/dev/random entropy on readonly file system

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My hostapd works very well on my raspberry Pi3. But if I put root filesystem in readonly, it does not work. I have put some folders like /var/run and /tmp in a ramdisk filesystem.



I have seen something in log files when the root filesystem is readonly:



random: Cannot read from /dev/random: Resource temporarily unavailable
random: Got 0/20 bytes from /dev/random
random: Only 0/20 bytes of strong random data available from /dev/random
random: Not enough entropy pool available for secure operations


So I think something is wrong with /dev/random when the root filesystem is in readonly mode.



What should I do to fix that ?



-- Edit --
Here is the output of ls -l /dev/random:



crw-rw-rw- 1 root root 1, 8 nov. 12 16:17 /dev/random



devices random




share|improve this question






















  • Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
    – Andy Dalton
    Nov 10 '17 at 21:37











  • Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
    – Andy Dalton
    Nov 13 '17 at 16:01










  • It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
    – Bob5421
    Nov 14 '17 at 18:20










  • Raspberry pi 3 has a RNG.
    – Andy Dalton
    Nov 14 '17 at 21:18










  • Okay so what should i do to make it work ?
    – Bob5421
    Nov 15 '17 at 13:17














up vote
2
down vote

favorite












My hostapd works very well on my raspberry Pi3. But if I put root filesystem in readonly, it does not work. I have put some folders like /var/run and /tmp in a ramdisk filesystem.



I have seen something in log files when the root filesystem is readonly:



random: Cannot read from /dev/random: Resource temporarily unavailable
random: Got 0/20 bytes from /dev/random
random: Only 0/20 bytes of strong random data available from /dev/random
random: Not enough entropy pool available for secure operations


So I think something is wrong with /dev/random when the root filesystem is in readonly mode.



What should I do to fix that ?



-- Edit --
Here is the output of ls -l /dev/random:



crw-rw-rw- 1 root root 1, 8 nov. 12 16:17 /dev/random



devices random




share|improve this question






















  • Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
    – Andy Dalton
    Nov 10 '17 at 21:37











  • Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
    – Andy Dalton
    Nov 13 '17 at 16:01










  • It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
    – Bob5421
    Nov 14 '17 at 18:20










  • Raspberry pi 3 has a RNG.
    – Andy Dalton
    Nov 14 '17 at 21:18










  • Okay so what should i do to make it work ?
    – Bob5421
    Nov 15 '17 at 13:17












up vote
2
down vote

favorite









up vote
2
down vote

favorite











My hostapd works very well on my raspberry Pi3. But if I put root filesystem in readonly, it does not work. I have put some folders like /var/run and /tmp in a ramdisk filesystem.



I have seen something in log files when the root filesystem is readonly:



random: Cannot read from /dev/random: Resource temporarily unavailable
random: Got 0/20 bytes from /dev/random
random: Only 0/20 bytes of strong random data available from /dev/random
random: Not enough entropy pool available for secure operations


So I think something is wrong with /dev/random when the root filesystem is in readonly mode.



What should I do to fix that ?



-- Edit --
Here is the output of ls -l /dev/random:



crw-rw-rw- 1 root root 1, 8 nov. 12 16:17 /dev/random



devices random




share|improve this question














My hostapd works very well on my raspberry Pi3. But if I put root filesystem in readonly, it does not work. I have put some folders like /var/run and /tmp in a ramdisk filesystem.



I have seen something in log files when the root filesystem is readonly:



random: Cannot read from /dev/random: Resource temporarily unavailable
random: Got 0/20 bytes from /dev/random
random: Only 0/20 bytes of strong random data available from /dev/random
random: Not enough entropy pool available for secure operations


So I think something is wrong with /dev/random when the root filesystem is in readonly mode.



What should I do to fix that ?



-- Edit --
Here is the output of ls -l /dev/random:



crw-rw-rw- 1 root root 1, 8 nov. 12 16:17 /dev/random




devices random





share|improve this question













share|improve this question




share|improve this question








edited Nov 12 '17 at 17:38

























asked Nov 10 '17 at 20:59









Bob5421

1112




1112











  • Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
    – Andy Dalton
    Nov 10 '17 at 21:37











  • Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
    – Andy Dalton
    Nov 13 '17 at 16:01










  • It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
    – Bob5421
    Nov 14 '17 at 18:20










  • Raspberry pi 3 has a RNG.
    – Andy Dalton
    Nov 14 '17 at 21:18










  • Okay so what should i do to make it work ?
    – Bob5421
    Nov 15 '17 at 13:17
















  • Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
    – Andy Dalton
    Nov 10 '17 at 21:37











  • Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
    – Andy Dalton
    Nov 13 '17 at 16:01










  • It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
    – Bob5421
    Nov 14 '17 at 18:20










  • Raspberry pi 3 has a RNG.
    – Andy Dalton
    Nov 14 '17 at 21:18










  • Okay so what should i do to make it work ?
    – Bob5421
    Nov 15 '17 at 13:17















Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
– Andy Dalton
Nov 10 '17 at 21:37





Can you add the output of ls -l /dev/random (to your question, not as a response comment)?
– Andy Dalton
Nov 10 '17 at 21:37













Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
– Andy Dalton
Nov 13 '17 at 16:01




Do you have the hardware random number generator enabled? If no, you might take a look at: nico-maas.de/?p=1562 You'll want to install and configure package rng-tools.
– Andy Dalton
Nov 13 '17 at 16:01












It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
– Bob5421
Nov 14 '17 at 18:20




It is a raspberry pi3 so i do not know if there is an hardware random number genrator...
– Bob5421
Nov 14 '17 at 18:20












Raspberry pi 3 has a RNG.
– Andy Dalton
Nov 14 '17 at 21:18




Raspberry pi 3 has a RNG.
– Andy Dalton
Nov 14 '17 at 21:18












Okay so what should i do to make it work ?
– Bob5421
Nov 15 '17 at 13:17




Okay so what should i do to make it work ?
– Bob5421
Nov 15 '17 at 13:17















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