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Fri Dec 29 2023 Paul Howarth <paul@city-fan.org> - 2.12.0-2
- Address CVE 2023-48795 (a.k.a. the "Terrapin Attack", a vulnerability found
in the SSH protocol re: treatment of packet sequence numbers) as follows:
- The vulnerability only impacts encrypt-then-MAC digest algorithms in tandem
with CBC ciphers, and ChaCha20-poly1305; of these, Paramiko currently only
implements ``hmac-sha2-(256|512)-etm`` in tandem with 'AES-CBC'
- As the fix for the vulnerability requires both ends of the connection to
cooperate, the below changes will only take effect when the remote end is
OpenSSH ≥ 9.6 (or equivalent, such as Paramiko in server mode, as of this
patch version) and configured to use the new "strict kex" mode
- Paramiko will always attempt to use "strict kex" mode if offered by the
server, unless you override this by specifying 'strict_kex=False' in
'Transport.__init__'
- Paramiko will now raise an 'SSHException' subclass ('MessageOrderError')
when protocol messages are received in unexpected order; this includes
situations like receiving 'MSG_DEBUG' or 'MSG_IGNORE' during initial key
exchange, which are no longer allowed during strict mode
- Key (re)negotiation, i.e. 'MSG_NEWKEYS', whenever it is encountered, now
resets packet sequence numbers (this should be invisible to users during
normal operation, only causing exceptions if the exploit is encountered,
which will usually result in, again, 'MessageOrderError')
- Sequence number rollover will now raise 'SSHException' if it occurs during
initial key exchange (regardless of strict mode status)
- Tweak 'ext-info-(c|s)' detection during KEXINIT protocol phase; the original
implementation made assumptions based on an OpenSSH implementation detail
- 'Transport' grew a new 'packetizer_class' kwarg for overriding the
packet-handler class used internally; this is mostly for testing, but advanced
users may find this useful when doing deep hacks
- A handful of lower-level classes (notably 'paramiko.message.Message' and
'paramiko.pkey.PKey') previously returned 'bytes' objects from their
implementation of '__str__', even under Python 3, and there was never any
'__bytes__' method; these issues have been fixed by renaming '__str__' to
'__bytes__' and relying on Python's default "stringification returns the
output of '__repr__'" behavior re: any real attempts to 'str()' such objects
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Sun Nov 06 2022 Paul Howarth <paul@city-fan.org> - 2.12.0-1
- Update to 2.12.0 (rhbz#2140281)
- Add a 'transport_factory' kwarg to 'SSHClient.connect' for advanced users
to gain more control over early Transport setup and manipulation (GH#2054,
GH#2125)
- Update '~paramiko.client.SSHClient' so it explicitly closes its wrapped
socket object upon encountering socket errors at connection time; this
should help somewhat with certain classes of memory leaks, resource
warnings, and/or errors (though we hasten to remind everyone that Client
and Transport have their own '.close()' methods for use in non-error
situations!) (GH#1822)
- Raise '~paramiko.ssh_exception.SSHException' explicitly when blank private
key data is loaded, instead of the natural result of 'IndexError'; this
should help more bits of Paramiko or Paramiko-adjacent codebases to
correctly handle this class of error (GH#1599, GH#1637)
- Use SPDX-format license tag
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Fri Jul 22 2022 Fedora Release Engineering <releng@fedoraproject.org> - 2.11.0-3
- Rebuilt for https://fedoraproject.org/wiki/Fedora_37_Mass_Rebuild
-
Tue Jun 14 2022 Python Maint <python-maint@redhat.com> - 2.11.0-2
- Rebuilt for Python 3.11
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Tue May 17 2022 Paul Howarth <paul@city-fan.org> - 2.11.0-1
- Update to 2.11.0
- Align signature verification algorithm with OpenSSH re: zero-padding
signatures that don't match their nominal size/length; this shouldn't
affect most users, but will help Paramiko-implemented SSH servers handle
poorly behaved clients such as PuTTY (GH#1933)
- OpenSSH 7.7 and older has a bug preventing it from understanding how to
perform SHA2 signature verification for RSA certificates (specifically
certs - not keys), so when we added SHA2 support it broke all clients using
