Warning messages about unsandboxed downloads

[dino99]

READ ME FIRST
=============
This is a cosmetic issue. The warning message is just that— a warning. Though the message comes up, there is no problem with the install/upgrade happening like normal. That said, feel free to ignore it. It will get fixed, but it's nowhere near as urgent as bugs that actually result in the wrong behavior rather than just a simple extra message.

update-notifier SRU
-------------------
[Impact]
Cosmetic. Warnings when installing packages using update-notifier downloading stuff

[Test case]

Install flashplugin-installer with apt and check that the output does not contain a message like this:

W: Can't drop privileges for downloading as file '...' couldn't be accessed by user '_apt'

[Regression Potential]

It just chowns /var/lib/update-notifier/package-data-downloads/partial/ to _apt:root, there should not be any regression.

Original report
---------------

Recently we got new versions for synaptic 0.82+build1 & apt 1.1.3, but now get that error when installing/upgrading some packages:

Setting up libc6-dbg:amd64 (2.21-0ubuntu5) ...
Processing triggers for libc-bin (2.21-0ubuntu5) ...
W: Can't drop privileges for downloading as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

From nautilus, i'm seeing a /root/ folder locked (x on its icon) and the folder is empty (no /.synaptic/ sub-folder or file), so the above error.

oem@u64:~$ ls -l .synaptic
total 4
-rw-rw-r-- 1 oem oem 0 Aug 25 11:19 options
-rw-rw-r-- 1 oem oem 236 Aug 25 11:19 synaptic.conf

oem@u64:~$ ls -l /var/lib/apt/lists/
....
-rw-r----- 1 root root 0 Sep 20 06:36 lock
drwx------ 2 _apt root 16384 Sep 24 15:25 partial
......

oem@u64:~$ sudo ls -l /var/lib/update-notifier/package-data-downloads/
.....
drwxr-xr-x 2 _apt root 4096 Sep 22 23:33 partial

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: synaptic 0.82+build1
ProcVersionSignature: Ubuntu 4.3.0-1.10-generic 4.3.0
Uname: Linux 4.3.0-1-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19.2-0ubuntu8
Architecture: amd64
CurrentDesktop: GNOME
Date: Fri Dec 4 05:23:25 2015
SourcePackage: synaptic
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tsu Jan (tsujan2000)]

On Debian I get messages like this when the download process is completed:

W: Can't drop privileges for downloading as file '/var/cache/apt/archives/partial/PACKAGE' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

However, after I close the dialog, I can update the packages. Of course PACKAGE isn't there after it's downloaded completely. Why Synaptic searches for it in that folder, I don't know.

[dino99 (9d9)]

synaptic 0.82.5 does not solve that issue

[Tsu Jan (tsujan2000)]

On Debian, this issue is fixed by apt-1.2, although another irrelevant message is shown now:

The method driver /usr/lib/apt/methods/https could not be found.

[dino99 (9d9)]

Thanks Tsu

so many changes recently with the apt package !!!
http://metadata.ftp-master.debian.org/changelogs/main/a/apt/apt_1.2.1_changelog

[Tsu Jan (tsujan2000)]

I was wrong: the problem still persists with apt-1.2 :( It showed up again the second time I used Synaptic after the upgrade.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Flames_in_Paradise (ellisistfroh-deactivatedaccount)]

@ddino99: The link u provided seems to be broken, so look at this:
https://launchpad.net/ubuntu/xenial/+source/apt/+changelog

And , yes, thats impressive!

