[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
Next I was trying the same LXD setup that failed before on a different host (to check if it would be reproducible). Current LXD setup (Failing): - LXD is at 4.10 (most recent on latest/stable channel) - Kernel 5.4.0-60 Current Bare-Metal setup (working) - Kernel 5.10.6-051006 New LXD try #0 - LXD on other system (Failing) - same system that has the working bare metal - Same setup as the other LXD based tests - Kernel 5.10.6-051006 => Same issue, the access is blocked even if I add the paths as local override New LXD try #1 - older hirsute kernel (failing) - Same setup as the other tests with LXD - Kernel 5.8.0-36 New BareMetal #1 - older hirsute kernel (working): - Kernel 5.8.0-36 New LXD try #2 - Focal kernel (failing) - Same setup as the other tests with LXD - Kernel 5.4.0-54 New BareMetal #2 - Focal kernel (working): - Kernel 5.4.0-54 New LXD try #3 - recheck on 5.10 (failing) - Same setup as the other tests with LXD - Kernel 5.10.6-051006 New LXD try #4 - recheck on 5.8 (failing now) - Same setup as the other tests with LXD - Kernel 5.8.0-36 New LXD try #5 - Other 5.10 this time from H-proposed (TBD) - Same setup as the other tests with LXD - The former 5.10 I tried was a mainline build (https://kernel.ubuntu.com/~kernel-ppa/mainline/) - Kernel 5.10.6-051006 So there is no new kernel that makes it work. And the problem should be reproducible in many places. I'll add the steps to drive KVM in a container to the description to ease repro ** Summary changed: - qemu can't access files that are added as rules on hot-add + qemu can't access files - even with manual overrides (only an issue in Containers) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apparmor in Ubuntu. https://bugs.launchpad.net/bugs/1912214 Title: qemu can't access files - even with manual overrides (only an issue in Containers) Status in apparmor package in Ubuntu: New Bug description: Hi, to be clear I consider it quite likely that the error is on my side, but I'd appreciate guidance how to continue resolve. I have rubber ducked my setup with a coworker and talked to jjohansen if the profile would contain an obvious fault (it did not). So hereby I'm filing a bug hoping to get some help on this case. ## 1. What happened I was trying to add a feature to libvirt to support chained qcow files. That means instead of adding just one path libvirt has to process the chain of backing files and add all of those. That works already on guest start, but not on hot-add of devices. But while I see my code appending the rules I'd expect and issuing the apparmor_parser calls I'd expect it still fails. I'd love to get the profile at runtime to ensure things really are loaded as expected. But as discussed on IRC that won't work. So I tested and simplified and wonder for the test below why things fail. ## 2. how to reproduce I was debugging various cases (see below updates) and found that just one combination fails (also see comment #5). I'm rather sure now that libvirt adds the path correctly, but even adding the denied path that is needed to the local overrides does not help. Use a Hirsute Container and enable this PPA: https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/4393 # First get a KVM capable container (the issue only triggers in containers) $ lxc profile create kvm $ cat > kvm_profile.yaml << EOF config: boot.autostart: "true" linux.kernel_modules: openvswitch,nbd,ip_tables,ip6_tables,kvm security.nesting: "true" security.privileged: "true" description: "" devices: eth0: mtu: "9000" name: eth0 nictype: bridged parent: lxdbr0 type: nic kvm: path: /dev/kvm type: unix-char mem: path: /dev/mem type: unix-char tun: path: /dev/net/tun type: unix-char name: kvm EOF $ lxc profile edit kvm < kvm_profile.yaml $ lxc launch ubuntu-daily:h h-libvirt-new --profile default --profile kvm All following steps are in the container $ sudo add-apt-repository ppa:ci-train-ppa-service/4393 $ apt update $ apt upgrade -y $ apt install uvtool-libvirt Then - to underline that the rules should be ok - also add it manually as local override (therefore we don't need to theorize or check if the rule was indeed added by libvirt - but since it works on bare metal we know it was added). # Allow the access that libvirt does not yet allow $ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' > /etc/apparmor.d/local/abstractions/libvirt-qemu $ echo '"/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk,' >> /etc/apparmor.d/local/abstractions/libvirt-qemu # Check the profile can be loaded and contains these $ apparmor_parser -r /etc/apparmor.d/libvirt/libvirt-85410987-d91b-487a-8f2c-911f0136c877 $ apparmor_parser -p
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
FYI:
here the open that is denied from strace
6408 0.000148 openat(AT_FDCWD,
"/var/lib/libvirt/images/testdisk-snap-base.qcow2", O_RDONLY|O_CLOEXEC) = -1
EACCES (Permission denied) <0.40>
^^ nothing special in there.
