Jaime Caamaño Ruiz <[email protected]> writes: >> Agree. I will try to address this issue. I think we can have a >> separate >> run time/log directory for OVN. ovn-controller needs to talk to the >> local ovsdb-server >> and br-int.mgmt and other related socket interfaces, so it needs >> access >> to >> the /var/run/openvswitch/ folder. I think we can solve this. > > I have a (yet to be submitted patch) on my side that changes OVN to run > as the same user as OVS. Thought it as less disruptive than also > changing the log directory.
That sounds interesting. > openvswitch-ipsec still logs as root though and I dont see a way around > that so it probably needs to log to a different directory. > > Jaime. > > -----Original Message----- > From: Numan Siddique <[email protected]> > To: Aaron Conole <[email protected]> > Cc: Jaime Caamaño Ruiz <[email protected]>, ovs-discuss <ovs-discuss@ope > nvswitch.org> > Subject: Re: [ovs-discuss] Handling conf.db ownership on OVS_USER_ID > changes > Date: Thu, 2 May 2019 19:20:28 +0530 > > > > > On Mon, Apr 29, 2019, 9:36 PM Aaron Conole <[email protected]> wrote: >> Jaime Caamaño Ruiz <[email protected]> writes: >> >> >> As a "security concern" you mean something among the lines where >> one >> >> of ovs-* processes running under openvswitch user would go ahead >> and >> >> create a file with its owner that later one of ovn processes would >> >> blindly reuse without checking that it actually belongs to >> root:root? >> > >> > One example is that the OVS user could create link as any OVN log >> file >> > to other file owned by root and then OVN would write to that file. >> >> There's a long-standing issue of OVN running as root. I don't see >> any >> reason it should. > > Agree. I will try to address this issue. I think we can have a separate > run time/log directory for OVN. ovn-controller needs to talk to the > local ovsdb-server > and br-int.mgmt and other related socket interfaces, so it needs access > to > the /var/run/openvswitch/ folder. I think we can solve this. > > Thanks > Numan > >> >> Can you give a more concrete example? I believe logrotate is >> running >> >> under root and should be able to rotate everything? >> > >> > The logrotate configuration for openvswitch logs has a 'su' >> directive >> > to run under the openvswitch user, precisely to prevent something >> > similar to the above. So it wont be able to rotate root owned logs >> in >> > the openvswitch directory. How it fails precisely depends on global >> > logrotate configuration. For example it will fail to create the new >> log >> > file after rotation if the 'create' directive is used. Or it may >> fail >> > to compress the rotated log file as it wont be able to read it. >> > >> > BR >> > Jaime >> > >> > -----Original Message----- >> > From: Ansis Atteka <[email protected]> >> > To: [email protected] >> > Cc: [email protected], Ben Pfaff <[email protected]> >> > Subject: Re: [ovs-discuss] Handling conf.db ownership on >> OVS_USER_ID >> > changes >> > Date: Wed, 24 Apr 2019 19:07:24 -0700 >> > >> > On Tue, 23 Apr 2019 at 09:30, Jaime Caamaño Ruiz <[email protected]> >> > wrote: >> >> >> >> Hello >> >> >> >> So the non root owned log directory (and run directory) is shared >> >> between non root OVS processes and root OVN processes. Doesn't >> this >> >> raise some security concerns? >> > >> > As a "security concern" you mean something among the lines where >> one >> > of ovs-* processes running under openvswitch user would go ahead >> and >> > create a file with its owner that later one of ovn processes would >> > blindly reuse without checking that it actually belongs to >> root:root? >> > >> > >> >> >> >> Also, since logrotate rotates the logs with the OVS user, it may >> fail >> >> to some extent to rotate the root owned OVN log files. >> Consequences >> >> vary but in it's current state some logging might be lost. This >> could >> >> be improved but I would guess that the approprioate thing to do is >> to >> >> etiher use a different log directory for OVN or make its processes >> >> run >> >> with the OVS user also. Has any of this been considered? >> > >> > Can you give a more concrete example? I believe logrotate is >> running >> > under root and should be able to rotate everything? >> > >> > >> >> >> >> BR >> >> Jaime. >> >> >> >> >> >> -----Original Message----- >> >> From: Jaime Caamaño Ruiz <[email protected]> >> >> Reply-to: [email protected] >> >> To: Ansis Atteka <[email protected]> >> >> Cc: [email protected], Ben Pfaff <[email protected]> >> >> Subject: Re: [ovs-discuss] Handling conf.db ownership on >> OVS_USER_ID >> >> changes >> >> Date: Wed, 17 Apr 2019 12:52:32 +0200 >> >> >> >> > You also need to chown /var/log/openvswitch.