[dino99 (9d9)]

Debian have upgrade the package; so the link above is indeed dead. Hereis the full actual changelog (more complete than the launchpad changelog)
http://metadata.ftp-master.debian.org/changelogs/main/a/apt/apt_1.2.3_changelog

[Brian Murray (brian-murray)]

I was unable to recreate this given the situation described:

 $ sudo mv /root/.synaptic /root/synaptic
[ 3:56PM 10261 ] [ bdmurray@impulse:~/Documents/gtd ]
 $ sudo apt-get install --reinstall libc-bin
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.3.0-7 linux-headers-4.3.0-7-generic linux-image-4.3.0-7-generic linux-image-extra-4.3.0-7-generic linux-tools-4.3.0-7 linux-tools-4.3.0-7-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 207 not upgraded.
Need to get 0 B/1,172 kB of archives.
After this operation, 0 B of additional disk space will be used.
Sorry, your system lacks support for the snapshot feature
(Reading database ... 909633 files and directories currently installed.)
Preparing to unpack .../libc-bin_2.21-0ubuntu5_amd64.deb ...
Unpacking libc-bin (2.21-0ubuntu5) over (2.21-0ubuntu5) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up libc-bin (2.21-0ubuntu5) ...

[dino99 (9d9)]

@Brian

This is still happening on that fresh wily dist-upgraded to xenial, even with the latest apt 1.2.3 and gcc 5.3.1-1

Processing triggers for libc-bin (2.21-0ubuntu6) ...
W: Can't drop privileges for downloading as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

The main issue sems to be that .root folder LOCKED, that disable to subfolder creation.

Is that locked .root folder expected ?

[Tigerboy (tigersands)]

W: Can't drop privileges for downloading as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

following what appears to be the successful install of package xicc 0.2-3

fully upgraded 16.04

[Tigerboy (tigersands)]

Additionally:
/root/.synaptic/tmp does exist and it is owned by root with permissions 0700

The /root/.synaptic/tmp folder is empty

[Tigerboy (tigersands)]

dpkg.log:

2016-02-27 23:23:37 install xicc:amd64 <none> 0.2-3
2016-02-27 23:23:37 status half-installed xicc:amd64 0.2-3
2016-02-27 23:23:37 status unpacked xicc:amd64 0.2-3
2016-02-27 23:23:37 status unpacked xicc:amd64 0.2-3
2016-02-27 23:23:37 startup packages configure
2016-02-27 23:23:37 configure xicc:amd64 0.2-3 <none>
2016-02-27 23:23:37 status unpacked xicc:amd64 0.2-3
2016-02-27 23:23:37 status half-configured xicc:amd64 0.2-3
2016-02-27 23:23:37 status installed xicc:amd64 0.2-3
2016-02-27 23:23:38 startup packages configure

xicc shows as being fully installed & dpkg is fully operational.

[Julian Andres Klode (juliank)]

There is no bug in APT here. There is not even an error. It's a warning. In any case, this is synaptics fault, as that defines where to download the changelog instead of using APT's changelog code.

[Luis Ferro (luis-ferro)]

Then i suppose that a new bug is entered into synaptics and linked to this bug so that users affected by this can see that it is being handled insted of "ignored" by a invalid / triaged status?

Just tested on the "release" version of xenial and it still happens.

[Travisgevans (travisgevans)]

For the Synaptic message complaining about /var/cache/apt/archives/partial, setting the owner of that directory to _apt seems to avoid it, based on my tests in a VirtualBox VM of Wily upgraded to Xenial.

I haven't (yet) encountered an error complaining about /root/.synaptic/[…]. It seems really bizarre that it would insist on some system user being able to access something in root's home directory.

[The Powerpuff Girls (thepowerpuffgirls)]

I had this message a few times within the past few days of upgrading to Ubuntu 16.04, fresh, from Ubuntu 12.04.

I had this message about a half hour ago while installing apport.

- Blossom

[Travisgevans (travisgevans)]

I just now found a very similar message from the update-notifier cronjob:

/etc/cron.daily/update-notifier-common:
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20160407.1.orig.tar.gz [27.0 MB]
Fetched 27.0 MB in 1min 11s (378 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20160407.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20160407.1.orig.tar.gz
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20160407.1.orig.tar.gz
Flash Plugin installed.

So, apparently not unique to Synaptic?

[Brian Murray (brian-murray)]

The update-notifier-common message is unrelated to this bug and is only a warning (notice the W:) and the flash plugin is still installed.

[Gil Gamesh (gamesh-g)]

It's correct that it's a warning, but it is presented as an error. I get a pop-up window that says "An error occurred".

