Processed: Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
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reopen 575209
Bug #575209 {Done: Holger Levsen hol...@layer-acht.org} [general] general:
Error resolving hostname
reassign 575209 eglibc
Bug #575209 [general] general: Error resolving hostname
Bug reassigned from package 'general' to 'eglibc'.
found 575209 2.10.2-6
Bug #575209 [eglibc] general: Error resolving hostname
There is no source info for the package 'eglibc' at version '2.10.2-6' with
architecture ''
Unable to make a source version for version '2.10.2-6'
Bug Marked as found in versions 2.10.2-6.
found 575209 2.11-0exp6
Bug #575209 [eglibc] general: Error resolving hostname
There is no source info for the package 'eglibc' at version '2.11-0exp6' with
architecture ''
Unable to make a source version for version '2.11-0exp6'
Bug Marked as found in versions 2.11-0exp6.
severity 575209 important
Bug #575209 [eglibc] general: Error resolving hostname
Ignoring request to change severity of Bug 575209 to the same value.
retitle 575209 Please resolv domain names with hyphens as border chars
Bug #575209 [eglibc] general: Error resolving hostname
Changed Bug title to 'Please resolv domain names with hyphens as border chars'
from 'general: Error resolving hostname'
tags 575209 + patch
Bug #575209 [eglibc] Please resolv domain names with hyphens as border chars
Added tag(s) patch.
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Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
reopen 575209 reassign 575209 eglibc found 575209 2.10.2-6 found 575209 2.11-0exp6 severity 575209 important retitle 575209 Please resolv domain names with hyphens as border chars tags 575209 + patch thanks Hi Holger et al (please drop -devel out of the list of CCs if you feel this is getting off-topic), sorry, but I find it unacceptable to close this bug referring to a single paragraph in a (random) RFC [0]. However, there is a multitude of other reasons why I think this bug *is* an issue: - Sites with domain names like ker-.deviantart.com do already exist! Do you think they should be accessible by any other proprietary operating system, but not Debian? Not really! - There is already an inconsistency among the different implementations in Debian (or Linux as a whole), as e.g. ping and any other program using gethostbyname() fail to resolv, whereas nslookup and host succeed. - The advice in the cited RFC is already ignored. Domain names that start with a digit, e.g. 12345.foo.bar, can be resolved, whereas the RFC tells us They [labels] must start with a letter, end with a letter or digit [...]. So let's just relax the rules in the RFC (they are only recommendations after all) a bit more to also allow hyphens as border characters in labels. It doesn't harm anyone, it just enables us to resolv a few more actual domain names! For further discussion, please see the bug reports opened against ubuntu [1] and upstream [2]: [1] https://bugs.launchpad.net/glibc/+bug/144431 [2] http://sourceware.org/bugzilla/show_bug.cgi?id=4671 Technically speaking, what IMHO needs to be done is to allow hyphenchar as a borderchar in resolv/res_comp.c in eglibc. Please find my patch below (and while we are at at, why not allow underscorechar as well?). Cheers, Fabian --8-- --- eglibc-2.10.2.orig/resolv/res_comp.c +++ eglibc-2.10.2/resolv/res_comp.c @@ -146,8 +146,8 @@ || ((c) = 0x61 (c) = 0x7a)) #define digitchar(c) ((c) = 0x30 (c) = 0x39) -#define borderchar(c) (alphachar(c) || digitchar(c)) -#define middlechar(c) (borderchar(c) || hyphenchar(c) || underscorechar(c)) +#define borderchar(c) (alphachar(c) || digitchar(c) || hyphenchar(c)) +#define middlechar(c) (borderchar(c) || underscorechar(c)) #definedomainchar(c) ((c) 0x20 (c) 0x7f) int --8-- [0] There are even other RFCs that either relax or contradict against the advice of RFC 1035 (thanks Christoph Loehr, who could even write a short essay about this): RFC 1178: Don't use digits at the beginning of the name. Many programs accept a numerical internet address as well as a name. Unfortunately, some programs do not correctly distinguish between the two and may be fooled, for example, by a string beginning with a decimal digit. Names consisting entirely of hexadecimal digits, such as beef, are also problematic, since they can be interpreted entirely as hexadecimal numbers as well as alphabetic