When using a GDBus client in a non-trivial user namespace, the result of
geteuid() can differ from the uid in the namespace where the server is
running. This would result in connection attempts being rejected, because
the identity that the client claims to have does not match the identity
that the server derives from its credentials.
RFC 4422 allows us to send an empty authorization identity, which means we
want to authenticate as whatever identity the server can derive from our
out-of-band credentials. In particular, this resolves the authentication
failure when crossing between different Linux user namespaces.
Because D-Bus does not have a way to represent an empty initial response
as distinct from the absence of an initial response, we cannot use the
initial-response optimization (RFC 4422 §4.3.a) in this case, and must
fall back to waiting for the server to send a challenge.
Unfortunately, GDBus versions older than glib!2826 did not implement
the server side of this protocol correctly, and would respond to the
missing initial response in a way that breaks the SASL state machine
(expecting a response without sending a challenge), causing client and
server to deadlock with each waiting for the other to respond. Until
fixed versions of GDBus are widespread, we can't rely on having a server
that can cope with this, so gate it behind a flag, which can be set for
connections that are known to cross non-trivial namespace boundaries.
Originally inspired by
<1ed4723d38>,
and based on earlier work by Giuseppe Scrivano (in which the
cross-namespace behaviour was unconditional, rather than gated by a
flag).
Co-authored-by: Giuseppe Scrivano <giuseppe@scrivano.org>
Signed-off-by: Simon McVittie <smcv@collabora.com>
Instead of using a GDBusConnection, this does the handshake at a lower
level using specific strings in the SASL handshake, to verify that we
will interoperate with various clients including sd-bus, libdbus and
older versions of GDBus.
Signed-off-by: Simon McVittie <smcv@collabora.com>
This is an interoperability fix. The reference implementation of D-Bus
treats "DATA\r\n" as equivalent to "DATA \r\n", but sd-bus does not,
and only accepts the former.
Signed-off-by: Simon McVittie <smcv@collabora.com>
RFC 4422 appendix A defines the empty authorization identity to mean
the identity that the server associated with its authentication
credentials. In this case, this means whatever uid is in the
GCredentials object.
In particular, this means that clients in a different Linux user
namespace can authenticate against our server and will be authorized
as the version of their uid that is visible in the server's namespace,
even if the corresponding numeric uid returned by geteuid() in the
client's namespace was different. systemd's sd-bus has relied on this
since commit
1ed4723d38.
[Originally part of a larger commit; commit message added by smcv]
Signed-off-by: Simon McVittie <smcv@collabora.com>
Sending an "initial response" along with the AUTH command is meant
to be an optional optimization, and clients are allowed to omit it.
We must reply with our initial challenge, which in the case of EXTERNAL
is an empty string: the client responds to that with the authorization
identity.
If we do not reply to the AUTH command, then the client will wait
forever for our reply, while we wait forever for the reply that we
expect the client to send, resulting in deadlock.
D-Bus does not have a way to distinguish between an empty initial
response and the absence of an initial response, so clients that want
to use an empty authorization identity, such as systed's sd-bus,
cannot use the initial-response optimization and will fail to connect
to a GDBusServer that does not have this change.
[Originally part of a larger commit; commit message added by smcv.]
Signed-off-by: Simon McVittie <smcv@collabora.com>
This is an interoperability fix. If the line is exactly "DATA\r\n",
the reference implementation of D-Bus treats this as equivalent to
"DATA \r\n", meaning the data block consists of zero hex-encoded bytes.
In practice, D-Bus clients send empty data blocks as "DATA\r\n", and
in fact sd-bus only accepts that, rejecting "DATA \r\n".
[Originally part of a larger commit; commit message added by smcv]
Signed-off-by: Giuseppe Scrivano <giuseppe@scrivano.org>
Co-authored-by: Simon McVittie <smcv@collabora.com>
Signed-off-by: Simon McVittie <smcv@collabora.com>
This attribute will produce "deprecation" warnings when using it in
code that does not want dependencies on newer GLib versions.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Using GMemorySettingsBackend before any other GSettingsBackend would
cause the following error: "Tried to implement non-registered extension
point gsettings-backend". This is due to a missing call to
_g_io_modules_ensure_extension_points_registered() in the GMemorySettingsBackend
type definition which registers the gsettings-backend extension point.
