OpenSSH Release Notes

OpenSSH 8.3 was released on 2020-05-27. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: https://www.openssh.com/donations.html Future deprecation notice ========================= It is now possible[1] to perform chosen-prefix attacks against the SHA-1 algorithm for less than USD$50K. For this reason, we will be disabling the "ssh-rsa" public key signature algorithm by default in a near-future release. This algorithm is unfortunately still used widely despite the existence of better alternatives, being the only remaining public key signature algorithm specified by the original SSH RFCs. The better alternatives include: * The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These algorithms have the advantage of using the same key type as "ssh-rsa" but use the safe SHA-2 hash algorithms. These have been supported since OpenSSH 7.2 and are already used by default if the client and server support them. * The ssh-ed25519 signature algorithm. It has been supported in OpenSSH since release 6.5. * The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These have been supported by OpenSSH since release 5.7. To check whether a server is using the weak ssh-rsa public key algorithm, for host authentication, try to connect to it after removing the ssh-rsa algorithm from ssh(1)'s allowed list: ssh -oHostKeyAlgorithms=-ssh-rsa user@host If the host key verification fails and no other supported host key types are available, the server software on that host should be upgraded. A future release of OpenSSH will enable UpdateHostKeys by default to allow the client to automatically migrate to better algorithms. Users may consider enabling this option manually. Vendors of devices that implement the SSH protocol should ensure that they support the new signature algorithms for RSA keys. [1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust" Leurent, G and Peyrin, T (2020) https://eprint.iacr.org/2020/014.pdf Security ======== * scp(1): when receiving files, scp(1) could be become desynchronised if a utimes(2) system call failed. This could allow file contents to be interpreted as file metadata and thereby permit an adversary to craft a file system that, when copied with scp(1) in a configuration that caused utimes(2) to fail (e.g. under a SELinux policy or syscall sandbox), transferred different file names and contents to the actual file system layout. Exploitation of this is not likely as utimes(2) does not fail under normal circumstances. Successful exploitation is not silent - the output of scp(1) would show transfer errors followed by the actual file(s) that were received. Finally, filenames returned from the peer are (since openssh-8.0) matched against the user's requested destination, thereby disallowing a successful exploit from writing files outside the user's selected target glob (or directory, in the case of a recursive transfer). This ensures that this attack can achieve no more than a hostile peer is already able to achieve within the scp protocol. Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * sftp(1): reject an argument of "-1" in the same way as ssh(1) and scp(1) do instead of accepting and silently ignoring it. Changes since OpenSSH 8.2 ========================= The focus of this release is bug fixing. New Features ------------ * sshd(8): make IgnoreRhosts a tri-state option: "yes" to ignore rhosts/shosts, "no" allow rhosts/shosts or (new) "shosts-only" to allow .shosts files but not .rhosts. * sshd(8): allow the IgnoreRhosts directive to appear anywhere in a sshd_config, not just before any Match blocks; bz3148 * ssh(1): add %TOKEN percent expansion for the LocalFoward and RemoteForward keywords when used for Unix domain socket forwarding. bz#3014 * all: allow loading public keys from the unencrypted envelope of a private key file if no corresponding public key file is present. * ssh(1), sshd(8): prefer to use chacha20 from libcrypto where possible instead of the (slower) portable C implementation included in OpenSSH. * ssh-keygen(1): add ability to dump the contents of a binary key revocation list via "ssh-keygen -lQf /path" bz#3132 Bugfixes -------- * ssh(1): fix IdentitiesOnly=yes to also apply to keys loaded from a PKCS11Provider; bz#3141 * ssh-keygen(1): avoid NULL dereference when trying to convert an invalid RFC4716 private key. * scp(1): when performing remote-to-remote copies using "scp -3", start the second ssh(1) channel with BatchMode=yes enabled to avoid confusing and non-deterministic ordering of prompts. * ssh(1), ssh-keygen(1): when signing a challenge using a FIDO token, perform hashing of the message to be signed in the middleware layer rather than in OpenSSH code. This permits the use of security key middlewares that perform the hashing implicitly, such as Windows Hello. * ssh(1): fix incorrect error message for "too many known hosts files." bz#3149 * ssh(1): make failures when establishing "Tunnel" forwarding terminate the connection when ExitOnForwardFailure is enabled; bz#3116 * ssh-keygen(1): fix printing of fingerprints on private keys and add a regression test for same. * sshd(8): document order of checking AuthorizedKeysFile (first) and AuthorizedKeysCommand (subsequently, if the file doesn't match); bz#3134 * sshd(8): document that /etc/hosts.equiv and /etc/shosts.equiv are not considered for HostbasedAuthentication when the target user is root; bz#3148 * ssh(1), ssh-keygen(1): fix NULL dereference in private certificate key parsing (oss-fuzz #20074). * ssh(1), sshd(8): more consistency between sets of %TOKENS are accepted in various configuration options. * ssh(1), ssh-keygen(1): improve error messages for some common PKCS#11 C_Login failure cases; bz#3130 * ssh(1), sshd(8): make error messages for problems during SSH banner exchange consistent with other SSH transport-layer error messages and ensure they include the relevant IP addresses bz#3129 * various: fix a number of spelling errors in comments and debug/error messages * ssh-keygen(1), ssh-add(1): when downloading FIDO2 resident keys from a token, don't prompt for a PIN until the token has told us that it needs one. Avoids double-prompting on devices that implement on-device authentication. * sshd(8), ssh-keygen(1): no-touch-required FIDO certificate option should be an extension, not a critical option. * ssh(1), ssh-keygen(1), ssh-add(1): offer a better error message when trying to use a FIDO key function and SecurityKeyProvider is empty. * ssh-add(1), ssh-agent(8): ensure that a key lifetime fits within the values allowed by the wire format (u32). Prevents integer wraparound of the timeout values. bz#3119 * ssh(1): detect and prevent trivial configuration loops when using ProxyJump. bz#3057. Portability ----------- * Detect systems where signals flagged with SA_RESTART will interrupt select(2). POSIX permits implementations to choose whether select(2) will return when interrupted with a SA_RESTART-flagged signal, but OpenSSH requires interrupting behaviour. * Several compilation fixes for HP/UX and AIX. * On platforms that do not support setting process-wide routing domains (all excepting OpenBSD at present), fail to accept a configuration attempts to set one at process start time rather than fatally erroring at run time. bz#3126 * Improve detection of egrep (used in regression tests) on platforms that offer a poor default one (e.g. Solaris). * A number of shell portability fixes for the regression tests. * Fix theoretical infinite loop in the glob(3) replacement implementation. * Fix seccomp sandbox compilation problems for some Linux configurations bz#3085 * Improved detection of libfido2 and some compilation fixes for some configurations when --with-security-key-builtin is selected. Checksums: ========== - SHA1 (openssh-8.3.tar.gz) = 46c63b7ddbe46a0666222f7988c993866c31fcca - SHA256 (openssh-8.3.tar.gz) = M6CnZ+duGs4bzDio8hQNLwyLQChV+3wkUEO8HWLV35c= - SHA1 (/openssh-8.3p1.tar.gz) = 04c7adb9986f16746588db8988b910530c589819 - SHA256 (openssh-8.3p1.tar.gz) = 8r774Ecv5+t10jNA6xdTHLazqsJAdeIGa0H4FOEjh7I= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read https://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 8.2 was released on 2020-02-14. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: https://www.openssh.com/donations.html Future deprecation notice ========================= It is now possible[1] to perform chosen-prefix attacks against the SHA-1 hash algorithm for less than USD$50K. For this reason, we will be disabling the "ssh-rsa" public key signature algorithm that depends on SHA-1 by default in a near-future release. This algorithm is unfortunately still used widely despite the existence of better alternatives, being the only remaining public key signature algorithm specified by the original SSH RFCs. The better alternatives include: * The RFC8332 RSA SHA-2 signature algorithms rsa-sha2-256/512. These algorithms have the advantage of using the same key type as "ssh-rsa" but use the safe SHA-2 hash algorithms. These have been supported since OpenSSH 7.2 and are already used by default if the client and server support them. * The ssh-ed25519 signature algorithm. It has been supported in OpenSSH since release 6.5. * The RFC5656 ECDSA algorithms: ecdsa-sha2-nistp256/384/521. These have been supported by OpenSSH since release 5.7. To check whether a server is using the weak ssh-rsa public key algorithm for host authentication, try to connect to it after removing the ssh-rsa algorithm from ssh(1)'s allowed list: ssh -oHostKeyAlgorithms=-ssh-rsa user@host If the host key verification fails and no other supported host key types are available, the server software on that host should be upgraded. A future release of OpenSSH will enable UpdateHostKeys by default to allow the client to automatically migrate to better algorithms. Users may consider enabling this option manually. [1] "SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust" Leurent, G and Peyrin, T (2020) https://eprint.iacr.org/2020/014.pdf Security ======== * ssh(1), sshd(8), ssh-keygen(1): this release removes the "ssh-rsa" (RSA/SHA1) algorithm from those accepted for certificate signatures (i.e. the client and server CASignatureAlgorithms option) and will use the rsa-sha2-512 signature algorithm by default when the ssh-keygen(1) CA signs new certificates. Certificates are at special risk to the aforementioned SHA1 collision vulnerability as an attacker has effectively unlimited time in which to craft a collision that yields them a valid certificate, far more than the relatively brief LoginGraceTime window that they have to forge a host key signature. The OpenSSH certificate format includes a CA-specified (typically random) nonce value near the start of the certificate that should make exploitation of chosen-prefix collisions in this context challenging, as the attacker does not have full control over the prefix that actually gets signed. Nonetheless, SHA1 is now a demonstrably broken algorithm and futher improvements in attacks are highly likely. OpenSSH releases prior to 7.2 do not support the newer RSA/SHA2 algorithms and will refuse to accept certificates signed by an OpenSSH 8.2+ CA using RSA keys unless the unsafe algorithm is explicitly selected during signing ("ssh-keygen -t ssh-rsa"). Older clients/servers may use another CA key type such as ssh-ed25519 (supported since OpenSSH 6.5) or one of the ecdsa-sha2-nistp256/384/521 types (supported since OpenSSH 5.7) instead if they cannot be upgraded. Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh(1), sshd(8): the above removal of "ssh-rsa" from the accepted CASignatureAlgorithms list. * ssh(1), sshd(8): this release removes diffie-hellman-group14-sha1 from the default key exchange proposal for both the client and server. * ssh-keygen(1): the command-line options related to the generation and screening of safe prime numbers used by the diffie-hellman-group-exchange-* key exchange algorithms have changed. Most options have been folded under the -O flag. * sshd(8): the sshd listener process title visible to ps(1) has changed to include information about the number of connections that are currently attempting authentication and the limits configured by MaxStartups. * ssh-sk-helper(8): this is a new binary. It is used by the FIDO/U2F support to provide address-space isolation for token middleware libraries (including the internal one). It needs to be installed in the expected path, typically under /usr/libexec or similar. Changes since OpenSSH 8.1 ========================= This release contains some significant new features. FIDO/U2F Support ---------------- This release adds support for FIDO/U2F hardware authenticators to OpenSSH. U2F/FIDO are open standards for inexpensive two-factor authentication hardware that are widely used for website authentication. In OpenSSH FIDO devices are supported by new public key types "ecdsa-sk" and "ed25519-sk", along with corresponding certificate types. ssh-keygen(1) may be used to generate a FIDO token-backed key, after which they may be used much like any other key type supported by OpenSSH, so long as the hardware token is attached when the keys are used. FIDO tokens also generally require the user explicitly authorise operations by touching or tapping them. Generating a FIDO key requires the token be attached, and will usually require the user tap the token to confirm the operation: $ ssh-keygen -t ecdsa-sk -f ~/.ssh/id_ecdsa_sk Generating public/private ecdsa-sk key pair. You may need to touch your security key to authorize key generation. Enter file in which to save the key (/home/djm/.ssh/id_ecdsa_sk): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /home/djm/.ssh/id_ecdsa_sk Your public key has been saved in /home/djm/.ssh/id_ecdsa_sk.pub This will yield a public and private key-pair. The private key file should be useless to an attacker who does not have access to the physical token. After generation, this key may be used like any other supported key in OpenSSH and may be listed in authorized_keys, added to ssh-agent(1), etc. The only additional stipulation is that the FIDO token that the key belongs to must be attached when the key is used. FIDO tokens are most commonly connected via USB but may be attached via other means such as Bluetooth or NFC. In OpenSSH, communication with the token is managed via a middleware library, specified by the SecurityKeyProvider directive in ssh/sshd_config(5) or the $SSH_SK_PROVIDER environment variable for ssh-keygen(1) and ssh-add(1). The API for this middleware is documented in the sk-api.h and PROTOCOL.u2f files in the source distribution. OpenSSH includes a middleware ("SecurityKeyProvider=internal") with support for USB tokens. It is automatically enabled in OpenBSD and may be enabled in portable OpenSSH via the configure flag --with-security-key-builtin. If the internal middleware is enabled then it is automatically used by default. This internal middleware requires that libfido2 (https://github.com/Yubico/libfido2)and its dependencies be installed. We recommend that packagers of portable OpenSSH enable the built-in middleware, as it provides the lowest-friction experience for users. Note: FIDO/U2F tokens are required to implement the ECDSA-P256 "ecdsa-sk" key type, but hardware support for Ed25519 "ed25519-sk" is less common. Similarly, not all hardware tokens support some of the optional features such as resident keys. The protocol-level changes to support FIDO/U2F keys in SSH are documented in the PROTOCOL.u2f file in the OpenSSH source distribution. There are a number of supporting changes to this feature: * ssh-keygen(1): add a "no-touch-required" option when generating FIDO-hosted keys, that disables their default behaviour of requiring a physical touch/tap on the token during authentication. Note: not all tokens support disabling the touch requirement. * sshd(8): add a sshd_config PubkeyAuthOptions directive that collects miscellaneous public key authentication-related options for sshd(8). At present it supports only a single option "no-touch-required". This causes sshd to skip its default check for FIDO/U2F keys that the signature was authorised by a touch or press event on the token hardware. * ssh(1), sshd(8), ssh-keygen(1): add a "no-touch-required" option for authorized_keys and a similar extension for certificates. This option disables the default requirement that FIDO key signatures attest that the user touched their key to authorize them, mirroring the similar PubkeyAuthOptions sshd_config option. * ssh-keygen(1): add support for the writing the FIDO attestation information that is returned when new keys are generated via the "-O write-attestation=/path" option. FIDO attestation certificates may be used to verify that a FIDO key is hosted in trusted hardware. OpenSSH does not currently make use of this information, beyond optionally writing it to disk. FIDO2 resident keys ------------------- FIDO/U2F OpenSSH keys consist of two parts: a "key handle" part stored in the private key file on disk, and a per-device private key that is unique to each FIDO/U2F token and that cannot be exported from the token hardware. These are combined by the hardware at authentication time to derive the real key that is used to sign authentication challenges. For tokens that are required to move between computers, it can be cumbersome to have to move the private key file first. To avoid this requirement, tokens implementing the newer FIDO2 standard support "resident keys", where it is possible to effectively retrieve the key handle part of the key from the hardware. OpenSSH supports this feature, allowing resident keys to be generated using the ssh-keygen(1) "-O resident" flag. This will produce a public/private key pair as usual, but it will be possible to retrieve the private key part from the token later. This may be done using "ssh-keygen -K", which will download all available resident keys from the tokens attached to the host and write public/private key files for them. It is also possible to download and add resident keys directly to ssh-agent(1) without writing files to the file-system using "ssh-add -K". Resident keys are indexed on the token by the application string and user ID. By default, OpenSSH uses an application string of "ssh:" and an empty user ID. If multiple resident keys on a single token are desired then it may be necessary to override one or both of these defaults using the ssh-keygen(1) "-O application=" or "-O user=" options. Note: OpenSSH will only download and use resident keys whose application string begins with "ssh:" Storing both parts of a key on a FIDO token increases the likelihood of an attacker being able to use a stolen token device. For this reason, tokens should enforce PIN authentication before allowing download of keys, and users should set a PIN on their tokens before creating any resident keys. Other New Features ------------------ * sshd(8): add an Include sshd_config keyword that allows including additional configuration files via glob(3) patterns. bz2468 * ssh(1)/sshd(8): make the LE (low effort) DSCP code point available via the IPQoS directive; bz2986, * ssh(1): when AddKeysToAgent=yes is set and the key contains no comment, add the key to the agent with the key's path as the comment. bz2564 * ssh-keygen(1), ssh-agent(1): expose PKCS#11 key labels and X.509 subjects as key comments, rather than simply listing the PKCS#11 provider library path. PR138 * ssh-keygen(1): allow PEM export of DSA and ECDSA keys; bz3091 * ssh(1), sshd(8): make zlib compile-time optional, available via the Makefile.inc ZLIB flag on OpenBSD or via the --with-zlib configure option for OpenSSH portable. * sshd(8): when clients get denied by MaxStartups, send a notification prior to the SSH2 protocol banner according to RFC4253 section 4.2. * ssh(1), ssh-agent(1): when invoking the $SSH_ASKPASS prompt program, pass a hint to the program to describe the type of desired prompt. The possible values are "confirm" (indicating that a yes/no confirmation dialog with no text entry should be shown), "none" (to indicate an informational message only), or blank for the original ssh-askpass behaviour of requesting a password/phrase. * ssh(1): allow forwarding a different agent socket to the path specified by $SSH_AUTH_SOCK, by extending the existing ForwardAgent option to accepting an explicit path or the name of an environment variable in addition to yes/no. * ssh-keygen(1): add a new signature operations "find-principals" to look up the principal associated with a signature from an allowed- signers file. * sshd(8): expose the number of currently-authenticating connections along with the MaxStartups limit in the process title visible to "ps". Bugfixes -------- * sshd(8): make ClientAliveCountMax=0 have sensible semantics: it will now disable connection killing entirely rather than the current behaviour of instantly killing the connection after the first liveness test regardless of success. bz2627 * sshd(8): clarify order of AllowUsers / DenyUsers vs AllowGroups / DenyGroups in the sshd(8) manual page. bz1690 * sshd(8): better describe HashKnownHosts in the manual page. bz2560 * sshd(8): clarify that that permitopen=/PermitOpen do no name or address translation in the manual page. bz3099 * sshd(8): allow the UpdateHostKeys feature to function when multiple known_hosts files are in use. When updating host keys, ssh will now search subsequent known_hosts files, but will add updated host keys to the first specified file only. bz2738 * All: replace all calls to signal(2) with a wrapper around sigaction(2). This wrapper blocks all other signals during the handler