strings. Don't use non-alphanumeric characters in a name. [...] Don't expect case to be preserved. [...] This is a mitigation of RFC 1035, as there is no mention of hyphen characters at all. RFC 952: No blank or space characters are permitted as part of a name. No distinction is made between upper and lower case. The first character must be an alpha character. The last character must not be a minus sign or period. A host which serves as a GATEWAY should have -GATEWAY or -GW as part of its name. Hosts which do not serve as Internet gateways should not use -GATEWAY and -GW as part of their names. A host which is a TAC should have -TAC as the last part of its host name, if it is a DoD host. Single character names or nicknames are not allowed. this is contradictory, since there is c.psi.net, which is resolved by gethostbyname(). RFC 1123: The syntax of a legal Internet host name was specified in RFC-952 [DNS:4]. One aspect of host name syntax is hereby changed: the restriction on the first character is relaxed to allow either a letter or a digit. Host software MUST support this more liberal syntax. This is clearly another mitigation of RFC 1035. -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/4bab3935.2000...@greffrath.com
Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
On Thu, 2010-03-25 at 11:21 +0100, Fabian Greffrath wrote: reopen 575209 reassign 575209 eglibc found 575209 2.10.2-6 found 575209 2.11-0exp6 severity 575209 important retitle 575209 Please resolv domain names with hyphens as border chars tags 575209 + patch thanks Hi Holger et al (please drop -devel out of the list of CCs if you feel this is getting off-topic), sorry, but I find it unacceptable to close this bug referring to a single paragraph in a (random) RFC [0]. However, there is a multitude of other reasons why I think this bug *is* an issue: That 'random' RFC happens to be an Internet standard (STD 13) and still largely valid today. - Sites with domain names like ker-.deviantart.com do already exist! Do you think they should be accessible by any other proprietary operating system, but not Debian? Not really! So if Windows accepts it then it must be OK? I don't think we have to follow that rule. Otherwise you should be demanding support for NMB and WINS in glibc. - There is already an inconsistency among the different implementations in Debian (or Linux as a whole), as e.g. ping and any other program using gethostbyname() fail to resolv, whereas nslookup and host succeed. This is what happens when you ignore Internet standards. - The advice in the cited RFC is already ignored. Domain names that start with a digit, e.g. 12345.foo.bar, can be resolved, whereas the RFC tells us They [labels] must start with a letter, end with a letter or digit [...]. [...] It is not ignored; the standard was updated by RFC 1123 (STD 3). Ben. -- Ben Hutchings Once a job is fouled up, anything done to improve it makes it worse. signature.asc Description: This is a digitally signed message part
Re: Bug#575209: closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
Fabian Greffrath fab...@greffrath.com writes: - Sites with domain names like ker-.deviantart.com do already exist! Do you think they should be accessible by any other proprietary operating system, but not Debian? Not really! Anyone can enter bogus data in the DNS. Neither the existence of such data nor the failure to detect it by other operating systems are arguments for allowing it in Debian. Literally anyone can add an invalid A record and make an OS which accepts it. - There is already an inconsistency among the different implementations in Debian (or Linux as a whole), as e.g. ping and any other program using gethostbyname() fail to resolv, whereas nslookup and host succeed. This is not an inconsistency. gethostbyname(), getaddrinfo() etc look up hostnames, whereas dig, nslookup and host query the DNS. The distinction is that almost anything is allowed in DNS, while a hostname must obey the updated version of RFC 952 (as amended by RFC 1123). See e.g. http://www.mail-archive.com/dn...@ietf.org/msg01731.html for an excellent explanation of the difference. - The advice in the cited RFC is already ignored. Domain names that start with a digit, e.g. 12345.foo.bar, can be resolved, whereas the RFC tells us They [labels] must start with a letter, end with a letter or digit [...]