I guess this is potentially a different bug as I see the same thing with a warning about a weak digest algorithm similarly being presented as an error.

[jean-christophe manciot (manciot-jeanchristophe)]

After exiting from Synaptic, is it expected for the file /var/cache/apt/archives/lock to be still there?

[randolf (wolle321)]

Have this problem too, since I updated from 15.10 to 16.04.
Synaptic is not running, but the lock -file is still there:

randolf@ART-LT16:~$ ps aux | grep synaptic
randolf 14314 0.0 0.0 15796 1024 pts/4 S+ 10:47 0:00 grep --color=auto synaptic
randolf@ART-LT16:~$ ll /var/cache/apt/archives/lock
-rw-r----- 1 root root 0 Okt 21 2015 /var/cache/apt/archives/lock

Hope this helps, randolf

[Flames_in_Paradise (ellisistfroh-deactivatedaccount)]

Is the system missing a user called _apt ?

Was it forgotten to create one?

Is this warning serious or can/should it be silenced?

Who corrupted my system? Can we still trust the system or should we just install another distro, which doesn't suffer such?

Looks in any case quite messy AND it's an upgrade-regression.

[dino99 (9d9)]

This also happen on Yakkety with synaptic, but only once after opening a session (gnome-shell 64 bits); After that first 'upgrade' that ends with this warning, the next upgrades, inside the opened session, do not warns. This has no sad effects on upgrading, so it could be silenced.

[Kim Tucker (ktucker)]

In case useful, I have just done a fresh install of Xenial, followed by 'sudo apt-get install synaptic'. The following error arose when trying to install blubuntu-theme and blubuntu-wallpapers
W: Can't drop privileges for downloading as file '/root/.synaptic/tmp//tmp_sh' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied).
After completely removing via synaptic, it installed fine with apt-get.

[Bill Miller (wbmilleriii)]

It's not just synaptic. Happens with aptitude as well. I suspect it's a new requirement for a user named '_apt' which doesn't exist (because it wasn't added).

[Deleted (noone1)]

Is there a fix for this yet? It's still happening on Ubuntu 16.04 with all updates as of 07/24/2016.

[Tsu Jan (tsujan2000)]

Cleaning up Firefox bookmarks, I encountered this report again. Apparently, apt developers don't want to see this as a bug, so don't wait for a fix! To get rid of that annoying message, you should have an `_apt` user (which probably you have) and change the owner of the folder in question from `root:root` to `_apt:root`.

I'm on Debian and the above trick worked here months ago.

[feroz (ferozkhan27)]

Yet, anyone find out any workaround for this?

[feroz (ferozkhan27)]

ended up using 15.10.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[dino99 (9d9)]

@juliank (#16)

Michael Vogt has a different opinion that yours, so blaming apt again

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=808802
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=808802#20
"This is a bug indeed, the question is how it got triggered, that dir
should be owend by the _apt user."

oem@u64:~$ ls -dl /var/cache/apt/archives/partial/
drwx------ 2 _apt root 4096 Sep 24 05:26 /var/cache/apt/archives/partial/
oem@u64:~$ grep -B2 _apt /var/lib/dpkg/info/apt.postinst
 # add unprivileged user for the apt methods
 adduser --force-badname --system --home /nonexistent \
     --no-create-home --quiet _apt || true

 # Fixup any mistake in the home directory of the _apt user
 if dpkg --compare-versions "$2" lt-nl 1.1~exp10~; then
     usermod --home /nonexistent _apt

[dino99 (9d9)]

For the record, an other case has been fixed about _apt sandboxing

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=806406

oem@u64:~$ getent passwd
.....
_apt:x:123:65534::/nonexistent:/bin/false

[Julian Andres Klode (juliank)]

Michael and I don't have any different opinion here at all. You are complaining about root/.synaptic/tmp//tmp_cl - which is owned by synaptics - not about the /var/cache/apt/archives/partial or another apt owned directory.

