> On Dec. 27, 2015, 4:37 p.m., David Edmundson wrote: > > sddmauthhelper.cpp, line 74 > > <https://git.reviewboard.kde.org/r/126524/diff/1/?file=426085#file426085line74> > > > > Ideally we should check the *calling* user can read this file, as you > > technically have a security bug. > > > > Otherwise I could just select /etc/shadow as my background and suddenly > > it's available world readable. > > > > A distro/admin could theoretically set polkit up to allow any users to > > change the SDDM wallpaper. though TBH it'd never happen. > > > > Polkit-Qt has that information available. KAuth does not seem to > > publicly. > > Joshua Noack wrote: > Not sure if I understand you correctly... > In addition to the KAuth dialog where the user needs to authenticate, a > check if the user can read the file should be added? > Shouldn't the file chooser restrict the user here in the first place? > > David Edmundson wrote: > it needs to happen inside the helper, not on the client side. > > From a terminal I can manually start the sddm helper saying I want to set > /etc/shadow as the background. > > The helper will then check if the user is permitted to set the SDDM > wallpaper in policykit, which is up to the sysadmin's policy > If that returns true, the helper will procede to copy the file as root. > > That's a security hole as it would potentially allow me to read any file. > > Joshua Noack wrote: > Okay, I looked up policykit and don't see any rule in > /usr/share/polkit-1/ for it. > So... should I create a new rule (like org.kde.sddm.policy) ? But judging > from your words, it seems to be already possible? > > If you could tell me where the sysadmin sets his policies I would be > grateful. :p > > David Edmundson wrote: > We already have a policy. > > See org.kde.kcontrol.kcmsddm.policy > > our defaults are: > <defaults> > <allow_inactive>no</allow_inactive> > <allow_active>auth_admin_keep</allow_active> > </defaults> > > > which is good. > > However, we can't predict that every setup and every distro will have the > same setup. > They could change it to be > <allow_active>yes</allow_active> > > and then we have a problem. > > David Edmundson wrote: > https://git.reviewboard.kde.org/r/126724/ adds the API we need. > > Joshua Noack wrote: > Cool. When will the API changes be released? I don't have much interest > in fiddling with self-compiled development libraries.
Start of Feb. If you want, I can continue this patch and add the extra bit of code? - David ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://git.reviewboard.kde.org/r/126524/#review90132 ----------------------------------------------------------- On Dec. 28, 2015, 3:44 p.m., Joshua Noack wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://git.reviewboard.kde.org/r/126524/ > ----------------------------------------------------------- > > (Updated Dec. 28, 2015, 3:44 p.m.) > > > Review request for Plasma and David Edmundson. > > > Repository: sddm-kcm > > > Description > ------- > > For some reason sddm cannot handle absolute file paths to wallpapers > and also needs the wallpaper to be readable by others. > > This is fixed by copying the wallpaper to the root directory of the > selected theme. > > On save the sddmauthhelper copies the background from the absolute path > into the theme directory and sets the "background" key of the > theme.user.conf to the copied file. If previously a different background was > set it is removed beforehand. > > > Diffs > ----- > > sddmauthhelper.cpp 648b24c77e7570641d454fca9d121709a622bc36 > src/themeconfig.cpp bdd6dd29fd8eb052e2f2b2239b0c46ebbebec88c > > Diff: https://git.reviewboard.kde.org/r/126524/diff/ > > > Testing > ------- > > Copies and removes backgrounds as intended. > The wallpaper is shown in sddm. > > > Thanks, > > Joshua Noack > >
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