===========================
This release fixes a security issue in the media store, affecting all prior releases of Synapse. Server administrators are encouraged to update Synapse as soon as possible. We are not aware of these vulnerabilities being exploited in the wild.
Server administrators who are unable to update Synapse may use the workarounds described in the linked GitHub Security Advisory below.
Security advisory
-----------------
The following issue is fixed in 1.47.1.
- **[GHSA-3hfw-x7gx-437c](https://github.com/matrix-org/synapse/security/advisories/GHSA-3hfw-x7gx-437c) / [CVE-2021-41281](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41281): Path traversal when downloading remote media.**
Synapse instances with the media repository enabled can be tricked into downloading a file from a remote server into an arbitrary directory, potentially outside the media store directory.
The last two directories and file name of the path are chosen randomly by Synapse and cannot be controlled by an attacker, which limits the impact.
Homeservers with the media repository disabled are unaffected. Homeservers configured with a federation whitelist are also unaffected.
Fixed by [91f2bd090](https://github.com/matrix-org/synapse/commit/91f2bd090).
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Merge tag 'v1.47.1'
Synapse 1.47.1 (2021-11-23)
===========================
This release fixes a security issue in the media store, affecting all prior releases of Synapse. Server administrators are encouraged to update Synapse as soon as possible. We are not aware of these vulnerabilities being exploited in the wild.
Server administrators who are unable to update Synapse may use the workarounds described in the linked GitHub Security Advisory below.
Security advisory
-----------------
The following issue is fixed in 1.47.1.
- **[GHSA-3hfw-x7gx-437c](https://github.com/matrix-org/synapse/security/advisories/GHSA-3hfw-x7gx-437c) / [CVE-2021-41281](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41281): Path traversal when downloading remote media.**
Synapse instances with the media repository enabled can be tricked into downloading a file from a remote server into an arbitrary directory, potentially outside the media store directory.
The last two directories and file name of the path are chosen randomly by Synapse and cannot be controlled by an attacker, which limits the impact.
Homeservers with the media repository disabled are unaffected. Homeservers configured with a federation whitelist are also unaffected.
Fixed by [91f2bd090](https://github.com/matrix-org/synapse/commit/91f2bd090).
* Make lock better handle process being killed
If the process gets killed and restarted (so that it didn't have a
chance to drop its locks gracefully) then there may still be locks in
the DB that are for the same instance that haven't yet timed out but are
safe to delete.
We handle this case by a) checking if the current instance already has
taken out the lock, and b) if not then ignoring locks that are for the
same instance.
* Periodically check for old staged events
This is to protect against other instances dying and their locks timing
out.
* Remove unused Vagrant scripts
* Change package Architecture to any
* Preinstall the wheel package when building venvs.
Addresses the following warnings during Debian builds:
Using legacy 'setup.py install' for jaeger-client, since package 'wheel' is not installed.
Using legacy 'setup.py install' for matrix-synapse-ldap3, since package 'wheel' is not installed.
Using legacy 'setup.py install' for opentracing, since package 'wheel' is not installed.
Using legacy 'setup.py install' for psycopg2, since package 'wheel' is not installed.
Using legacy 'setup.py install' for systemd-python, since package 'wheel' is not installed.
Using legacy 'setup.py install' for pympler, since package 'wheel' is not installed.
Using legacy 'setup.py install' for threadloop, since package 'wheel' is not installed.
Using legacy 'setup.py install' for thrift, since package 'wheel' is not installed.
* Allow /etc/default/matrix-synapse to be missing
Per the systemd.exec manpage, prefixing an EnvironmentFile with "-":
> indicates that if the file does not exist, it will not be read and no
> error or warning message is logged.
Signed-off-by: Dan Callahan <danc@element.io>
When an event fetcher aborts due to an exception, `_event_fetch_ongoing`
must be decremented, otherwise the event fetcher would never be
replaced. If enough event fetchers were to fail, no more events would be
fetched and requests would get stuck waiting for events.
