1This is Dropbear, a smallish SSH 2 server and client. 2 3INSTALL has compilation instructions. 4 5MULTI has instructions on making a multi-purpose binary (ie a single binary 6which performs multiple tasks, to save disk space) 7 8SMALL has some tips on creating small binaries. 9 10See TODO for a few of the things I know need looking at, and please contact 11me if you have any questions/bugs found/features/ideas/comments etc :) 12 13Matt Johnston 14matt@ucc.asn.au 15 16 17In the absence of detailed documentation, some notes follow: 18============================================================================ 19 20Server public key auth: 21 22You can use ~/.ssh/authorized_keys in the same way as with OpenSSH, just put 23the key entries in that file. They should be of the form: 24 25ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAwVa6M6cGVmUcLl2cFzkxEoJd06Ub4bVDsYrWvXhvUV+ZAM9uGuewZBDoAqNKJxoIn0Hyd0Nk/yU99UVv6NWV/5YSHtnf35LKds56j7cuzoQpFIdjNwdxAN0PCET/MG8qyskG/2IE2DPNIaJ3Wy+Ws4IZEgdJgPlTYUBWWtCWOGc= someone@hostname 26 27You must make sure that ~/.ssh, and the key file, are only writable by the 28user. Beware of editors that split the key into multiple lines. 29 30NOTE: Dropbear ignores authorized_keys options such as those described in the 31OpenSSH sshd manpage, and will not allow a login for these keys. 32 33============================================================================ 34 35Client public key auth: 36 37Dropbear can do public key auth as a client, but you will have to convert 38OpenSSH style keys to Dropbear format, or use dropbearkey to create them. 39 40If you have an OpenSSH-style private key ~/.ssh/id_rsa, you need to do: 41 42dropbearconvert openssh dropbear ~/.ssh/id_rsa ~/.ssh/id_rsa.db 43dbclient -i ~/.ssh/id_rsa.db <hostname> 44 45Currently encrypted keys aren't supported, neither is agent forwarding. At some 46stage both hopefully will be. 47 48============================================================================ 49 50If you want to get the public-key portion of a Dropbear private key, look at 51dropbearkey's '-y' option. 52 53============================================================================ 54 55To run the server, you need to generate server keys, this is one-off: 56./dropbearkey -t rsa -f dropbear_rsa_host_key 57./dropbearkey -t dss -f dropbear_dss_host_key 58 59or alternatively convert OpenSSH keys to Dropbear: 60./dropbearconvert openssh dropbear /etc/ssh/ssh_host_dsa_key dropbear_dss_host_key 61 62============================================================================ 63 64If the server is run as non-root, you most likely won't be able to allocate a 65pty, and you cannot login as any user other than that running the daemon 66(obviously). Shadow passwords will also be unusable as non-root. 67 68============================================================================ 69 70The Dropbear distribution includes a standalone version of OpenSSH's scp 71program. You can compile it with "make scp", you may want to change the path 72of the ssh binary, specified by _PATH_SSH_PROGRAM in options.h . By default 73the progress meter isn't compiled in to save space, you can enable it by 74adding 'SCPPROGRESS=1' to the make commandline. 75