A directory inside your (well, root's) home directory is a different case altogether: It *should* be owned by you, not by _apt.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[chris pollock (cpollock)]

Wow, this is still going on after more than 10 months

/etc/cron.daily/update-notifier-common:
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz [27.2 MB]
Fetched 27.2 MB in 23s (1,179 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz
Flash Plugin installed.

[Evan Carroll (evancarroll)]

Also getting this, re: @Chris Pollock on the same package which is now required with the deprecation and removal of pepperflash on Oct 26.

[Pablo Catalina (xkill)]

I have similar problem with flashplugin-installer and ttf-mscorefonts-installer packages:

flashplugin-installer: processing...
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20161026.1.orig.tar.gz [27,2 MB]
Fetched 27,2 MB in 25s (1.085 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20161026.1.orig.tar.gz
Flash Plugin installed.
ttf-mscorefonts-installer: processing...
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/andale32.exe
Get:1 http://downloads.sourceforge.net/corefonts/andale32.exe [198 kB]
Fetched 198 kB in 2s (96,3 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/andale32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arial32.exe
Get:1 http://downloads.sourceforge.net/corefonts/arial32.exe [554 kB]
Fetched 554 kB in 2s (248 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/arial32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arialb32.exe
Get:1 http://downloads.sourceforge.net/corefonts/arialb32.exe [168 kB]
Fetched 168 kB in 2s (71,9 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/arialb32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/comic32.exe
Get:1 http://downloads.sourceforge.net/corefonts/comic32.exe [246 kB]
Fetched 246 kB in 2s (95,3 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/comic32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/courie32.exe
Get:1 http://downloads.sourceforge.net/corefonts/courie32.exe [646 kB]
Fetched 646 kB in 2s (273 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier...

[Julian Andres Klode (juliank)]

I think we should fix this, but an SRU for this seems a bit too much. There's more important stuff pending since months.

[Julian Andres Klode (juliank)]

Uploaded update-notifier 3.181 to fix this

https://launchpad.net/ubuntu/+source/update-notifier/3.181

[Ads20000 (ads20000)]

Julian we could just add it to the pile anyway? Happy to look up what work needs doing to sort that out and do the bits I can (I'm not a developer, but I know the bug description would need to be rewritten and I could give that a shot?)

[Julian Andres Klode (juliank)]

I'll SRU update-notifier next week I think. Yes, we need a concrete bug description as described in
https://wiki.ubuntu.com/StableReleaseUpdates

It should be easy to review anyway, but I want it to spend some time in artful first.

Synaptic also needs fixing, not sure about that.

[Launchpad Janitor (janitor)]

This bug was fixed in the package update-notifier - 3.181

---------------
update-notifier (3.181) artful; urgency=medium

  * Fix APT sandboxing for data downloads failing (LP: #1522675)

 -- Julian Andres Klode <email address hidden> Wed, 28 Jun 2017 22:25:25 +0200

[Ads20000 (ads20000)]

(sighs) I don't think I really understand this bug well enough to put it in the right format. Norbert and anyone else who really wants this fixed in Ubuntu that's not 17.10 please can you do that? Check '3.1. SRU Bug Template' on the link Julian gave and then edit the bug with the relevant details. Thank you! :D

[Martin Dünkelmann (nc-duenkekl3)]

W: Download is performed unsandboxed as root as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Keine Berechtigung)

Ubuntu Mate x64 17.04
Synaptic 0.84.2

I only want to install the updates and autoremove unessecary packages.....

[Ads20000 (ads20000)]

Martin, if you want to get this bug fixed please click on the link Julian gave in #89 and rewrite the bug so it can be fixed in Ubuntu 16.04 and 17.04. It won't be fixed until that happens (and, ideally, would be good if you could check it's working in 17.10, where it's already been patched, as well). We know it's a problem but someone needs to do the work to get it fixed (I don't feel able to sorry).

[Martin Dünkelmann (nc-duenkekl3)]

If https://wiki.ubuntu.com/StableReleaseUpdates#SRU_Bug_Template is the right one:

[Impact]

Updating packets via synaptic.
Befor they start OR after fonoshing the installing, the errir appears.

