On Tue, Jun 02, 2009 at 08:29:47AM -0500, Serge E. Hallyn wrote:
Quoting Daniel P. Berrange (berrange@redhat.com):
This patch is preparing the way for future work on allowing the libvirtd daemon to run as a less-privileged user ID. The idea is that we will switch from 'root' to 'libvirtd', but use Linux capabilties to keep the handful of higher privileges we need for our work. Thus any code which does a check of 'getuid() == 0' is guarenteed to break [1].
The way this patch approaches this problem, is to change the driver initialization function virStateInitialize() to have it be passed in a 'int privileged' flag from the libvirtd daemon. Each driver is updated to record this flag, and use it for checks where needed. The only real exception is the Xen driver, where we simply check access(2) against the file we need to open.
Hi Daniel,
just a few questions:
...
diff -r 5e3b5d1f91c2 qemud/qemud.c ... @@ -2871,7 +2870,7 @@ int main(int argc, char **argv) { sigaction(SIGPIPE, &sig_action, NULL);
/* Ensure the rundir exists (on tmpfs on some systems) */ - if (geteuid () == 0) { + if (getuid() == 0) {
Why this change?
I removed that line originally. And then put it back wrong. Will fix that.
logmode = O_CREAT | O_WRONLY; - if (uid != 0) + /* Only logrotate files in /var/log, so only append if running privileged */ + if (driver->privileged) + logmode |= O_APPEND; + else logmode |= O_TRUNC; - else - logmode |= O_APPEND;
Hmm, so if I run as unpriv user my logfiles will always be truncated?
Yeah, when running as privileged, logs are in /var/log where a logrotate script takes care of them. With non-privileged, we truncate because we don't want them to grow without bound forever. Arguably we could make this a config file option for the daemon... Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|