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to apparmor in Ubuntu.
https://bugs.launchpad.net/bugs/1912214
Title:
qemu can't access files that are added as rules on hot-add
Status in apparmor package in Ubuntu:
New
Bug description:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
## 2. how to reproduce
I was debugging various cases (see below updates) and found that just one
combination fails (also see comment #5)
I'm rather sure now that libvirt adds the path correctly, but even
adding the denied path that is needed to the local overrides does not
help.
Use a Hirsute Container and enable this PPA:
https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/4393
Then - to underline that the rule should be ok also add it manually as local
override.
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
$ echo '"/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk,' >>
/etc/apparmor.d/local/abstractions/libvirt-qem
# Check the profile can be loaded and contains these
$ apparmor_parser -r
/etc/apparmor.d/libvirt/libvirt-85410987-d91b-487a-8f2c-911f0136c877
$ apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-85410987-d91b-487a-8f2c-911f0136c877 | grep snap
"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
"/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk,
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
cat > hot-add-test.xml << EOF
EOF
# prep a guest to attach the disk to
uvt-simplestreams-libvirt --verbose sync --source
http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal
uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal
arch=amd64 label=daily
We have checked the "effective" profile that is loaded. JJohanssen didn't see
an obvious flaw in it. But for reference here:
root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
https://paste.ubuntu.com/p/yxdmMT6638/
# attach the disk
virsh attach-device f-test2 hot-add-test.xml
Libvirt (as usual) now adds rules for the image file.
With the new code from the PPA it does so twice - once for the snapshot and
once the base file.
But in any case we allow that access through our override.
You can see that on a little gimmick, since the flattened profile always has
those rules - and when libvirt is adding them we will sometimes now see
info="same as current profile, skipping".
If the local override isn't in place that does not show up.
So the rules libvirt adds are identical to what we have put into the local
override and that should allow the access.
But we get:
[699826.573035] audit: type=1400 audit(1611044559.393:2047):
apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-
new2_" profile="libvirt-85410987-d91b-487a-
8f2c-911f0136c877" name="/var/lib/libvirt/images/testdisk-snap-
base.qcow2" pid=111701 comm="qemu-system-x86" requested_mask="r"
denied_mask="r" fsuid=64055 ouid=64055
## 3. tracking apparmor_parser
I was using (for debug) a wrapper for apparmro_parser but all really
looks as expected
$ cat /usr/sbin/apparmor_parser.wrap
#!/bin/bash
echo "ARGS $@" | /usr/bin/systemd-cat
echo "Content of ${2}:" | /usr/bin/systemd-cat
/usr/bin/ls -laF "${2}" | /usr/bin/systemd-cat
/usr/bin/cat "${2}" | /usr/bin/systemd-cat
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
** Description changed: Hi, to be clear I consider it quite likely that the error is on my side, but I'd appreciate guidance how to continue resolve. I have rubber ducked my setup with a coworker and talked to jjohansen if the profile would contain an obvious fault (it did not). So hereby I'm filing a bug hoping to get some help on this case. ## 1. What happened I was trying to add a feature to libvirt to support chained qcow files. That means instead of adding just one path libvirt has to process the chain of backing files and add all of those. That works already on guest start, but not on hot-add of devices. But while I see my code appending the rules I'd expect and issuing the apparmor_parser calls I'd expect it still fails. I'd love to get the profile at runtime to ensure things really are loaded as expected. But as discussed on IRC that won't work. So I tested and simplified and wonder for the test below why things fail. ## 2. how to reproduce - I was taking my new code out of the equation - and to do so I was adding - the path that is needed to the local overrides. But it still is blocked. - So - right now - I'm assuming that my code worked in adding the lines, - but the access is still blocked. Therefore let us try to fix this one - first and only then I can debug into what might be failing on the new - code. + I was debugging various cases (see below updates) and found that just one + combination fails (also see comment #5) + I'm rather sure now that libvirt adds the path correctly, but even + adding the denied path that is needed to the local overrides does not + help. + + Use a Hirsute Container and enable this PPA: + https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/4393 + + Then - to underline that the rule should be ok also add it manually as local override. # Allow the access that libvirt does not yet allow $ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' > /etc/apparmor.d/local/abstractions/libvirt-qemu + $ echo '"/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk,' >> /etc/apparmor.d/local/abstractions/libvirt-qem + + # Check the profile can be loaded and contains these + $ apparmor_parser -r /etc/apparmor.d/libvirt/libvirt-85410987-d91b-487a-8f2c-911f0136c877 + $ apparmor_parser -p /etc/apparmor.d/libvirt/libvirt-85410987-d91b-487a-8f2c-911f0136c877 | grep snap + "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk, + "/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk, + # prep the disk chain to be hot-added qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2 /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2 cat > hot-add-test.xml << EOF EOF - # prep a guest to attach to + # prep a guest to attach the disk to uvt-simplestreams-libvirt --verbose sync --source http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal arch=amd64 label=daily We have checked the "effective" profile that is loaded. JJohanssen didn't see an obvious flaw in it. But for reference here: root@h-libvirt-orig:~# apparmor_parser -p /etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 | pastebinit https://paste.ubuntu.com/p/yxdmMT6638/ # attach the disk virsh attach-device f-test2 hot-add-test.xml - Libvirt/Qemu works as usual - except (known and expected) does not add a rule for "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2". But for that we have added out local override. - Yet it is denied access. + Libvirt (as usual) now adds rules for the image file. + With the new code from the PPA it does so twice - once for the snapshot and once the base file. + But in any case we allow that access through our override. + You can see that on a little gimmick, since the flattened profile always has those rules - and when libvirt is adding them we will sometimes now see info="same as current profile, skipping". + If the local override isn't in place that does not show up. + So the rules libvirt adds are identical to what we have put into the local override and that should allow the access. - apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new_ - " profile="libvirt-a2caaf89-0682-464d-92ba- - 5295cb5f5128" name="/var/lib/libvirt/images/testdisk-snap- - snapshot.qcow2" pid=2889044 comm="qemu-system-x86" requested_mask="r" - denied_mask="r" fsuid=64055 ouid=64055 + But we get: - ## 3. The rule is generally working + [699826.573035] audit: type=1400 audit(1611044559.393:2047): + apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new2_ + " profile="libvirt-85410987-d91b-487a-8f2c- + 911f0136c877"
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
I have the following alternations on the test now:
A1) on bare metal hirsute
A2) on LXD Hisute (on Focal Host)
B1) attach a single disk
B2) attach a disk with backing chain (profile is appended and reload twice)
C1) old libvirt code (can only do one disk)
C2) new libvirt code (iterates backing chain)
D1) do the same actions manually in qemu-monitor+apparmor tools
D2) run test through libvirt
Only A2+B2+C2+D2 is failing.
The rest I could clear by re-setting test environments to be sure old
traces/experiments are gone. I'll update the description.
P.S. I can stop libvirt with qemu at any point e.g. after adding one or both
rules to the guest and before qemu is told to access the files. The profile on
disk looks right and AFAICS it is loaded as that - yet the access from qemu is
denied then.
TL;DR: Still an odd fail, only in container environment and unclear why/what
happens.
Please guide me what you'd need next to get this any further.
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to apparmor in Ubuntu.
https://bugs.launchpad.net/bugs/1912214
Title:
qemu can't access files that are added as rules on hot-add
Status in apparmor package in Ubuntu:
New
Bug description:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
## 2. how to reproduce
I was taking my new code out of the equation - and to do so I was
adding the path that is needed to the local overrides. But it still is
blocked. So - right now - I'm assuming that my code worked in adding
the lines, but the access is still blocked. Therefore let us try to
fix this one first and only then I can debug into what might be
failing on the new code.
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
cat > hot-add-test.xml << EOF
EOF
# prep a guest to attach to
uvt-simplestreams-libvirt --verbose sync --source
http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal
uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal
arch=amd64 label=daily
We have checked the "effective" profile that is loaded. JJohanssen didn't see
an obvious flaw in it. But for reference here:
root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
https://paste.ubuntu.com/p/yxdmMT6638/
# attach the disk
virsh attach-device f-test2 hot-add-test.xml
Libvirt/Qemu works as usual - except (known and expected) does not add a rule
for "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2". But for that we
have added out local override.
Yet it is denied access.
apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new_
" profile="libvirt-a2caaf89-0682-464d-92ba-
5295cb5f5128" name="/var/lib/libvirt/images/testdisk-snap-
snapshot.qcow2" pid=2889044 comm="qemu-system-x86" requested_mask="r"
denied_mask="r" fsuid=64055 ouid=64055
## 3. The rule is generally working
To be clear, on the same system if I just open up a new profile and allow
this path to be accessed it works fine. See the working example below.
It must be somewhat that is tied to the way KVM guests get their profile
updates/assigned.
root@h-libvirt-orig:~# cat /etc/apparmor.d/test
#include
profile test flags=(attach_disconnected) {
#include
"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
"/usr/bin/md5sum" rmix,
}
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
[6939]
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
New test eliminating libvirt from the equation:
# Create one backing chain and one normal image
$ qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-nosnap.qcow2 100M
$ qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
$ qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
# Use a profile similar to those created by libvirt - our guest doesn't do
much, so he doesn't need much
$ cat > /etc/apparmor.d/qemu-testprofile << EOF
# Test profile for bug LP: #1912214
#include
profile qemu-testprofile flags=(attach_disconnected) {
#include
#include
}
EOF
$ touch /etc/apparmor.d/local/extrarules
$ apparmor_parser -r /etc/apparmor.d/qemu-testprofile
# Start qemu into the monitor under control of an apparmor profile
$ aa-exec -p qemu-testprofile -- qemu-system-x86_64 -serial none -monitor stdio
-m 64 -display none
# Attach and detach the disk
(qemu) drive_add 0
if=none,file=/var/lib/libvirt/images/testdisk-nosnap.qcow2,format=qcow2,id=disk1
# This can be detached (e.g. to iterate the test) via
(qemu) drive_del disk1
As-is this fails (expected) since it gets the access to the file blocked:
[58147.954482] audit: type=1400 audit(1611040852.319:86): apparmor="DENIED"
operation="open" profile="qemu-testprofile"
name="/var/lib/libvirt/images/testdisk-nosnap.qcow2" pid=23222
comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Now we can "manually play to be libvirt" and append the rule and reload the
profile.
In another console we can do:
$ echo '"/var/lib/libvirt/images/testdisk-nosnap.qcow2" rwk,' >
/etc/apparmor.d/local/extrarules
$ apparmor_parser -r /etc/apparmor.d/qemu-testprofile
Once that is done the `drive_add` command above will work.
Now if we allow the snapshot file but not the base image in apparmor.
And then attach the snapshot, we expect qemu to parse the snapshot, identify
the backing file and fail to access that.
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/extrarules
$ apparmor_parser -r /etc/apparmor.d/qemu-testprofile
(qemu) drive_add 0
if=none,file=/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2,format=qcow2,id=disk1
Could not open backing file: Could not open
'/var/lib/libvirt/images/testdisk-snap-base.qcow2': Permission denied
[58777.551226] audit: type=1400 audit(1611041481.906:96): apparmor="DENIED"
operation="open" profile="qemu-testprofile"
name="/var/lib/libvirt/images/testdisk-snap-base.qcow2" pid=23222
comm="qemu-system-x86" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Perfect - still as expected.
Now if we add both rules we expect this to work.
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/extrarules
$ echo '"/var/lib/libvirt/images/testdisk-snap-base.qcow2" rwk,' >>
/etc/apparmor.d/local/extrarules
$ apparmor_parser -r /etc/apparmor.d/qemu-testprofile
(qemu) drive_add 0
if=none,file=/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2,format=qcow2,id=disk1
And indeed it does work fine.
This also works fine in the containers ... good, but no help for debugging this.
** Description changed:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
## 2. how to reproduce
I was taking my new code out of the equation - and to do so I was adding
the path that is needed to the local overrides. But it still is blocked.
So - right now - I'm assuming that my code worked in adding the lines,
but the access is still blocked. Therefore let us try to fix this one
first and only then I can debug into what might be failing on the new
code.
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
Also my new code that I was trying to finish for submission works on
bare metal ... ? /me is puzzled
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to apparmor in Ubuntu.
https://bugs.launchpad.net/bugs/1912214
Title:
qemu can't access files that are added as rules on hot-add
Status in apparmor package in Ubuntu:
New
Bug description:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
## 2. how to reproduce
I was taking my new code out of the equation - and to do so I was
adding the path that is needed to the local overrides. But it still is
blocked. So - right now - I'm assuming that my code worked in adding
the lines, but the access is still blocked. Therefore let us try to
fix this one first and only then I can debug into what might be
failing on the new code.
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
cat > hot-add-test.xml << EOF
EOF
# prep a guest to attach to
uvt-simplestreams-libvirt --verbose sync --source
http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal
uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal
arch=amd64 label=daily
We have checked the "effective" profile that is loaded. JJohanssen didn't see
an obvious flaw in it. But for reference here:
root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
https://paste.ubuntu.com/p/yxdmMT6638/
# attach the disk
virsh attach-device f-test2 hot-add-test.xml
Libvirt/Qemu works as usual - except (known and expected) does not add a rule
for "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2". But for that we
have added out local override.
Yet it is denied access.
apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new_
" profile="libvirt-a2caaf89-0682-464d-92ba-
5295cb5f5128" name="/var/lib/libvirt/images/testdisk-snap-
snapshot.qcow2" pid=2889044 comm="qemu-system-x86" requested_mask="r"
denied_mask="r" fsuid=64055 ouid=64055
## 3. The rule is generally working
To be clear, on the same system if I just open up a new profile and allow
this path to be accessed it works fine. See the working example below.
It must be somewhat that is tied to the way KVM guests get their profile
updates/assigned.
root@h-libvirt-orig:~# cat /etc/apparmor.d/test
#include
profile test flags=(attach_disconnected) {
#include
"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
"/usr/bin/md5sum" rmix,
}
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
[6939] aa_change_onexec("test")
[6939] exec md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
0f7fc62d270b69ee1b51453fa614d3e4
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
[6944] aa_change_onexec("test")
[6944] exec md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
md5sum: /var/lib/libvirt/images/testdisk-snap-base.qcow2: Permission denied
## 4. tracking apparmor_parser
I was using (for debug) a wrapper for apparmro_parser but all really
looks as expected
$ cat /usr/sbin/apparmor_parser.wrap
#!/bin/bash
echo "ARGS $@" | /usr/bin/systemd-cat
echo "Content of ${2}:" | /usr/bin/systemd-cat
/usr/bin/ls -laF "${2}" | /usr/bin/systemd-cat
/usr/bin/cat "${2}" | /usr/bin/systemd-cat
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
On bare metal this (the simplified case that I described above with the rule in
the local include file) seems to work just fine.
I'll later (sorry sprint week) or tomorrow - re-setup the very same on a
container again.
** Description changed:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
-
## 2. how to reproduce
I was taking my new code out of the equation - and to do so I was adding
the path that is needed to the local overrides. But it still is blocked.
So - right now - I'm assuming that my code worked in adding the lines,
but the access is still blocked. Therefore let us try to fix this one
first and only then I can debug into what might be failing on the new
code.
-
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
cat > hot-add-test.xml << EOF
-
-
-
-
-
-
-
-
+
+
+
+
+
+
+
+
EOF
# prep a guest to attach to
uvt-simplestreams-libvirt --verbose sync --source
http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal
uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal
arch=amd64 label=daily
We have checked the "effective" profile that is loaded. JJohanssen didn't see
an obvious flaw in it. But for reference here:
- root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
+ root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
https://paste.ubuntu.com/p/yxdmMT6638/
# attach the disk
- virsh attach-device f-test2 hot-add-test.xm
-
+ virsh attach-device f-test2 hot-add-test.xml
Libvirt/Qemu works as usual - except (known and expected) does not add a rule
for "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2". But for that we
have added out local override.
Yet it is denied access.
apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new_
" profile="libvirt-a2caaf89-0682-464d-92ba-
5295cb5f5128" name="/var/lib/libvirt/images/testdisk-snap-
snapshot.qcow2" pid=2889044 comm="qemu-system-x86" requested_mask="r"
denied_mask="r" fsuid=64055 ouid=64055
-
## 3. The rule is generally working
To be clear, on the same system if I just open up a new profile and allow
this path to be accessed it works fine. See the working example below.
It must be somewhat that is tied to the way KVM guests get their profile
updates/assigned.
-
root@h-libvirt-orig:~# cat /etc/apparmor.d/test
#include
profile test flags=(attach_disconnected) {
- #include
+ #include
- "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
- "/usr/bin/md5sum" rmix,
+ "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
+ "/usr/bin/md5sum" rmix,
}
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
[6939] aa_change_onexec("test")
[6939] exec md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
0f7fc62d270b69ee1b51453fa614d3e4
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
- root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
+ root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
[6944] aa_change_onexec("test")
[6944] exec md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
md5sum:
[Touch-packages] [Bug 1912214] Re: qemu can't access files that are added as rules on hot-add
Note/TODO (to myself): I have run and failed with that in containers,
try it on bare metal if it is any different.
--
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to apparmor in Ubuntu.
https://bugs.launchpad.net/bugs/1912214
Title:
qemu can't access files that are added as rules on hot-add
Status in apparmor package in Ubuntu:
New
Bug description:
Hi,
to be clear I consider it quite likely that the error is on my side, but I'd
appreciate guidance how to continue resolve. I have rubber ducked my setup with
a coworker and talked to jjohansen if the profile would contain an obvious
fault (it did not).
So hereby I'm filing a bug hoping to get some help on this case.
## 1. What happened
I was trying to add a feature to libvirt to support chained qcow files.
That means instead of adding just one path libvirt has to process the chain
of backing files and add all of those. That works already on guest start, but
not on hot-add of devices.
But while I see my code appending the rules I'd expect and issuing the
apparmor_parser calls I'd expect it still fails.
I'd love to get the profile at runtime to ensure things really are loaded as
expected.
But as discussed on IRC that won't work. So I tested and simplified and
wonder for the test below why things fail.
## 2. how to reproduce
I was taking my new code out of the equation - and to do so I was
adding the path that is needed to the local overrides. But it still is
blocked. So - right now - I'm assuming that my code worked in adding
the lines, but the access is still blocked. Therefore let us try to
fix this one first and only then I can debug into what might be
failing on the new code.
# Allow the access that libvirt does not yet allow
$ echo '"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,' >
/etc/apparmor.d/local/abstractions/libvirt-qemu
# prep the disk chain to be hot-added
qemu-img create -f qcow2 /var/lib/libvirt/images/testdisk-snap-base.qcow2 100M
qemu-img create -f qcow2 -b /var/lib/libvirt/images/testdisk-snap-base.qcow2
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
cat > hot-add-test.xml << EOF
EOF
# prep a guest to attach to
uvt-simplestreams-libvirt --verbose sync --source
http://cloud-images.ubuntu.com/daily arch=amd64 label=daily release=focal
uvt-kvm create --host-passthrough --password=ubuntu f-test2 release=focal
arch=amd64 label=daily
We have checked the "effective" profile that is loaded. JJohanssen didn't see
an obvious flaw in it. But for reference here:
root@h-libvirt-orig:~# apparmor_parser -p
/etc/apparmor.d/libvirt/libvirt-e033b910-be06-4975-826f-b6fba368d928 |
pastebinit
https://paste.ubuntu.com/p/yxdmMT6638/
# attach the disk
virsh attach-device f-test2 hot-add-test.xm
Libvirt/Qemu works as usual - except (known and expected) does not add a rule
for "/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2". But for that we
have added out local override.
Yet it is denied access.
apparmor="DENIED" operation="open" namespace="root//lxd-h-libvirt-new_
" profile="libvirt-a2caaf89-0682-464d-92ba-
5295cb5f5128" name="/var/lib/libvirt/images/testdisk-snap-
snapshot.qcow2" pid=2889044 comm="qemu-system-x86" requested_mask="r"
denied_mask="r" fsuid=64055 ouid=64055
## 3. The rule is generally working
To be clear, on the same system if I just open up a new profile and allow
this path to be accessed it works fine. See the working example below.
It must be somewhat that is tied to the way KVM guests get their profile
updates/assigned.
root@h-libvirt-orig:~# cat /etc/apparmor.d/test
#include
profile test flags=(attach_disconnected) {
#include
"/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2" rwk,
"/usr/bin/md5sum" rmix,
}
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
[6939] aa_change_onexec("test")
[6939] exec md5sum /var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
0f7fc62d270b69ee1b51453fa614d3e4
/var/lib/libvirt/images/testdisk-snap-snapshot.qcow2
root@h-libvirt-orig:~# apparmor_parser -r /etc/apparmor.d/test; aa-exec -v -p
test -- md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
[6944] aa_change_onexec("test")
[6944] exec md5sum /var/lib/libvirt/images/testdisk-snap-base.qcow2
md5sum: /var/lib/libvirt/images/testdisk-snap-base.qcow2: Permission denied
## 4. tracking apparmor_parser
I was using (for debug) a wrapper for apparmro_parser but all really
looks as expected
$ cat /usr/sbin/apparmor_parser.wrap
#!/bin/bash
echo "ARGS $@" | /usr/bin/systemd-cat
echo "Content of ${2}:" | /usr/bin/systemd-cat
/usr/bin/ls -laF "${2}" | /usr/bin/systemd-cat
/usr/bin/cat
