control center should make copy of background image to avoid permission issues with unity greeter

[RobinJ]

This happens on both my laptop (Ubuntu 12.04 LTS, AMD64, Unity 2D, nvidia-current) and my desktop (Ubuntu 12.04 LTS, AMD64, Unity, nvidia-current).
I think it just used to work in Beta 2.
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On both computers, my wallpaper is set to `/home/robin/Ubuntu One/Wallpapers/Mockingjay.jpg`, and I already tried `chmod 777`. All I get at the login screen is the default wallpaper, in stead of the user-specified wallpaper.

File: `/home/robin/Ubuntu One/Wallpapers/Mockingjay.jpg`
-rw-rw-r-- 1 robin robin 1031328 Apr 26 20:05 Mockingjay.jpg

robin@RobinJ:/var/log/lightdm$ sudo cat x-0-greeter.log | grep jpg
[+1.30s] DEBUG: background.vala:67: Making background /home/robin/Ubuntu One/Wallpapers/Mockingjay.jpg at 1280x800
[+1.30s] DEBUG: background.vala:144: Error loading background: Failed to open file '/home/robin/Ubuntu One/Wallpapers/Mockingjay.jpg': Permission denied
[+1.40s] DEBUG: background.vala:116: Render of background /home/robin/Ubuntu One/Wallpapers/Mockingjay.jpg complete

Shouldn't `-rw-rw-r--` mean that everyone has reading permissions to that file?

[Sebastien Bacher (seb128)]

Thank you for your bug report, what permissions are set for your user directory and the UbuntuOne one?

[RobinJ (robinj)]

@seb128
drwx------ 27 robin robin 12288 May 3 20:25 robin
drwxrwxr-x 13 robin robin 4096 Apr 29 21:59 Ubuntu One
drwxrwxr-x 4 robin robin 4096 Apr 27 18:42 Wallpapers
-rw-rw-r-- 1 robin robin 1031328 Apr 26 20:05 Mockingjay.jpg

Maybe it's an idea to copy the chosen wallpaper to a directory LightDM always has access to.

[RobinJ (robinj)]

chmod 777 on the image has no effect.

[h-bomb (h-bomb)]

I have even tried copying the picture to /usr/share/backgrounds/ and setting the permissions to 777 and that still doesn't even work. It amazes me that these half baked features get rolled out. Also, it appears to me that only the default pictures that are included in ubuntu are able to be shown for the user on the login screen. (If you have the wallpaper set to the auto change then those wont even show).

[Ajna Fern (ajnafern)]

woops, didn't realize it would post all of that, is there a way i can edit my last comment? (or can an admin? i don't really want my email address on here)

[Grzegorz G. (grzesiek1e5)]

I can use non-standard wallpaper (in /home/username/Public for example) and it's shown in LightDM. Try to add execute permissions, maybe it will help.

[Timothy Arceri (t-fridey)]

drwx------ 27 robin robin 12288 May 3 20:25 robin

Your home directory is not set to readable unless you are logged in.

[Ajna Fern (ajnafern)]

how is this invalid? it's perfectly reasonable to want your home directory readable by only your account, unity-greeter should work with that

[Timothy Arceri (t-fridey)]

Lol, you can't have both. You are not logged in at the greeter screen so you cannot have unity-greeter read from a directory that is only readable to your user account. The two things are mutually exclusive.
If you dont want your directory readable by other users/when your not logged in then you need to store your background images outside of your home directory.

Just to put the last nail in this coffin any hack to allow unity-greeter to access a directory it doesn't have access to would mean a huge security flaw in linux. As effectively your saying anyone should be able to access files they don't have permissions to.

[Ajna Fern (ajnafern)]

----- Original Message -----

From: Timothy Arceri <email address hidden>

Lol, you can't have both. You are not logged in at the greeter screen so you cannot have unity-greeter read from a directory that is only readable to your user account. The two things are mutually exclusive.
If you dont want your directory readable by other users/when your not logged in then you need to store your background images outside of your home directory.

Just to put the last nail in this coffin any hack to allow unity-greeter
to access a directory it doesn't have access to would mean a huge
security flaw in linux. As effectively your saying anyone should be able
to access files they don't have permissions to.

--

I see exactly what you are saying, it would be a security flaw to allow unity-greeter to see your home folder with those permission.

But surely it's very reasonable to have your home folder only viewable by yourself, i'm sure lots of people dont't want all their files visible to other users of their computer.
What i suggest is have Ubuntu automaticly copy your desktop background to a common folder, so unity-greeter can use that folder.

[Timothy Arceri (t-fridey)]

>What i suggest is have Ubuntu automaticly copy your desktop background to a common folder, so unity-greeter can use that folder.

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I think you are confusing two different issues. Currently you cannot change the Unity Greeter background without editing a config file, or using a third party tweaking tool so you cannot blame ubuntu for not copying images it doesnt know about.

The Desktop background image is not the same as the Unity greeter (lightdm) background.

[Ajna Fern (ajnafern)]

>I think you are confusing two different issues. Currently you cannot
change the Unity Greeter background without editing a config file, or
using a third party tweaking tool so you cannot blame ubuntu for not
copying images it doesnt know about.

>The Desktop background image is not the same as the Unity greeter
(lightdm) background.

I don't know waht you mean "two different issues". You change the greeter background by changing your own desktop background, when logging in it has the desktop background of the currently selected user. so the lightdm background is the same as the desktop background

[Timothy Arceri (t-fridey)]

Ok yes seems you are right. I didn't realise this feature made it into 12.04 final release. In that case its a possible issue with Gnome Control Panel rather than Unity Greeter. As the control panel is what would need to make the copy of the image.