"W: Download is performed unsandboxed as root as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Keine Berechtigung)"

Ubuntu Mate x64 17.04
Synaptic 0.84.2

[Test Case]

Start synaptic.
Update the repositorys.
Go into the updates section.
Double click on every package, which can be updated.
Click on "apply" to install the updates.

[Regression Potential]

Don't know.

[Other Info]

Don't know

[Julian Andres Klode (juliank)]

Different issue, Martin, I only fixed the update-notifier task so far.

[Impact]
Cosmetic. Warnings when installing packages using update-notifier downloading stuff

[Test case]

Install flashplugin-installer with apt and check that the output does not contain a message like this:

W: Can't drop privileges for downloading as file '...' couldn't be accessed by user '_apt'

[Regression Potential]

It just chowns /var/lib/update-notifier/package-data-downloads/partial/ to _apt:root, there should not be any regression.

[Martin Dünkelmann (nc-duenkekl3)]

Oh, is there already a bug report, where I can add my comment?

[Julian Andres Klode (juliank)]

Well this bug deals with both issues...

[Rocdufer (lepcis)]

First, recall user _apt was added recently. Second, not all comments appear to have the same original; some ones refer access rights, so some comments suggest change owner or ACL of some directory. However, another comments point out something that appears to be a parsing error over the directory path. For example, in comment #94, the path:

 "W: Download is performed unsandboxed as root as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Keine Berechtigung)"

looks quite extraneous, because it has an empty directory name at "/tmp/ /tmp_cl". The error I got is quite similar, except it says "/tmp/ /tmp_sh", but in my system I later found directory .synaptic/tmp was empty.

For the first problem, I do no see user _apt included in group sudo. And for the second, I remember that while doing a system upgrade I was notified about a change in MIME types. This could be a trace for a parsing error. Hope this comment may help to solve the warning.

[Andrew (publicface)]

As of ubuntu 16.04.3, the problem demonstrated below, still exists. Here is the solution as to how to install it on a clean system. Note carefully, I always use apt-get, not synaptic. Also note that the _apt user already exists.

sudo chown _apt /var/lib/update-notifier/package-data-downloads/partial/
sudo apt-get install ttf-mscorefonts-installer

First, the Broken before chown to demonstrate the issue:
sudo apt-get install ttf-mscorefonts-installer
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  cabextract libmspack0
The following NEW packages will be installed:
  cabextract libmspack0 ttf-mscorefonts-installer
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 87.9 kB of archives.
After this operation, 338 kB of additional disk space will be used.
Do you want to continue? [Y/n]
Get:1 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 libmspack0 amd64 0.5-1ubuntu0.16.04.1 [37.0 kB]
Get:2 http://us.archive.ubuntu.com/ubuntu xenial/universe amd64 cabextract amd64 1.6-1 [21.4 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu xenial/multiverse amd64 ttf-mscorefonts-installer all 3.4+nmu1ubuntu2 [29.5 kB]
Fetched 87.9 kB in 0s (118 kB/s)
Preconfiguring packages ...
Selecting previously unselected package libmspack0:amd64.
(Reading database ... 241441 files and directories currently installed.)
Preparing to unpack .../libmspack0_0.5-1ubuntu0.16.04.1_amd64.deb ...
Unpacking libmspack0:amd64 (0.5-1ubuntu0.16.04.1) ...
Selecting previously unselected package cabextract.
Preparing to unpack .../cabextract_1.6-1_amd64.deb ...
Unpacking cabextract (1.6-1) ...
Selecting previously unselected package ttf-mscorefonts-installer.
Preparing to unpack .../ttf-mscorefonts-installer_3.4+nmu1ubuntu2_all.deb ...
Unpacking ttf-mscorefonts-installer (3.4+nmu1ubuntu2) ...
Processing triggers for libc-bin (2.23-0ubuntu9) ...
Processing triggers for man-db (2.7.5-1) ...
Processing triggers for fontconfig (2.11.94-0ubuntu1.1) ...
Processing triggers for update-notifier-common (3.168.5) ...
ttf-mscorefonts-installer: processing...
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/andale32.exe
Get:1 http://downloads.sourceforge.net/corefonts/andale32.exe [198 kB]
Fetched 198 kB in 1s (132 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/andale32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arial32.exe
Get:1 http://downloads.sourceforge.net/corefonts/arial32.exe [554 kB]
Fetched 554 kB in 1s (364 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/arial32.exe' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
ttf-mscorefonts-installer: downloading http://downloads.sourceforge.net/corefonts/arialb32.exe
Get:1 http://downloads.so...

