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
snovitoll@gmail.com,
syzbot+c2a7e5c5211605a90865@syzkaller.appspotmail.com
Subject: Re: [PATCH] net/qrtr: restrict length in qrtr_tun_write_iter()
Date: Sun, 21 Feb 2021 18:39:12 +0600 [thread overview]
Message-ID: <20210221123912.3185059-1-snovitoll@gmail.com> (raw)
In-Reply-To: <3b27dac1-45b9-15ad-c25e-2f5f3050907e@gmail.com>
> Do we really expect to accept huge lengths here ?
Sorry for late response but I couldnt find any reference to the max
length of incoming data for qrtr TUN interface.
> qrtr_endpoint_post() will later attempt a netdev_alloc_skb() which will need
> some extra space (for struct skb_shared_info)
Thanks, you're right, qrtr_endpoint_post() will alloc another slab buffer.
We can check the length of skb allocation but we need to do following:
int qrtr_endpoint_post(.., const void *data, size_t len)
{
..
when QRTR_PROTO_VER_1:
hdrlen = sizeof(*data);
when QRTR_PROTO_VER_2:
hdrlen = sizeof(*data) + data->optlen;
len = (KMALLOC_MAX_SIZE - hdrlen) % data->size;
skb = netdev_alloc_skb(NULL, len);
..
skb_put_data(skb, data + hdrlen, size);
So it requires refactoring as in qrtr_tun_write_iter() we just allocate and
pass it to qrtr_endpoint_post() and there
we need to do len calculation as above *before* netdev_alloc_skb(NULL, len).
Perhaps there is a nicer solution though.
next prev parent reply other threads:[~2021-02-21 12:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 9:20 [PATCH] net/qrtr: restrict user-controlled length in qrtr_tun_write_iter() Sabyrzhan Tasbolatov
2021-02-04 0:28 ` Jakub Kicinski
2021-02-04 9:02 ` [PATCH] net/qrtr: replaced useless kzalloc with kmalloc " Sabyrzhan Tasbolatov
2021-02-04 18:51 ` Jakub Kicinski
2021-02-04 18:53 ` Jakub Kicinski
2021-02-04 0:40 ` [PATCH] net/qrtr: restrict user-controlled length " patchwork-bot+netdevbpf
2021-02-12 11:51 ` Eric Dumazet
2021-02-21 12:39 ` Sabyrzhan Tasbolatov [this message]
2021-02-22 8:45 ` [PATCH] net/qrtr: restrict " Eric Dumazet
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