When vsnprintf() truncated output, dest was advanced by the entire
size of dest leaving it just past the end. Then the fall-through \0
termination scribbled one past the end. The explicit null termination
is not necessary since vsnprintf() always includes the terminator even
when truncated.
Additionally these functions encourage calling with zero-length sizes,
while assuming non-zero sizes with potential buffer overflows.
Simply short-circuit the relevant functions when size == 0.
Fixes https://github.com/systemd/systemd/issues/6252
During early boot, we'd call getrandom(), and immediately fall back to
reading from /dev/urandom unless we got the full requested number of bytes.
Those two sources are the same, so the most likely result is /dev/urandom
producing some pseudorandom numbers for us, complaining widely on the way.
Let's change our behaviour to be more conservative:
- if the numbers are only used to initialize a hash table, a short read is OK,
we don't really care if we get the first part of the seed truly random and
then some pseudorandom bytes. So just do that and return "success".
- if getrandom() returns -EAGAIN, fall back to rand() instead of querying
/dev/urandom again.
The idea with those two changes is to avoid generating a warning about
reading from an /dev/urandom when the kernel doesn't have enough entropy.
- only in the cases where we really need to make the best effort possible
(sd_id128_randomize and firstboot password hashing), fall back to
/dev/urandom.
When calling getrandom(), drop the checks whether the argument fits in an int —
getrandom() should do that for us already, and we call it with small arguments
only anyway.
Note that this does not really change the (relatively high) number of random
bytes we request from the kernel. On my laptop, during boot, PID 1 and all
other processes using this code through libsystemd request:
74780 bytes with high_quality_required == false
464 bytes with high_quality_required == true
and it does not eliminate reads from /dev/urandom completely. If the kernel was
short on entropy and getrandom() would fail, we would fall back to /dev/urandom
for those 464 bytes.
When falling back to /dev/urandom, don't lose the short read we already got,
and just read the remaining bytes.
If getrandom() syscall is not available, we fall back to /dev/urandom same
as before.
Fixes#4167 (possibly partially, let's see).
The only implementation that we care about — glibc — provides us
with 31 bits of entropy. Let's use 24 bits of that, instead of throwing
all but 8 away.
This way logind will get woken up only when an actual event took place,
and not for every key press on the system.
The ioctl EVIOCSMASK was added by @dvdhrm already in October 2015, for
the use in logind, among others, hence let's actually make use of it
now.
While we are at it, also fix usage of the EVIOCGSW ioctl, where we
assumed a byte array, even though a unsigned long native endian array is
returned.
This patch is a bit more complex thant I hoped. In particular the single
IOScheduling= property exposed on the bus is split up into
IOSchedulingClass= and IOSchedulingPriority= (though compat is
retained). Otherwise the asymmetry between setting props and getting
them is a bit too nasty.
Fixes#5613
Apart from bugs (as in #6152), this can happen if we ever make
our requirements for environment entries more stringent. As with
the rest of deserialization, we should just warn and continue.
Also called "ANSI-C Quoting" in info:(bash) ANSI-C Quoting.
The escaping rules are a POSIX proposal, and are described in
http://austingroupbugs.net/view.php?id=249. There's a lot of back-and-forth on
the details of escaping of control characters, but we'll be only using a small
subset of the syntax that is common to all proposals and is widely supported.
Unfortunately dash and fish and maybe some other shells do not support it (see
the man page patch for a list).
This allows environment variables to be safely exported using show-environment
and imported into the shell. Shells which do not support this syntax will have
to do something like
export $(systemctl show-environment|grep -v '=\$')
or whatever is appropriate in their case. I think csh and fish do not support
the A=B syntax anyway, so the change is moot for them.
Fixes#5536.
v2:
- also escape newlines (which currently disallowed in shell values, so this
doesn't really matter), and tabs (as $'\t'), and ! (as $'!'). This way quoted
output can be included directly in both interactive and noninteractive bash.
