Split the single directory fd that chaseat() used to take into two separate
fds: a root_fd that sets the chroot boundary (symlinks may not escape it,
absolute symlinks resolve relative to it), and a dir_fd that path resolution
starts from. This makes the chroot semantics of chaseat() explicit at every
call site instead of encoding them in the CHASE_AT_RESOLVE_IN_ROOT flag,
which is removed. It also decouples the starting directory from the root
boundary, so callers can descend from any inode inside the tree without
having to reopen the root separately.
XAT_FDROOT passed as root_fd means "no containment" (host root); as dir_fd
it means "start at root_fd". For a smoother transition, AT_FDCWD is also
accepted as root_fd and treated as XAT_FDROOT. When root_fd points to a
directory that is actually the host root, it is normalized to XAT_FDROOT
up front so the existing shortcut path can kick in.
Absolute paths returned by chaseat() are now relative to root_fd, and
relative paths are relative to dir_fd. The result is absolute only when
there is no chroot boundary (root_fd is XAT_FDROOT), or when an absolute
symlink made resolution jump out of the dir_fd subtree; otherwise callers
get a relative path they can feed straight back into an openat()-style
call against dir_fd. Specifically, when dir_fd == root_fd and we're not
operating on the host's root directory, we return a relative path even if
we received an absolute path or resolved an absolute symlink to allow
passing the path directly to openat() style functions. We do this to not
have to go modify every caller of chaseat() to make sure they deal properly
with any absolute paths they might receive. Only when root_fd != dir_fd do
we have to return an absolute path to indicate that the path is relative to
root_fd and not dir_fd.
The shortcut that skips the per-component walk is reworked around a new
chase_xopenat() helper that funnels CHASE_NOFOLLOW, CHASE_MUST_BE_* and
CHASE_TRIGGER_AUTOFS through xopenat_full()'s O_NOFOLLOW, O_DIRECTORY,
XO_REGULAR, XO_SOCKET and XO_TRIGGER_AUTOMOUNT flags. As a result these
flags no longer force us off the shortcut and can be dropped from
CHASE_NO_SHORTCUT_MASK, and the old openat_opath_with_automount() helper
goes away. A CHASE_MUST_BE_ANY alias is introduced for shortcut callers
(stat/access paths) that don't go through xopenat_full() and still need
to bail on those flags locally.
All *_and_* helpers built on top of chaseat() (chase_and_openat,
chase_and_opendirat, chase_and_statat, chase_and_accessat,
chase_and_fopenat_unlocked, chase_and_unlinkat, chase_and_open_parent_at)
gain the same root_fd parameter, and every call site in the tree is
ported to the new signature.
chase_and_open() is also fixed to correctly handle CHASE_EXTRACT_FILENAME
without CHASE_PARENT.
Coverity flags ALIGN(sizeof(struct passwd/group)) + bufsize as
potential overflows in the getpw/getgr helpers. Add asserts to
make the bounds explicit for static analyzers.
CID#1548047
CID#1548049
CID#1548069
CID#1548070
Follow-up for 75673cd8ae
If /proc/self/gid_map is empty, the kernel will refuse setgroups(),
so don't attempt it if that's the case on top of the /proc/self/setgroups
check we already have.
The buffer will be used by a library outside of our code base,
and may not be initialized even on success. Let's initialize
them for safety.
Hopefully fixes the following fuzzer warning:
```
==2039==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x7f9ad8be3ae6 in _nss_files_getsgnam_r (/lib/x86_64-linux-gnu/libnss_files.so.2+0x8ae6) (BuildId: 013bf05b4846ebbdbebdb05585acc9726c2fabce)
#1 0x7f9ad93e5902 in getsgnam_r (/lib/x86_64-linux-gnu/libc.so.6+0x126902) (BuildId: 0323ab4806bee6f846d9ad4bccfc29afdca49a58)
#2 0x7f9ad9b98153 in nss_sgrp_for_group /work/build/../../src/systemd/src/shared/user-record-nss.c:357:21
#3 0x7f9ad9b98926 in nss_group_record_by_gid /work/build/../../src/systemd/src/shared/user-record-nss.c:431:21
#4 0x7f9ad9bcebd7 in groupdb_by_gid_fallbacks /work/build/../../src/systemd/src/shared/userdb.c:1372:29
Uninitialized value was created by a heap allocation
#0 0x556fd5294302 in malloc /src/llvm-project/compiler-rt/lib/msan/msan_interceptors.cpp:1021:3
#1 0x7f9ad9b9811d in nss_sgrp_for_group /work/build/../../src/systemd/src/shared/user-record-nss.c:353:23
#2 0x7f9ad9b98926 in nss_group_record_by_gid /work/build/../../src/systemd/src/shared/user-record-nss.c:431:21
#3 0x7f9ad9bcebd7 in groupdb_by_gid_fallbacks /work/build/../../src/systemd/src/shared/userdb.c:1372:29
```
Now that the necessary functions from log.h have been moved to macro.h,
we can stop including log.h in macro.h. This requires modifying source
files all over the tree to include log.h instead.