[Martin Dünkelmann (nc-duenkekl3)]

Ubuntu Mate x64 17.10
Problem still exists...

[Martin Dünkelmann (nc-duenkekl3)]

@Ads20000

[Ads20000 (ads20000)]

Still exists in 17.10? You might need to file a new bug, Julian will know what to do here I presume, since he pushed the fix...

[Steve Langasek (vorlon)]

On a system upgraded to 17.10, I see the correct permissions:

drwx------ 2 _apt root 4096 Nov 1 00:10 /var/lib/update-notifier/package-data-downloads/partial/

Martin, are you seeing this also or do you see something different?

[Julian Andres Klode (juliank)]

I'd say it's probably the synaptic one for Martin. We should change its directory to be _apt owned too, though it's not really clear to me which directories that are.

This should all be fixed in a hopefully near future with apt 1.6 or 1.7 opening these files as root and passing them down to the unprivileged processes via a socket. That's not yet implemented, though I do have mvo's branch from 2013 or so as a base.

[Norbert (nrbrtx)]

Got this bug again on fresh installation of kUbuntu 16.04 LTS during installation of kubuntu-restricted-extras (especially fonts).

[Chelmite (steve-kelem)]

I'm getting this error on Ubuntu 17.10:
W: Download is performed unsandboxed as root as file '/root/.synaptic/tmp//tmp_cl' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)

I have a user _apt, and it owns /var/lib/update-notifier/package-data-downloads/partial/

It looks like the problems are 2-fold:
1. The double-slash in '/root/.synaptic/tmp//tmp_cl' is equivalent to /tmp_cl, isn't it? That doesn't exist, and probably shouldn't. The double-slash should probably be a single slash.
2. Why is _apt supposed to be able to access anything in /root? If /root/.synaptic/tmp is a special case, then somebody or some program needs to change its ownership. Right now it's:
drwx------ 2 root root /root/.synaptic/tmp

[Adrien Beau (adrienbeau)]

@Chelmite The double slash is equivalent to a single slash, so there is not much of a problem here, just a very minor cosmetic issue. Synaptic is certainly the one who told APT to download stuff in /root/.synaptic/tmp, so it is the one which should have changed the ownership to _apt beforehand. You can easily fix that yourself.

[JohnWashington (ubuntu-johnwash)]

@Adrien
I was happy until "You can easily fix that yourself". For every Launchpad reader that can, there's 100s who can't. And many thousands who don't even know Launchpad exists.

[Martin Dünkelmann (nc-duenkekl3)]

Definitely.
This bug is a fault from the synaptic-, apt- or OS- developers....

[Norbert (nrbrtx)]

Got this bug while installing ttf-mscorefonts-installer?

385 users are affected.
How long?
Is it so difficult to fix this bug?

[Ads20000 (ads20000)]

Norbert, making comments on bugs attacking developers for not doing enough to fix the bug just annoys the developers, it doesn't help fix the bug. Either take more proactive action as necessary (I don't know what's needed at the moment) or be patient. Also check the readme at the start of the description, it's cosmetic so it's Low priority by definition, you can't change that unless if you fight elsewhere to change the Importance descriptors.

[Norbert (nrbrtx)]

OK, Ads20000. This bug is annoying. Nothing more. Yesterday another newbie installed Ubuntu 16.04 LTS after my recommendation. He was very dissapointed seeing this message.

Ubuntu developers should understand that annoying bugs should be fixed as fast as possible as Critical bugs. It does not matter that such bugs do not result in data loss. Such bugs makes negative reputation of whole Ubuntu. So they should be fixed.

