Bionic amd64 netboot image has incorrect permissions on kernel

[Bryan Hughes]

Bionic's amd64 netboot image has changed permissions on the included kernel that breaks many tftp daemon configurations. The permissions of 'ubuntu-installer/amd64/linux' contained in netboot.tar.gz for bionic are 0600, however they should be 0644, which matches read permissions on all files in netboot.tar.gz. Prior releases and the current cosmic release all follow these other read permissions on all files in netboot.tar.gz.

Because many tftp daemons run as a different user than the owner of files being served, permitting read from other on this file (and additional files required for netboot) is necessary to allow access and ultimately to PXE boot the image.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1812258/+editstatus and add the package name in the text box next to the word Package.

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[Bryan Hughes (bryanhughes)]

I am not aware of the netinstall image being associated with any existing package.

[Dimitri John Ledkov (xnox)]

netboot images, are generated by debian-installer "source" package, and then published separately.

The most up to date netboot image, is available from bionic-updates as usual:

http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-amd64/

I got the current installer, currently pointed at 20101020ubuntu543.4.

Instead there i downloaded:
http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-amd64/20101020ubuntu543.4/images/netboot/netboot.tar.gz

And the permissions look ok to me there:

$ less netboot.tar.gz | grep amd64/linux
-rw-r--r-- root/root 8277752 2018-12-07 19:31 ./ubuntu-installer/amd64/linux

(note I'm using lesspipe)

Are you sure you are not affected by like a weird umask? are you unpacking the tarball as a regular user, or root?

[Bryan Hughes (bryanhughes)]

Thanks for the clarification. I'm pulling from: http://archive.ubuntu.com/ubuntu/dists/bionic/main/installer-amd64/current/images/netboot/netboot.tar.gz

The permissions appear to be fixed for the kernel in the url you provided. I'll modify my provisioning tools to pull from bionic-updates in the future.