My openvpn server process on openwrt crashes if openvpn is started with cryptodev engine, with below logs, Please note, crash happens only during packet exchange between server and client that to after some duration, and duration differs if cipher is changed or prng nsl is changed. i.e. higher the nsl longer the duration [b] Thu Jun 28 11:54:51 2018 client2/:57348 RAND_bytes() failed [b]Thu Jun 28 11:54:51 2018 client2/:57348 ERROR: Random number generator cannot obtain entropy for PRNG[/b][/b] Thu Jun 28 11:54:51 2018 client2/:57348 Exiting due to fatal error Thu Jun 28 11:54:51 2018 client2/:57348 Closing TUN/TAP interface Thu Jun 28 11:54:51 2018 client2/:57348 /sbin/ifconfig tun0 0.0.0.0 ifconfig: SIOCSIFADDR: Operation not permitted Thu Jun 28 11:54:51 2018 client2/:57348 Linux ip addr del failed: external program exited with error status: 1 ... Openvpn works fine if cryptodev engine is not used! Am I missing some configuration here ? or cryptodev needs to be compiled with some specific flags? Any pointers , suggestions would greatly help Thanks.

We already read your other post: https://forums.openvpn.net/viewtopic.php?f=4&t=26063#p79691 Please do not post duplicates. [quote=amaze100 post_id=79696 time=1530196508 user_id=44432] My openvpn server process on openwrt crashes if openvpn is started with cryptodev engine [/quote]Openvpn does [b]not[/b] crash it exits with the reason why. [quote=amaze100 post_id=79696 time=1530196508 user_id=44432] Thu Jun 28 11:54:51 2018 client2/:57348 ERROR: [b]Random number generator cannot obtain entropy for PRNG[/b] Thu Jun 28 11:54:51 2018 client2/:57348 [b]Exiting[/b] due to fatal error [/quote]So you have to fix your PRNG or entropy source .. [quote=""The Openvpn Manual]--[b]engine [engine-name] [/b] [list]Enable [b]OpenSSL hardware-based crypto engine[/b] functionality.[/list] [/quote] So this is openssl .. [quote=amaze100 post_id=79696 time=1530196508 user_id=44432] Openvpn works fine if cryptodev engine is not used! [/quote]So [i]why[/i] use it ? :geek:

Openvpn with cryptodev engine crashes with entropy error

amaze100

My openvpn server process on openwrt crashes if openvpn is started with cryptodev engine, with below logs,

Please note, crash happens only during packet exchange between server and client that to after some duration,
and duration differs if cipher is changed or prng nsl is changed.
i.e. higher the nsl longer the duration

Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 RAND_bytes() failed
Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 ERROR: Random number generator cannot obtain entropy for PRNG
Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 Exiting due to fatal error
Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 Closing TUN/TAP interface
Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 /sbin/ifconfig tun0 0.0.0.0
ifconfig: SIOCSIFADDR: Operation not permitted
Thu Jun 28 11:54:51 2018 client2/<<ip>>:57348 Linux ip addr del failed: external program exited with error status: 1
...

Openvpn works fine if cryptodev engine is not used!

Am I missing some configuration here ? or cryptodev needs to be compiled with some specific flags?
Any pointers , suggestions would greatly help

Thanks.

TinCanTech

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amaze100

Sorry for the duplicate.

How should I fix the entropy source for engine? In case of w/o engine, /dev/random and /dev/urandom take care of it.
any pointers for hw engine?

We use 'cryptodev engine' because we want use available hardware acceleration for the crypto operations.