Messages in this thread | | | Date | Tue, 6 Apr 2010 13:26:42 +1000 | From | Simon Horman <> | Subject | Re: [PATCH] IPVS: replace sprintf to snprintf to avoid stack buffer overflow |
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On Tue, Apr 06, 2010 at 10:58:28AM +0800, Changli Gao wrote: > On Tue, Apr 6, 2010 at 10:50 AM, <wzt.wzt@gmail.com> wrote: > > IPVS not check the length of pp->name, use sprintf will cause stack buffer overflow. > > struct ip_vs_protocol{} declare name as char *, if register a protocol as: > > struct ip_vs_protocol ip_vs_test = { > > .name = "aaaaaaaa....128...aaa", > > .debug_packet = ip_vs_tcpudp_debug_packet, > > }; > > > > when called ip_vs_tcpudp_debug_packet(), sprintf(buf, "%s TRUNCATED", pp->name); > > will cause stack buffer overflow. > > > > Long messages will be truncated instead of buffer overflow. We need to > find a way to handle long messages elegantly.
Its really a corner case. In practice protocol modules don't have really long names. And if one was merged that did, the buffer size could be increased at that time.
So while I think its reasonable to protect against something unexpected in a protocol-module name crashing the system. Especially as that can be achieved without any real overhead. I don't think we need to sanitise the output. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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