apt update hangs when repository url is redirect url

[Seyeong Kim]

[Impact]

When using redirect url on /etc/apt/sources.list

apt update command hangs

this is affected with commit
https://anonscm.debian.org/git/apt/apt.git/commit/?id=dd547ebaffd2aceb42e2908f1d5f0ab386af6cb1

In my test, moving below[1] code after[2]

[1]
###
if (ContentLength == 0)
    return true;
###
[2]
if (Encoding == Closes)
    Encoding = Stream;

###

it worked fine.

[Test Case]

echo "deb http://packages.cloudfoundry.org/debian stable main" > /etc/apt/sources.list.d/cloudfoundry-cli.list

apt update

[Regression]
Could cause some other zero-content redirects to break again (seems unlikely...).

[Julian Andres Klode (juliank)]

Ack, that seems to make sense. Strange.

[Julian Andres Klode (juliank)]

OK, so I need to dig a bit further into this. I think if I move the if I break things elsewhere. IIRC, I added the if that early because, when apt received a redirect with Content-Length: 0, it started hanging, and that fixed it. But maybe it breaks some other stuff now.

[Julian Andres Klode (juliank)]

It's working fine in bionic, but I can confirm it failed in xenial.

[Julian Andres Klode (juliank)]

OK, so:

xenial: affected
artful, bionic: NOT affected

So I might just want to revert this commit in an apt 1.2.26 release and look at it again later.

[Seyeong Kim (xtrusia)]

Hello Julian, no news for this?

[Julian Andres Klode (juliank)]

I was sort of waiting for 16.04.4 to be released and then lost track of it. Uploading fixed version today.

[Julian Andres Klode (juliank)]

Uploaded.

[Seyeong Kim (xtrusia)]

Thanks a lot!

[Brian Murray (brian-murray)]

Hello Seyeong, or anyone else affected,

Accepted apt into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/apt/1.2.26 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Seyeong Kim (xtrusia)]

Hello,

I verified this -proposed pkg is working.

1. upgrade apt pkg
2. insert above url in test case to sources.list
3. apt update
4. check if it hangs or not

dpkg -l

ii apt 1.2.26 amd64 commandline package manager

Thanks

[Launchpad Janitor (janitor)]

This bug was fixed in the package apt - 1.2.26

---------------
apt (1.2.26) xenial; urgency=medium

  * Revert "http: A response with Content-Length: 0 has no content"
    - broke Content-Length: 0 redirects (in xenial only) (LP: #1751225)
  * travis: Migrate to Docker to make CI work again

 -- Julian Andres Klode <email address hidden> Tue, 06 Mar 2018 09:43:16 +0100

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for apt has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.