. So let's just relax the rules in the RFC (they are only recommendations after all) a bit more to also allow hyphens as border characters in labels. It doesn't harm anyone, it just enables us to resolv a few more actual domain names! This rule has been formally changed by the standards track RFC 1123. That is something quite different than the cited RFC is already ignored! the advice of RFC 1035 which is the standards track RFC describing the *domain name system* which is so much more than host names. It is irrelevant wrt the discussion of valid hostnames. Unfortunately this RFC is one of the most confusing ever written, mixing a lot of irrelevant informational data with the actual standard. It should have merely referred to RFC 822 (updated several times) and RFC 952 (amended several times) for the restrictions on valid mail and host names. The verbose examples copying restrictions imposed by other standards have always been confusing, and of course even more so after the other standards were changed... RFC 1178: which is an informational RFC. RFC 952: which is the standards RFC describing valid hostnames. This should be obeyed, as amended by other RFCs. RFC 1123: which is a standards track RFC updating and clarifying lots of other standards. Among the changes is the modification of RFC 952 wrt labels starting with a digit. You forgot to mention RFC 2181 which is a standards track RFC trying to fix a few of the errors in RFC 1035, among those the mixture of standard requirements and informational text. Although as irrelevant to this discussion as RFC 1035 itself, I believe it helps understand the distinction between valid DNS labels and valid host or mail names. Bjørn -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/874ok4o80p@nemi.mork.no
Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
On Thu, 2010-03-25 at 13:15, Ben Hutchings wrote: On Thu, 2010-03-25 at 11:21 +0100, Fabian Greffrath wrote: - The advice in the cited RFC is already ignored. Domain names that start with a digit, e.g. 12345.foo.bar, can be resolved, whereas the RFC tells us They [labels] must start with a letter, end with a letter or digit [...]. [...] It is not ignored; the standard was updated by RFC 1123 (STD 3). Yes. I forgot to mention that in original post. Sorry. -- Kind regards, Milan signature.asc Description: Digital signature
Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
On Thu, Mar 25, 2010 at 01:15:06PM +, Ben Hutchings wrote: - Sites with domain names like ker-.deviantart.com do already exist! Do you think they should be accessible by any other proprietary operating system, but not Debian? Not really! So if Windows accepts it then it must be OK? I don't think we have to follow that rule. Otherwise you should be demanding support for NMB and WINS in glibc. /me sweeps the winbind package under the rug - There is already an inconsistency among the different implementations in Debian (or Linux as a whole), as e.g. ping and any other program using gethostbyname() fail to resolv, whereas nslookup and host succeed. This is what happens when you ignore Internet standards. This doesn't ignore Internet standards at all. nslookup and host are tools for querying DNS, which is *not* the same thing as querying a hostname. It's valid and reasonable for those tools to return the records present in DNS even when those records aren't well-formed hostnames. -- Steve Langasek Give me a lever long enough and a Free OS Debian Developer to set it on, and I can move the world. Ubuntu Developerhttp://www.debian.org/ slanga...@ubuntu.com vor...@debian.org signature.asc Description: Digital signature
Re: Bug#575209 closed by Holger Levsen hol...@layer-acht.org (Re: Bug#575209: general: Error resolving hostname [resent])
Am 25.03.2010 14:15, schrieb Ben Hutchings: So if Windows accepts it then it must be OK? I don't think we have to follow that rule. Otherwise you should be demanding support for NMB and WINS in glibc. Mac OS X, too, BTW. But that's not what I wanted to say. I wanted to say that I consider it a disadvantage that [e]glibc persists on the one part of RFC 1035 that forbids labels to start or end with hyphens, while in turn allowing labels to start with digits, which is forbidden by the very same RFC. At the time of my writing I did not know this standard was updated. - Fabian -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/4bab661b.8070...@greffrath.com
