diff options
Diffstat (limited to 'sshd.8')
-rw-r--r-- | sshd.8 | 64 |
1 files changed, 42 insertions, 22 deletions
@@ -33,13 +33,13 @@ | |||
33 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | 33 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
34 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 34 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
35 | .\" | 35 | .\" |
36 | .\" $OpenBSD: sshd.8,v 1.304 2018/07/22 12:16:59 dtucker Exp $ | 36 | .\" $OpenBSD: sshd.8,v 1.312 2020/01/25 06:03:10 djm Exp $ |
37 | .Dd $Mdocdate: July 22 2018 $ | 37 | .Dd $Mdocdate: January 25 2020 $ |
38 | .Dt SSHD 8 | 38 | .Dt SSHD 8 |
39 | .Os | 39 | .Os |
40 | .Sh NAME | 40 | .Sh NAME |
41 | .Nm sshd | 41 | .Nm sshd |
42 | .Nd OpenSSH SSH daemon | 42 | .Nd OpenSSH daemon |
43 | .Sh SYNOPSIS | 43 | .Sh SYNOPSIS |
44 | .Nm sshd | 44 | .Nm sshd |
45 | .Bk -words | 45 | .Bk -words |
@@ -253,16 +253,13 @@ Whenever a client connects, the daemon responds with its public | |||
253 | host key. | 253 | host key. |
254 | The client compares the | 254 | The client compares the |
255 | host key against its own database to verify that it has not changed. | 255 | host key against its own database to verify that it has not changed. |
256 | Forward security is provided through a Diffie-Hellman key agreement. | 256 | Forward secrecy is provided through a Diffie-Hellman key agreement. |
257 | This key agreement results in a shared session key. | 257 | This key agreement results in a shared session key. |
258 | The rest of the session is encrypted using a symmetric cipher, currently | 258 | The rest of the session is encrypted using a symmetric cipher. |
259 | 128-bit AES, Blowfish, 3DES, CAST128, Arcfour, 192-bit AES, or 256-bit AES. | ||
260 | The client selects the encryption algorithm | 259 | The client selects the encryption algorithm |
261 | to use from those offered by the server. | 260 | to use from those offered by the server. |
262 | Additionally, session integrity is provided | 261 | Additionally, session integrity is provided |
263 | through a cryptographic message authentication code | 262 | through a cryptographic message authentication code (MAC). |
264 | (hmac-md5, hmac-sha1, umac-64, umac-128, | ||
265 | hmac-sha2-256 or hmac-sha2-512). | ||
266 | .Pp | 263 | .Pp |
267 | Finally, the server and the client enter an authentication dialog. | 264 | Finally, the server and the client enter an authentication dialog. |
268 | The client tries to authenticate itself using | 265 | The client tries to authenticate itself using |
@@ -429,25 +426,39 @@ comments). | |||
429 | Public keys consist of the following space-separated fields: | 426 | Public keys consist of the following space-separated fields: |
430 | options, keytype, base64-encoded key, comment. | 427 | options, keytype, base64-encoded key, comment. |
431 | The options field is optional. | 428 | The options field is optional. |
432 | The keytype is | 429 | The supported key types are: |
433 | .Dq ecdsa-sha2-nistp256 , | 430 | .Pp |
434 | .Dq ecdsa-sha2-nistp384 , | 431 | .Bl -item -compact -offset indent |
435 | .Dq ecdsa-sha2-nistp521 , | 432 | .It |
436 | .Dq ssh-ed25519 , | 433 | sk-ecdsa-sha2-nistp256@openssh.com |
437 | .Dq ssh-dss | 434 | .It |
438 | or | 435 | ecdsa-sha2-nistp256 |
439 | .Dq ssh-rsa ; | 436 | .It |
440 | the comment field is not used for anything (but may be convenient for the | 437 | ecdsa-sha2-nistp384 |
