Date: Mon, 28 Mar 2011 21:55:03 +0000 From: Alexander Best <arundel@freebsd.org> To: Maksim Yevmenkin <maksim.yevmenkin@gmail.com> Cc: freebsd-bluetooth@freebsd.org Subject: Re: l2ping(8) and -f switch Message-ID: <20110328215503.GA43845@freebsd.org> In-Reply-To: <AANLkTi=QagnGN3cADEcXTW-j3G_pDu3KCUY09uN_KTzV@mail.gmail.com> References: <20110328001258.GA70156@freebsd.org> <alpine.NEB.2.00.1103280751410.3331@galant.ukfsn.org> <20110328101804.GA39095@freebsd.org> <alpine.NEB.2.00.1103281452520.27263@galant.ukfsn.org> <AANLkTikLj7QumdtPcB=wGBdyxOyHBusCzUbrtXVC%2BYt1@mail.gmail.com> <20110328195952.GA26987@freebsd.org> <AANLkTin_%2B8dxE8Go1Bk1vdFg2-bUZ-fn3OHX1RTRmfKa@mail.gmail.com> <20110328203413.GB26987@freebsd.org> <20110328213746.GA42088@freebsd.org> <AANLkTi=QagnGN3cADEcXTW-j3G_pDu3KCUY09uN_KTzV@mail.gmail.com>
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On Mon Mar 28 11, Maksim Yevmenkin wrote: > On Mon, Mar 28, 2011 at 2:37 PM, Alexander Best <arundel@freebsd.org> wrote: > > On Mon Mar 28 11, Alexander Best wrote: > >> On Mon Mar 28 11, Maksim Yevmenkin wrote: > >> > On Mon, Mar 28, 2011 at 12:59 PM, Alexander Best <arundel@freebsd.org> wrote: > >> > > On Mon Mar 28 11, Maksim Yevmenkin wrote: > >> > >> On Mon, Mar 28, 2011 at 7:04 AM, Iain Hibbert <plunky@rya-online.net> wrote: > >> > >> > On Mon, 28 Mar 2011, Alexander Best wrote: > >> > >> > > >> > >> >> On Mon Mar 28 11, Iain Hibbert wrote: > >> > >> >> > On Mon, 28 Mar 2011, Alexander Best wrote: > >> > >> >> > > >> > >> >> > > thus i believe making the -f switch only accessable to super-users (in > >> > >> >> > > accordance with ping(8)/ping6(8)) would increase security. > >> > >> >> > > >> > >> >> > what stops the user from recompiling l2ping without this restriction? > >> > >> >> > >> > >> >> nothing. but what stops him from recompiling ping(8) or ping6(8) without the > >> > >> >> restriction? still it's there. > >> > >> > > >> > >> > AFAIK you need superuser privileges to even send ICMP_ECHO packets, thats > >> > >> > why ping is traditionally a suid program and making a new binary won't > >> > >> > help normal users.. I'm guessing that l2ping doesn't have the same > >> > >> > restrictions? > >> > >> > >> > >> Guys, > >> > >> > >> > >> first of all thanks for the patch. > >> > >> > >> > >> i think one really needs to understand what "flood" really means in > >> > >> l2ping(8). "flood" ping(8) basically floods the link with icmp echo > >> > >> requests without waiting for remote system to reply. yes, this is > >> > >> potentially dangerous and thus its reasonable to require super-user > >> > >> privileges. "flood" l2ping(8) is NOT the same. all l2ping(8) does is > >> > >> "flood" mode > >> > >> > >> > >> 1) sends l2cap echo request > >> > >> 2) waits for l2cap echo response (or timeout) > >> > >> 3) repeats > >> > >> > >> > >> in other words, there is no delay between each l2cap echo > >> > >> request-response transaction. its not really "flood". i'm not sure if > >> > >> it really worth to go all the way to restricting this. however, if > >> > >> people think that it should be restricted, i will not object. > >> > > > >> > > how about removing the term "flood" from the l2ping(2) man page, if the -f > >> > > semantics can't actually be called that way? > >> > > >> > that would be fine. l2ping(8) -h calls it > >> > > >> > -f No delay (sort of flood) > >> > > >> > and l2ping(8) man page calls it > >> > > >> > -f ``Flood'' ping, i.e., no delay between packets. > >> > > >> > it would be nice to make those consistent :) i'm not sure what the > >> > best name would be though. > >> > >> another possibility would be to allow l2ping -i 0 and say that the -f flag is > >> an alias for that. > > the existing code provides exactly this behavior. perhaps just a man > page and usage() change? hmmm...no actually. l2ping -i 0 is not a valid parameter, since -i has to be greater than 0. so it's not possible to simply say "-f is an alias for -i 0", because that implies that -i 0 should work (which it doesn't). > > > the following patch will implement this behavior. > > if we are going to go this route then why not just get rid of the > "flood" variable all together? just set wait to 0 (zero) if -f was > specified. also, we should probably use strtol(3) instead of atoi(3). i've thought of that. however that would mean l2ping -f -i 3 would set the delay to 3 seconds and usually an -f switch implies "force". so i think the current behavior of -f having a higher priority than any -i X option should be kept. > > thanks, > max -- a13x
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