This introduce LOG_ITEM() macro that checks arbitrary formats in
log_struct().
Then, drop _printf_ attribute from log_struct_internal(), as it does not
help so much, and compiler checked only the first format string.
Hopefully, this silences false-positive warnings by Coverity.
We generally use utmpx instead of utmp (both are actually identical on
Linux, but utmpx is POSIX, while utmp is not). Let's fix one left-over
case.
UT_NAMESIZE does not exist in utmpx world, it has no direct counterpart,
hence let's just sizeof_field() to determine the size of the actual
field. (which comes to the same result of course: 32).
These are wrappers around getpwuid_r() and friends, and will allocate the
right-sized buffer for this call.
We so far had multiple implementations of a buffer allocation loop
around getpwuid_r() and friends, and they all suck in some way. Let's
clean this up and add a common implementation, and use it everywhere.
Also, be more careful with error numbers, in particular systematically
turn ENOENT into ENOSRCH (the former is what is returned if /etc/passwd
is absent, which we want to consider identical to user not existing,
which is ENOSRCH). We so far did this at some invocations, but not all.
There are some invocations of getpwuid() left in the codebase. We really
should fix those too, and have a single unified implementation of the
logic, but those are not as trivial to convert, so left for another
time.
The branch explicitly checks that all of these ret_ variables are NULL,
so they will never be used.
Follow-up for 83e9b584db
CID#1533239
CID#1533240
CID#1533241
Let's rename return parameters to ret_xyz, and let's guarantee the usual
rule to initialize all return parameters on success, and not touch any
on failure.
path_simplify_full()/path_simplify() are changed to allow a NULL path, for
which a NULL is returned. Generally, callers have already asserted before that
the argument is nonnull. This way path_simplify_full()/path_simplify() and
path_simplify_alloc() behave consistently.
In sd-device.c, logging in device_set_syspath() is intentionally dropped: other
branches don't log.
In mount-tool.c, logging in parse_argv() is changed to log the user-specified
value, not the simplified string. In an error message, we should show the
actual argument we got, not some transformed version.
Fixes
| ../git/src/basic/user-util.c:708:30: error: use of undeclared identifier 'LOCK_EX'; did you mean 'LOCK_BSD'?
| 708 | r = unposix_lock(fd, LOCK_EX);
| | ^~~~~~~
| | LOCK_BSD
Signed-off-by: Khem Raj <raj.khem@gmail.com>
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.
This allows sysusers to operate with --root that is an empty directory.
It may be useful to, for example, populate the user database before installing
anything else.
firstboot was already doing this, so drop the duplicated call there.
The check of u==UID_NOBODY is just a register comparison, but
synthesize_nobody() requires a system call, so let's invert the order in the
condition. Since most calls into this module are not for nobody, we should
save one syscall in the common case.
/bin/sh as a shell is punishing. There is no good reason to make
the occasional root login unpleasant.
Since /bin/sh is usually /bin/bash in compat mode, i.e. if one is
available, the other will be too, /bin/bash is almost as good as a default.
But to avoid a regression in the situation where /bin/bash (or
DEFAULT_USER_SHELL) is not installed, we check with access() and fall back
to /bin/sh. This should make this change in behaviour less risky.
(FWIW, e.g. Fedora/RHEL use /bin/bash as default for root.)
This is a follow-up of sorts for 53350c7bba,
which added the default-user-shell option, but most likely with the idea
of using /bin/bash less ;)
Fixes#24369.
We now have a local implementation in string-util-fundamental.c, but
it's useful at a lot of other places, hence let's give it a more
expressive name and share it across the tree.
Follow-up for: 8d9156660d
Also break some long lines for more uniform formatting. No functional change.
I went over all log_struct, log_struct_errno, log_unit_struct,
log_unit_struct_errno calls, and they seem fine.
This is a debugging feature. It's sometimes incredibly useful to be able
to run a second instance of homed that operates on another dir than
/home/.
Specifically, if you build homed from the source tree you can now run an
instance of it pretty reasonably directly from the build tree via:
sudo SYSTEMD_HOME_DEBUG_SUFFIX=foo SYSTEMD_HOMEWORK_PATH=$(pwd)/build/systemd-homework SYSTEMD_HOME_ROOT=/home/foo ./build/systemd-homed
And then talk to it via
sudo SYSTEMD_HOME_DEBUG_SUFFIX=foo homectl …
(you might need to tweak your dbus policy for this to work fully though)
Daan De Meyer
Luca Boccassi
Yu Watanabe
Daan De Meyer
Mike Yuan
Lennart Poettering
Mike Gilbert
Luca Boccassi
Zbigniew Jędrzejewski-Szmek
Khem Raj
jcg
наб