Documentation Security Beat

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== firewalld ==
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[[Category:Docs Project]]
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[[Category:Draft documentation]]
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[[Category:Documentation beats]]
  
Fedora 18 uses '''firewalld''' instead of '''iptables''' as the default firewall service. Using '''firewalld''' will allow for changes to be made to policy without restarting the service. In addition, current status and changes will be available via D-Bus. This improves support for dynamic environments like libvirtd.
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== Hardlink and symlink restrictions ==
  
== Secure Boot ==
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A long-standing class of security issues is the link-based time-of-check-time-of-use race, most commonly seen in world-writable directories like /tmp. The common method of exploitation of this flaw is to cross privilege boundaries when following a given link (i.e. a root process follows a link belonging to another user).  In Fedora 19,  we permit links to only be followed when outside a sticky world-writable directory, or when the uid of the link and follower match, or when the directory owner matches the link's owner.  In previous releases, this was enforced by SELinux policy and in this release, we have enabled these restrictions via the following sysctl settings in /usr/lib/sysctl.d/00-system.conf as an additional layer of protection:
  
UEFI Secure Boot will be supported in Fedora 18. This will allow Fedora to boot on systems that have Secure Boot enabled. Tools are available for administrators to create custom certificates to sign local changes to GRUB or the kernel.
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fs.protected_hardlinks = 1
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fs.protected_symlinks = 1
  
== rngd ==
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Refer to http://lwn.net/Articles/503660/ and https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=800179c9b8a1e796e441674776d11cd4c05d61d7 for more detailed information about this change. Note that in addition to this,
 
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Random number generation is improved by enabling rngd by default.
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== Secure Containers ==
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Using SELinux and '''virt-sandbox''', services can be run in secure sandboxes, even as root. The '''virt-sandbox-service''' package will create mount points and a libvirt container.
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== SELinux boolean renaming ==
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In order to clarify the purpose of SELinux booleans, all settings that begin with "allow" will be renamed to reflect their domain. Existing policy booleans will continue to be supported.
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== SELinux Systemd Access Control ==
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Support has been added to '''systemd''' to check unit files against SELinux settings before allowing a process to start or stop the service.
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== usermode ==
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'''usermode''', a wrapper to provide superuser privileges to unprivileged users, is being phased out in favor of '''polkit'''.
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== halt, poweroff, reboot Configuration Moved ==
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The ability to use halt(8), poweroff(8) and reboot(8) commands by unprivileged users is now controlled using <code>polkit</code>, see the actions in <code>/usr/share/polkit-1/actions/org.freedesktop.login1.policy</code> .  The PAM configuration files <code>/etc/pam.d/{halt,poweroff,reboot}</code> are no longer used and their content, if any, is ignored.
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== openssh-6.1p1 and chroot users ==
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The openssh package was updated to latest upstream release. The '''openssh''' server doesn't use the SELinux chroot_user_t type anymore. Since ''''openssh-6.1p1-1''', chrooted users have their system userdomains. It's up
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to an administrator to use right SELinux user for his users. It's strongly recommend to use the guest_u for these users to lock them down (bug #830237).
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[[Category:Docs Project]]
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[[Category:Draft documentation]]
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[[Category:Documentation beats]]
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Revision as of 14:10, 20 March 2013

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Hardlink and symlink restrictions

A long-standing class of security issues is the link-based time-of-check-time-of-use race, most commonly seen in world-writable directories like /tmp. The common method of exploitation of this flaw is to cross privilege boundaries when following a given link (i.e. a root process follows a link belonging to another user). In Fedora 19, we permit links to only be followed when outside a sticky world-writable directory, or when the uid of the link and follower match, or when the directory owner matches the link's owner. In previous releases, this was enforced by SELinux policy and in this release, we have enabled these restrictions via the following sysctl settings in /usr/lib/sysctl.d/00-system.conf as an additional layer of protection:

fs.protected_hardlinks = 1
fs.protected_symlinks = 1

Refer to http://lwn.net/Articles/503660/ and https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=800179c9b8a1e796e441674776d11cd4c05d61d7 for more detailed information about this change. Note that in addition to this,