[tech] Funny endless redirection

From: Stephane Bortzmeyer

Date: Sat, 16 Jan 2021 10:58:05 +0100

Since we have no list tag for operational issues, I guess that [tech]

is OK.

The capsule gemini.marmaladefoo.com has a funny

redirection. <gemini://gemini.marmaladefoo.com/geminaut?name=gerald>

redirects to <gemini://gemini.marmaladefoo.com/geminaut?name=gerald/>

which redirects to

<gemini://gemini.marmaladefoo.com/geminaut?name=gerald//> and so on

until you run out of slashes :-)

May be it will reactivate the discussion on a way to get the contact

of a capsule, to report issues.

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From: Luke Emmet

Date: Sat, 16 Jan 2021 10:51:54 +0000

On 16-Jan-2021 09:58, Stephane Bortzmeyer wrote:

> The capsule gemini.marmaladefoo.com has a funny

> redirection. <gemini://gemini.marmaladefoo.com/geminaut?name=gerald>

> redirects to <gemini://gemini.marmaladefoo.com/geminaut?name=gerald/>

> which redirects to

> <gemini://gemini.marmaladefoo.com/geminaut?name=gerald//> and so on

> until you run out of slashes :-)

Hmm - there is something strange about that URL - it might be molly

brown redirecting. I'll investigate.

But anyway, the URL is not a valid one - were you just playing around or

did you follow a link from somewhere that linked to that URL?

There is a CGI demo here

gemini://gemini.marmaladefoo.com/cgi-bin/hello-world.cgi where you can

put your name, e.g.

gemini://gemini.marmaladefoo.com/cgi-bin/hello-world.cgi?name=gerald

> May be it will reactivate the discussion on a way to get the contact

> of a capsule, to report issues.

There is an email address for yours truly on the root page of the capsule!

?- Luke

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From: Luke Emmet

Date: Sat, 16 Jan 2021 11:04:26 +0000

On 16-Jan-2021 10:51, Luke Emmet wrote:

>

> On 16-Jan-2021 09:58, Stephane Bortzmeyer wrote:

>> The capsule gemini.marmaladefoo.com has a funny

>> redirection. <gemini://gemini.marmaladefoo.com/geminaut?name=gerald>

>> redirects to <gemini://gemini.marmaladefoo.com/geminaut?name=gerald/>

>> which redirects to

>> <gemini://gemini.marmaladefoo.com/geminaut?name=gerald//> and so on

>> until you run out of slashes :-)

>

> Hmm - there is something strange about that URL - it might be molly

> brown redirecting. I'll investigate.

>

Yes - it seems to be a molly brown bug.

If you take a valid URL that references a folder not having a trailing

slash, and add a query to it, molly brown goes off on an endless redirect.

For example, try this one:

gemini://gemini.circumlunar.space/capcom?foo

1. Here the "capcom" folder exists with an index.gmi therein

2. Molly brown thereby puts a slash on the end of the URL, but what it

should do is put a slash after the capcom maybe, thus

gemini://gemini.circumlunar.space/capcom/?foo

not

gemini://gemini.circumlunar.space/capcom?foo/

in this second case, molly brown will redirect again to

gemini://gemini.circumlunar.space/capcom?foo//

and so on.

I'll let solderpunk know.

In the mean time, I suggest not to construct strange parameterised URLs

to folder URLs on molly brown!

?- Luke

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From: Stephane Bortzmeyer

Date: Sat, 16 Jan 2021 12:04:56 +0100

On Sat, Jan 16, 2021 at 10:51:54AM +0000,

Luke Emmet <luke at marmaladefoo.com> wrote

a message of 28 lines which said:

> But anyway, the URL is not a valid one - were you just playing

> around or did you follow a link from somewhere that linked to that

> URL?

Following a link. (Unfortunately, Lupa does not register where did the

URL in its database comes from.)

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From: Luke Emmet

Date: Sat, 16 Jan 2021 11:45:45 +0000

On 16-Jan-2021 11:04, Stephane Bortzmeyer wrote

>> But anyway, the URL is not a valid one - were you just playing

>> around or did you follow a link from somewhere that linked to that

>> URL?

> Following a link. (Unfortunately, Lupa does not register where did the

> URL in its database comes from.)

For client authors, there is also the recommendation in the Gemini "best

practices" doc to not automatically follow more than N (suggested N=5)

redirects. This would prevent getting stuck in any intentional or

inadvertent redirect tar pits that await.

I think there is are some intentional infinite redirect loops in the

client torture tests as well as the usual inadvertent server or CGI bugs

out in the geminiverse.

gemini://gemini.circumlunar.space/docs/best-practices.gmi

?- Luke

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From: Stephane Bortzmeyer

Date: Sat, 16 Jan 2021 12:54:38 +0100

On Sat, Jan 16, 2021 at 10:51:54AM +0000,

Luke Emmet <luke at marmaladefoo.com> wrote

a message of 28 lines which said:

> > May be it will reactivate the discussion on a way to get the contact

> > of a capsule, to report issues.

> There is an email address for yours truly on the root page of the capsule!

It's also that your email server denylists mine:

<luke at marmaladefoo.com>: host mx2.mythic-beasts.com[2a00:1098:0:82:1000:0:2:1]

said: 550 Block listed: https://www.spamhaus.org/sbl/query/SBLCSS (in reply

to MAIL FROM command)

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From: Stephane Bortzmeyer

Date: Sat, 16 Jan 2021 12:59:29 +0100

On Sat, Jan 16, 2021 at 11:04:26AM +0000,

Luke Emmet <luke at marmaladefoo.com> wrote

a message of 47 lines which said:

> Yes - it seems to be a molly brown bug.

A side effect of crawlers is that they exercice a lot of code and find

many bugs that would not have been detected by normal use :-)

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