preventing races between handlers, and sets SA_RESTART which should reduce the potential for short read/write operations. * sftp(1): fix a race condition in the SIGCHILD handler that could turn in to a kill(-1); bz3084 * sshd(8): fix a case where valid (but extremely large) SSH channel IDs were being incorrectly rejected. bz3098 * ssh(1): when checking host key fingerprints as answers to new hostkey prompts, ignore whitespace surrounding the fingerprint itself. * All: wait for file descriptors to be readable or writeable during non-blocking connect, not just readable. Prevents a timeout when the server doesn't immediately send a banner (e.g. multiplexers like sslh) * sshd_config(5): document the sntrup4591761x25519-sha512@tinyssh.org key exchange algorithm. PR151 Portability ----------- * sshd(8): multiple adjustments to the Linux seccomp sandbox: - Non-fatally deny IPC syscalls in sandbox - Allow clock_gettime64() in sandbox (MIPS / glibc >= 2.31) - Allow clock_nanosleep_time64 in sandbox (ARM) bz3100 - Allow clock_nanosleep() in sandbox (recent glibc) bz3093 * Explicit check for memmem declaration and fix up declaration if the system headers lack it. bz3102 Checksums: ========== - SHA1 (openssh-8.2.tar.gz) = 0daae2a8c47c489a8784f2c38c4b39e6159ba678 - SHA256 (openssh-8.2.tar.gz) = +UmInEIoHJqYqWneMb/kgRbLcq8WDCo7+ooYcjzW4jg= - SHA1 (openssh-8.2p1.tar.gz) = d1ab35a93507321c5db885e02d41ce1414f0507c - SHA256 (openssh-8.2p1.tar.gz) = Q5JRUebPbO4UUBkMDpr03Da0HBJzdhnt/4vOvf9k5nE= Note: the openssh-8.2 tarball for OpenBSD that was initially released advertised an incorrect version for "ssh -V" and the sshd server banner. The above tarball replace the incorrect release, which has been renamed to openssh-8.2.tar.gz.incorrect. These are the checksums for the original, incorrect tarball: - SHA1 (openssh-8.2.tar.gz) = 77584c22fbb89269398acdf53c1e554400584ba8 - SHA256 (openssh-8.2.tar.gz) = UttLaaSYXVK1O65cYvyQzyQ5sCfuJ4Lwrs8zNsPrluQ= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read https://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 8.1 was released on 2019-10-09. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Security ======== * ssh(1), sshd(8), ssh-add(1), ssh-keygen(1): an exploitable integer overflow bug was found in the private key parsing code for the XMSS key type. This key type is still experimental and support for it is not compiled by default. No user-facing autoconf option exists in portable OpenSSH to enable it. This bug was found by Adam Zabrocki and reported via SecuriTeam's SSD program. * ssh(1), sshd(8), ssh-agent(1): add protection for private keys at rest in RAM against speculation and memory side-channel attacks like Spectre, Meltdown and Rambleed. This release encrypts private keys when they are not in use with a symmetric key that is derived from a relatively large "prekey" consisting of random data (currently 16KB). Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh-keygen(1): when acting as a CA and signing certificates with an RSA key, default to using the rsa-sha2-512 signature algorithm. Certificates signed by RSA keys will therefore be incompatible with OpenSSH versions prior to 7.2 unless the default is overridden (using "ssh-keygen -t ssh-rsa -s ..."). Changes since OpenSSH 8.0 ========================= This release is focused on bug-fixing. New Features ------------ * ssh(1): Allow %n to be expanded in ProxyCommand strings * ssh(1), sshd(8): Allow prepending a list of algorithms to the default set by starting the list with the '^' character, E.g. "HostKeyAlgorithms ^ssh-ed25519" * ssh-keygen(1): add an experimental lightweight signature and verification ability. Signatures may be made using regular ssh keys held on disk or stored in a ssh-agent and verified against an authorized_keys-like list of allowed keys. Signatures embed a namespace that prevents confusion and attacks between different usage domains (e.g. files vs email). * ssh-keygen(1): print key comment when extracting public key from a private key. bz#3052 * ssh-keygen(1): accept the verbose flag when searching for host keys in known hosts (i.e. "ssh-keygen -vF host") to print the matching host's random-art signature too. bz#3003 * All: support PKCS8 as an optional format for storage of private keys to disk. The OpenSSH native key format remains the default, but PKCS8 is a superior format to PEM if interoperability with non-OpenSSH software is required, as it may use a less insecure key derivation function than PEM's. Bugfixes -------- * ssh(1): if a PKCS#11 token returns no keys then try to login and refetch them. Based on patch from Jakub Jelen; bz#2430 * ssh(1): produce a useful error message if the user's shell is set incorrectly during "match exec" processing. bz#2791 * sftp(1): allow the maximum uint32 value for the argument passed to -b which allows better error messages from later validation. bz#3050 * ssh(1): avoid pledge sandbox violations in some combinations of remote forwarding, connection multiplexing and ControlMaster. * ssh-keyscan(1): include SHA2-variant RSA key algorithms in KEX proposal; allows ssh-keyscan to harvest keys from servers that disable old SHA1 ssh-rsa. bz#3029 * sftp(1): print explicit "not modified" message if a file was requested for resumed download but was considered already complete. bz#2978 * sftp(1): fix a typo and make <esc><right> move right to the closest end of a word just like <esc><left> moves left to the closest beginning of a word. * sshd(8): cap the number of permitopen/permitlisten directives allowed to appear on a single authorized_keys line. * All: fix a number of memory leaks (one-off or on exit paths). * Regression tests: a number of fixes and improvements, including fixes to the interop tests, adding the ability to run most tests on builds that disable OpenSSL support, better support for running tests under Valgrind and a number of bug-fixes. * ssh(1), sshd(8): check for convtime() refusing to accept times that resolve to LONG_MAX Reported by Kirk Wolf bz2977 * ssh(1): slightly more instructive error message when the user specifies multiple -J options on the command-line. bz3015 * ssh-agent(1): process agent requests for RSA certificate private keys using correct signature algorithm when requested. bz3016 * sftp(1): check for user@host when parsing sftp target. This allows user@[1.2.3.4] to work without a path. bz#2999 * sshd(8): enlarge format buffer size for certificate serial number so the log message can record any 64-bit integer without truncation. bz#3012 * sshd(8): for PermitOpen violations add the remote host and port to be able to more easily ascertain the source of the request. Add the same logging for PermitListen violations which where not previously logged at all. * scp(1), sftp(1): use the correct POSIX format style for left justification for the transfer progress meter. bz#3002 * sshd(8) when examining a configuration using sshd -T, assume any attribute not provided by -C does not match, which allows it to work when sshd_config contains a Match directive with or without -C. bz#2858 * ssh(1), ssh-keygen(1): downgrade PKCS#11 "provider returned no slots" warning from log level error to debug. This is common when attempting to enumerate keys on smartcard readers with no cards plugged in. bz#3058 * ssh(1), ssh-keygen(1): do not unconditionally log in to PKCS#11 tokens. Avoids spurious PIN prompts for keys not selected for authentication in ssh(1) and when listing public keys available in a token using ssh-keygen(1). bz#3006 Portability ----------- * ssh(1): fix SIGWINCH delivery of Solaris for multiplexed sessions bz#3030 * ssh(1), sshd(8): fix typo that prevented detection of Linux VRF * sshd(8): add no-op implementation of pam_putenv to avoid build breakage on platforms where the PAM implementation lacks this function (e.g. HP-UX). bz#3008 * sftp-server(8): fix Solaris privilege sandbox from preventing the legacy sftp rename operation from working (was refusing to allow hard links to files owned by other users). bz#3036 * All: add a proc_pidinfo()-based closefrom() for OS X to avoid the need to brute-force close all high-numbered file descriptors. bz#3049 * sshd(8): in the Linux seccomp-bpf sandbox, allow mprotect(2) with PROT_(READ|WRITE|NONE) only. This syscall is used by some hardened heap allocators. Github PR142 * sshd(8): in the Linux seccomp-bpf sandbox, allow the s390-specific ioctl for ECC hardware support. * All: use "doc" man page format if the mandoc(1) tool is present on the system. Previously configure would not select the "doc" man page format if mandoc was present but nroff was not. * sshd(8): don't install duplicate STREAMS modules on Solaris; check if STREAMS modules are already installed on a pty before installing since when compiling with XPG>=4 they will likely be installed already. Prevents hangs and duplicate lines on the terminal. bz#2945 and bz#2998, Checksums: ========== - SHA1 (openssh-8.1.tar.gz) = bf7b0c65a7c0afa5ba9c787f345b8a24fa459add - SHA256 (openssh-8.1.tar.gz) = vamkKxZTFfgxQXSxGeJ1vbuot0H3Vx9bNBgrvChSrFg= - SHA1 (openssh-8.1p1.tar.gz) = c44b96094869f177735ae053d92bd5fcab1319de - SHA256 (openssh-8.1p1.tar.gz) = AvXb7zg10HU1VvlzzVe0wZtrH2zSTANEXiOsd8obk/8= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 8.0 was released on 2019-04-17. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Security ======== This release contains mitigation for a weakness in the scp(1) tool and protocol (CVE-2019-6111): when copying files from a remote system to a local directory, scp(1) did not verify that the filenames that the server sent matched those requested by the client. This could allow a hostile server to create or clobber unexpected local files with attacker-controlled content. This release adds client-side checking that the filenames sent from the server match the command-line request, The scp protocol is outdated, inflexible and not readily fixed. We recommend the use of more modern protocols like sftp and rsync for file transfer instead. Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * scp(1): Relating to the above changes to scp(1); the scp protocol relies on the remote shell for wildcard expansion, so there is no infallible way for the client's wildcard matching to perfectly reflect the server's. If there is a difference between client and server wildcard expansion, the client may refuse files from the server. For this reason, we have provided a new "-T" flag to scp that disables these client-side checks at the risk of reintroducing the attack described above. * sshd(8): Remove support for obsolete "host/port" syntax. Slash- separated host/port was added in 2001 as an alternative to host:port syntax for the benefit of IPv6 users. These days there are establised standards for this like [::1]:22 and the slash syntax is easily mistaken for CIDR notation, which OpenSSH supports for some things. Remove the slash notation from ListenAddress and PermitOpen; bz#2335 Changes since OpenSSH 7.9 ========================= This release is focused on new features and internal refactoring. New Features ------------ * ssh(1), ssh-agent(1), ssh-add(1): Add support for ECDSA keys in PKCS#11 tokens. * ssh(1), sshd(8): Add experimental quantum-computing resistant key exchange method, based on a combination of Streamlined NTRU Prime 4591^761 and X25519. * ssh-keygen(1): Increase the default RSA key size to 3072 bits, following NIST Special Publication 800-57's guidance for a 128-bit equivalent symmetric security level. * ssh(1): Allow "PKCS11Provider=none" to override later instances of the PKCS11Provider directive in ssh_config; bz#2974 * sshd(8): Add a log message for situations where a connection is dropped for attempting to run a command but a sshd_config ForceCommand=internal-sftp restriction is in effect; bz#2960 * ssh(1): When prompting whether to record a new host key, accept the key fingerprint as a synonym for "yes". This allows the user to paste a fingerprint obtained out of band at the prompt and have the client do the comparison for you. * ssh-keygen(1): When signing multiple certificates on a single command-line invocation, allow automatically incrementing the certificate serial number. * scp(1), sftp(1): Accept -J option as an alias to ProxyJump on the scp and sftp command-lines. * ssh-agent(1), ssh-pkcs11-helper(8), ssh-add(1): Accept "-v" command-line flags to increase the verbosity of output; pass verbose flags though to subprocesses, such as ssh-pkcs11-helper started from ssh-agent. * ssh-add(1): Add a "-T" option to allowing testing whether keys in an agent are usable by performing a signature and a verification. * sftp-server(8): Add a "lsetstat@openssh.com" protocol extension that replicates the functionality of the existing SSH2_FXP_SETSTAT operation but does not follow symlinks. bz#2067 * sftp(1): Add "-h" flag to chown/chgrp/chmod commands to request they do not follow symlinks. * sshd(8): Expose $SSH_CONNECTION in the PAM environment. This makes the connection 4-tuple available to PAM modules that wish to use it in decision-making. bz#2741 * sshd(8): Add a ssh_config "Match final" predicate Matches in same pass as "Match canonical" but doesn't require hostname canonicalisation be enabled. bz#2906 * sftp(1): Support a prefix of '@' to suppress echo of sftp batch commands; bz#2926 * ssh-keygen(1): When printing certificate contents using "ssh-keygen -Lf /path/certificate", include the algorithm that the CA used to sign the cert. Bugfixes -------- * sshd(8): Fix authentication failures when sshd_config contains "AuthenticationMethods any" inside a Match block that overrides a more restrictive default. * sshd(8): Avoid sending duplicate keepalives when ClientAliveCount is enabled. * sshd(8): Fix two race conditions related to SIGHUP daemon restart. Remnant file descriptors in recently-forked child processes could block the parent sshd's attempt to listen(2) to the configured addresses. Also, the restarting parent sshd could exit before any child processes that were awaiting their re-execution state had completed reading it, leaving them in a fallback path. * ssh(1): Fix stdout potentially being redirected to /dev/null when ProxyCommand=- was in use. * sshd(8): Avoid sending SIGPIPE to child processes if they attempt to write to stderr after their parent processes have exited; bz#2071 * ssh(1): Fix bad interaction between the ssh_config ConnectTimeout and ConnectionAttempts directives - connection attempts after the first were ignoring the requested timeout; bz#2918 * ssh-keyscan(1): Return a non-zero exit status if no keys were found; bz#2903 * scp(1): Sanitize scp filenames to allow UTF-8 characters without terminal control sequences; bz#2434 * sshd(8): Fix confusion between ClientAliveInterval and time-based RekeyLimit that could cause connections to be incorrectly closed. bz#2757 * ssh(1), ssh-add(1): Correct some bugs in PKCS#11 token PIN handling at initial token login. The attempt to read the PIN could be skipped in some cases, particularly on devices with integrated PIN readers. This would lead to an inability to retrieve keys from these tokens. bz#2652 * ssh(1), ssh-add(1): Support keys on PKCS#11 tokens that set the CKA_ALWAYS_AUTHENTICATE flag by requring a fresh login after the C_SignInit operation. bz#2638 * ssh(1): Improve documentation for ProxyJump/-J, clarifying that local configuration does not apply to jump hosts. * ssh-keygen(1): Clarify manual - ssh-keygen -e only writes public keys, not private. * ssh(1), sshd(8): be more strict in processing protocol banners, allowing \r characters only immediately before

. * Various: fix a number of memory leaks, including bz#2942 and bz#2938 * scp(1), sftp(1): fix calculation of initial bandwidth limits. Account for bytes written before the timer starts and adjust the schedule on which recalculations are performed. Avoids an initial burst of traffic and yields more accurate bandwidth limits; bz#2927 * sshd(8): Only consider the ext-info-c extension during the initial key eschange. It shouldn't be sent in subsequent ones, but if it is present we should ignore it. This prevents sshd from sending a SSH_MSG_EXT_INFO for REKEX for buggy these clients. bz#2929 * ssh-keygen(1): Clarify manual that ssh-keygen -F (find host in authorized_keys) and -R (remove host from authorized_keys) options may accept either a bare hostname or a [hostname]:port combo. bz#2935 * ssh(1): Don't attempt to connect to empty SSH_AUTH_SOCK; bz#2936 * sshd(8): Silence error messages when sshd fails to load some of the default host keys. Failure to load an explicitly-configured hostkey is still an error, and failure to load any host key is still fatal. pr/103 * ssh(1): Redirect stderr of ProxyCommands to /dev/null when ssh is started with ControlPersist; prevents random ProxyCommand output from interfering with session output. * ssh(1): The ssh client was keeping a redundant ssh-agent socket (leftover from authentication) around for the life of the connection; bz#2912 * sshd(8): Fix bug in HostbasedAcceptedKeyTypes and PubkeyAcceptedKeyTypes options. If only RSA-SHA2 siganture types were specified, then authentication would always fail for RSA keys as the monitor checks only the base key (not the signature algorithm) type against *AcceptedKeyTypes. bz#2746 * ssh(1): Request correct signature types from ssh-agent when certificate keys and RSA-SHA2 signatures are in use. Portability ----------- * sshd(8): On Cygwin, run as SYSTEM where possible, using S4U for token creation if it supports MsV1_0 S4U Logon. * sshd(8): On Cygwin, use custom user/group matching code that respects the OS' behaviour of case-insensitive matching. * sshd(8): Don't set $MAIL if UsePAM=yes as PAM typically specifies the user environment if it's enabled; bz#2937 * sshd(8) Cygwin: Change service name to cygsshd to avoid collision with Microsoft's OpenSSH port. * Allow building against OpenSSL -dev (3.x) * Fix a number of build problems against version configurations and versions of OpenSSL. Including bz#2931 and bz#2921 * Improve warnings in cygwin service setup. bz#2922 * Remove hardcoded service name in cygwin setup. bz#2922 Checksums: ========== - SHA1 (openssh-8.0.tar.gz) = 8aaa99091fc7e5a92a4a320e1e5521046b3f95f0 - SHA256 (openssh-8.0.tar.gz) = 1xvSJk1KYSnOLPYEUzyCVwTEQ7MHOaCO65DzeNuuLdo= - SHA1 (openssh-8.0p1.tar.gz) = 756dbb99193f9541c9206a667eaa27b0fa184a4f - SHA256 (openssh-8.0p1.tar.gz) = vZQ4eeaUmOgDHra39E0IzcN9WaeraJqgtDcyDDSB/Wg= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 7.9 was released on 2018-10-19. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh(1), sshd(8): the setting of the new CASignatureAlgorithms option (see below) bans the use of DSA keys as certificate authorities. * sshd(8): the authentication success/failure log message has changed format slightly. It now includes the certificate fingerprint (previously it included only key ID and CA key fingerprint). Changes since OpenSSH 7.8 ========================= This is primarily a bugfix release. New Features ------------ * ssh(1), sshd(8): allow most port numbers to be specified using service names from getservbyname(3) (typically /etc/services). * ssh(1): allow the IdentityAgent configuration directive to accept environment variable names. This supports the use of multiple agent sockets without needing to use fixed paths. * sshd(8): support signalling sessions via the SSH protocol. A limited subset of signals is supported and only for login or command sessions (i.e. not subsystems) that were not subject to a forced command via authorized_keys or sshd_config. bz#1424 * ssh(1): support "ssh -Q sig" to list supported signature options. Also "ssh -Q help" to show the full set of supported queries. * ssh(1), sshd(8): add a CASignatureAlgorithms option for the client and server configs to allow control over which signature formats are allowed for CAs to sign certificates. For example, this allows banning CAs that sign certificates using the RSA-SHA1 signature algorithm. * sshd(8), ssh-keygen(1): allow key revocation lists (KRLs) to revoke keys specified by SHA256 hash. * ssh-keygen(1): allow creation of key revocation lists directly from base64-encoded SHA256 fingerprints. This supports revoking keys using only the information contained in sshd(8) authentication log messages. Bugfixes -------- * ssh(1), ssh-keygen(1): avoid spurious "invalid format" errors when attempting to load PEM private keys while using an incorrect passphrase. bz#2901 * sshd(8): when a channel closed message is received from a client, close the stderr file descriptor at the same time stdout is closed. This avoids stuck processes if they were waiting for stderr to close and were insensitive to stdin/out closing. bz#2863 * ssh(1): allow ForwardX11Timeout=0 to disable the untrusted X11 forwarding timeout and support X11 forwarding indefinitely. Previously the behaviour of ForwardX11Timeout=0 was undefined. * sshd(8): when compiled with GSSAPI support, cache supported method OIDs regardless of whether GSSAPI authentication is enabled in the main section of sshd_config. This avoids sandbox violations if GSSAPI authentication was later enabled in a Match block. bz#2107 * sshd(8): do not fail closed when configured with a text key revocation list that contains a too-short key. bz#2897 * ssh(1): treat connections with ProxyJump specified the same as ones with a ProxyCommand set with regards to hostname canonicalisation (i.e. don't try to canonicalise the hostname unless CanonicalizeHostname is set to 'always'). bz#2896 * ssh(1): fix regression in OpenSSH 7.8 that could prevent public- key authentication using certificates hosted in a ssh-agent(1) or against sshd(8) from OpenSSH <7.8. Portability ----------- * All: support building against the openssl-1.1 API (releases 1.1.0g and later). The openssl-1.0 API will remain supported at least until OpenSSL terminates security patch support for that API version. * sshd(8): allow the futex(2) syscall in the Linux seccomp sandbox; apparently required by some glibc/OpenSSL combinations. * sshd(8): handle getgrouplist(3) returning more than _SC_NGROUPS_MAX groups. Some platforms consider this limit more as a guideline. Checksums: ========== - SHA1 (openssh-7.9.tar.gz) = 7c50a86b8f591decd172ed7f5527abc533098dec - SHA256 (openssh-7.9.tar.gz) = nSVigtHGn3+xKXRqpSnp4YOyEPPAb+pCHdWS9Eh/IPY= - SHA1 (openssh-7.9p1.tar.gz) = 993aceedea8ecabb1d0dd7293508a361891c4eaa - SHA256 (openssh-7.9p1.tar.gz) = a0s7oiU9hO03ccgFByjVl8kc/OiYcTvre2SjBbbxGq0= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 7.8 was released on 2018-08-24. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh-keygen(1): write OpenSSH format private keys by default instead of using OpenSSL's PEM format. The OpenSSH format, supported in OpenSSH releases since 2014 and described in the PROTOCOL.key file in the source distribution, offers substantially better protection against offline password guessing and supports key comments in private keys. If necessary, it is possible to write old PEM-style keys by adding "-m PEM" to ssh-keygen's arguments when generating or updating a key. * sshd(8): remove internal support for S/Key multiple factor authentication. S/Key may still be used via PAM or BSD auth. * ssh(1): remove vestigal support for running ssh(1) as setuid. This used to be required for hostbased authentication and the (long gone) rhosts-style authentication, but has not been necessary for a long time. Attempting to execute ssh as a setuid binary, or with uid != effective uid will now yield a fatal error at runtime. * sshd(8): the semantics of PubkeyAcceptedKeyTypes and the similar HostbasedAcceptedKeyTypes options have changed. These now specify signature algorithms that are accepted for their respective authentication mechanism, where previously they specified accepted key types. This distinction matters when using the RSA/SHA2 signature algorithms "rsa-sha2-256", "rsa-sha2-512" and their certificate counterparts. Configurations that override these options but omit these algorithm names may cause unexpected authentication failures (no action is required for configurations that accept the default for these options). * sshd(8): the precedence of session environment variables has changed. ~/.ssh/environment and environment="..." options in authorized_keys files can no longer override SSH_* variables set implicitly by sshd. * ssh(1)/sshd(8): the default IPQoS used by ssh/sshd has changed. They will now use DSCP AF21 for interactive traffic and CS1 for bulk. For a detailed rationale, please see the commit message: https://cvsweb.openbsd.org/src/usr.bin/ssh/readconf.c#rev1.284 Changes since OpenSSH 7.7 ========================= This is primarily a bugfix release. New Features ------------ * ssh(1)/sshd(8): add new signature algorithms "rsa-sha2-256-cert- v01@openssh.com" and "rsa-sha2-512-cert-v01@openssh.com" to explicitly force use of RSA/SHA2 signatures in authentication. * sshd(8): extend the PermitUserEnvironment option to accept a whitelist of environment variable names in addition to global "yes" or "no" settings. * sshd(8): add a PermitListen directive to sshd_config(5) and a corresponding permitlisten= authorized_keys option that control which listen addresses and port numbers may be used by remote forwarding (ssh -R ...). * sshd(8): add some countermeasures against timing attacks used for account validation/enumeration. sshd will enforce a minimum time or each failed authentication attempt consisting of a global 5ms minimum plus an additional per-user 0-4ms delay derived from a host secret. * sshd(8): add a SetEnv directive to allow an administrator to explicitly specify environment variables in sshd_config. Variables set by SetEnv override the default and client-specified environment. * ssh(1): add a SetEnv directive to request that the server sets an environment variable in the session. Similar to the existing SendEnv option, these variables are set subject to server configuration. * ssh(1): allow "SendEnv -PATTERN" to clear environment variables previously marked for sending to the server. bz#1285 * ssh(1)/sshd(8): make UID available as a %-expansion everywhere that the username is available currently. bz#2870 * ssh(1): allow setting ProxyJump=none to disable ProxyJump functionality. bz#2869 Bugfixes -------- * sshd(8): avoid observable differences in request parsing that could be used to determine whether a target user is valid. * all: substantial internal refactoring * ssh(1)/sshd(8): fix some memory leaks; bz#2366 * ssh(1): fix a pwent clobber (introduced in openssh-7.7) that could occur during key loading, manifesting as crash on some platforms. * sshd_config(5): clarify documentation for AuthenticationMethods option; bz#2663 * ssh(1): ensure that the public key algorithm sent in a public key SSH_MSG_USERAUTH_REQUEST matches the content of the signature blob. Previously, these could be inconsistent when a legacy or non-OpenSSH ssh-agent returned a RSA/SHA1 signature when asked to make a RSA/SHA2 signature. * sshd(8): fix failures to read authorized_keys caused by faulty supplemental group caching. bz#2873 * scp(1): apply umask to directories, fixing potential mkdir/chmod race when copying directory trees bz#2839 * ssh-keygen(1): return correct exit code when searching for and hashing known_hosts entries in a single operation; bz#2772 * ssh(1): prefer the ssh binary pointed to via argv[0] to $PATH when re-executing ssh for ProxyJump. bz#2831 * sshd(8): do not ban PTY allocation when a sshd session is restricted because the user password is expired as it breaks password change dialog. (regression in openssh-7.7). * ssh(1)/sshd(8): fix error reporting from select() failures. * ssh(1): improve documentation for -w (tunnel) flag, emphasising that -w implicitly sets Tunnel=point-to-point. bz#2365 * ssh-agent(1): implement EMFILE mitigation for ssh-agent. ssh-agent will no longer spin when its file descriptor limit is exceeded. bz#2576 * ssh(1)/sshd(8): disable SSH2_MSG_DEBUG messages for Twisted Conch clients. Twisted Conch versions that lack a version number in their identification strings will mishandle these messages when running on Python 2.x (https://twistedmatrix.com/trac/ticket/9422) * sftp(1): notify user immediately when underlying ssh process dies expectedly. bz#2719 * ssh(1)/sshd(8): fix tunnel forwarding; regression in 7.7 release. bz#2855 * ssh-agent(1): don't kill ssh-agent's listening socket entirely if it fails to accept(2) a connection. bz#2837 * sshd(8): relax checking of authorized_keys environment="..." options to allow underscores in variable names (regression introduced in 7.7). bz#2851 * ssh(1): add some missing options in the configuration dump output (ssh -G). bz#2835 Portability ----------- * sshd(8): Expose details of completed authentication to PAM auth modules via SSH_AUTH_INFO_0 in the PAM environment. bz#2408 * Fix compilation problems caused by fights between zlib and OpenSSL colliding uses of "free_func" * Improve detection of unsupported compiler options. Recently these may have manifested as "unsupported -Wl,-z,retpoline" warnings during linking. * sshd(8): some sandbox support for Linux/s390 bz#2752. * regress tests: unbreak key-options.sh test on platforms without openpty(3). bz#2856 * use getrandom(2) for PRNG seeding when built without OpenSSL. Checksums: ========== - SHA1 (openssh-7.8.tar.gz) = ed5511cd42b543cd15166a9cbc56705f23b847e7 - SHA256 (openssh-7.8.tar.gz) = TDqIsMEmghsBUNCrSCPyCxChfitntyOLXNC694py1XE - SHA1 (openssh-7.8p1.tar.gz) = 27e267e370315561de96577fccae563bc2c37a60 - SHA256 (openssh-7.8p1.tar.gz) = GkhLsVFSwYO7JRThEqow3TQTjDz7Ay7uVJCmbFBxRMo Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 7.7 was released on 2018-04-02. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh(1)/sshd(8): Drop compatibility support for some very old SSH implementations, including ssh.com <=2.* and OpenSSH <= 3.*. These versions were all released in or before 2001 and predate the final SSH RFCs. The support in question isn't necessary for RFC-compliant SSH implementations. Changes since OpenSSH 7.6 ========================= This is primarily a bugfix release. New Features ------------ * All: Add experimental support for PQC XMSS keys (Extended Hash- Based Signatures) based on the algorithm described in https://tools.ietf.org/html/draft-irtf-cfrg-xmss-hash-based-signatures-12 The XMSS signature code is experimental and not compiled in by default. * sshd(8): Add a "rdomain" criteria for the sshd_config Match keyword to allow conditional configuration that depends on which routing domain a connection was received on (currently supported on OpenBSD and Linux). * sshd_config(5): Add an optional rdomain qualifier to the ListenAddress directive to allow listening on different routing domains. This is supported only on OpenBSD and Linux at present. * sshd_config(5): Add RDomain directive to allow the authenticated session to be placed in an explicit routing domain. This is only supported on OpenBSD at present. * sshd(8): Add "expiry-time" option for authorized_keys files to allow for expiring keys. * ssh(1): Add a BindInterface option to allow binding the outgoing connection to an interface's address (basically a more usable BindAddress) * ssh(1): Expose device allocated for tun/tap forwarding via a new %T expansion for LocalCommand. This allows LocalCommand to be used to prepare the interface. * sshd(8): Expose the device allocated for tun/tap forwarding via a new SSH_TUNNEL environment variable. This allows automatic setup of the interface and surrounding network configuration automatically on the server. * ssh(1)/scp(1)/sftp(1): Add URI support to ssh, sftp and scp, e.g. ssh://user@host or sftp://user@host/path. Additional connection parameters described in draft-ietf-secsh-scp-sftp-ssh-uri-04 are not implemented since the ssh fingerprint format in the draft uses the deprecated MD5 hash with no way to specify the any other algorithm. * ssh-keygen(1): Allow certificate validity intervals that specify only a start or stop time (instead of both or neither). * sftp(1): Allow "cd" and "lcd" commands with no explicit path argument. lcd will change to the local user's home directory as usual. cd will change to the starting directory for session (because the protocol offers no way to obtain the remote user's home directory). bz#2760 * sshd(8): When doing a config test with sshd -T, only require the attributes that are actually used in Match criteria rather than (an