java.net.BindException: bind failed: EACCES (Permission denied) on a rooted device

Question

The following code throws "java.net.BindException: bind failed: EACCES (Permission denied)" on a rooted tablet:

 DatagramSocket ds = new DatagramSocket(67);

I thought binding to privileged port 67 was allowed on a rooted device. Could anyone shed some light on this?

score 1 · Accepted Answer · edited May 23 '17 at 12:16

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Just because a device is "rooted", that does not give permission to arbitrary apps to do anything they want with root privileges. Rooted devices merely allow arbitrary apps to request to use the su command line to execute new processes with root privileges via a command line.

See this, for example.

edited May 23 '17 at 12:16

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answered Mar 18 '16 at 05:41

Doug Stevenson

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Thank you for the prompt answer. I am using Runtime.getRuntime().exec("su -c ifconfig eth0 up") in the code. Does it help invoke the privilege? – Hong Mar 18 '16 at 05:57
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No, your main app process will never be able to do things with root privileges. – Doug Stevenson Mar 18 '16 at 06:09
Thank you for the clarification. Do you happen to know a way to get around this? – Hong Mar 18 '16 at 06:20
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If I knew a workaround, I would not have said "never" in the above comment. – Doug Stevenson Mar 18 '16 at 06:33
Could you do me one more favor: is it possible to compile to custom ROM to allow apps to have root privileges? – Hong Mar 19 '16 at 03:47
Sorry, I have no idea about that. – Doug Stevenson Mar 19 '16 at 04:05

java.net.BindException: bind failed: EACCES (Permission denied) on a rooted device

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