438 | .It | ||
439 | ecdsa-sha2-nistp521 | ||
440 | .It | ||
441 | sk-ssh-ed25519@openssh.com | ||
442 | .It | ||
443 | ssh-ed25519 | ||
444 | .It | ||
445 | ssh-dss | ||
446 | .It | ||
447 | ssh-rsa | ||
448 | .El | ||
449 | .Pp | ||
450 | The comment field is not used for anything (but may be convenient for the | ||
441 | user to identify the key). | 451 | user to identify the key). |
442 | .Pp | 452 | .Pp |
443 | Note that lines in this file can be several hundred bytes long | 453 | Note that lines in this file can be several hundred bytes long |
444 | (because of the size of the public key encoding) up to a limit of | 454 | (because of the size of the public key encoding) up to a limit of |
445 | 8 kilobytes, which permits DSA keys up to 8 kilobits and RSA | 455 | 8 kilobytes, which permits RSA keys up to 16 kilobits. |
446 | keys up to 16 kilobits. | ||
447 | You don't want to type them in; instead, copy the | 456 | You don't want to type them in; instead, copy the |
448 | .Pa id_dsa.pub , | 457 | .Pa id_dsa.pub , |
449 | .Pa id_ecdsa.pub , | 458 | .Pa id_ecdsa.pub , |
459 | .Pa id_ecdsa_sk.pub , | ||
450 | .Pa id_ed25519.pub , | 460 | .Pa id_ed25519.pub , |
461 | .Pa id_ed25519_sk.pub , | ||
451 | or the | 462 | or the |
452 | .Pa id_rsa.pub | 463 | .Pa id_rsa.pub |
453 | file and edit it. | 464 | file and edit it. |
@@ -589,8 +600,8 @@ IPv6 addresses can be specified by enclosing the address in square brackets. | |||
589 | Multiple | 600 | Multiple |
590 | .Cm permitopen | 601 | .Cm permitopen |
591 | options may be applied separated by commas. | 602 | options may be applied separated by commas. |
592 | No pattern matching is performed on the specified hostnames, | 603 | No pattern matching or name lookup is performed on the |
593 | they must be literal domains or addresses. | 604 | specified hostnames, they must be literal host names and/or addresses. |
594 | A port specification of | 605 | A port specification of |
595 | .Cm * | 606 | .Cm * |
596 | matches any port. | 607 | matches any port. |
@@ -613,6 +624,13 @@ option. | |||
613 | Permits tty allocation previously disabled by the | 624 | Permits tty allocation previously disabled by the |
614 | .Cm restrict | 625 | .Cm restrict |
615 | option. | 626 | option. |
627 | .It Cm no-touch-required | ||
628 | Do not require demonstration of user presence | ||
629 | for signatures made using this key. | ||
630 | This option only makes sense for the FIDO authenticator algorithms | ||
631 | .Cm ecdsa-sk | ||
632 | and | ||
633 | .Cm ed25519-sk . | ||
616 | .It Cm restrict | 634 | .It Cm restrict |
617 | Enable all restrictions, i.e. disable port, agent and X11 forwarding, | 635 | Enable all restrictions, i.e. disable port, agent and X11 forwarding, |
618 | as well as disabling PTY allocation | 636 | as well as disabling PTY allocation |
@@ -656,6 +674,8 @@ restrict,command="uptime" ssh-rsa AAAA1C8...32Tv== | |||
656 | user@example.net | 674 | user@example.net |
657 | restrict,pty,command="nethack" ssh-rsa AAAA1f8...IrrC5== | 675 | restrict,pty,command="nethack" ssh-rsa AAAA1f8...IrrC5== |
658 | user@example.net | 676 | user@example.net |
677 | no-touch-required sk-ecdsa-sha2-nistp256@openssh.com AAAAInN...Ko== | ||
678 | user@example.net | ||
659 | .Ed | 679 | .Ed |
660 | .Sh SSH_KNOWN_HOSTS FILE FORMAT | 680 | .Sh SSH_KNOWN_HOSTS FILE FORMAT |
661 | The | 681 | The |