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Date: Fri, 11 Apr 2014 15:50:27 +0200 From: Mateusz Guzik <mguzik@...hat.com> To: "Wang, Xiaoming" <xiaoming.wang@...el.com> Cc: davem@...emloft.net, kuznet@....inr.ac.ru, jmorris@...ei.org, yoshfuji@...ux-ipv6.org, kaber@...sh.net, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, chuansheng.liu@...el.com, dongxing.zhang@...el.com Subject: Re: [PATCH] net: ipv4: current group_info should be put after using. On Fri, Apr 11, 2014 at 10:53:21PM -0400, Wang, Xiaoming wrote: > This is a typical refcount leak exploitable by unprivileged users. > Current group_info had been got in ping_init_sock and > group_info->usage increased. But the usage hasn't decreased > anywhere in ping. This will make this group_info never freed. > The patch is fine, however I had a brainfart with my last sentence about commit message, sorry for that. group_info *can be freed* by malicious user while still being pointed to by something, that's the biggest problem with refcount leaks, therefore this message needs some reworking. I think that discussion about various consequences of refcount leak in commit message is not necessary. how about: Plug a group_info refcount leak in ping_init. group_info is only needed during initialization and the code failed to release the reference on exit. While here move grabbing the reference to a place where it is actually needed. ==== Please cc: me if you resend the patch. Thanks, -- Mateusz Guzik -- 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
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