We don't need a cpp toolchain for building glib so lets just
automatically disable tests requiring one when not available.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
The test was flacky because we were only relying on the presence of a
file, while the callback could have not been called yet, while ensure
for both assumptions to be true before stop iterating the loop.
Fix a regression from commit abddb42d14, where it could pass `NULL` to
`g_task_get_cancellable()`, triggering a critical warning. This could
happen because the lifetime of `data->task` is not as long as the
lifetime of the `ConnectionAttempt`, but the code assumed it was.
Fix the problem by keeping a strong ref to that `GCancellable` around
until the `ConnectionAttempt` is finished being destroyed.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Fixes: #2687
These headers have all been written manually, by looking through the git
log for each file and noting the copyright of each significant
contribution.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1415
While `gio_xdgmime` is unlocked, the data which `type` points to in the
xdgmime cache might get invalidated, leaving `type` as a dangling
pointer. That would not bode well for the `g_strdup (type)` call to
insert a new entry into the `type_comment_cache` once `gio_xdgmime` is
re-acquired.
This was spotted using static analysis, and the symptoms have not
knowingly been seen in the wild.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Coverity CID: #1474702
This will catch buggy implementations of GProxyResolver before they are
able to return bogus results to higher level code. In particular, if
g_proxy_resolver_lookup() returns NULL, it'd better set an error to
explain why.
It doesn't make sense for a proxy resolver to return NULL without an
error on the first call. Whereas a DNS resolver would do this to
indicate that a query completed successfully but found no results, a
proxy resolver should return "direct://" instead. Therefore, if we are
going to return NULL, we ought to have an error as well. Let's make sure
this actually happens by adding some fallback errors just in case
GProxyResolver feeds us weird results.
Additionally, we should not return any errors except
G_IO_ERROR_CANCELLED after the very first iteration. This is an API
contract of GSocketAddressEnumerator. Let's add some checks to ensure
this.
Note that we have inadequate test coverage for GProxyAddressEnumerator.
It's tested here only via GSocketClient. We could do a bit better by
testing it directly as well. For example, I've added tests to see what
happens when GProxyResolver returns both a valid and an invalid URI, but
it's not so interesting here because GSocketClient always uses the valid
result and ignores the error from GProxyAddressEnumerator.
Fixes#2597
This has no practical impact, since it's only a test, and none of the
test code would have hit this bug, but the GTestProxyResolver's check to
see if the URI scheme is simple:// currently only compares the first
four bytes of the string, so it's actually only checking for the "simp"
and would match anything else after that, e.g. "simpleton://". This is
surely not intended.
This was causing intermittent failures on macOS, depending on whether
the tmpdir ended with a `/` or `/some-dir`. `g_strrstr()` is not the
right function to use to extract a basename from a path, for this
reason.
When it failed, the macOS test was failing with:
```
ok 16 /gsubprocess/env
Bail out! GLib-GIO:ERROR:../gio/tests/gsubprocess.c:1507:test_cwd: assertion failed (basename == tmp_lineend_basename): ("/T\n" == "/\n")
```
The test now passes reliably, which means that it can be removed from
the list of expected failures on macOS.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1392
Creating a `GAppInfo` from a commandline isn’t currently supported on
macOS, but the implementation was incorrectly returning `NULL` without
setting the `GError`.
This was being caught by the new tests in `gio/tests/file.c`.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
On macOS the comparison was failing as one of the paths had a trailing
slash while the other didn’t.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
We used to do get and set atomic operations pair, but these may be
unsafe in some cases as threads may rely on data that is changed in
in between them, however this is not a problem if we do exchange the
pointers.
So just use exchange ops, in this way we can avoid lock/unlock mutex
dances