*.log files. >> >> >> >> OVS seems to be already handling this. I dont know the details but >> I >> >> guess that before dropping capabilities, OVS chowns these by >> itself. >> >> >> >> > However, >> >> > what about other daemons, like ovn? Do they share run time dir? >> >> > Haven't looked into this in a while and don't have a setup to >> check >> >> > myself. >> >> >> >> The permisions of the openvswitch run directory are already being >> >> handled by the service unit file. There is read access to files >> >> created >> >> there by OVS and AFAIK what it ultimately makes it a no problem >> for >> >> OVN >> >> is that it still runs as root with the provided unit files. If >> anyone >> >> changes this to a user different than the openvswitch user, then >> that >> >> is an already existing issue. Am I missing something here? >> >> >> >> Agree with you other considerations. >> >> >> >> BR >> >> Jaime. >> >> >> >> -----Original Message----- >> >> From: Ansis Atteka <[email protected]> >> >> To: [email protected] >> >> Cc: [email protected], Ben Pfaff <[email protected]> >> >> Subject: Re: [ovs-discuss] Handling conf.db ownership on >> OVS_USER_ID >> >> changes >> >> Date: Tue, 16 Apr 2019 18:21:48 -0700 >> >> >> >> On Tue, 16 Apr 2019 at 17:20, Jaime Caamaño Ruiz <[email protected] >> > >> >> wrote: >> >> > >> >> > My intention was doing it at systemd unit (prestart) for file >> >> > conf.db >> >> > (and .conf.db.~lock~ that stays around) only. >> >> >> >> You also need to chown /var/log/openvswitch.*.log files. >> >> > >> >> > I was not thinking on absolutely fool proof mechanism, among >> other >> >> > things because the admin might have customized the location for >> the >> >> > database. Also, updating and restarting the service are things >> that >> >> > would usually be monitored. So best effort. >> >> >> >> make sure that best effort solution informs admin in case of error >> so >> >> that he does not have to go file by file to find the offending >> one. >> >> >> >> > >> >> > At systemd unit prestart the service is stopped and OVS nor >> nobody >> >> > should really be messing with the database files owned by OVS. >> If >> >> > the >> >> > spec file is changing things back to root unappropriately then >> that >> >> > should be changed too. >> >> >> >> Yes. >> >> >> >> > >> >> > The runtime /run/openvswitch directory is also controlled by >> >> > systemd >> >> > and at least on my system is removed if the service is not >> active, >> >> > either by graceful or ungraceful exit. >> >> >> >> I somewhat agree with this, because back in those days we were >> using >> >> SystemV where the init.d managed lifecycle of run directory.. >> >> However, >> >> what about other daemons, like ovn? Do they share run time dir? >> >> Haven't looked into this in a while and don't have a setup to >> check >> >> myself. >> >> >> >> > >> >> > I guess we will need to look for specific issues. Any hint to >> find >> >> > that >> >> > patch? >> >> >> >> 1. test upgrade to your patched OVS and also from your patched OVS >> to >> >> another future version >> >> 2. if you change existing spec files that are shared with on >> Fedora >> >> or >> >> RHEL/CentOS make sure you don't break anything for them. >> >> 3. prefer consistency w.r.t. default behavior across deb and rpm >> >> packages (if you change user by default consider to do that for >> all >> >> platforms) >> >> 4. besides database you will also need to set right access bits to >> >> log >> >> files. On my Ubuntu it is "-rw-r----- 1 root adm " which means: >> >> 4.1. you have to chown it; OR >> >> 4.2. add openvswitch user to adm group and chmod that file >> >> 5. test logrotation. Maybe you can use a one forced logrotation >> >> invocation to change the ownrer. >> >> 6. check that other stuff like ovs-monitor-ipsec is not affected. >> It >> >> stil need to talk with StrongSwan or libreswan that best to my >> >> knowledge still runs as root. >> >> 7. if you use USER= then: >> >> 7.1. For Linux datapath make sure you retain CAP_NET_ADMIN Linux >> >> Capabilities >> >> 7.2. I don't know if there are special privileges you need to >> retain >> >> for DPDK. And in future possibly AF_XDP. >> >> 8. I haven't looked in a while but check if ovn (that has its own >> >> Systemd service file) shares run dir with OVS >> >> >> >> > >> >> > BR >> >> > Jaime. >> >> > >> >> > -----Original Message----- >> >> > From: Ansis Atteka <[email protected]> >> >> > To: [email protected] >> >> > Cc: [email protected], Ben Pfaff <[email protected]> >> >> > Subject: Re: [ovs-discuss] Handling conf.db ownership on >> >> > OVS_USER_ID >> >> > changes >> >> > Date: Tue, 16 Apr 2019 16:11:44 -0700 >> >> > >> >> > On Tue, 16 Apr 2019 at 15:36, Jaime Caamaño Ruiz <jcaamano@suse. >> de> >> >> > wrote: >> >> > > >> >> > > > On any given system, I would expect ovsdb-server to run as >> the >> >> > > > same >> >> > > > user >> >> > > > every time. Is there a reason to sometimes use a different >> >> > > > user? >> >> > > >> >> > > Well, changing from root which was the only supported option >> in >> >> > > the >> >> > > past and current default to a different user (like the >> suggested >> >> > > openvswitch), this one time, might be somewhat common. And the >> >> > > scenario >> >> > > that I am looking at is suporting a pianless upgrade through >> it. >> >> > >> >> > Actually debian packages still by default use "root" user. Not >> >> > "openvswitch". >> >> > >> >> > Long time ago there was an attempt to change the default user >> >> > across >> >> > all different flavor packages to openvswitch (you can lookup the >> >> > patch >> >> > on mailing