On 03/04/2011 03:45 PM, Denys Vlasenko wrote:
On Tue, 2011-03-01 at 10:46 +0100, Michal Toman wrote:
Hi,
making Retrace Server able to handle F15 crashes, I found a problem. So far, we are using tmpfs for chroots, because it is significantly faster to retrace in memory than on HDD. Everything works perfectly for F14 (and also RHEL6), however for F15 it does not.
F15 introduces file capabilities and these are not working in tmpfs.
What are file capabilities and why do we need them?
File capabilities split root privileges into smaller parts (eg. reading files, executing as root...). It is an alternative to SUID bit - the process only has the privileges it needs, instead of SUID bit providing full root access. Capabilities are set when unpacking rpm. If the target filesystem does not support capabilities, installation fails.
It is a kernel problem, probably fixed in rawhide (and F15?) https://bugzilla.redhat.com/show_bug.cgi?id=648653 (not tested). Retrace on ext4 HDD works, but of course, it is much slower. With both our testing machines running RHEL-6 and test day approaching, we should think what to do.