Date: Sun, 24 Mar 2024 11:20:36 -0700 From: Lee Brown <leeb@ratnaling.org> To: freebsd-hackers@freebsd.org Subject: Re: Removing or changing the ping interval restriction for non-root users Message-ID: <CAFPNf58PS1qozfVt30GHnf4Jyi2p=j6ic-JVXQ3iCBb3d82m8A@mail.gmail.com> In-Reply-To: <4f8b035c-b2cc-4606-a691-f1d86827282b@app.fastmail.com> References: <954e1d80-d44f-4c3d-88a7-122dc0f25de4@app.fastmail.com> <2D5DD001-DD98-4A8E-9458-6754E6D977EE@cschubert.com> <4f8b035c-b2cc-4606-a691-f1d86827282b@app.fastmail.com>
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[-- Attachment #1 --] net/fping will allow sub-second intervals: $ ping -i .1 10.1.1.1 ping: -i interval too short: Operation not permitted $ fping --interval=1 --vcount=20 --period=50 10.1.1.1 20 lines of result Better than changing base IMHO (POLA) On Sun, Mar 24, 2024 at 8:04 AM Tom Forbes <tom@tomforb.es> wrote: > I've personally never come across this limitation on any system that I've > used, however it is a good point that there are bound to be systems that > have the same limitation. After digging a bit more into the history the > limitation was added in this commit[1] in 1998 with the explicit intention > to "secure options from user-level D.O.S attacks". > > A lot of things have changed since 1998, and setting an arbitrary high > limit to prevent "ping" and "ping6" from being used to DOS networked > devices would be a pretty suspect decision if it was suggested today. I > expect a few other distributions have inherited this limit from the > original contribution, but to me that doesn't lend a strong argument to > keeping it if the underlying reason it exists doesn't make sense anymore > _and_ if removing/reducing it is a backwards-compatible, simple and > non-invasive change. > > Tom > > 1. > https://github.com/freebsd/freebsd-src/commit/526f06b278d9252add168aa18b60242c08771165 > > > On Sun, 24 Mar 2024, at 2:48 PM, Cy Schubert wrote: > > On March 24, 2024 5:57:01 AM PDT, Tom Forbes <tom@tomforb.es> wrote: > >Hello, > >I maintain a small project called gping[1] that recently added support > for FreeBSD. One of the issues I ran into with running this on FreeBSD was > that the `ping` command seems to disallow intervals of less than 1 second > if you are not running as root[2]. This check was last touched 23 years ago > and I'm curious as to why this restriction exists? I assume it's from an > earlier time in the internets history, and perhaps is related to potential > misuse of the command to flood targets with packets via ping? > > > >If it is then I'd like to suggest that this limitation be removed or is > reduced to `0.1` seconds instead? Using `ping` for this kind of thing isn't > a viable attack today, and the 1 second limitation seems like it would get > in the way of useful uses of the ping command. > > > >Also this is my first post to any *BSD mailing list, so please let me > know if this is not the right place to ask this question or propose this! > > > >Thanks, > >Tom > > > >1. https://github.com/orf/gping > >2. > https://github.com/freebsd/freebsd-src/blame/8a56ef8d75b42ee7228247466c8c1712de6e3b6f/sbin/ping/ping6.c#L441 > Other UNIX-like systems have the same restriction. At $JOB we use Solaris > and various Linux systems. All maintain the same restriction. Other BSDs > are the same.I don't think FreeBSD should be an outlier. > > Maybe setgid bit or a capability to remove the restriction may be a > better solution. But to reduce the timeout to essentially remove it is IMO > unwise. > > -- > Cheers, > Cy Schubert <Cy.Schubert@cschubert.com> > FreeBSD UNIX: <cy@FreeBSD.org> Web: https://FreeBSD.org > NTP: <cy@nwtime.org> Web: https://nwtime.org > e^(i*pi)+1=0 > > Pardon the typos. Small keyboard in use. > > > [-- Attachment #2 --] <div dir="ltr"><div>net/fping will allow sub-second intervals:</div><div><br></div>$ ping -i .1 10.1.1.1<div>ping: -i interval too short: Operation not permitted</div><div><br></div><div>$ fping --interval=1 --vcount=20 --period=50 10.1.1.1</div><div>20 lines of result</div><div><br></div><div>Better than changing base IMHO (POLA)<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Mar 24, 2024 at 8:04 AM Tom Forbes <<a href="mailto:tom@tomforb.es">tom@tomforb.es</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg-7303959741559428101"><u></u><div><div>I've personally never come across this limitation on any system that I've used, however it is a good point that there are bound to be systems that have the same limitation. After digging a bit more into the history the limitation was added in this commit[1] in 1998 with the explicit intention to "secure options from user-level D.O.S attacks".