incomplete list of) all criteria. Bugfixes -------- * ssh(1)/sshd(8): More strictly check signature types during key exchange against what was negotiated. Prevents downgrade of RSA signatures made with SHA-256/512 to SHA-1. * sshd(8): Fix support for client that advertise a protocol version of "1.99" (indicating that they are prepared to accept both SSHv1 and SSHv2). This was broken in OpenSSH 7.6 during the removal of SSHv1 support. bz#2810 * ssh(1): Warn when the agent returns a ssh-rsa (SHA1) signature when a rsa-sha2-256/512 signature was requested. This condition is possible when an old or non-OpenSSH agent is in use. bz#2799 * ssh-agent(1): Fix regression introduced in 7.6 that caused ssh-agent to fatally exit if presented an invalid signature request message. * sshd_config(5): Accept yes/no flag options case-insensitively, as has been the case in ssh_config(5) for a long time. bz#2664 * ssh(1): Improve error reporting for failures during connection. Under some circumstances misleading errors were being shown. bz#2814 * ssh-keyscan(1): Add -D option to allow printing of results directly in SSHFP format. bz#2821 * regress tests: fix PuTTY interop test broken in last release's SSHv1 removal. bz#2823 * ssh(1): Compatibility fix for some servers that erroneously drop the connection when the IUTF8 (RFC8160) option is sent. * scp(1): Disable RemoteCommand and RequestTTY in the ssh session started by scp (sftp was already doing this.) * ssh-keygen(1): Refuse to create a certificate with an unusable number of principals. * ssh-keygen(1): Fatally exit if ssh-keygen is unable to write all the public key during key generation. Previously it would silently ignore errors writing the comment and terminating newline. * ssh(1): Do not modify hostname arguments that are addresses by automatically forcing them to lower-case. Instead canonicalise them to resolve ambiguities (e.g. ::0001 => ::1) before they are matched against known_hosts. bz#2763 * ssh(1): Don't accept junk after "yes" or "no" responses to hostkey prompts. bz#2803 * sftp(1): Have sftp print a warning about shell cleanliness when decoding the first packet fails, which is usually caused by shells polluting stdout of non-interactive startups. bz#2800 * ssh(1)/sshd(8): Switch timers in packet code from using wall-clock time to monotonic time, allowing the packet layer to better function over a clock step and avoiding possible integer overflows during steps. * Numerous manual page fixes and improvements. Portability ----------- * sshd(8): Correctly detect MIPS ABI in use at configure time. Fixes sandbox violations on some environments. * sshd(8): Remove UNICOS support. The hardware and software are literal museum pieces and support in sshd is too intrusive to justify maintaining. * All: Build and link with "retpoline" flags when available to mitigate the "branch target injection" style (variant 2) of the Spectre branch-prediction vulnerability. * All: Add auto-generated dependency information to Makefile. * Numerous fixed to the RPM spec files. Checksums: ========== - SHA1 (openssh-7.7.tar.gz) = 24812e05fa233014c847c7775748316e7f8a836c - SHA256 (openssh-7.7.tar.gz) = T4ua1L/vgAYqwB0muRahvnm5ZUr3PLY9nPljaG8egvo= - SHA1 (openssh-7.7p1.tar.gz) = 446fe9ed171f289f0d62197dffdbfdaaf21c49f2 - SHA256 (openssh-7.7p1.tar.gz) = 1zvn5oTpnvzQJL4Vowv/y+QbASsvezyQhK7WIXdea48= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com

OpenSSH 7.6 was released on 2017-10-03. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * ssh(1): delete SSH protocol version 1 support, associated configuration options and documentation. * ssh(1)/sshd(8): remove support for the hmac-ripemd160 MAC. * ssh(1)/sshd(8): remove support for the arcfour, blowfish and CAST ciphers. * Refuse RSA keys <1024 bits in length and improve reporting for keys that do not meet this requirement. * ssh(1): do not offer CBC ciphers by default. Changes since OpenSSH 7.5 ========================= This is primarily a bugfix release. It also contains substantial internal refactoring. Security -------- * sftp-server(8): in read-only mode, sftp-server was incorrectly permitting creation of zero-length files. Reported by Michal Zalewski. New Features ------------ * ssh(1): add RemoteCommand option to specify a command in the ssh config file instead of giving it on the client's command line. This allows the configuration file to specify the command that will be executed on the remote host. * sshd(8): add ExposeAuthInfo option that enables writing details of the authentication methods used (including public keys where applicable) to a file that is exposed via a $SSH_USER_AUTH environment variable in the subsequent session. * ssh(1): add support for reverse dynamic forwarding. In this mode, ssh will act as a SOCKS4/5 proxy and forward connections to destinations requested by the remote SOCKS client. This mode is requested using extended syntax for the -R and RemoteForward options and, because it is implemented solely at the client, does not require the server be updated to be supported. * sshd(8): allow LogLevel directive in sshd_config Match blocks; bz#2717 * ssh-keygen(1): allow inclusion of arbitrary string or flag certificate extensions and critical options. * ssh-keygen(1): allow ssh-keygen to use a key held in ssh-agent as a CA when signing certificates. bz#2377 * ssh(1)/sshd(8): allow IPQoS=none in ssh/sshd to not set an explicit ToS/DSCP value and just use the operating system default. * ssh-add(1): added -q option to make ssh-add quiet on success. * ssh(1): expand the StrictHostKeyChecking option with two new settings. The first "accept-new" will automatically accept hitherto-unseen keys but will refuse connections for changed or invalid hostkeys. This is a safer subset of the current behaviour of StrictHostKeyChecking=no. The second setting "off", is a synonym for the current behaviour of StrictHostKeyChecking=no: accept new host keys, and continue connection for hosts with incorrect hostkeys. A future release will change the meaning of StrictHostKeyChecking=no to the behaviour of "accept-new". bz#2400 * ssh(1): add SyslogFacility option to ssh(1) matching the equivalent option in sshd(8). bz#2705 Bugfixes -------- * ssh(1): use HostKeyAlias if specified instead of hostname for matching host certificate principal names; bz#2728 * sftp(1): implement sorting for globbed ls; bz#2649 * ssh(1): add a user@host prefix to client's "Permission denied" messages, useful in particular when using "stacked" connections (e.g. ssh -J) where it's not clear which host is denying. bz#2720 * ssh(1): accept unknown EXT_INFO extension values that contain \0 characters. These are legal, but would previously cause fatal connection errors if received. * ssh(1)/sshd(8): repair compression statistics printed at connection exit * sftp(1): print '?' instead of incorrect link count (that the protocol doesn't provide) for remote listings. bz#2710 * ssh(1): return failure rather than fatal() for more cases during session multiplexing negotiations. Causes the session to fall back to a non-mux connection if they occur. bz#2707 * ssh(1): mention that the server may send debug messages to explain public key authentication problems under some circumstances; bz#2709 * Translate OpenSSL error codes to better report incorrect passphrase errors when loading private keys; bz#2699 * sshd(8): adjust compatibility patterns for WinSCP to correctly identify versions that implement only the legacy DH group exchange scheme. bz#2748 * ssh(1): print the "Killed by signal 1" message only at LogLevel verbose so that it is not shown at the default level; prevents it from appearing during ssh -J and equivalent ProxyCommand configs. bz#1906, bz#2744 * ssh-keygen(1): when generating all hostkeys (ssh-keygen -A), clobber existing keys if they exist but are zero length. zero-length keys could previously be made if ssh-keygen failed or was interrupted part way through generating them. bz#2561 * ssh(1): fix pledge(2) violation in the escape sequence "~&" used to place the current session in the background. * ssh-keyscan(1): avoid double-close() on file descriptors; bz#2734 * sshd(8): avoid reliance on shared use of pointers shared between monitor and child sshd processes. bz#2704 * sshd_config(8): document available AuthenticationMethods; bz#2453 * ssh(1): avoid truncation in some login prompts; bz#2768 * sshd(8): Fix various compilations failures, inc bz#2767 * ssh(1): make "--" before the hostname terminate argument processing after the hostname too. * ssh-keygen(1): switch from aes256-cbc to aes256-ctr for encrypting new-style private keys. Fixes problems related to private key handling for no-OpenSSL builds. bz#2754 * ssh(1): warn and do not attempt to use keys when the public and private halves do not match. bz#2737 * sftp(1): don't print verbose error message when ssh disconnects from under sftp. bz#2750 * sshd(8): fix keepalive scheduling problem: activity on a forwarded port from preventing the keepalive from being sent; bz#2756 * sshd(8): when started without root privileges, don't require the privilege separation user or path to exist. Makes running the regression tests easier without touching the filesystem. * Make integrity.sh regression tests more robust against timeouts. bz#2658 * ssh(1)/sshd(8): correctness fix for channels implementation: accept channel IDs greater than 0x7FFFFFFF. Portability ----------- * sshd(9): drop two more privileges in the Solaris sandbox: PRIV_DAX_ACCESS and PRIV_SYS_IB_INFO; bz#2723 * sshd(8): expose list of completed authentication methods to PAM via the SSH_AUTH_INFO_0 PAM environment variable. bz#2408 * ssh(1)/sshd(8): fix several problems in the tun/tap forwarding code, mostly to do with host/network byte order confusion. bz#2735 * Add --with-cflags-after and --with-ldflags-after configure flags to allow setting CFLAGS/LDFLAGS after configure has completed. These are useful for setting sanitiser/fuzzing options that may interfere with configure's operation. * sshd(8): avoid Linux seccomp violations on ppc64le over the socketcall syscall. * Fix use of ldns when using ldns-config; bz#2697 * configure: set cache variables when cross-compiling. The cross- compiling fallback message was saying it assumed the test passed, but it wasn't actually set the cache variables and this would cause later tests to fail. * Add clang libFuzzer harnesses for public key parsing and signature verification. Checksums: ========== - SHA1 (openssh-7.6.tar.gz) = 157fe3989a245c58fcdb34d9fe722a3c4e14c008 - SHA1 (openssh-7.6p1.tar.gz) = a6984bc2c72192bed015c8b879b35dd9f5350b3b - SHA256 (openssh-7.6.tar.gz) = Xu3bdpCcu65vM2FnW7b6IKLgd4Kvf2P3WBTMw+I7Bao= - SHA256 (openssh-7.6p1.tar.gz) = oyPK7t3+FFuqoNsW6Y14Sx+8fdQ2pr8fR539XNHSFyM= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and Ben Lindstrom.

