Mercurial > dropbear
view libtomcrypt/notes/tech0005.txt @ 1289:a23386821e9f
Add -c <command> option to force a specific command
This change adds a -c option to dropbear, to force the session to use a
specific command, in a similar fashion to OpenSSH's ForceCommand
configuration option.
This is useful to provide a simple fixed service over ssh, without
requiring an authorized key file for the per-key forced_command option.
This setting takes precedence over the channel session's provided
command, and the per-key forced_command setting.
Signed-off-by: Jeremy Kerr <[email protected]>
| author | Jeremy Kerr <jk@ozlabs.org> |
|---|---|
| date | Tue, 12 Apr 2016 21:01:08 +0800 |
| parents | 0cbe8f6dbf9e |
| children | f849a5ca2efc |
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Tech Note 0005 Minimizing Code Space Tom St Denis Introduction ------------ Tweaking... You can disable whole classes of algorithms on the command line with the LTC_NO_* defines. From there you can manually turn on what you want to enable. The following build with GCC 3.4.4 on an AMD64 box gets you AES, CTR mode, SHA-256, HMAC, Yarrow, full RSA PKCS #1, PKCS #5 and ASN.1 DER in roughly 40KB of code (49KB on the ARMv4) (both excluding the math library). CFLAGS="-DLTC_NO_CIPHERS -DLTC_NO_HASHES -DLTC_NO_PRNGS -DLTC_NO_MACS -DLTC_NO_MODES -DLTC_NO_PK -DRIJNDAEL -DLTC_CTR_MODE -DSHA256 \ -DLTC_HMAC -DYARROW -DMRSA -DMPI -DTFM_DESC -DARGTYPE=3 -Os -DLTC_SMALL_CODE -fomit-frame-pointer" make IGNORE_SPEED=1 Obviously this won't get you performance but if you need to pack a crypto lib in a device with limited means it's more than enough... Neato eh?