<br></div><div><br></div><div>A lot of things have changed since 1998, and setting an arbitrary high limit to prevent "ping" and "ping6" from being used to DOS networked devices would be a pretty suspect decision if it was suggested today. I expect a few other distributions have inherited this limit from the original contribution, but to me that doesn't lend a strong argument to keeping it if the underlying reason it exists doesn't make sense anymore _and_ if removing/reducing it is a backwards-compatible, simple and non-invasive change.<br></div><div><br></div><div>Tom<br></div><ol><li><a href="https://github.com/freebsd/freebsd-src/commit/526f06b278d9252add168aa18b60242c08771165" target="_blank">https://github.com/freebsd/freebsd-src/commit/526f06b278d9252add168aa18b60242c08771165</a><br></li></ol><div><br></div><div>On Sun, 24 Mar 2024, at 2:48 PM, Cy Schubert wrote:<br></div><blockquote type="cite" id="m_-7303959741559428101qt"><div>On March 24, 2024 5:57:01 AM PDT, Tom Forbes <<a href="mailto:tom@tomforb.es" target="_blank">tom@tomforb.es</a>> wrote:<br></div><div>>Hello,<br></div><div>>I maintain a small project called gping[1] that recently added support for FreeBSD. One of the issues I ran into with running this on FreeBSD was that the `ping` command seems to disallow intervals of less than 1 second if you are not running as root[2]. This check was last touched 23 years ago and I'm curious as to why this restriction exists? I assume it's from an earlier time in the internets history, and perhaps is related to potential misuse of the command to flood targets with packets via ping?<br></div><div>><br></div><div>>If it is then I'd like to suggest that this limitation be removed or is reduced to `0.1` seconds instead? Using `ping` for this kind of thing isn't a viable attack today, and the 1 second limitation seems like it would get in the way of useful uses of the ping command.<br></div><div>><br></div><div>>Also this is my first post to any *BSD mailing list, so please let me know if this is not the right place to ask this question or propose this!<br></div><div>><br></div><div>>Thanks,<br></div><div>>Tom<br></div><div>><br></div><div>>1. <a href="https://github.com/orf/gping" target="_blank">https://github.com/orf/gping</a><br></div><div>>2. <a href="https://github.com/freebsd/freebsd-src/blame/8a56ef8d75b42ee7228247466c8c1712de6e3b6f/sbin/ping/ping6.c#L441" target="_blank">https://github.com/freebsd/freebsd-src/blame/8a56ef8d75b42ee7228247466c8c1712de6e3b6f/sbin/ping/ping6.c#L441</a><br></div><div>Other UNIX-like systems have the same restriction. At $JOB we use Solaris and various Linux systems. All maintain the same restriction. Other BSDs are the same.I don't think FreeBSD should be an outlier.<br></div><div><br></div><div>Maybe setgid bit or a capability to remove the restriction may be a better solution. But to reduce the timeout to essentially remove it is IMO unwise. <br></div><div><br></div><div>-- <br></div><div>Cheers,<br></div><div>Cy Schubert <<a href="mailto:Cy.Schubert@cschubert.com" target="_blank">Cy.Schubert@cschubert.com</a>><br></div><div>FreeBSD UNIX: <<a href="mailto:cy@FreeBSD.org" target="_blank">cy@FreeBSD.org</a>> Web:  <a href="https://FreeBSD.org" target="_blank">https://FreeBSD.org</a><br></div><div>NTP:                    <<a href="mailto:cy@nwtime.org" target="_blank">cy@nwtime.org</a>>   Web:  <a href="https://nwtime.org" target="_blank">https://nwtime.org</a><br></div><div>                                                   e^(i*pi)+1=0<br></div><div><br></div><div>Pardon the typos. Small keyboard in use.<br></div><div><br></div></blockquote><div><br></div></div></div></blockquote></div>
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