OpenSSH 7.5 was released on 2017-03-20. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. OpenSSH also includes transitional support for the legacy SSH 1.3 and 1.5 protocols that may be enabled at compile-time. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Future deprecation notice ========================= We plan on retiring more legacy cryptography in future releases, specifically: * In the next major release (expected June-August), removing remaining support for the SSH v.1 protocol (currently client-only and compile- time disabled). * In the same release, removing support for Blowfish and RC4 ciphers and the RIPE-MD160 HMAC. (These are currently run-time disabled). * In the same release, removing the remaining CBC ciphers from being offered by default in the client (These have not been offered in sshd by default for several years). * Refusing all RSA keys smaller than 1024 bits (the current minimum is 768 bits) This list reflects our current intentions, but please check the final release notes for future releases. Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * This release deprecates the sshd_config UsePrivilegeSeparation option, thereby making privilege separation mandatory. Privilege separation has been on by default for almost 15 years and sandboxing has been on by default for almost the last five. * The format of several log messages emitted by the packet code has changed to include additional information about the user and their authentication state. Software that monitors ssh/sshd logs may need to account for these changes. For example: Connection closed by user x 1.1.1.1 port 1234 [preauth] Connection closed by authenticating user x 10.1.1.1 port 1234 [preauth] Connection closed by invalid user x 1.1.1.1 port 1234 [preauth] Affected messages include connection closure, timeout, remote disconnection, negotiation failure and some other fatal messages generated by the packet code. * [Portable OpenSSH only] This version removes support for building against OpenSSL versions prior to 1.0.1. OpenSSL stopped supporting versions prior to 1.0.1 over 12 months ago (i.e. they no longer receive fixes for security bugs). Changes since OpenSSH 7.4 ========================= This is a bugfix release. Security -------- * ssh(1), sshd(8): Fix weakness in CBC padding oracle countermeasures that allowed a variant of the attack fixed in OpenSSH 7.3 to proceed. Note that the OpenSSH client disables CBC ciphers by default, sshd offers them as lowest-preference options and will remove them by default entriely in the next release. Reported by Jean Paul Degabriele, Kenny Paterson, Martin Albrecht and Torben Hansen of Royal Holloway, University of London. * sftp-client(1): [portable OpenSSH only] On Cygwin, a client making a recursive file transfer could be maniuplated by a hostile server to perform a path-traversal attack. creating or modifying files outside of the intended target directory. Reported by Jann Horn of Google Project Zero. New Features ------------ * ssh(1), sshd(8): Support "=-" syntax to easily remove methods from algorithm lists, e.g. Ciphers=-*cbc. bz#2671 Bugfixes -------- * sshd(1): Fix NULL dereference crash when key exchange start messages are sent out of sequence. * ssh(1), sshd(8): Allow form-feed characters to appear in configuration files. * sshd(8): Fix regression in OpenSSH 7.4 support for the server-sig-algs extension, where SHA2 RSA signature methods were not being correctly advertised. bz#2680 * ssh(1), ssh-keygen(1): Fix a number of case-sensitivity bugs in known_hosts processing. bz#2591 bz#2685 * ssh(1): Allow ssh to use certificates accompanied by a private key file but no corresponding plain *.pub public key. bz#2617 * ssh(1): When updating hostkeys using the UpdateHostKeys option, accept RSA keys if HostkeyAlgorithms contains any RSA keytype. Previously, ssh could ignore RSA keys when only the ssh-rsa-sha2-* methods were enabled in HostkeyAlgorithms and not the old ssh-rsa method. bz#2650 * ssh(1): Detect and report excessively long configuration file lines. bz#2651 * Merge a number of fixes found by Coverity and reported via Redhat and FreeBSD. Includes fixes for some memory and file descriptor leaks in error paths. bz#2687 * ssh-keyscan(1): Correctly hash hosts with a port number. bz#2692 * ssh(1), sshd(8): When logging long messages to stderr, don't truncate "\r

" if the length of the message exceeds the buffer. bz#2688 * ssh(1): Fully quote [host]:port in generated ProxyJump/-J command- line; avoid confusion over IPv6 addresses and shells that treat square bracket characters specially. * ssh-keygen(1): Fix corruption of known_hosts when running "ssh-keygen -H" on a known_hosts containing already-hashed entries. * Fix various fallout and sharp edges caused by removing SSH protocol 1 support from the server, including the server banner string being incorrectly terminated with only

(instead of \r

), confusing error messages from ssh-keyscan bz#2583 and a segfault in sshd if protocol v.1 was enabled for the client and sshd_config contained references to legacy keys bz#2686. * ssh(1), sshd(8): Free fd_set on connection timeout. bz#2683 * sshd(8): Fix Unix domain socket forwarding for root (regression in OpenSSH 7.4). * sftp(1): Fix division by zero crash in "df" output when server returns zero total filesystem blocks/inodes. * ssh(1), ssh-add(1), ssh-keygen(1), sshd(8): Translate OpenSSL errors encountered during key loading to more meaningful error codes. bz#2522 bz#2523 * ssh-keygen(1): Sanitise escape sequences in key comments sent to printf but preserve valid UTF-8 when the locale supports it; bz#2520 * ssh(1), sshd(8): Return reason for port forwarding failures where feasible rather than always "administratively prohibited". bz#2674 * sshd(8): Fix deadlock when AuthorizedKeysCommand or AuthorizedPrincipalsCommand produces a lot of output and a key is matched early. bz#2655 * Regression tests: several reliability fixes. bz#2654 bz#2658 bz#2659 * ssh(1): Fix typo in ~C error message for bad port forward cancellation. bz#2672 * ssh(1): Show a useful error message when included config files can't be opened; bz#2653 * sshd(8): Make sshd set GSSAPIStrictAcceptorCheck=yes as the manual page (previously incorrectly) advertised. bz#2637 * sshd_config(5): Repair accidentally-deleted mention of %k token in AuthorizedKeysCommand; bz#2656 * sshd(8): Remove vestiges of previously removed LOGIN_PROGRAM; bz#2665 * ssh-agent(1): Relax PKCS#11 whitelist to include libexec and common 32-bit compatibility library directories. * sftp-client(1): Fix non-exploitable integer overflow in SSH2_FXP_NAME response handling. * ssh-agent(1): Fix regression in 7.4 of deleting PKCS#11-hosted keys. It was not possible to delete them except by specifying their full physical path. bz#2682 Portability ----------- * sshd(8): Avoid sandbox errors for Linux S390 systems using an ICA crypto coprocessor. * sshd(8): Fix non-exploitable weakness in seccomp-bpf sandbox arg inspection. * ssh(1): Fix X11 forwarding on OSX where X11 was being started by launchd. bz#2341 * ssh-keygen(1), ssh(1), sftp(1): Fix output truncation for various that contain non-printable characters where the codeset in use is ASCII. * build: Fix builds that attempt to link a kerberised libldns. bz#2603 * build: Fix compilation problems caused by unconditionally defining _XOPEN_SOURCE in wide character detection. * sshd(8): Fix sandbox violations for clock_gettime VSDO syscall fallback on some Linux/X32 kernels. bz#2142 Checksums: ========== - SHA1 (openssh-7.5.tar.gz) = 81384df377e38551f7659a4c250383d0bbd25341 - SHA1 (openssh-7.5p1.tar.gz) = 5e8f185d00afb4f4f89801e9b0f8b9cee9d87ebd - SHA256 (openssh-7.5.tar.gz) = Gmk8jOdGdKa7NixUN5J+bTMfeum5Vx8Nv+leAdQNq3U= - SHA256 (openssh-7.5p1.tar.gz) = mEbjxfq58FR0ALTSwBeZL5FCIrP9H47ubH3GvF5Z+fA= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and Ben Lindstrom.

OpenSSH 7.4 was released on 2016-12-19. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. OpenSSH also includes transitional support for the legacy SSH 1.3 and 1.5 protocols that may be enabled at compile-time. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Future deprecation notice ========================= We plan on retiring more legacy cryptography in future releases, specifically: * In approximately August 2017, removing remaining support for the SSH v.1 protocol (client-only and currently compile-time disabled). * In the same release, removing support for Blowfish and RC4 ciphers and the RIPE-MD160 HMAC. (These are currently run-time disabled). * Refusing all RSA keys smaller than 1024 bits (the current minimum is 768 bits) * The next release of OpenSSH will remove support for running sshd(8) with privilege separation disabled. * The next release of portable OpenSSH will remove support for OpenSSL version prior to 1.0.1. This list reflects our current intentions, but please check the final release notes for future releases. Potentially-incompatible changes ================================ This release includes a number of changes that may affect existing configurations: * This release removes server support for the SSH v.1 protocol. * ssh(1): Remove 3des-cbc from the client's default proposal. 64-bit block ciphers are not safe in 2016 and we don't want to wait until attacks like SWEET32 are extended to SSH. As 3des-cbc was the only mandatory cipher in the SSH RFCs, this may cause problems connecting to older devices using the default configuration, but it's highly likely that such devices already need explicit configuration for key exchange and hostkey algorithms already anyway. * sshd(8): Remove support for pre-authentication compression. Doing compression early in the protocol probably seemed reasonable in the 1990s, but today it's clearly a bad idea in terms of both cryptography (cf. multiple compression oracle attacks in TLS) and attack surface. Pre-auth compression support has been disabled by default for >10 years. Support remains in the client. * ssh-agent will refuse to load PKCS#11 modules outside a whitelist of trusted paths by default. The path whitelist may be specified at run-time. * sshd(8): When a forced-command appears in both a certificate and an authorized keys/principals command= restriction, sshd will now refuse to accept the certificate unless they are identical. The previous (documented) behaviour of having the certificate forced-command override the other could be a bit confusing and error-prone. * sshd(8): Remove the UseLogin configuration directive and support for having /bin/login manage login sessions. Changes since OpenSSH 7.3 ========================= This is primarily a bugfix release. Security -------- * ssh-agent(1): Will now refuse to load PKCS#11 modules from paths outside a trusted whitelist (run-time configurable). Requests to load modules could be passed via agent forwarding and an attacker could attempt to load a hostile PKCS#11 module across the forwarded agent channel: PKCS#11 modules are shared libraries, so this would result in code execution on the system running the ssh-agent if the attacker has control of the forwarded agent-socket (on the host running the sshd server) and the ability to write to the filesystem of the host running ssh-agent (usually the host running the ssh client). Reported by Jann Horn of Project Zero. * sshd(8): When privilege separation is disabled, forwarded Unix- domain sockets would be created by sshd(8) with the privileges of 'root' instead of the authenticated user. This release refuses Unix-domain socket forwarding when privilege separation is disabled (Privilege separation has been enabled by default for 14 years). Reported by Jann Horn of Project Zero. * sshd(8): Avoid theoretical leak of host private key material to privilege-separated child processes via realloc() when reading keys. No such leak was observed in practice for normal-sized keys, nor does a leak to the child processes directly expose key material to unprivileged users. Reported by Jann Horn of Project Zero. * sshd(8): The shared memory manager used by pre-authentication compression support had a bounds checks that could be elided by some optimising compilers. Additionally, this memory manager was incorrectly accessible when pre-authentication compression was disabled. This could potentially allow attacks against the privileged monitor process from the sandboxed privilege-separation process (a compromise of the latter would be required first). This release removes support for pre-authentication compression from sshd(8). Reported by Guido Vranken using the Stack unstable optimisation identification tool (http://css.csail.mit.edu/stack/) * sshd(8): Fix denial-of-service condition where an attacker who sends multiple KEXINIT messages may consume up to 128MB per connection. Reported