Gracefully handle xattr not supported

[orlandohohmeier]

Description

I'm running buildah bud in a docker container on macOS and the COPY command fails as the llistxattr operation isn't supported.

Steps to reproduce the issue:

1. Build the stabe buildah image
2. Run and bind-mount a volume with files to COPY into a container images docker run -it --tty --rm --device /dev/fuse -v $(pwd):/workspace --security-opt seccomp=unconfined \ --security-opt apparmor=unconfined 5c55a682c0b4
3. Execbuildah bud /workspace

Test Dockerfile in /workspace plus random files with and without extended attributes on the host system.

FROM scratch
COPY . .

N.B. Commands such as touch ./test; setfattr -n user.hello -v world ./test fail as well as extended attributed are indeed not supported even when bind-mounting on macOS. Related: https://github.com/moby/moby/issues/1070

Describe the results you received:

Buildah

STEP 1: FROM scratch
STEP 2: COPY . .
error building at STEP "COPY . .": error adding sources [/workspace/test]: error reading "/workspace/test": error during bulk transfer for copier.request{Request:"GET", Root:"/", preservedRoot:"/workspace/test", rootPrefix:"/workspace/test", Directory:"/", preservedDirectory:"/workspace/test", Globs:[]string{"/"}, preservedGlobs:[]string{"/workspace/test"}, StatOptions:copier.StatOptions{CheckForArchives:false, Excludes:[]string(nil)}, GetOptions:copier.GetOptions{UIDMap:[]idtools.IDMap(nil), GIDMap:[]idtools.IDMap(nil), Excludes:[]string{""}, ExpandArchives:false, StripSetuidBit:true, StripSetgidBit:true, StripStickyBit:false, StripXattrs:false, KeepDirectoryNames:false}, PutOptions:copier.PutOptions{UIDMap:[]idtools.IDMap(nil), GIDMap:[]idtools.IDMap(nil), ChownDirs:(*idtools.IDPair)(nil), ChmodDirs:(*os.FileMode)(nil), ChownFiles:(*idtools.IDPair)(nil), ChmodFiles:(*os.FileMode)(nil), StripXattrs:false, IgnoreXattrErrors:false}, MkdirOptions:copier.MkdirOptions{UIDMap:[]idtools.IDMap(nil), GIDMap:[]idtools.IDMap(nil), ChownNew:(*idtools.IDPair)(nil), ChmodNew:(*os.FileMode)(nil)}}: copier: get: "/"("/"): error getting extended attributes for "/Dockerfile": error listing extended attributes of "/Dockerfile": operation not supported
ERRO exit status 125   

Strace ... llistxattr resumed>0xc000482000, 65536) = -1 EOPNOTSUPP (Operation not supported)

Describe the results you expected:

I'd love for buildha to skip extened attributes (and just warn) if they're not supported by the underlying filesystem or the possibility to adjust the Copier GET StripXattrs option from the CLI.

Output of rpm -q buildah or apt list buildah:

buildah-1.16.2-1.fc33.x86_64

Output of buildah version:

Version:         1.16.2
Go Version:      go1.15
Image Spec:      1.0.1-dev
Runtime Spec:    1.0.2-dev
CNI Spec:        0.4.0
libcni Version:  
image Version:   5.5.2
Git Commit:      
Built:           Thu Jan  1 00:00:00 1970
OS/Arch:         linux/amd64

Output of podman version if reporting a podman build issue:

(paste your output here)

*Output of `cat /etc/release`:**

Fedora release 33 (Thirty Three)
NAME=Fedora
VERSION="33 (Container Image)"
ID=fedora
VERSION_ID=33
VERSION_CODENAME=""
PLATFORM_ID="platform:f33"
PRETTY_NAME="Fedora 33 (Container Image)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:33"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f33/system-administrators-guide/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=33
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=33
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Container Image"
VARIANT_ID=container
Fedora release 33 (Thirty Three)
Fedora release 33 (Thirty Three)

Output of uname -a:

Linux 3a6643d58591 5.4.39-linuxkit #1 SMP Fri May 8 23:03:06 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf:

# This file is is the configuration file for all tools
# that use the containers/storage library.
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver
driver = "overlay"

# Temporary storage location
runroot = "/var/run/containers/storage"

# Primary Read/Write location of container storage
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
"/var/lib/shared",
]

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partitioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = "false"

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev,fsync=0"

# Set to skip a PRIVATE bind mount on the storage home directory.
# skip_mount_home = "false"

# Size is used to set a maximum size of the container image.
# size = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# metadata_size is used to set the `pvcreate --metadatasize` options when
# creating thin devices. Default is 128k
# metadata_size = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0"

[rhatdan]

@nalind @giuseppe I don't think this something we could do in Buildah? I would think this would have to be done with seccomp filtering or a flag to the fuse-filesystem to tell the kernel to return success when these xattrs are written.

The reason buildah can't do anything about this, is at the point that dnf or apt are writing the XATTRs, buildah is not involved. This is between the container process and the file system.

[nalind]

The reader for the updated ADD and COPY is in our copier package, so we can fix that.

[rhatdan]

Ok, but it would not fix it for RUN command.

[orlandohohmeier]

@rhatdan true that but in the case I'm envisioning, that shouldn't be an issue.