Date: Fri, 03 Apr 2015 14:41:58 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: Mateusz Guzik <mjguzik@gmail.com>, Ian Lepore <ian@freebsd.org>, svn-src-all@freebsd.org, src-committers@freebsd.org, "Robert N. M. Watson" <rwatson@FreeBSD.org>, svn-src-head@freebsd.org Subject: Re: svn commit: r280971 - in head: contrib/ipfilter/tools share/man/man4 sys/contrib/ipfilter/netinet sys/netinet sys/netipsec sys/netpfil/pf Message-ID: <551E8A96.6030806@selasky.org> In-Reply-To: <20150403112927.GQ64665@FreeBSD.org> References: <551DA5EA.1080908@selasky.org> <551DAC9E.9010303@selasky.org> <358EC58D-1F92-411E-ADEB-8072020E9EB3@FreeBSD.org> <551DEF26.4000403@selasky.org> <4B7DAA59-389F-41AE-99D8-034A7AA61C99@FreeBSD.org> <551E520E.1040708@selasky.org> <6DF5FB51-8135-4144-BD3A-6E4127A23AA7@FreeBSD.org> <551E5C38.7070203@selasky.org> <78DD67BD-621C-451D-8E30-EC9BF396716F@FreeBSD.org> <551E6E72.8050208@selasky.org> <20150403112927.GQ64665@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 04/03/15 13:29, Gleb Smirnoff wrote: > On Fri, Apr 03, 2015 at 12:41:54PM +0200, Hans Petter Selasky wrote: > H> "ip_do_randomid" is zero by default, and is not documented anywhere: > H> > H> grep -r ip_do_randomid share/ > > It is documented in inet(4). > > The actual sysctl knob doesn't match the kernel symbol name, which is > allowed in sysctl(9). > Hi, Will you mind if I rephrase that paragraph in the "inet.4" manual page from: "This closes a minor information leak which allows remote observers to determine the rate of packet generation on the machine by watching the counter." Into: "This prevents high-speed information exchange between internal and external observers using packet frequency modulation. An outside observer can ping the outside facing port at a fixed rate watching the counter. An inside observer can ping the inside facing port watching the same counter. Even though packets don't flow between the two ports, data can be exchanged by watching changes in the packet rate. It is believed that data can be exchanged in Kb/s range this way. Setting this sysctl also prevents remote and internal observers to determine the rate of packet generation on the machine by watching the counter." --HPS
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?551E8A96.6030806>