Re: [libvirt] [RFC] security_dac: don't chown iso file
On 10/05/2011 06:33 AM, Daniel P. Berrange wrote: On Tue, Oct 04, 2011 at 12:49:03PM -0500, Serge E. Hallyn wrote: Quoting Serge E. Hallyn (serge.hal...@canonical.com): isos are read-only, so libvirt doesn't need to chown them. In one of our testing setups, libvirt uses mirrorred isos. Since libvirt chowns the files, (and especially does not chown them back) the mirror refuses to update the iso. This patch prevents libvirt from chowning files. Does this seem reasonable? any feedback on this? Does it seem ok? Unfortunately while this would fix the use case you describe, it would also break other use cases. What we really need todo with the DAC driver is replace all the chown() code, with code that sets ACLs instead. Well actually we would need to keep the chown code as a fallback for filesystems which don't support ACLs, but as long as we prefer ACLs by default that'd be OK. Of course when we have ACLs, we'd only need to grant 'r' to the file for CDROMs which would be better than what we do now. In the meantime, I think you can solve the problem with your mirror by mounting the share read-only. When the filesystem is read-only, libvirt will attempt the chown/chgrp and fail, but notice the failure is due to a r/o (or root-squash) filesystem, and ignore the failure. -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [RFC] security_dac: don't chown iso file
Quoting Laine Stump (la...@laine.org): On 10/05/2011 06:33 AM, Daniel P. Berrange wrote: On Tue, Oct 04, 2011 at 12:49:03PM -0500, Serge E. Hallyn wrote: Quoting Serge E. Hallyn (serge.hal...@canonical.com): isos are read-only, so libvirt doesn't need to chown them. In one of our testing setups, libvirt uses mirrorred isos. Since libvirt chowns the files, (and especially does not chown them back) the mirror refuses to update the iso. This patch prevents libvirt from chowning files. Does this seem reasonable? any feedback on this? Does it seem ok? Unfortunately while this would fix the use case you describe, it would also break other use cases. What we really need todo with the DAC driver is replace all the chown() code, with code that sets ACLs instead. Well actually we would need to keep the chown code as a fallback for filesystems which don't support ACLs, but as long as we prefer ACLs by default that'd be OK. Of course when we have ACLs, we'd only need to grant 'r' to the file for CDROMs which would be better than what we do now. In the meantime, I think you can solve the problem with your mirror by mounting the share read-only. When the filesystem is read-only, libvirt will attempt the chown/chgrp and fail, but notice the failure is due to a r/o (or root-squash) filesystem, and ignore the failure. Thanks for the suggestion, Laine. I suspect the dir they're using needs to be writeable, but I'll ask if it is feasible to use a read-only bind mount of the directory. thanks, -serge -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [RFC] security_dac: don't chown iso file
Quoting Serge E. Hallyn (serge.hal...@canonical.com): isos are read-only, so libvirt doesn't need to chown them. In one of our testing setups, libvirt uses mirrorred isos. Since libvirt chowns the files, (and especially does not chown them back) the mirror refuses to update the iso. This patch prevents libvirt from chowning files. Does this seem reasonable? Hi, any feedback on this? Does it seem ok? thanks, -serge Signed-off-by: Serge Hallyn serge.hal...@canonical.com --- src/security/security_dac.c |2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/src/security/security_dac.c b/src/security/security_dac.c index af02236..e7db324 100644 --- a/src/security/security_dac.c +++ b/src/security/security_dac.c @@ -555,6 +555,8 @@ virSecurityDACSetSecurityAllLabel(virSecurityManagerPtr mgr, /* XXX fixme - we need to recursively label the entire tree :-( */ if (vm-def-disks[i]-type == VIR_DOMAIN_DISK_TYPE_DIR) continue; + if (vm-def-disks[i]-device == VIR_DOMAIN_DISK_DEVICE_CDROM) + continue; if (virSecurityDACSetSecurityImageLabel(mgr, vm, vm-def-disks[i]) 0) -- 1.7.5.4 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
