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.
We shouldn't report that the file is empty if the stating fails. Let's do the
same as in other places, and just ignore the error and let the subsequent
operation fail.
No functional change, just preparation for later commits.
These can be used in kernel-install later.
Note, unlike the our usual coding style, the arguments for
boot_entry_token_ensure() and parse_boot_entry_token_type() are
referenced, updated, and may freed, hence, always pass initialized
values. That's why they are not named as 'ret_xyz'.
Chasing symlinks is a core function that's used in a lot of places
so it deservers a less verbose names so let's rename it to chase()
and chaseat().
We also slightly change the pattern used for the chaseat() helpers
so we get chase_and_openat() and similar.
So far we asked via a comment that @default should stay the first group
and @known the last group in the list. Let's enforce that statically, in
code, too.
Let's group these 4 syscalls, as they offer similar things and I guess
might be used in conjunction quite often, as they offer unprivileged
sandboxing.
Fixes: #26913
No functional change. (We already checked for ELFCLASS32 or ELFCLASS64 before,
so even though there's a new check for other architectures, the only caller
only passes ELFCLASS32 or ELFCLASS64.)
On top of taking a directory file descriptor, we use xopenat() so
that the function can also be used to work on existing file
descriptors to image files including all the logic to use O_DIRECT
and fallback to O_RDONLY if needed.
btrfs_get_block_device_fd() returns -ENOTTY if fstatfs().f_type !=
BTRFS_SUPER_MAGIC
btrfs_get_block_device_fd() is run by verify_fsroot_dir() by
verify_xbootldr() by find_xbootldr_and_warn() if
statx($presumed-XBOOTLDR).stx_dev_major == 0 ("maybe a btrfs device")
Every bootctl verb_install() runs find_xbootldr_and_warn(), by default
with /boot
If your /boot .stx_dev_major=0 but /not/ btrfs, bootctl install/update
quietly exits 1 with no note so as to what exactly failed (debug also
empty, and the strace isn't exactly clear since no syscall actually
failed)
This is the case on ZFS and the Debian filesystem layout: /boot/efi is
the ESP, and everything else under / is ZFS:
$ sudo env SYSTEMD_LOG_LEVEL=debug bootctl update
Found cgroup2 on /sys/fs/cgroup/, full unified hierarchy
Found container virtualization none.
File system "/boot" is not a FAT EFI System Partition (ESP) file system.
Using EFI System Partition at /boot/efi.
Checking whether /boot/efi/EFI/systemd/ contains any files…
$ echo $?
1
and funnier still:
$ sudo bootctl update --graceful
$ echo $?
1
Which is great, and also breaks postinst, which runs precisely the
latter, with no feedback at all
By checking for -ENOTTY we accept that the path being investigated
"is not it" if it's on ZFS (and any other filesystem that returns
.stx_dev_major == 0 but isn't btrfs)
Lennart Poettering
Yu Watanabe
William Roberts
Zbigniew Jędrzejewski-Szmek
Daan De Meyer
Luca Boccassi
Frantisek Sumsal
наб