On Linux, if getsockopt SO_PEERCRED is used on a TCP socket, one
might expect it to fail with an appropriate error like ENOTSUP or
EPROTONOSUPPORT. However, it appears that in fact it succeeds, but
yields a credentials structure with pid 0, uid -1 and gid -1. These
are not real process, user and group IDs that can be allocated to a
real process (pid 0 needs to be reserved to give kill(0) its documented
special semantics, and similarly uid and gid -1 need to be reserved for
setresuid() and setresgid()) so it is not meaningful to signal them to
high-level API users.
An API user with Linux-specific knowledge can still inspect these fields
via g_credentials_get_native() if desired.
Similarly, if SO_PASSCRED is used to receive a SCM_CREDENTIALS message
on a receiving Unix socket, but the sending socket had not enabled
SO_PASSCRED at the time that the message was sent, it is possible
for it to succeed but yield a credentials structure with pid 0, uid
/proc/sys/kernel/overflowuid and gid /proc/sys/kernel/overflowgid. Even
if we were to read those pseudo-files, we cannot distinguish between
the overflow IDs and a real process that legitimately has the same IDs
(typically they are set to 'nobody' and 'nogroup', which can be used
by a real process), so we detect this situation by noticing that
pid == 0, and to save syscalls we do not read the overflow IDs from
/proc at all.
This results in a small API change: g_credentials_is_same_user() now
returns FALSE if we compare two credentials structures that are both
invalid. This seems like reasonable, conservative behaviour: if we cannot
prove that they are the same user, we should assume they are not.
Signed-off-by: Simon McVittie <smcv@collabora.com>
The compiler can’t work out from the combination of other conditions
that it’s not possible for (m2 == NULL) to hold true when memcmp() is
called, so add an explicit condition.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Fixes: #1897
Otherwise we’ll end up using the host’s `objcopy`, which will output
object files in the wrong format.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Fixes: #1916
Since we have the type of the GValue we're going to initialize, we can
allow passing an empty (but valid) GValue when retrieving the default
value of a GParamSpec.
This will eliminate additional checks and an unnecessary reset.
Previously, these GTimeZone objects were being cached in the `time_zones` cache, but dropped from it when their final ref was dropped (which was frequently). That meant additional reads of `/etc/localtime` next time they were created, which was noticeable on profiles. Keep a permanent ref to the UTC and local timezones.
This removes the limitation of select() that only FDs with values lower
than FD_SETSIZE can be used. Previously, if the out/err pipe FDs had
high values (which could happen if a large process, like Firefox, was
spawning subprocesses while having a lot of FDs open), GLib would abort
due to an assertion failure in libc.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Fixes: #954
glibc declares memcpy() with the first two arguments (the pointers)
annotated as non-null via an attribute, which results in the undefined
behaviour sanitizer considering it to be UB to pass a null pointer
in the second argument, even if we are copying 0 bytes (and hence not
actually dereferencing the pointer).
This shows up in array-test when run with the undefined behaviour
sanitizer.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Note that I deliberately haven't used g_autoptr here, because while we
encourage GLib users to use g_autoptr in their own code, GLib itself
still supports being compiled in environments like MSVC that can't
support g_autoptr.
Signed-off-by: Simon McVittie <smcv@collabora.com>
The user_data for g_ptr_array_sort_with_data is passed directly, not
with an extra layer of pointer like the data pointers.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Fixes: 52c130f8
Let's not encourage library users to sprinkle casts through their code
when they don't need to.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Fixes: 52c130f8
This is like `GMutexLocker`, in that if you are able to use
`g_autoptr()`, it makes popping a `GMainContext` off the thread-default
main context stack easier when exiting a function.
A few uses of `G_GNUC_{BEGIN,END}_IGNORE_DEPRECATIONS` are needed to
avoid warnings when building apps against GLib with
`GLIB_VERSION_MAX_ALLOWED < GLIB_VERSION_2_64`.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
We may need to declare autocleanups for new types, which will be marked
as ‘deprecated’ if the code which includes GLib doesn’t declare a high
enough `GLIB_VERSION_MAX_ALLOWED`. Despite that, we still need to
declare the autocleanups.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
The token parsing done by g_variant_parse() uses recursive function
calls, so at some point it will hit the stack limit. As with previous
changes to `GVariantType` parsing (commit 7c4e6e9fbe), limit the level
of nesting of containers parsed by g_variant_parse() to something
reasonable. We guarantee 64 levels of nesting, which should be enough
for anyone, and is the same as what we guarantee for types.
oss-fuzz#10286
Signed-off-by: Philip Withnall <withnall@endlessm.com>
This reverts commit 4aba03562b, preserving
the new tests but adjusting them to assert that the old behaviour is
restored.
As expected, there were a few projects which broke because of this.
Unfortunately, in one case the breakage crosses a project boundary:
sysprof ships D-Bus introspection XML, which is consumed by mutter and
passed through gdbus-codegen.
Since sysprof cannot add this annotation without breaking its existing
users, a warning is also not appropriate.
https://gitlab.gnome.org/GNOME/jhbuild/issues/41https://gitlab.gnome.org/GNOME/sysprof/issues/17https://gitlab.gnome.org/GNOME/glib/issues/1726
On closer reading of `man 3 timezone`, it’s actually permissible for
`TZ` to contain an absolute path which points to a tzfile file outside
the system time zone database. This is indeed what happens when building
GLib under Fedora’s toolbox, so relax that check in the tests.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
There are a lot of Unix-like systems which have not implemented the
os-release spec. On such system, we can use POSIX uname function as a
fallback to get basic information of the system.
/etc/os-release is a spec designed for Linux. While other OSes can
implement it, it doesn't make sense to use Linux as the default value
on systems which don't use Linux.