RSA certificates with these servers; this has been fixed in a manner similar
to what OpenSSH's own client does - a version check is performed and the
algorithm used is downgraded if needed (GH#2017)
- Recent versions of Cryptography have deprecated Blowfish algorithm support;
in lieu of an easy method for users to remove it from the list of
algorithms Paramiko tries to import and use, we've decided to remove it
from our "preferred algorithms" list, which will both discourage use of a
weak algorithm, and avoid warnings (GH#2038, GH#2039)
- Windows-native SSH agent support as merged in 2.10 could encounter
'Errno 22' 'OSError' exceptions in some scenarios (e.g. server not cleanly
closing a relevant named pipe); this has been worked around and should be
less problematic (GH#2008, GH#2010)
- Add SSH config token expansion (eg '%h', '%p') when parsing 'ProxyJump'
directives (GH#1951)
- Apply unittest 'skipIf' to tests currently using SHA1 in their critical
path, to avoid failures on systems starting to disable SHA1 outright in
their crypto backends (e.g. RHEL 9) (GH#2004, GH#2011)
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Tue Apr 26 2022 Paul Howarth <paul@city-fan.org> - 2.10.4-1
- Update to 2.10.4
- Update 'camelCase' method calls against the 'threading' module to be
'snake_case'; this and related tweaks should fix some deprecation warnings
under Python 3.10 (GH#1838, GH#1870, GH#2028)
- '~paramiko.pkey.PKey' instances' '__eq__' did not have the usual safety
guard in place to ensure they were being compared to another 'PKey' object,
causing occasional spurious 'BadHostKeyException', among other things
(GH#1964, GH#2023, GH#2024)
- Servers offering certificate variants of hostkey algorithms (e.g.
'ssh-rsa-cert-v01@openssh.com') could not have their host keys verified by
Paramiko clients, as it only ever considered non-cert key types for that
part of connection handshaking (GH#2035)
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Mon Mar 21 2022 Paul Howarth <paul@city-fan.org> - 2.10.3-2
- Skip tests that would fail without SHA-1 signing support in backend, such as
on EL-9 (GH#2011)
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Sat Mar 19 2022 Paul Howarth <paul@city-fan.org> - 2.10.3-1
- Update to 2.10.3
- Certificate-based pubkey auth was inadvertently broken when adding SHA2
support in version 2.9.0 (GH#1963, GH#1977)
- Switch from module-global to thread-local storage when recording thread IDs
for a logging helper; this should avoid one flavor of memory leak for
long-running processes (GH#2002, GH#2003)
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Tue Mar 15 2022 Paul Howarth <paul@city-fan.org> - 2.10.2-1
- Update to 2.10.2
- Fix Python 2 compatibility breakage introduced in 2.10.1 (GH#2001)
- Re-enable sftp tests, no longer failing under mock
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Sun Mar 13 2022 Paul Howarth <paul@city-fan.org> - 2.10.1-1
- Update to 2.10.1
- CVE-2022-24302: Creation of new private key files using
'~paramiko.pkey.PKey' subclasses was subject to a race condition between
file creation and mode modification, which could be exploited by an
attacker with knowledge of where the Paramiko-using code would write out
such files; this has been patched by using 'os.open' and 'os.fdopen' to
ensure new files are opened with the correct mode immediately (we've left
the subsequent explicit 'chmod' in place to minimize any possible
disruption, though it may get removed in future backwards-incompatible
updates)
- Add support for the '%C' token when parsing SSH config files (GH#1976)
- Add support for OpenSSH's Windows agent as a fallback when Putty/WinPageant
isn't available or functional (GH#1509, GH#1837, GH#1868)
- Significantly speed up low-level read/write actions on
'~paramiko.sftp_file.SFTPFile' objects by using 'bytearray'/'memoryview'
(GH#892); this is unlikely to change anything for users of the higher level
methods like 'SFTPClient.get' or 'SFTPClient.getfo', but users of
'SFTPClient.open' will likely see orders of magnitude improvements for
files larger than a few megabytes in size
- Add 'six' explicitly to install-requires; it snuck into active use at some
point but has only been indicated by transitive dependency on 'bcrypt'
until they somewhat-recently dropped it (GH#1985); this will be short-lived
until we drop Python 2 support