list). However, as you noticed upgrades are tricky. >> >> > Hence >> >> > packages built from our debian/rules and >> rhel/openvswitch.spec.in >> >> > files still use "root" as default user. The packages built with >> >> > rhel/openvswitch-fedora.spec.in are an exception where the user >> >> > indeed >> >> > is "openvswitch". Unless you passed --without libcapng flag to >> >> > rpmbuild invocation. Then the user would still be "root". >> >> > >> >> > Here are the difficulties with automating the change of file >> >> > ownership: >> >> > 1. from which context to change ownership? As chown must be >> invoked >> >> > from something that runs under root then there is not much >> choice - >> >> > either package installation time (%post scriptlet) or daemon >> >> > startup >> >> > time (assuming you are not using Systemd's USER= feature in spec >> >> > file) >> >> > or something that admin explicitly has to invoke from bash as >> >> > "root". >> >> > 1.1. if it is package installation time then you can't update >> user >> >> > gracefully at daemon init time. It will be possible only at >> >> > installation time. >> >> > 1.2. if it is installation time then you can run into weird race >> >> > conditions where some code that was executed under root (as >> package >> >> > %post scriptlets) or previous instance of OVS that was still >> >> > running >> >> > as root could change ownership back to root for some files and >> >> > cause >> >> > unexpected "permission denied" issues (the patch I mentioned was >> >> > affected with these rare race conditions) >> >> > 2. for which files to change ownership? What happens if Unix >> domain >> >> > socket file remained on fileystem with "root" permissions when >> OVS >> >> > was >> >> > abruptly killed? What if someone else put a file under ovs >> >> > directories >> >> > with non-root user - should you blindly chown that too? What if >> >> > %post >> >> > scriptlet that runs under root non-atomically created a file and >> in >> >> > next line chown() it back - is there a window for race? Should >> you >> >> > follow directories/symlinks recursively? Changing user for >> conf.db >> >> > file is not enough... >> >> > >> >> > I am not saying it is impossible to change user gracefully on >> >> > upgrades. I am saying that code may have to be reorganized quite >> a >> >> > bit >> >> > to eliminate the issues I raised above. >> >> > >> >> > Alternatively, for Centos, RHEL and Fedora one can use SElinux >> to >> >> > confine processes and leave them running as root (instead of >> >> > running >> >> > them under limited privilege user). I believe on SUSE (and >> Debian) >> >> > once could use AppArmor to achieve the same results. At least >> for >> >> > SElinux it was a little bit easier to make upgrade seamless than >> >> > with >> >> > Linux user confinement approach. >> >> > >> >> > > >> >> > > So if that makes sense to you, I will go ahead with the patch. >> >> > > >> >> > > BR >> >> > > Jaime. >> >> > > >> >> > > -----Original Message----- >> >> > > From: Ben Pfaff <[email protected]> >> >> > > To: [email protected] >> >> > > Cc: [email protected] >> >> > > Subject: Re: [ovs-discuss] Handling conf.db ownership on >> >> > > OVS_USER_ID >> >> > > changes >> >> > > Date: Tue, 16 Apr 2019 15:25:24 -0700 >> >> > > >> >> > > On Tue, Apr 16, 2019 at 11:32:21PM +0200, Jaime Caamaño Ruiz >> >> > > wrote: >> >> > > > When sysconfig OVS_USER_ID is changed to a different user, >> it >> >> > > > requires >> >> > > > a manual ownership change of the OVS conf.db database if >> >> > > > existing >> >> > > > or >> >> > > > otherwise ovsdb-server will fail to (re)start. I was >> wondering >> >> > > > if >> >> > > > I >> >> > > > am >> >> > > > missing any particular reason why this is change of >> ownership >> >> > > > is >> >> > > > not >> >> > > > automatically being handled through the service unit file as >> it >> >> > > > is >> >> > > > being done with other items. >> >> > > >> >> > > On any given system, I would expect ovsdb-server to run as the >> >> > > same >> >> > > user >> >> > > every time. Is there a reason to sometimes use a different >> user? >> >> > > >> >> > > Or, perhaps you are saying that, just before invoking ovsdb- >> >> > > server, >> >> > > the >> >> > > service unit should chown (or whatever) the database file to >> the >> >> > > user >> >> > > that it is going to use to invoke ovsdb-server. That might be >> >> > > reasonable, but no one has thought to do it yet. Do you want >> to >> >> > > submit >> >> > > a patch? >> >> > > >> >> > > Thanks, >> >> > > >> >> > > Ben. >> >> > > >> >> > > _______________________________________________ >> >> > > discuss mailing list >> >> > > [email protected] >> >> > > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss >> >> > >> >> > >> >> >> >> >> > >> > >> > _______________________________________________ >> > discuss mailing list >> > [email protected] >> > https://mail.openvswitch.org/mailman/listinfo/ovs-discuss >> _______________________________________________ >> discuss mailing list >> [email protected] >> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss _______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
