[Android]dropbear on android

Dropbear 是一套来自澳大利亚的 *nix SSH 工具集，以体积微小著称，因此在嵌入式环境被广泛中使用。

1. 编译 dropbear
$ wget %7Ematt/dropbear/releases/dropbear-0.52.tar.gz
$ wget

$ tar zxvf dropbear-0.52.tar.gz
$ cd dropbear-0.52
$ patch -p1 < ../dropbear0.52-android.patch
patching file common-session.c
patching file loginrec.c
patching file runopts.h
patching file svr-auth.c
patching file svr-authpasswd.c
patching file svr-authpubkey.c
patching file svr-chansession.c
patching file svr-runopts.c

1) zlib support
所使用的编译器未有zlib库支持，因此需要先未其增加zlib支持，/home/install为交叉编译器所在目录。
$ ls -l /home/install
lrwxrwxrwx 1 root root 54 2009-11-28 10:50 /home/install -> /home/goosen/works/buildroot/build_arm/staging_dir/usr

$ ./configure --prefix=/home/install
$ make CC=arm-linux-gcc
$ make install

2) 静态编译 dropbear
$ cd dropbear-0.52/
$ ./configure --host=arm-linux
//$ STATIC=1 make PROGRAMS="dropbear dropbearkey"
$ STATIC=1 make


2. 配置 dropbear
1) generate keys
~ $: adb shell
# mkdir /data/dropbear
# dropbearkey -t rsa -f /data/dropbear/dropbear_rsa_host_key
# dropbearkey -t dss -f /data/dropbear/dropbear_dss_host_key

2) start dropbear

# dropbear -h
Dropbear sshd v0.52
Usage: dropbear [options]
Options are:
-A Android Mode, specify a user explicitly
-N Android Mode, user name
-C Android Mode, password
-R Android Mode, public key file (authorized_keys)
-U Android Mode, UID
-G Android Mode, GID
-b bannerfile    Display the contents of bannerfile before user login
(default: none)
-d dsskeyfile    Use dsskeyfile for the dss host key
(default: /etc/dropbear/dropbear_dss_host_key)
-r rsakeyfile    Use rsakeyfile for the rsa host key
(default: /etc/dropbear/dropbear_rsa_host_key)
-F        Don't fork into background
-E        Log to stderr rather than syslog
-m        Don't display the motd on login
-w        Disallow root logins
-s        Disable password logins
-g        Disable password logins for root
-j        Disable local port forwarding
-k        Disable remote port forwarding
-a        Allow connections to forwarded ports from any host
-p [address:]port
Listen on specified tcp port (and optionally address),
up to 10 can be specified
(default port is 22 if none specified)
-P PidFile    Create pid file PidFile
(default /var/run/dropbear.pid)
-i        Start for inetd
-W (default 24576, larger may be faster, max 1MB)
-K   (0 is never, default 0)
-I   (0 is never, default 0)

# ln -s /data/dropbear /etc/dropbear
# dropbear -E

让android启动的时候自动启动 dropbear, 编辑 /init.rc，增加，
#dropbear start
service dropbear /system/sbin/dropbear -E
oneshot

3) connect (u can use dyndns from market to get a domain name )
$ ssh [e-mail]

# cat /home/root/.profile
PATH=/usr/bin:/usr/sbin:/bin:/sbin:/system/sbin:/system/bin:/system/xbin:/data/local/bin
export PATH
# ps | grep 'dropbear'
797 root       436 S    /system/sbin/dropbear -E
973 root       492 S    /system/sbin/dropbear -E
984 root       492 S    /system/sbin/dropbear -E
1036 root      3044 S    grep dropbear

注，此处是~/.profile文件（默认环境变量），而不是~/.bashrc。不过/data/dropbear/.profile 未起作用，暂时不明。


3. 碰到的问题及解决方法
1）为用户设置密码出现，
# passwd root
passwd: unknown uid 0

修改 /etc/passwd 如下，
/ # cat /etc/passwd
#root:x:1000:1000:Linux User,,,:/home/root:/bin/sh
root:x:0:0:Linux User,,,:/home/root:/bin/sh

2）登录的时候dropbear提示，
user 'root' has invalid shel

确保/etc/passwd与/etc/shells中shell的设置一致,
# cat /etc/shells
#/system/bin/sh
/bin/sh

源码、补丁及参考的相关文档如下，
http://blog.csdn.net/tekkamanitachi/archive/2009/06/26/4300854.aspx        

~matt/dropbear/releases/dropbear-0.52.tar.gz
http://blog.linjian.org/articles/dropbear-pam-patch/