Mercurial > dropbear
view SMALL @ 1653:76189c9ffea2
External Public-Key Authentication API (#72)
* Implemented dynamic loading of an external plug-in shared library to delegate public key authentication
* Moved conditional compilation of the plugin infrastructure into the configure.ac script to be able to add -ldl to dropbear build only when the flag is enabled
* Added tags file to the ignore list
* Updated API to have the constructor to return function pointers in the pliugin instance. Added support for passing user name to the checkpubkey function. Added options to the session returned by the plugin and have dropbear to parse and process them
* Added -rdynamic to the linker flags when EPKA is enabled
* Changed the API to pass a previously created session to the checkPubKey function (created during preauth)
* Added documentation to the API
* Added parameter addrstring to plugin creation function
* Modified the API to retrieve the auth options. Instead of having them as field of the EPKASession struct, they are stored internally (plugin-dependent) in the plugin/session and retrieved through a pointer to a function (in the session)
* Changed option string to be a simple char * instead of unsigned char *
| author | fabriziobertocci <fabriziobertocci@gmail.com> |
|---|---|
| date | Wed, 15 May 2019 09:43:57 -0400 |
| parents | b9d3f725e00b |
| children | 13cb8cc1b0e4 |
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Tips for a small system: If you only want server functionality (for example), compile with make PROGRAMS=dropbear rather than just make dropbear so that client functionality in shared portions of Dropbear won't be included. The same applies if you are compiling just a client. --- The following are set in options.h: - You can safely disable blowfish and twofish ciphers, and MD5 hmac, without affecting interoperability - If you're compiling statically, you can turn off host lookups - You can disable either password or public-key authentication, though note that the IETF draft states that pubkey authentication is required. - Similarly with DSS and RSA, you can disable one of these if you know that all clients will be able to support a particular one. The IETF draft states that DSS is required, however you may prefer to use RSA. DON'T disable either of these on systems where you aren't 100% sure about who will be connecting and what clients they will be using. - Disabling the MOTD code and SFTP-SERVER may save a small amount of codesize - You can disable x11, tcp and agent forwarding as desired. None of these are essential, although agent-forwarding is often useful even on firewall boxes. --- If you are compiling statically, you may want to disable zlib, as it will use a few tens of kB of binary-size (./configure --disable-zlib). You can create a combined binary, see the file MULTI, which will put all the functions into one binary, avoiding repeated code. If you're compiling with gcc, you might want to look at gcc's options for stripping unused code. The relevant vars to set before configure are: LDFLAGS=-Wl,--gc-sections CFLAGS="-ffunction-sections -fdata-sections" You can also experiment with optimisation flags such as -Os, note that in some cases these flags actually seem to increase size, so experiment before deciding. Of course using small C libraries such as uClibc and dietlibc can also help. If you have any queries, mail me and I'll see if I can help.