nbdkit-release-notes-1.16 - Man Page

release notes for nbdkit 1.16

Description

These are the release notes for nbdkit stable release 1.16. This describes the major changes since 1.14.

nbdkit 1.16.0 was released on 14th November 2019.

Security

Two security issues were found during development of nbdkit 1.16. Fixes for these were backported to older stable branches.  Upgrading to the fixed versions is highly recommended.  The new nbdkit-security(1) man page contains an up to date list of past security issues.

CVE-2019-14850 denial of service due to premature opening of back-end connection

See the full announcement and links to mitigation, tests and fixes here: https://www.redhat.com/archives/libguestfs/2019-September/msg00084.html

CVE-2019-14851 assertion failure by issuing commands in the wrong order

This CVE was caused by the fix to the previous issue.

See the full announcement and links to mitigation, tests and fixes here: https://www.redhat.com/archives/libguestfs/2019-September/msg00272.html

New features

Add support for fast zeroing.  Plugins can expose this using the new .can_fast_zero method (Eric Blake).

nbdkit-partitioning-plugin(1) allows use of mbr-id=default or type-guid=default to go back to the default MBR byte or partition type GUID.

New --mask-handshake server flag can be used for testing client feature negotiation (Eric Blake).

The client export name is passed to nbdkit-captive(1) --run parameter as $exportname (Eric Blake).

Captive --run commands which fail (eg. aborting) now cause nbdkit to exit with an error instead of errors being silently ignored (Eric Blake).

File descriptors can be passed to password parameters, eg: password=-3 which means that the password should be read from file descriptor 3.

nbdkit can now serve over the AF_VSOCK protocol (thanks Stefan Hajnoczi).

New --log=null option discards error messages.

Plugins

Python 2 support has been dropped from nbdkit-python-plugin(3) in line with Python 2 end of life at the beginning of 2020.  Python ≥ 3.3 is required by this plugin.  If you wish to continue to use Python 2 then you will need to use nbdkit 1.14.

New nbdkit-info-plugin(1) which returns various server information back to the client.  It can be used for testing server latency amongst other things.

nbdkit-data-plugin(1) now allows you to write BYTE*N to get repeated bytes (eg. nbdkit data data="0x55*4096").

nbdkit-ssh-plugin(1) new parameter compression=true|false to control transport compression.

nbdkit-vddk-plugin(1) is no longer compiled on non-x86 platforms since VMware has only ever shipped VDDK on x86.

nbdkit-sh-plugin(1) scripts can now see the client exportname and can use the magic_config_key feature.

Filters

New nbdkit-retry-filter(1) which can reopen the plugin transparently on certain types of failures (lots of help from Eric Blake).

API

Macros NBDKIT_VERSION_MAJOR, NBDKIT_VERSION_MINOR, NBDKIT_VERSION_MICRO expose the compile-time version of nbdkit to plugins and filters (Eric Blake).

Filters (which unlike plugins do not have a public stable API) must now exactly match the version of nbdkit when loaded (Eric Blake).

New .can_fast_zero method (Eric Blake).

New nbdkit_export_name server function for reading the export name passed by the client.

New nbdkit_peer_name server function to return the client address (like getpeername(2)).

New server functions for safely parsing integers: nbdkit_parse_int, nbdkit_parse_unsigned, nbdkit_parse_int8_t, nbdkit_parse_uint8_t, nbdkit_parse_int16_t, nbdkit_parse_uint16_t, nbdkit_parse_int32_t, nbdkit_parse_uint32_t, nbdkit_parse_int64_t, nbdkit_parse_uint64_t.

Bug fixes

.trim with FUA flag set now works (Eric Blake).

Documentation

The previous release notes have been turned into man pages.

Tests

Several tests now optionally use nbdsh(1) instead of qemu-io.

You can now fuzz nbdkit using either American Fuzzy Lop or clang’s libFuzzer.

Several tests have had sleep times increased to make them more stable when run on slow or heavily loaded machines.

Internals

Reproducible builds (Chris Lamb).

Compile code with -Wshadow warning (Eric Blake).

The internal backend system has been extensively overhauled.  In particular this means that we now validate request ranges as requests are passed between filters and down to the plugin, making it easier to find bugs in filters early (Eric Blake).

Plugin size and can_* flags are cached more aggressively by the server (Eric Blake).

Variable Length Arrays (VLAs) on stack are now banned throughout the code.

The nbd-protocol.h header describing the NBD protocol is now shared with libnbd(3).

Plugin .unload method is now called after all worker threads have exited, avoiding races at server shutdown.

Code was audited using Coverity and various problems were fixed.

See Also

nbdkit(1).

Authors

Eric Blake

Richard W.M. Jones

License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Referenced By

nbdkit(1).

2020-06-29 nbdkit-1.21.13