Re: [PATCH] net: sock: validate data_len before allocating skb insock_alloc_send_pskb()
From: Jason Wang
Date: Thu May 31 2012 - 02:10:22 EST
On 05/31/2012 02:02 PM, Michael S. Tsirkin wrote:
On Thu, May 31, 2012 at 02:00:14PM +0800, Jason Wang wrote:
On 05/30/2012 03:02 PM, David Miller wrote:
From: Eric Dumazet<eric.dumazet@xxxxxxxxx>
Date: Wed, 30 May 2012 08:46:23 +0200
Why doing this test in the while (1) block, it should be done before the
loop...
Or even in the caller, note net/unix/af_unix.c does this right.
if (len> SKB_MAX_ALLOC)
data_len = min_t(size_t,
len - SKB_MAX_ALLOC,
MAX_SKB_FRAGS * PAGE_SIZE);
skb = sock_alloc_send_pskb(sk, len - data_len, data_len,
msg->msg_flags& MSG_DONTWAIT,&err);
My impression is that the callers should be fixed to. It makes no sense
to penalize the call sites that get this right.
And yes, if we do check it in sock_alloc_send_pskb() it should be done
at function entry, not inside the loop.
Sure, so is it ok for me to send a V2 that just do the fixing in
sock_alloc_sned_pskb() as it's simple and easy to be accepted by
stable version?
For the fix of callers, I want to post fixes on top as I find
there's some code duplication of {tun|macvtap|packet}_alloc_skb()
and I want to unify them to a common helper in sock.c. Then I can
fix this issue in the new helper.
Are packet sockets really affected?
If yes the only call site that gets this right is unix sockets?
Not affected, only code duplication. It's no harm the check the data_len
again for packet sockets, so better to unify the code and fix the issue
in one place?
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