We open the target path with O_DIRECTORY|O_NOFOLLOW, and if that doesn't work,
we call unlink() on the path. In neither case we will follow the symlink, so
we can relax our check to also not follow symlinks.
Fixes#5864.
*scanf functions set errno on i/o error. For sscanf, this doesn't really apply,
so (based on the man page), it seems that errno is unlikely to be ever set to a
useful value. So just ignore errno. The error message includes the string that
was parsed, so it should be always pretty clear why parsing failed.
On the other hand, detect trailing characters and minus prefix that weren't
converted properly. This matches what our safe_ato* functions do. Add tests to
elucidate various edge cases.
All those uses were correct, but I think it's better to be explicit.
Using implicit errno is too error prone, and with this change we can require
(in the sense of a style guideline) that the code is always specified.
Helpful query: git grep -n -P 'log_[^s][a-z]+\(.*%m'
Enable masking the /proc folder using the 'InaccessiblePaths' unit
option.
This also slightly simplify mounts setup as the bind_remount_recursive
function will only open /proc/self/mountinfo once.
This is based on the suggestion at:
https://lists.freedesktop.org/archives/systemd-devel/2017-April/038634.html
timex::time::tv_usec and timex::freq can have different sizes
depending on the host architecture. On x32 in particular,
it is 8 bytes long while the long int type is only 4 bytes
long. Hence, using li as a format specifier will trigger
a format error. Thus, introduce a new format specifier
PRI_TIMEX which is defined as PRIi64 on x32 and li
everywhere else.
This reverts commit 6355e75610.
The previously mentioned commit inadvertently broke a lot of SELinux related
functionality for both unprivileged users and systemd instances running as
MANAGER_USER. In particular, setting the correct SELinux context after a User=
directive is used would fail to work since we attempt to set the security
context after changing UID. Additionally, it causes activated socket units to
be mislabeled for systemd --user processes since setsockcreatecon() would never
be called.
Reverting this fixes the issues with labeling outlined above, and reinstates
SELinux access checks on unprivileged user services.
libidn2 2.0.0 supports IDNA2008, in contrast to libidn which supports IDNA2003.
https://bugzilla.redhat.com/show_bug.cgi?id=1449145
From that bug report:
Internationalized domain names exist for quite some time (IDNA2003), although
the protocols describing them have evolved in an incompatible way (IDNA2008).
These incompatibilities will prevent applications written for IDNA2003 to
access certain problematic domain names defined with IDNA2008, e.g., faß.de is
translated to domain xn--fa-hia.de with IDNA2008, while in IDNA2003 it is
translated to fass.de domain. That not only causes incompatibility problems,
but may be used as an attack vector to redirect users to different web sites.
v2:
- keep libidn support
- require libidn2 >= 2.0.0
v3:
- keep dns_name_apply_idna caller dumb, and keep the #ifdefs inside of the
function.
- use both ±IDN and ±IDN2 in the version string
The single log level is split into an array of log levels. Which index in the
array is used can be determined for each compilation unit separately by setting
a macro before including log.h. All compilation units use the same index
(LOG_REALM_SYSTEMD), so there should be no functional change.
v2:
- the "realm" is squished into the level (upper bits that are not used by
priority or facility), and unsquished later in functions in log.c.
v3:
- rename REALM_PLUS_LEVEL to LOG_REALM_PLUS_LEVEL and REALM to LOG_REALM_REMOVE_LEVEL.
Since all our python scripts have a proper python3 shebang, there is no benefit
to letting meson autodetect them. On linux, meson will just uses exec(), so the
shebang is used anyway. The only difference should be in how meson reports the
script and that the detection won't fail for (most likely misconfigured)
non-UTF8 locales.
Closes#5855.
This is useful on systems like NixOS, where python3 is not in
/usr/bin/python3 as well as for people using alternative ways to
install python such as virtualenv/pyenv.
