Date: Wed, 14 Nov 2012 07:45:23 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: arch@freebsd.org, Baptiste Daroussin <bapt@freebsd.org> Subject: Re: Increasing MAXLOGNAME from 17 to 33 Message-ID: <20121114054523.GU73505@kib.kiev.ua> In-Reply-To: <75177878-EA36-4472-BAEA-984A59F91057@bsdimp.com> References: <20121113111806.GE62533@ithaqua.etoilebsd.net> <20121113115034.GJ73505@kib.kiev.ua> <20121113183412.GA75103@ithaqua.etoilebsd.net> <20121113184238.GO73505@kib.kiev.ua> <20121113184512.GP73505@kib.kiev.ua> <20121113225905.GB75103@ithaqua.etoilebsd.net> <75177878-EA36-4472-BAEA-984A59F91057@bsdimp.com>
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[-- Attachment #1 --] On Tue, Nov 13, 2012 at 04:04:33PM -0700, Warner Losh wrote: > > On Nov 13, 2012, at 3:59 PM, Baptiste Daroussin wrote: > > > On Tue, Nov 13, 2012 at 08:45:12PM +0200, Konstantin Belousov wrote: > >> On Tue, Nov 13, 2012 at 08:42:38PM +0200, Konstantin Belousov wrote: > >>> On Tue, Nov 13, 2012 at 07:34:12PM +0100, Baptiste Daroussin wrote: > >>>> On Tue, Nov 13, 2012 at 01:50:34PM +0200, Konstantin Belousov wrote: > >>>>> On Tue, Nov 13, 2012 at 12:18:06PM +0100, Baptiste Daroussin wrote: > >>>>>> Hi, > >>>>>> > >>>>>> I want to increase MAXLOGNAME in sys/param.h from 17 to 33 to allow 32-character > >>>>>> long usernames, the PR: misc/161091 and misc/133926 already requested for it. > >>>>>> > >>>>>> utmpx already allow 32 character long user names. > >>>>>> > >>>>>> I plan to bump the __FreeBSD_version at the same time because of the ABI > >>>>>> breakage. > >>>>>> > >>>>>> This is simplify life of lots administrator, this value, is a common value for > >>>>>> other operating systems. > >>>>>> > >>>>>> Do anyone have objections about it? > >>>>> > >>>>> Yes, I have. Do not break the ABI, it is plain prohibited. > >>>>> You might consider increasing the constant only if providing ABI > >>>>> compatibility shims. > >>>>> > >>>>> In fact, the cursory look over the whole base system indicates that ABI > >>>>> breakage might be not that big and could be mitigated with relatively > >>>>> limited amount of the efforts. > >>>> > >>>> Thanks cognet for the help on the following. > >>>> > >>>> After auditing base, it seems like this patch is enough > >>>> http://people.freebsd.org/~bapt/maxlogname-33.diff > >>> Regarding the patch, the dereferencing of p->p_session should be done > >>> under the proc lock to guarantee stability of p_pgrp, and under session > >>> mutex to prevent s_login modifications. Altogether, this means that the > >>> if() shall be moved down right before bcopy and locks unlocked on return. > >>> > >> Sorry, sent the reply too early. > >> > >> The alternative is to check for the length of the local 'login' variable > >> after unlocks, right before copyout. > >> > > like this? > > http://people.freebsd.org/~bapt/report-erange-if-login-is-larger-then-MAXLOGNAME.diff > > Isn't that check too late? > No, it is not, The uap->namelen is clamped before the block shown in the patch. I think that the patch is fine and should be merged into stable branches as well. While there, you could add a space between 'return' and '(' in the last line of the sys_getlogin(), in separate commit. Thanks. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEUEARECAAYFAlCjL/MACgkQC3+MBN1Mb4jsuwCfbB3jKttSWxgygkBP/zLgaxJO s5EAmIZmvAqICNYDa/xakg5L29cO9Cc= =V9cY -----END PGP SIGNATURE-----
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