by Shi Lei of Gear Team, Qihoo 360. * sshd(8): Validate address ranges for AllowUser and DenyUsers directives at configuration load time and refuse to accept invalid ones. It was previously possible to specify invalid CIDR address ranges (e.g. user@127.1.2.3/55) and these would always match, possibly resulting in granting access where it was not intended. Reported by Laurence Parry. New Features ------------ * ssh(1): Add a proxy multiplexing mode to ssh(1) inspired by the version in PuTTY by Simon Tatham. This allows a multiplexing client to communicate with the master process using a subset of the SSH packet and channels protocol over a Unix-domain socket, with the main process acting as a proxy that translates channel IDs, etc. This allows multiplexing mode to run on systems that lack file- descriptor passing (used by current multiplexing code) and potentially, in conjunction with Unix-domain socket forwarding, with the client and multiplexing master process on different machines. Multiplexing proxy mode may be invoked using "ssh -O proxy ..." * sshd(8): Add a sshd_config DisableForwarding option that disables X11, agent, TCP, tunnel and Unix domain socket forwarding, as well as anything else we might implement in the future. Like the 'restrict' authorized_keys flag, this is intended to be a simple and future-proof way of restricting an account. * sshd(8), ssh(1): Support the "curve25519-sha256" key exchange method. This is identical to the currently-supported method named "curve25519-sha256@libssh.org". * sshd(8): Improve handling of SIGHUP by checking to see if sshd is already daemonised at startup and skipping the call to daemon(3) if it is. This ensures that a SIGHUP restart of sshd(8) will retain the same process-ID as the initial execution. sshd(8) will also now unlink the PidFile prior to SIGHUP restart and re-create it after a successful restart, rather than leaving a stale file in the case of a configuration error. bz#2641 * sshd(8): Allow ClientAliveInterval and ClientAliveCountMax directives to appear in sshd_config Match blocks. * sshd(8): Add %-escapes to AuthorizedPrincipalsCommand to match those supported by AuthorizedKeysCommand (key, key type, fingerprint, etc.) and a few more to provide access to the contents of the certificate being offered. * Added regression tests for string matching, address matching and string sanitisation functions. * Improved the key exchange fuzzer harness. Bugfixes -------- * ssh(1): Allow IdentityFile to successfully load and use certificates that have no corresponding bare public key. bz#2617 certificate id_rsa-cert.pub (and no id_rsa.pub). * ssh(1): Fix public key authentication when multiple authentication is in use and publickey is not just the first method attempted. bz#2642 * regress: Allow the PuTTY interop tests to run unattended. bz#2639 * ssh-agent(1), ssh(1): improve reporting when attempting to load keys from PKCS#11 tokens with fewer useless log messages and more detail in debug messages. bz#2610 * ssh(1): When tearing down ControlMaster connections, don't pollute stderr when LogLevel=quiet. * sftp(1): On ^Z wait for underlying ssh(1) to suspend before suspending sftp(1) to ensure that ssh(1) restores the terminal mode correctly if suspended during a password prompt. * ssh(1): Avoid busy-wait when ssh(1) is suspended during a password prompt. * ssh(1), sshd(8): Correctly report errors during sending of ext- info messages. * sshd(8): fix NULL-deref crash if sshd(8) received an out-of- sequence NEWKEYS message. * sshd(8): Correct list of supported signature algorithms sent in the server-sig-algs extension. bz#2547 * sshd(8): Fix sending ext_info message if privsep is disabled. * sshd(8): more strictly enforce the expected ordering of privilege separation monitor calls used for authentication and allow them only when their respective authentication methods are enabled in the configuration * sshd(8): Fix uninitialised optlen in getsockopt() call; harmless on Unix/BSD but potentially crashy on Cygwin. * Fix false positive reports caused by explicit_bzero(3) not being recognised as a memory initialiser when compiled with -fsanitize-memory. * sshd_config(5): Use 2001:db8::/32, the official IPv6 subnet for configuration examples. Portability ----------- * On environments configured with Turkish locales, fall back to the C/POSIX locale to avoid errors in configuration parsing caused by that locale's unique handling of the letters 'i' and 'I'. bz#2643 * sftp-server(8), ssh-agent(1): Deny ptrace on OS X using ptrace(PT_DENY_ATTACH, ..) * ssh(1), sshd(8): Unbreak AES-CTR ciphers on old (~0.9.8) OpenSSL. * Fix compilation for libcrypto compiled without RIPEMD160 support. * contrib: Add a gnome-ssh-askpass3 with GTK+3 support. bz#2640 * sshd(8): Improve PRNG reseeding across privilege separation and force libcrypto to obtain a high-quality seed before chroot or sandboxing. * All: Explicitly test for broken strnvis. NetBSD added an strnvis and unfortunately made it incompatible with the existing one in OpenBSD and Linux's libbsd (the former having existed for over ten years). Try to detect this mess, and assume the only safe option if we're cross compiling. Checksums: ========== - SHA1 (openssh-7.4.tar.gz) = 1e2073f95d5ead8f2814b4b6c0700bcd533c410f - SHA1 (openssh-7.4p1.tar.gz) = 2330bbf82ed08cf3ac70e0acf00186ef3eeb97e0 - SHA256 (openssh-7.4.tar.gz) = +GEXh7Xr2J87cq1uA97hF9e+3lfOQ2LKxXGdmFXREf0 - SHA256 (openssh-7.4p1.tar.gz) = Gx/EoU4gJCkxgZJO0khy5vLgYpPz6JJqN2uK7EgfGdE= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and Ben Lindstrom.

OpenSSH 7.3 was released on 2016-08-01. It is available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. OpenSSH also includes transitional support for the legacy SSH 1.3 and 1.5 protocols that may be enabled at compile-time. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Future deprecation notice ========================= We plan on retiring more legacy cryptography in a near-future release, specifically: * Refusing all RSA keys smaller than 1024 bits (the current minimum is 768 bits) * Removing server-side support for the SSH v.1 protocol (currently compile-time disabled). * In approximately 1 year, removing all support for the SSH v.1 protocol (currently compile-time disabled). This list reflects our current intentions, but please check the final release notes for future releases. Changes since OpenSSH 7.2 ========================= This is primarily a bugfix release. Security -------- * sshd(8): Mitigate a potential denial-of-service attack against the system's crypt(3) function via sshd(8). An attacker could send very long passwords that would cause excessive CPU use in crypt(3). sshd(8) now refuses to accept password authentication requests of length greater than 1024 characters. Independently reported by Tomas Kuthan (Oracle), Andres Rojas and Javier Nieto. * sshd(8): Mitigate timing differences in password authentication that could be used to discern valid from invalid account names when long passwords were sent and particular password hashing algorithms are in use on the server. CVE-2016-6210, reported by EddieEzra.Harari at verint.com * ssh(1), sshd(8): Fix observable timing weakness in the CBC padding oracle countermeasures. Reported by Jean Paul Degabriele, Kenny Paterson, Torben Hansen and Martin Albrecht. Note that CBC ciphers are disabled by default and only included for legacy compatibility. * ssh(1), sshd(8): Improve operation ordering of MAC verification for Encrypt-then-MAC (EtM) mode transport MAC algorithms to verify the MAC before decrypting any ciphertext. This removes the possibility of timing differences leaking facts about the plaintext, though no such leakage has been observed. Reported by Jean Paul Degabriele, Kenny Paterson, Torben Hansen and Martin Albrecht. * sshd(8): (portable only) Ignore PAM environment vars when UseLogin=yes. If PAM is configured to read user-specified environment variables and UseLogin=yes in sshd_config, then a hostile local user may attack /bin/login via LD_PRELOAD or similar environment variables set via PAM. CVE-2015-8325, found by Shayan Sadigh. New Features ------------ * ssh(1): Add a ProxyJump option and corresponding -J command-line flag to allow simplified indirection through a one or more SSH bastions or "jump hosts". * ssh(1): Add an IdentityAgent option to allow specifying specific agent sockets instead of accepting one from the environment. * ssh(1): Allow ExitOnForwardFailure and ClearAllForwardings to be optionally overridden when using ssh -W. bz#2577 * ssh(1), sshd(8): Implement support for the IUTF8 terminal mode as per draft-sgtatham-secsh-iutf8-00. * ssh(1), sshd(8): Add support for additional fixed Diffie-Hellman 2K, 4K and 8K groups from draft-ietf-curdle-ssh-kex-sha2-03. * ssh-keygen(1), ssh(1), sshd(8): support SHA256 and SHA512 RSA signatures in certificates; * ssh(1): Add an Include directive for ssh_config(5) files. * ssh(1): Permit UTF-8 characters in pre-authentication banners sent from the server. bz#2058 Bugfixes -------- * ssh(1), sshd(8): Reduce the syslog level of some relatively common protocol events from LOG_CRIT. bz#2585 * sshd(8): Refuse AuthenticationMethods="" in configurations and accept AuthenticationMethods=any for the default behaviour of not requiring multiple authentication. bz#2398 * sshd(8): Remove obsolete and misleading "POSSIBLE BREAK-IN ATTEMPT!" message when forward and reverse DNS don't match. bz#2585 * ssh(1): Close ControlPersist background process stderr except in debug mode or when logging to syslog. bz#1988 * misc: Make PROTOCOL description for direct-streamlocal@openssh.com channel open messages match deployed code. bz#2529 * ssh(1): Deduplicate LocalForward and RemoteForward entries to fix failures when both ExitOnForwardFailure and hostname canonicalisation are enabled. bz#2562 * sshd(8): Remove fallback from moduli to obsolete "primes" file that was deprecated in 2001. bz#2559. * sshd_config(5): Correct description of UseDNS: it affects ssh hostname processing for authorized_keys, not known_hosts; bz#2554 * ssh(1): Fix authentication using lone certificate keys in an agent without corresponding private keys on the filesystem. bz#2550 * sshd(8): Send ClientAliveInterval pings when a time-based RekeyLimit is set; previously keepalive packets were not being sent. bz#2252 Portability ----------- * ssh(1), sshd(8): Fix compilation by automatically disabling ciphers not supported by OpenSSL. bz#2466 * misc: Fix compilation failures on some versions of AIX's compiler related to the definition of the VA_COPY macro. bz#2589 * sshd(8): Whitelist more architectures to enable the seccomp-bpf sandbox. bz#2590 * ssh-agent(1), sftp-server(8): Disable process tracing on Solaris using setpflags(__PROC_PROTECT, ...). bz#2584 * sshd(8): On Solaris, don't call Solaris setproject() with UsePAM=yes it's PAM's responsibility. bz#2425 Checksums: ========== - SHA1 (openssh-7.3.tar.gz) = b1641e5265d9ec68a9a19decc3a7edd1203cbd33 - SHA256 (openssh-7.3.tar.gz) = vS0X35qrX9OOPBkyDMYhOje/DBwHBVEV7nv5rkzw4vM= - SHA1 (openssh-7.3p1.tar.gz) = bfade84283fcba885e2084343ab19a08c7d123a5 - SHA256 (openssh-7.3p1.tar.gz) = P/uYmm3KppWUw7VQ1IVaWi4XGMzd5/XjY4e0JCIPvsw= Please note that the SHA256 signatures are base64 encoded and not hexadecimal (which is the default for most checksum tools). The PGP key used to sign the releases is available as RELEASE_KEY.asc from the mirror sites. Reporting Bugs: =============== - Please read http://www.openssh.com/report.html Security bugs should be reported directly to openssh@openssh.com OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt, Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and Ben Lindstrom.

Portable OpenSSH 7.2p2 was released on 2016-03-10. It will be available from the mirrors listed at https://www.openssh.com/. OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support. OpenSSH also includes transitional support for the legacy SSH 1.3 and 1.5 protocols that may be enabled at compile-time. Once again, we would like to thank the OpenSSH community for their continued support of the project, especially those who contributed code or patches, reported bugs, tested snapshots or donated to the project. More information on donations may be found at: http://www.openssh.com/donations.html Changes since OpenSSH 7.2p1 =========================== This release fixes a security bug: * sshd(8): sanitise X11 authentication credentials to avoid xauth command injection when X11Forwarding is enabled. Full details of the vulnerability are available at: http://www.openssh.com/txt/x11fwd.adv Checksums: ========== - SHA1 (openssh-7.2p2.tar.gz) = 70e35d7d6386fe08abbd823b3a12a3ca44ac6d38 - SHA256 (openssh-7.2p2.tar.gz) = pyeB0aBDh2oiT/GwAy2qQJTYdWWmhSh1nBwsq1SCVIw= Please note that the SHA256 signature