In a way, metrics are a key-value concept, where the key is a triplet of
metrics family name, object name, and "fields". Let's put them together
in the varlink call, and put the value last, separately from that.
Also, update docs a bit, i.e be explicit about the metrics *family* name
everyhwere.
If we're asked to look up our own user namespace mapping, don't go
via fd as trying to setns() to our own user namespace in
userns_enter_and_pin() would fail with EPERM as the kernel doesn't
allow switching to your own userns.
probe_sector_size() returns 1 when it successfully determines the sector size,
0 when falling back to the default. blockdev_get_sector_size() returns 0 on
success. probe_sector_size_prefer_ioctl() was passing blockdev_get_sector_size()
return value through directly, so caller is checking r > 0 to detect a
successfully probed sector size never saw it for block devices.
In context_load_partition_table(), this caused fs_secsz to stay at 4096 bytes
even on 512-byte sector block devices, making verity hash partition sizes wrong
unless --sector-size=512 was passed explicitly.
Fix by returning 1 on success from the block device path to match probe_sector_size()
convention.
This adds the ability to download OCI images via importd.
Not a fan of the OCI format tbh, in particular its security properties
are a bit sad. But I guess it exists and is very popular, hence we might
as well add support for it, even if it comes at much weaker security
properties than DDIs.
Fixes#36447
This introduces PinnedResources as a structure combining pinned
references to a root directory, root image, or root mstack. This is not
only easier to work with, but essential to make certain unpriv things
work, as we need some mechanism to pin resources before we drop into a
userns which might possibly not provide access anymore to those
resources.
Hence this does two things: introduce the new structure, and immediately
hook it up so that we pin things properly before dropping into userns,
and then makes use of this after dropping the right way, and enables
unpriv userns operation.
The concept is generic enough to eventually implement extension images +
mount images with the same structure, but in order to keep the changes
managable this is left for another time.
(This also makes one further clean-up: client-side verity-reuse checks
are moved server side if we are unpriv. Previously we'd do them client
side, but they were doomed to fail because of lack of privs. Hence let's
drop the client side if we are unpriv and purely do them server-side in
that case.)
So far we opened a new Varlink connection for every mountfsd/nsresourced
method call. Given each tool only does a very small number of calls
(usually 1…5) on them and the connections are cheap this is not too
wasteful. Nonetheless, let's do something about it, and allow reusing
the connection for multiple calls.
This not only makes things a bit more efficient, but has one more
important benefit: Varlink connections pin the security context of the
client when connecting. This means that varlink method calls done with a
connection established while some code was privileged will still operate
as privieged once privs are dropped, until the connection is closed.
This pinning effect is really nice, as it gives us behaviour in a
"capability system" like scheme. Later code is going to use that to
continue doing certain priv userns ops even after unsharing userns and
becoming fully unpriv.
A later commit will add transient allocation of user namespaces with
dynamic UID range assignment. That creates certain permission issues.
Let's hence allow them to be handled gracefully in case the 'ignore'
field is set for a mount.
This is not just refactoring, but has the big benefit that it makes us
indepdendent from a temporary directory we might not have enough access
to create. (This matters with the new PrivateUsers=managed).
We have two very similar checks in place: in some contexts we want to
know if *any* RootDirectory= is configured, in the other we want to
suppress if it is configured to our regular root. Let's add a helper for
both (even if we only need it once), to make the mirrored behaviour
clear.
Let's flush out all response state from the job, but let's keep the
request data previously configured, in particular the headers set. This
is useful to re-request a resource, just with a slightly modified or
identical URL.
Lennart Poettering
Yu Watanabe
Daan De Meyer
Nandakumar Raghavan
Zbigniew Jędrzejewski-Szmek
Yaping Li