Unlikely, but even if find_esp() or friends called with unnormalized or
relative 'root', let's make the result path normalized and absolute.
Note, before 63105f33ed, these functions
returned an absolute and normalized path. But the commit made the result
path simply concatenated with root.
Follow-up for 63105f33ed.
Before this commit, if `original_path` is given,
it will always be used to overwrite `path`.
After this commit, it's controlled by the newly-added
switch `overwrite_with_origin`.
The release file that accompanies the confext images needs to be
host compatible to be able to be merged into the host /etc/ directory.
This commit checks for version compatibility between the image file and
the host file.
Adds a new image type called IMAGE_CONFEXT which is similar to IMAGE_SYSEXT but works
for the /etc/ directory instead of /usr/ and /opt/. This commit also adds the ability to
parse the release file that is present with the confext image in /etc/confext-release.d/
directory.
If we don't find a single useful partition table, refusing dissection.
(Except in systemd-dissect, when we are supposed to show DDI
information, in that case allow this to run and show general DDI
information, i.e. size, UUID and name at least)
This is to dissect_image_file() what dissect_loop_device_and_warn() is
to dissect_loop_device(), i.e. it dissects the image file and logs an
error string if that fails instead of just returning an error.
Fixes:
- Comment style
- Alignment style
- cleanup macro usage
- incorrect error message[1]
1. Thanks to tempusfugit991@gmail.com for pointing out the error
message mistake.
Signed-off-by: William Roberts <william.c.roberts@intel.com>
If a root directory is specified, and e.g. /var under the root directory
is a symlink to the host's /var, then we wrongly read host's machine ID,
even if O_NOFOLLOW is set.
Let's chase the path with CHASE_NOFOLLOW to refuse such case.
Also, refuse null ID, otherwise we may setup machine ID with NULL.
Prevent attackers from spoofing the tpmKey portion of the AuthSession by
adding a trusted key to the LUKS header metadata. Also, use a persistent
object rather than a transient object.
This provides the following benifits:
1. No way to MITM the tpmKey portion of the session, see [1] for
details.
2. Strengthens the encrypted sessions, note that the bindKey could be
dropped now.
3. Speed, once it's created we just use it.
4. Owner Auth is needed to call create primary, so using the SRK
creates a scratch space for normal users.
This is a "first to set" model, in where the first person to set the key
in the LUKS header wins. Thus, setup should be done in a known good
state. If an SRK, which is a primary key at a special persistent
address, is found, it will use whatever is there. If not, it creates an
SRK. The SRK follows the convetions used through the tpm2-software
organization code on GitHub [2], however, a split has occured between
Windows and Linux with respect to SRK templates. The Linux SRK is
generated with the unique field size set to 0, in Windows, it properly
sets the size to key size in bytes and the unique data to all 0's of that
size. Note the proper templates for SRKs is covered in spec [3].
However, the most important thing, is that both SRKs are passwordless,
and thus they should be interchangable. If Windows is the first to make
the SRK, systemd will gladly accept it and vice-versa.
1. Without the bindKey being utilized, an attacker was able to intercept
this and fake a key, thus being able to decrypt and encrypt traffic as
needed. Introduction of the bindKey strengthened this, but allows for
the attacker to brute force AES128CFB using pin guesses. Introduction of
the salt increases the difficulty of this attack as well as DA attacks
on the TPM objects itself.
2. https://github.com/tpm2-software
3. https://trustedcomputinggroup.org/wp-content/uploads/TCG-TPM-v2.0-Provisioning-Guidance-Published-v1r1.pdfFixes: #20668Fixes: #22637
Signed-off-by: William Roberts <william.c.roberts@intel.com>
pam_nologin looks for /etc/nologin and /run/nologin.
user-sessions creates (and removes) /run/nologin, but also removes
/etc/nologin. (This behaviour is unchanged since the introduction
of the binary in e92787416c691c3f34f47349e5eae3fa68eae856.)
By not removing pam_nologin we fully drop compatibility with PAM < 1.1.
This has the advantage that now /etc/nologin can be used by administrator to
disable user logins, e.g. for extended maintanance. We already specified
PAM >= 1.1.2 as dependency, so this was already covered.
The makes the code match the man page.
Fixes#26965.
We also rework the internals of find-esp to work on directory file
descriptors instead of absolute paths and do a lot of general cleanups.
By passing the parent directory file descriptor to verify_fsroot_dir()
along with the name of the directory we're operating on, we can get rid
of the fallback that goes via path to open the parent directory if '..'
fails due to permission errors.
Let's make btrfs_get_block_device_fd() more generic by renaming it
to btrfs_get_block_device_at() so it can operate on only paths, dir_fd
and path, or only on fd by using xopenat().
Otherwise, directory with zero access mode cannot be removed.
This is a revised version of 808c8b25ee,
- dropped O_NOFOLLOW from fd_reopen()
- fixed error handling on opening path in rm_rf().
sysexts are meant to extend /usr. All extension images and directories are opened and merged in a
single, read-only overlayfs layer, mounted on /usr.
So far, we had fallback storage directories in /usr/lib/extensions and /usr/local/lib/extensions.
This is problematic for three reasons.
Firstly, technically, for directory-based extensions the kernel will reject
creating such an overlay, as there is a recursion problem. It actively
validates that a lowerdir is not a child of another lowerdir, and fails with
-ELOOP if it is. So having a sysext /usr/lib/extensions/myextdir/ would result
in an overlayfs config lowerdir=/usr/lib/extensions/myextdir/usr/:/usr which is
not allowed, as indicated by Christian the kernel performs this check:
/*
* Check if this layer root is a descendant of:
* - another layer of this overlayfs instance
* - upper/work dir of any overlayfs instance
*/
<...>
/* Walk back ancestors to root (inclusive) looking for traps */
while (!err && parent != next) {
if (is_lower && ovl_lookup_trap_inode(sb, parent)) {
err = -ELOOP;
pr_err("overlapping %s path\n", name);
Secondly, there's a confusing aspect to this recursive storage. If you
have /usr/lib/extensions/myext.raw which contains /usr/lib/extensions/mynested.raw
'systemd-sysext merge' will only pick up the first one, but both will appear in
the merged root under /usr/lib/extensions/. So you have two extension images, both
appear in your merged filesystem, but only one is actually in use.
Finally, there's a conceptual aspect: the idea behind sysexts and hermetic /usr
is that the /usr tree is not modified locally, but owned by the vendor. Dropping
extensions in /usr thus goes contrary to this foundational concept.
Let's use more _cleanup_ expressions. Various other modernizations. No
actual code changes, except for maybe a conversion to use heap memory
when generating an array of fds, instead of stack as before. Given that
fdstores are typically user controlled, that should be a wise idea.
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Ludwig Nussel
Mike Yuan
Luca Boccassi
Daan De Meyer
maanyagoenka
Lennart Poettering
William Roberts