CVE-2021-42072

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

An issue was discovered in Barrier before 2.4.0. The barriers component (aka the server-side implementation of Barrier) does not sufficiently verify the identify of connecting clients. Clients can thus exploit weaknesses in the provided protocol to cause denial-of-service or stage further attacks that could lead to information leaks or integrity corruption.

This update for barrier fixes the following issues:

Updated to version 2.4.0:

Barrier now supports client identity verification (fixes CVE-2021-42072, CVE-2021-42073).

Previously a malicious client could connect to Barrier server without any authentication and send application-level messages. This made the attack surface of Barrier significantly larger. Additionally, in case the malicious client got possession of a valid screen name by brute forcing or other means it could modify the clipboard contents of the server. To support seamless upgrades from older versions of Barrier this is currently disabled by default. The feature can be enabled in the settings dialog. If enabled, older clients of Barrier will be rejected. Barrier now uses SHA256 fingerprints for establishing security of encrypted SSL connections. After upgrading client to new version the existing server fingerprint will need to be approved again. Client and server will show both SHA1 and SHA256 server fingerprints to allow interoperability with older versions of Barrier.

Bugfixes:

• Fixed build failure on mips*el and riscv64 architecture.
• Barrier no longer uses openssl CLI tool for any operations and hooks into the openssl library directly.
• More X11 clipboard MIME types have been mapped to corresponding converters (#344).
• Fixed setup of multiple actions associated with a hotkey.
• Fixed setup of hotkeys with special characters such as comma and semicolon (#778).
• Fixed transfer of non-ASCII characters coming from a Windows server in certain cases (#527).
• Barrier will now regenerate server certificate if it's invalid instead of failing to launch (#802)
• Added support for additional keys on Sun Microsystems USB keyboards (#784).
• Updated Chinese translation.
• Updated Slovak translation.
• Theme icons are now preferred to icons distributed together with Barrier (#471).

Features:

• Added --drop-target option that improves drag and drop support on Windows when Barrier is being run as a portable app.
• The --enable-crypto command line option has been made the default to reduce chances of accidental security mishaps when configuring Barrier from command line. A new --disable-crypto command line option has been added to explicitly disable encryption.
• Added support for randomart images for easier comparison of SSL certificate fingerprints. The algorithm is identical to what OpenSSH uses.
• Implemented a configuration option for Server GUI auto-start.
• Made it possible to use keyboard instead of mouse to modify screen layout.
• Added support for keyboard backlight media keys
• Added support for Eisu_toggle and Muhenkan keys
• Added --profile-dir option that allows to select custom profile directory.

submitted upstream at https://github.com/symless/synergy-core/pull/6261

• Bug #4749 - Clipboard thread race condition causes assertion
• Bug #4720 - Plugin download shows 'Could not get Linux package
• Bug #4712 - Unable to send clipboard with size above 1KB when
• Bug #4690 - Log line 'activeDesktop' does not use logging
• Enhancement #4901 - Auto restart when running from GUI in
• Bug #4650 - SSL error log message repeats excessively and
• Bug #4601 - Large clipboard data with SSL causes 'protocol is
• Bug #4593 - Locking Windows server causes SSL_ERROR_SSL to
• Bug #4538 - Windows service crashes intermittently with no
• Bug #4566 - Client or server crashes with 'ssl handshake
• Bug #4706 - Installer is not output to build config dir
• Bug #4704 - Plugin 'ns' release build is overwritten with
• Bug #4697 - Timing can allow an SSL socket to be used after
• Enhancement #4661 - Log error but do not crash when failing
• Enhancement #4708 - Download ns plugin for specific Mac
• Enhancement #4587 - Include OpenSSL binaries in source for
• Enhancement #4695 - Automatically upload plugins as

This update for barrier fixes the following issues:

Updated to version 2.4.0:

Barrier now supports client identity verification (fixes CVE-2021-42072, CVE-2021-42073).

Previously a malicious client could connect to Barrier server without any authentication and send application-level messages. This made the attack surface of Barrier significantly larger. Additionally, in case the malicious client got possession of a valid screen name by brute forcing or other means it could modify the clipboard contents of the server. To support seamless upgrades from older versions of Barrier this is currently disabled by default. The feature can be enabled in the settings dialog. If enabled, older clients of Barrier will be rejected. Barrier now uses SHA256 fingerprints for establishing security of encrypted SSL connections. After upgrading client to new version the existing server fingerprint will need to be approved again. Client and server will show both SHA1 and SHA256 server fingerprints to allow interoperability with older versions of Barrier.

Bugfixes:

• Fixed build failure on mips*el and riscv64 architecture.
• Barrier no longer uses openssl CLI tool for any operations and hooks into the openssl library directly.
• More X11 clipboard MIME types have been mapped to corresponding converters (#344).
• Fixed setup of multiple actions associated with a hotkey.
• Fixed setup of hotkeys with special characters such as comma and semicolon (#778).
• Fixed transfer of non-ASCII characters coming from a Windows server in certain cases (#527).
• Barrier will now regenerate server certificate if it's invalid instead of failing to launch (#802)
• Added support for additional keys on Sun Microsystems USB keyboards (#784).
• Updated Chinese translation.
• Updated Slovak translation.
• Theme icons are now preferred to icons distributed together with Barrier (#471).

Features:

• Added --drop-target option that improves drag and drop support on Windows when Barrier is being run as a portable app.
• The --enable-crypto command line option has been made the default to reduce chances of accidental security mishaps when configuring Barrier from command line. A new --disable-crypto command line option has been added to explicitly disable encryption.
• Added support for randomart images for easier comparison of SSL certificate fingerprints. The algorithm is identical to what OpenSSH uses.
• Implemented a configuration option for Server GUI auto-start.
• Made it possible to use keyboard instead of mouse to modify screen layout.
• Added support for keyboard backlight media keys
• Added support for Eisu_toggle and Muhenkan keys
• Added --profile-dir option that allows to select custom profile directory.

submitted upstream at https://github.com/symless/synergy-core/pull/6261

• Bug #4749 - Clipboard thread race condition causes assertion
• Bug #4720 - Plugin download shows 'Could not get Linux package
• Bug #4712 - Unable to send clipboard with size above 1KB when
• Bug #4690 - Log line 'activeDesktop' does not use logging
• Enhancement #4901 - Auto restart when running from GUI in
• Bug #4650 - SSL error log message repeats excessively and
• Bug #4601 - Large clipboard data with SSL causes 'protocol is
• Bug #4593 - Locking Windows server causes SSL_ERROR_SSL to
• Bug #4538 - Windows service crashes intermittently with no
• Bug #4566 - Client or server crashes with 'ssl handshake
• Bug #4706 - Installer is not output to build config dir
• Bug #4704 - Plugin 'ns' release build is overwritten with
• Bug #4697 - Timing can allow an SSL socket to be used after
• Enhancement #4661 - Log error but do not crash when failing
• Enhancement #4708 - Download ns plugin for specific Mac
• Enhancement #4587 - Include OpenSSL binaries in source for
• Enhancement #4695 - Automatically upload plugins as

These are all security issues fixed in the barrier-2.4.0-1.1 package on the GA media of openSUSE Tumbleweed.