tahoe-lafs/trac-2024-07-25

make new introducer furls unguessable #1802

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opened 2012-09-06 01:17:51 +00:00 by davidsarah · 9 comments

davidsarah commented

2012-09-06 01:17:51 +00:00

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In source:src/allmydata/introducer/server.py, new introducer furls are created with the guessable swissnum "introducer".

New furls should instead be created as random, by omitting the "introducer" argument to tub.registerReference and using furlFile=os.path.join(self.basedir, "private", "introducer.furl") instead. Existing furls will not change because introducer.furl will already exist, so this is backward-compatible.

The full security benefit is not obtained without #860, but there's no reason to continue generating guessable furls for new introducers in the meantime.

In source:src/allmydata/introducer/server.py, new introducer furls are created with the guessable swissnum "introducer". New furls should instead be created as random, by omitting the `"introducer"` argument to [tub.registerReference](http://foolscap.lothar.com/docs/api/foolscap.pb.Tub-class.html#registerReference) and using ``` furlFile=os.path.join(self.basedir, "private", "introducer.furl") ``` instead. Existing furls will not change because `introducer.furl` will already exist, so this is backward-compatible. The full security benefit is not obtained without #860, but there's no reason to continue generating guessable furls for new introducers in the meantime.

tahoe-lafs added the

labels 2012-09-06 01:17:51 +00:00

tahoe-lafs added this to the 1.10.0 milestone 2012-09-06 01:17:51 +00:00

zooko commented

2012-09-06 02:01:36 +00:00

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I guess this is a forward-compatibility feature because people who use it before we've landed this will have a persistent guessable furl, which could interfere with future access control features (#860).

warner commented

2012-12-20 17:58:46 +00:00

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I'll try to write the patch for this over the weekend.. should be a simple use of tub.registerReference(ref, furlFile=) .

Hm. The introducer currently writes its furl to NODEDIR/introducer.furl, and our docs recommend copying it from that location to all the clients. To fit with out current pattern of putting all secrets in NODEDIR/private/, we should change that to NODEDIR/private/introducer.furl. Which is a pity, because if we used tub.registerReference(ref, furlFile=NODEDIR/introducer.furl), we'd get automatic backwards-compatibility: any existing nodes that upgrade to the new code will keep using their same old (guessable) FURLs, but new nodes will create a new (unguessable) FURL. And users could force the creation of a new (unguessable) FURL by just deleting introducer.furl and restarting.

I suppose the fix will be to this:

if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl does not, copy it into NODEDIR/private/introducer.furl
then use furlFile=NODEDIR/private/introducer.furl

The only downside of that would be leaving the old NODEDIR/introducer.furl lying around, where it might get stale if the connection hints change. Anyone think we should delete the old one after copying it into private/ ?

I'll try to write the patch for this over the weekend.. should be a simple use of `tub.registerReference(ref, furlFile=)` . Hm. The introducer currently writes its furl to `NODEDIR/introducer.furl`, and our docs recommend copying it from that location to all the clients. To fit with out current pattern of putting all secrets in `NODEDIR/private/`, we should change that to `NODEDIR/private/introducer.furl`. Which is a pity, because if we used `tub.registerReference(ref, furlFile=NODEDIR/introducer.furl)`, we'd get automatic backwards-compatibility: any existing nodes that upgrade to the new code will keep using their same old (guessable) FURLs, but new nodes will create a new (unguessable) FURL. And users could force the creation of a new (unguessable) FURL by just deleting `introducer.furl` and restarting. I suppose the fix will be to this: * if `NODEDIR/introducer.furl` exists and `NODEDIR/private/introducer.furl` does not, copy it into `NODEDIR/private/introducer.furl` * then use `furlFile=NODEDIR/private/introducer.furl` The only downside of that would be leaving the old `NODEDIR/introducer.furl` lying around, where it might get stale if the connection hints change. Anyone think we should delete the old one after copying it into private/ ?

davidsarah commented

2012-12-21 06:02:01 +00:00

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Replying to warner:

The only downside of that would be leaving the old NODEDIR/introducer.furl lying around, where it might get stale if the connection hints change. Anyone think we should delete the old one after copying it into private/ ?

We should move the file into private/

Replying to [warner](/tahoe-lafs/trac-2024-07-25/issues/1802#issuecomment-130935): > The only downside of that would be leaving the old `NODEDIR/introducer.furl` lying around, where it might get stale if the connection hints change. Anyone think we should delete the old one after copying it into private/ ? We should move the file into private/

warner commented

2012-12-21 06:27:45 +00:00

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Oh, yeah, good point. So like this?:

if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl also exists, log a message and then delete NODEDIR/introducer.furl
if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl does not, move it into NODEDIR/private/introducer.furl
use furlFile=NODEDIR/private/introducer.furl

Oh, yeah, good point. So like this?: * if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl also exists, log a message and then delete NODEDIR/introducer.furl * if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl does not, move it into NODEDIR/private/introducer.furl * use furlFile=NODEDIR/private/introducer.furl

davidsarah commented

2012-12-21 07:06:48 +00:00

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Replying to warner:

if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl also exists, log a message and then delete NODEDIR/introducer.furl

Perhaps, print a message telling the user to delete one of them, and then exit.

if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl does not, move it into NODEDIR/private/introducer.furl

use furlFile=NODEDIR/private/introducer.furl

Replying to [warner](/tahoe-lafs/trac-2024-07-25/issues/1802#issuecomment-130937): > * if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl also exists, log a message and then delete NODEDIR/introducer.furl Perhaps, print a message telling the user to delete one of them, and then exit. > * if NODEDIR/introducer.furl exists and NODEDIR/private/introducer.furl does not, move it into NODEDIR/private/introducer.furl > * use furlFile=NODEDIR/private/introducer.furl +1

warner commented

2013-03-20 22:12:54 +00:00

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please see the last patch on https://github.com/warner/tahoe-lafs/tree/1802-unguessable-introducer and review.

please see the last patch on <https://github.com/warner/tahoe-lafs/tree/1802-unguessable-introducer> and review.

David-Sarah Hopwood <david-sarah@jacaranda.org> commented

2013-03-21 00:27:04 +00:00

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In changeset:9be1a94043ce1518:

Censor the introducer and helper furls' swissnums from the web welcome page. refs #1802

Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org>

In changeset:9be1a94043ce1518: ``` Censor the introducer and helper furls' swissnums from the web welcome page. refs #1802 Signed-off-by: David-Sarah Hopwood <david-sarah@jacaranda.org> ```

warner commented

2013-03-21 18:42:20 +00:00

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Local smoke tests look good. Thanks for taking case of the helper furl too!

tahoe-lafs added the

fixed

label 2013-03-21 18:42:20 +00:00

warner closed this issue

2013-03-21 18:42:20 +00:00

daira commented

2013-07-10 01:00:31 +00:00