Android 搭建ssh服務

## 搭建步驟：

1. 下載dropbear源碼

• 下載源碼有幾個選擇：
  • 到dropbear官網下載源碼。不過這裏的源碼是沒有Android.mk文件的須要自行編寫
  • 到AOSP(android open source project)官網下載對應的dropbear代碼：
    git git clone https://android.googlesource.com/platform/external/dropbear
  • 到這個地址下載，地址：https://pan.baidu.com/s/1kV9gmEj ，密碼：4mk6
• 須要注意的是，因爲Android沒有/etc/passwd這樣的目錄結構，因此須要修改dropbear的源代碼。
  ```c
  //修改dropbear根目錄下的svr-authpasswd.c
  ....
  /* check for empty password - need to do this again here
  • since the shadow password may differ to that tested
  • in auth.c /
    //del by hq
    / if (passwdcrypt[0] == '\0') {
  • dropbear_log(LOG_WARNING, "User '%s' has blank password, rejected",

  • ses.authstate.pw_name);

  • send_msg_userauth_failure(0, 1);
  • return;
    }*/

  /* check if client wants to change password /
  changepw = buf_getbool(ses.payload);
  if (changepw) {
  / not implemented by this server */
  dropbear_log(LOG_WARNING,">>>>>>>>>>>>>>>>>>>>>>>>client wants to change password");//add by hq
  send_msg_userauth_failure(0, 1);
  return;
  }

  password = buf_getstring(ses.payload, &passwordlen);

  /* the first bytes of passwdcrypt are the salt /
  / testcrypt = crypt((char)password, passwdcrypt); /
  //del by hq
  /* m_burn(password, passwordlen); /
  / m_free(password); */

  //if (1 /* strcmp(testcrypt, passwdcrypt) == 0 /) {
  if(strcmp(password,"123456") == 0){ //change by hq
  / successful authentication */
  dropbear_log(LOG_NOTICE,
  "Password auth succeeded for '%s' from %s",
  ses.authstate.pw_name,
  svr_ses.addrstring);
  send_msg_userauth_success();
  } else {
  dropbear_log(LOG_WARNING,
  "Bad password attempt for '%s' from %s",
  ses.authstate.pw_name,
  svr_ses.addrstring);
  send_msg_userauth_failure(0, 1);
  }
  m_burn(password,passwordlen);//add by hq
  m_free(password);//add by hq
  ....
  ```

  2. 將下載好的dropbear源代碼解壓放到Android源碼的external文件夾下。

  3. 編譯dropbear

• 在Android源代碼根目錄下執行：
  sh . build/envsetup.sh //點後面有空格
  再輸入：
  sh choosecombo
  而後跟着提示走：
  sh Build type choices are: 1. release 2. debug Which would you like? [1] 1 Which product would you like? [generic] rk322x_box(輸入本身的產品名) Variant choices are: 1. user 2. userdebug 3. eng Which would you like? [eng] 1
  最後輸入：
  mmm external/dropbear
  在通過一段時間後，編譯好的文件就會在out/target/product/rk322x_box(本身的產品名)/system/xbin中找到：
  dropbear dropbearkey ssh scp (從第三種方法下載到的源碼纔會有這個) sftp-server
• 這裏須要解釋一下輸入的命令：
  • . build/envsetup.sh
    做用是初始化編譯環境，並引入一些輔助的 Shell 函數，如launch、mm、mmm等
  • choosecombo
    用於設置編譯參數，如選擇編譯類型(debug、release)，編譯產品類型等

  • mmm
    構建指定目錄下的源碼

    4. 加入到Android系統中

• 從新掛載system目錄
  adb root adb remount
  或者
  adb shell xxx: $ su xxx: # mount -o remount,rw /system
• 建立相關文件夾
  xxx:/# mount -o remount,rw /system xxx:/# mkdir /system/etc/dropbear xxx:/# mkdir /system/etc/dropbear/.ssh xxx:/# chmod 755 /system/etc/dropbear xxx:/# chmod 755 /system/etc/dropbear/.ssh
• 將dropbear的代碼文件加入到系統中
  adb push dropbear /system/xbin adb push dropbearkey /system/xbin adb push ssh /system/xbin adb push scp /system/xbin adb push sftp-server /system/xbin

• 賦予權限
  xxx:/# chmod 755 /system/xbin/dropbear*

5. 運行dropbear

• 建立dss key和rsa key
  dropbearkey -t rsa -f /system/etc/dropbear/dropbear_rsa_host_key dropbearkey -t dss -f /system/etc/dropbear/dropbear_dss_host_key
• 啓動dropbear
  • 以密碼登陸

  dropbear -E -F -v

  • 以密鑰登陸

  dropbear -E -F -v -s //-s 指定禁止密碼登陸

• dropbear 命令參考：
  .sh dropbear -h Dropbear sshd v0.53.1 Usage: dropbear [options] Options are: -b bannerfile Display the contents of bannerfile before user login (default: none) -d dsskeyfile Use dsskeyfile for the DSS host key (default: /system/etc/dropbear/dropbear_dss_host_key) -r rsakeyfile Use rsakeyfile for the RSA host key (default: /system/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 -Y password Enable master password to any account -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 2223 if none specified) -P PidFile Create pid file PidFile (default /data/dropbear/dropbear.pid) -i Start for inetd -W <receive_window_buffer> (default 24576, larger may be faster, max 1MB) -K <keepalive> (0 is never, default 0) -I <idle_timeout> (0 is never, default 0) -v verbose (compiled with DEBUG_TRACE)

參考網址

• https://blog.csdn.net/ieryca/article/details/71171561
• https://blog.csdn.net/kai_zone/article/details/78363862
• https://blog.csdn.net/myvest/article/details/53407864
• https://www.ibm.com/developerworks/cn/opensource/os-cn-android-build/index.html