From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH] net: sock: validate data_len before allocating skb in sock_alloc_send_pskb() Date: Thu, 31 May 2012 14:00:14 +0800 Message-ID: <4FC708EE.2020908@redhat.com> References: <20120530054702.6146.8503.stgit@amd-6168-8-1.englab.nay.redhat.com> <1338360383.2760.84.camel@edumazet-glaptop> <20120530.030205.1337682162603770949.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, mst@redhat.com To: David Miller Return-path: In-Reply-To: <20120530.030205.1337682162603770949.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 05/30/2012 03:02 PM, David Miller wrote: > From: Eric Dumazet > 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. > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html