[Adrien Beau (adrienbeau)]

Norbert, it is *extremely* inappropriate to edit the bug description to publicize your workaround. Adding instructions to set the sandbox user to "root" at the start of the bug description is quite simply awful.

I have reverted that change.

[Norbert (nrbrtx)]

@Adrien Beau (adrienbeau)
you can propose your fix anywhere where you want.
All APT works as root, there is not security hole here. We can trust its HTTP transport.

By the way Ubuntu developers should understand that annoying bugs should be fixed as fast as possible as Critical bugs. It does not matter that such bugs do not result in data loss. Such bugs makes negative reputation of whole Ubuntu. So they should be fixed.

[Norbert (nrbrtx)]

Techinal part about my fix is in https://bugs.launchpad.net/ubuntu/+source/synaptic/+bug/1522675/comments/85 .
Do APT/Ubuntu/Debian/Canonical have any comments on it?

[Julian Andres Klode (juliank)]

Uploaded update-notifier to xenial-proposed.

[Brian Murray (brian-murray)]

Hello dino99, or anyone else affected,

Accepted update-notifier into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/update-notifier/3.168.8 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!

[Norbert (nrbrtx)]

Installed update-notifier 3.168.8 from xenial-proposed.

I do not get any "W: Can't drop privileges for downloading" during execution of

$ sudo apt-get install --reinstall flashplugin-installer ttf-mscorefonts-installer

But aptitude is still complains when getting changelogs from terminal `aptitude changelog apt` or interactively by <C> (see bug https://bugs.launchpad.net/bugs/1752907 ).

Thank you!

If others know other ways to test, please do it.

[dino99 (9d9)]

Hopes someone will do the change too for synaptic, which display that error only the first upgrade is done.

[Brian Murray (brian-murray)]

bdmurray@clean-xenial-amd64:~$ apt-cache policy update-notifier
update-notifier:
  Installed: 3.168.1
  Candidate: 3.168.7
  Version table:
     3.168.7 500
        500 http://192.168.10.7/ubuntu xenial-updates/main amd64 Packages
        500 http://192.168.10.7/ubuntu xenial-security/main amd64 Packages
 *** 3.168.1 100
        100 /var/lib/dpkg/status
     3.168 500
        500 http://192.168.10.7/ubuntu xenial/main amd64 Packages
bdmurray@clean-xenial-amd64:~$ sudo apt install flashplugin-installer
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  libpango1.0-0 libpangox-1.0-0
Suggested packages:
  x-ttcidfont-conf ttf-mscorefonts-installer ttf-bitstream-vera | ttf-dejavu ttf-xfree86-nonfree xfs
The following NEW packages will be installed:
  flashplugin-installer libpango1.0-0 libpangox-1.0-0
0 upgraded, 3 newly installed, 0 to remove and 556 not upgraded.
Need to get 6,798 B/51.9 kB of archives.
After this operation, 445 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
...
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20180206.1.orig.tar.gz
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20180206.1.orig.tar.gz [30.5 MB]
Fetched 30.5 MB in 5s (5,929 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20180206.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20180206.1.orig.tar.gz

With the version from -proposed:

Setting up update-notifier-common (3.168.8) ...
flashplugin-installer: processing...
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20180206.1.orig.tar.gz
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20180206.1.orig.tar.gz [30.5 MB]
Fetched 30.5 MB in 8s (3,434 kB/s)
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20180206.1.orig.tar.gz
Flash Plugin installed.
Setting up libcairo-perl (1.106-1build1) ...

[Ads20000 (ads20000)]

Updated the other tag too, think that's the right thing to do? Please revert if not!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

This bug was fixed in the package update-notifier - 3.168.8

---------------
update-notifier (3.168.8) xenial; urgency=medium

  * Fix APT sandboxing for data downloads failing (LP: #1522675)

 -- Julian Andres Klode <email address hidden> Fri, 02 Mar 2018 12:27:35 +0100

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for update-notifier 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.