[openssl-users] API SSL_Connect fails and always returns SSL_ERROR_WANT_READ causes infinite loop in application

[Matt Caswell]

Sounds like a bug. Can you raise this as an issue on github?

https://github.com/openssl/openssl/issues

Thanks

Matt


On 21/11/17 08:53, mahesh gs wrote:
> Hi,
> 
> We were able to further localize this problem and found the problem is
> with the function "BIO_dgram_sctp_wait_for_dry". In this function after
> enabling the "sctp_sender_dry_event" we are trying to do MSG_PEEK to
> peek to the message at SCTP layer, in this case the size of the message
> waiting in the lower layer is 15 which size is exactly the size of
> "Handshake Alert" that is received from the server and waiting to be
> read. Dry event is never read from the lower layer that causes the
> SUB_STATE_ERROR and intern causes the SSL_Connect to loop in application.
> 
> Current version of openssl we are using is 01.01.00g.
> 
> We have tested and able to reproduce this issue with the OPENSSL
> 01.00.02k version that is packaged with RHEL 7.4 as well.
> 
> 
> Thanks,
> Mahesh G S
> 
> On Mon, Nov 20, 2017 at 4:42 PM, mahesh gs <mahesh116 at gmail.com
> <mailto:mahesh116 at gmail.com>> wrote:
> 
>     Hi Matt,
> 
>     Thanks for the response.
> 
>     We debugged through openssl code to get to know the reason why
>     client is not reading "SSL Alert".
> 
>     Once the "ClientKeyExchange" is sent openssl trying to send out the
>     "ChangeCipherSpec"  message which is creating the problem. 
> 
>     The pre-work function for "ChangeCipherSpec" enables SCTP dry event
>     and wait for dry event notification.
> 
>     Inline image 1
> 
> 
>     In this scenario, dry notification is never sent from SCTP.
>     "dtls_wait_for_dry" always returns "WORK_MORE_A". Hereafter flow
>     never enters "read_state_machine" where alert is to be red.This
>     causes SSL_Connect to be in infinite loop.
> 
> 
>     Thanks,
>     Mahesh G S
> 
>     On Fri, Nov 17, 2017 at 3:36 PM, Matt Caswell <matt at openssl.org
>     <mailto:matt at openssl.org>> wrote:
> 
> 
> 
>         On 17/11/17 06:42, mahesh gs wrote:
>         >  Why
>         > does client respond with "Client key exchange" even if the the handshake
>         > failure alert is sent from server?
> 
>         The client will send its entire flight of messages before it
>         attempts to
>         read anything from the server. So, in this case, the
>         ClientKeyExchange
>         message is still sent because the client hasn't read the alert yet.
> 
>         Matt
> 
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