lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 14 May 2014 12:52:01 -0700 From: Eric Dumazet <eric.dumazet@...il.com> To: Zoltan Kiss <zoltan.kiss@...rix.com> Cc: netdev@...r.kernel.org, "xen-devel@...ts.xenproject.org" <xen-devel@...ts.xenproject.org>, kvm@...r.kernel.org, David Miller <davem@...emloft.net> Subject: Re: Moving frags and SKBTX_DEV_ZEROCOPY skbs On Wed, 2014-05-14 at 20:41 +0100, Zoltan Kiss wrote: > On 14/05/14 15:23, Eric Dumazet wrote: > > On Wed, 2014-05-14 at 14:40 +0100, Zoltan Kiss wrote: > >> Hi, > >> > >> Recently I've investigated issues around SKBTX_DEV_ZEROCOPY skbs where > >> the frags list were modified. I came across this function skb_shift(), > >> which moves frags between skbs. And there are a lot more of such kind, > >> skb_split or skb_try_coalesce, for example. > >> It could be a dangerous thing if a frag is referenced from an skb which > >> doesn't have the original destructor_arg, and to avoid that > >> skb_orphan_frags should be called. Although probably these functions are > >> not normally touched in usual usecases, I think it would be useful to > >> review core skb functions proactively and add an skb_orphan_frags > >> everywhere where the frags could be referenced from other places. > >> Any opinion about this? > > > > > > For skb_shift(), it is currently used from tcp stack only, where > > this SKBTX_DEV_ZEROCOPY thing is not used, so I do not think there is a > > bug for the moment. > It is called from tcp_input.c, which suggests it can be called on > incoming TCP packets. Nope. We split outgoing packets, stored in the socket write queue. These packets are locally generated by tcp_sendmsg() and tcp_sendpage(), no way we use SKBTX_DEV_ZEROCOPY yet. This split happens when we receive an ACK, that's why it is in tcp_input.c -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists