[PATCH v2 0/3] Fix CIs skipping filesystem, EFI secure boot and EFI capsule tests
After my previous patch to fix filesystem tests [1] was merged, I noticed the GitLab CI was still skipping them and wanted to figure out why. In short: libguestfs tools (virt-make-fs, guestmount) fail because they need an installed kernel and the host /dev/fuse device, loop mounts need the host /dev/loop* devices, and mounting filesystems (loop and guestmount) fails because Docker containers need extra permissions to mount devices normally disabled for host security.
[1] https://patchwork.ozlabs.org/project/uboot/patch/20210520190947.21773-1-alpe...
Patch #1 is meant to install a kernel into the container image that libguestfs can use, but the image will need to be regenerated manually.
Patch #2 makes virt-make-fs work, which should make these EFI tests run again. But guestmount doesn't work with this much because it needs more permissions to actually mount a filesystem.
Patch #3 makes mounting filesystems and loop devices work, which should make the filesystem tests run again. This is separate from patch #2 because the parts using guestmount can theoretically be rewritten to use guestfish which would make the filesystem tests work without this patch, and giving mount permissions to the container processes seem to be insecure. So, this patch can be dropped if you think the impact isn't worth it.
Similar changes to patch #2, #3 should be applicable to the GitLab CI and probably necessary to get the same effect, but I don't think its configuration is accessible to me.
Changes in v2: - Always pass in /dev/fuse to Azure's docker run invocation. - Drop patch to install kernel in CI scripts
v1: https://patchwork.ozlabs.org/project/uboot/list/?series=247294
Alper Nebi Yasak (3): tools: docker: Install a readable kernel for libguestfs-tools Azure: Add fuse device for test.py tests Azure: Add loop devices and CAP_SYS_ADMIN for sandbox test.py tests
.azure-pipelines.yml | 17 ++++++++++++++++- tools/docker/Dockerfile | 4 ++++ 2 files changed, 20 insertions(+), 1 deletion(-)
The filesystem and EFI (capsule and secure boot) test setups try to use guestmount and virt-make-fs respectively to prepare disk images to run tests on. However, these libguestfs tools need a kernel image and fail with the following message (revealed in debug/trace mode) if it can't find one:
supermin: failed to find a suitable kernel (host_cpu=x86_64).
I looked for kernels in /boot and modules in /lib/modules.
If this is a Xen guest, and you only have Xen domU kernels installed, try installing a fullvirt kernel (only for supermin use, you shouldn't boot the Xen guest with it).
This failure then causes these tests to be skipped in CIs. Install a kernel package in the Docker containers so the CIs can run these tests with libguestfs tools again (assuming the container is run with necessary host devices and privileges). As this kernel would be only used for virtualization, we can use the kernel package specialized for that. On Ubuntu systems kernel images are not readable by non-root users, so explicitly add read permissions with chmod as well.
Signed-off-by: Alper Nebi Yasak alpernebiyasak@gmail.com Acked-by: Heinrich Schuchardt xypron.glpk@gmx.de ---
Changes in v2: - Add tag "Acked-by: Heinrich Schuchardt xypron.glpk@gmx.de"
tools/docker/Dockerfile | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile index d2f0074ee8a6..563b16639e54 100644 --- a/tools/docker/Dockerfile +++ b/tools/docker/Dockerfile @@ -71,6 +71,7 @@ RUN apt-get update && apt-get install -y \ libssl-dev \ libudev-dev \ libusb-1.0-0-dev \ + linux-image-kvm \ lzma-alone \ lzop \ mount \ @@ -99,6 +100,9 @@ RUN apt-get update && apt-get install -y \ zip \ && rm -rf /var/lib/apt/lists/*
+# Make kernels readable for libguestfs tools to work correctly +RUN chmod +r /boot/vmlinu* /lib/modules/*/vmlinu* || true + # Manually install libmpfr4 for the toolchains RUN wget http://mirrors.kernel.org/ubuntu/pool/main/m/mpfr4/libmpfr4_3.1.4-1_amd64.de... && dpkg -i libmpfr4_3.1.4-1_amd64.deb && rm libmpfr4_3.1.4-1_amd64.deb
On 6/13/21 4:07 PM, Alper Nebi Yasak wrote:
The filesystem and EFI (capsule and secure boot) test setups try to use guestmount and virt-make-fs respectively to prepare disk images to run tests on. However, these libguestfs tools need a kernel image and fail with the following message (revealed in debug/trace mode) if it can't find one:
supermin: failed to find a suitable kernel (host_cpu=x86_64). I looked for kernels in /boot and modules in /lib/modules. If this is a Xen guest, and you only have Xen domU kernels installed, try installing a fullvirt kernel (only for supermin use, you shouldn't boot the Xen guest with it).This failure then causes these tests to be skipped in CIs. Install a kernel package in the Docker containers so the CIs can run these tests with libguestfs tools again (assuming the container is run with necessary host devices and privileges). As this kernel would be only used for virtualization, we can use the kernel package specialized for that. On Ubuntu systems kernel images are not readable by non-root users, so explicitly add read permissions with chmod as well.
Signed-off-by: Alper Nebi Yasak alpernebiyasak@gmail.com Acked-by: Heinrich Schuchardt xypron.glpk@gmx.de
Changes in v2:
Add tag "Acked-by: Heinrich Schuchardt xypron.glpk@gmx.de"
tools/docker/Dockerfile | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile index d2f0074ee8a6..563b16639e54 100644 --- a/tools/docker/Dockerfile +++ b/tools/docker/Dockerfile @@ -71,6 +71,7 @@ RUN apt-get update && apt-get install -y \ libssl-dev \ libudev-dev \ libusb-1.0-0-dev \
- linux-image-kvm \ lzma-alone \ lzop \ mount \
@@ -99,6 +100,9 @@ RUN apt-get update && apt-get install -y \ zip \ && rm -rf /var/lib/apt/lists/*
+# Make kernels readable for libguestfs tools to work correctly +RUN chmod +r /boot/vmlinu* /lib/modules/*/vmlinu* || true
/lib/modules/4.15.0-1092-kvm# find . -name 'vm*' does not find any file.
We don't need '|| true' if you do not refer to non-existent files.
Best regards
Heinrich
- # Manually install libmpfr4 for the toolchains RUN wget http://mirrors.kernel.org/ubuntu/pool/main/m/mpfr4/libmpfr4_3.1.4-1_amd64.de... && dpkg -i libmpfr4_3.1.4-1_amd64.deb && rm libmpfr4_3.1.4-1_amd64.deb
On 14/06/2021 20:29, Heinrich Schuchardt wrote:
On 6/13/21 4:07 PM, Alper Nebi Yasak wrote:
supermin: failed to find a suitable kernel (host_cpu=x86_64). I looked for kernels in /boot and modules in /lib/modules.[...]
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile index d2f0074ee8a6..563b16639e54 100644 --- a/tools/docker/Dockerfile +++ b/tools/docker/Dockerfile @@ -71,6 +71,7 @@ RUN apt-get update && apt-get install -y \ libssl-dev \ libudev-dev \ libusb-1.0-0-dev \
- linux-image-kvm \ lzma-alone \ lzop \ mount \
@@ -99,6 +100,9 @@ RUN apt-get update && apt-get install -y \ zip \ && rm -rf /var/lib/apt/lists/*
+# Make kernels readable for libguestfs tools to work correctly +RUN chmod +r /boot/vmlinu* /lib/modules/*/vmlinu* || true
/lib/modules/4.15.0-1092-kvm# find . -name 'vm*' does not find any file.
We don't need '|| true' if you do not refer to non-existent files.
I included both dirs as libguestfs checks both of them. If that doesn't convince you, I can send a v3 with just `chmod +r /boot/vmlinu*`.
I actually misread the error message above as mentioning both dirs for kernel so I didn't explicitly write it in the commit message, but the source code [1] confirms that both are checked.
[1] https://github.com/libguestfs/supermin/blob/master/src/format_ext2_kernel.ml...
(sorry for the late reply)
On 6/21/21 8:12 PM, Alper Nebi Yasak wrote:
On 14/06/2021 20:29, Heinrich Schuchardt wrote:
On 6/13/21 4:07 PM, Alper Nebi Yasak wrote:
supermin: failed to find a suitable kernel (host_cpu=x86_64). I looked for kernels in /boot and modules in /lib/modules.[...]
diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile index d2f0074ee8a6..563b16639e54 100644 --- a/tools/docker/Dockerfile +++ b/tools/docker/Dockerfile @@ -71,6 +71,7 @@ RUN apt-get update && apt-get install -y \ libssl-dev \ libudev-dev \ libusb-1.0-0-dev \
- linux-image-kvm \ lzma-alone \ lzop \ mount \
@@ -99,6 +100,9 @@ RUN apt-get update && apt-get install -y \ zip \ && rm -rf /var/lib/apt/lists/*
+# Make kernels readable for libguestfs tools to work correctly +RUN chmod +r /boot/vmlinu* /lib/modules/*/vmlinu* || true
/lib/modules/4.15.0-1092-kvm# find . -name 'vm*' does not find any file.
We don't need '|| true' if you do not refer to non-existent files.
I included both dirs as libguestfs checks both of them. If that doesn't convince you, I can send a v3 with just `chmod +r /boot/vmlinu*`.
We are on Ubuntu. We only need to consider files that Ubuntu actually provides.
Best regards
Heinrich
I actually misread the error message above as mentioning both dirs for kernel so I didn't explicitly write it in the commit message, but the source code [1] confirms that both are checked.
[1] https://github.com/libguestfs/supermin/blob/master/src/format_ext2_kernel.ml...
(sorry for the late reply)
The EFI secure boot and capsule test setups need to prepare disk images for their tests using virt-make-fs, which requires access to the host fuse device. This is not exposed to the docker container by default and has to be added explicitly. Add it.
Signed-off-by: Alper Nebi Yasak alpernebiyasak@gmail.com ---
Changes in v2: - Always pass in /dev/fuse to Azure's docker run invocation.
.azure-pipelines.yml | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/.azure-pipelines.yml b/.azure-pipelines.yml index 35ab7f30b276..976868dd2eb7 100644 --- a/.azure-pipelines.yml +++ b/.azure-pipelines.yml @@ -318,7 +318,8 @@ jobs: # as sandbox testing need create files like spi flash images, etc. # (TODO: clean up this in the future) chmod 777 . - docker run -v $PWD:$(work_dir) $(ci_runner_image) /bin/bash $(work_dir)/test.sh + # Some tests using libguestfs-tools need the fuse device to run + docker run --device /dev/fuse:/dev/fuse -v $PWD:$(work_dir) $(ci_runner_image) /bin/bash $(work_dir)/test.sh
- job: build_the_world displayName: 'Build the World'
The filesystem test setup needs to prepare disk images for its tests, with either guestmount or loop mounts. The former requires access to the host fuse device (added in a previous patch), the latter requires access to host loop devices. Both mounts also need additional privileges since docker's default configuration prevents the containers from mounting filesystems (for host security).
Add any available loop devices to the container and try to add as few privileges as possible to run these tests, which narrow down to adding SYS_ADMIN capability and disabling apparmor confinement. However, this much still seems to be insecure enough to let malicious container processes escape as root on the host system [1].
[1] https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escap...
Since the mentioned tests are marked to run only on the sandbox board, add these additional devices and privileges only when testing with that.
An alternative to using mounts is modifying the filesystem tests to use virt-make-fs (like some EFI tests do), but it fails to generate a partitionless FAT filesystem image on Debian systems. Other more feasible alternatives are using guestfish or directly using libguestfs Python bindings to create and populate the images, but switching the test setups to these is nontrivial and is left as future work.
Signed-off-by: Alper Nebi Yasak alpernebiyasak@gmail.com ---
Changes in v2: - Always pass in /dev/fuse to Azure's docker run invocation. - Remove "and some EFI tests" from comment (no longer applies to that block of code).
.azure-pipelines.yml | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/.azure-pipelines.yml b/.azure-pipelines.yml index 976868dd2eb7..e36a27c97d56 100644 --- a/.azure-pipelines.yml +++ b/.azure-pipelines.yml @@ -318,8 +318,22 @@ jobs: # as sandbox testing need create files like spi flash images, etc. # (TODO: clean up this in the future) chmod 777 . + # Filesystem tests need extra docker args to run + set -- + if [[ "${TEST_PY_BD}" == "sandbox" ]]; then + # mount -o loop needs the loop devices + if modprobe loop; then + for d in $(find /dev -maxdepth 1 -name 'loop*'); do + set -- "$@" --device $d:$d + done + fi + # Needed for mount syscall (for guestmount as well) + set -- "$@" --cap-add SYS_ADMIN + # Default apparmor profile denies mounts + set -- "$@" --security-opt apparmor=unconfined + fi # Some tests using libguestfs-tools need the fuse device to run - docker run --device /dev/fuse:/dev/fuse -v $PWD:$(work_dir) $(ci_runner_image) /bin/bash $(work_dir)/test.sh + docker run "$@" --device /dev/fuse:/dev/fuse -v $PWD:$(work_dir) $(ci_runner_image) /bin/bash $(work_dir)/test.sh
- job: build_the_world displayName: 'Build the World'
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Heinrich Schuchardt