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In EAP-TLS method of authentication if a server sends Change Cipher Spec message to the client, I couldn't find references to SSL3_ST_CR_CHANGE_A. The enum is defined for SSL3_ST_CR_CHANGE_A in ssl3.h, but I looked at OpenSSL's source code: s3_clnt.c:ssl3_connect(), and I don't see any case that handles it.

The openssl version which I am using is openssl-1.0.1e, does any other version supports this.

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The change_cipher_spec message is not a handshake message; it has its own special record type. It is handled in s3_pkt.c:ssl3_read_bytes().

OpenSSL handles the handshake as a state machine; the state variable contains the current status. Whenever a handshake message is received, the status changes. The change_cipher_spec message, being always small (its length is 1 byte, exactly), is handled on-the-fly just like an alert message. When received, it does not change the state variable, but instead sets the change_cipher_spec field to 1. When a change_cipher_spec is expected, the next message should be a Finished, and the code processing the Finished message checks the change_cipher_spec field.

  • Thanks for the response, Actually i did not get any log saying that it has processed the change spec thats took me confusion. – Anbazhakan Anbu Nov 11 '14 at 6:54
  • Once the expected finish processed i received another client_hello_requset in the same handshake as a encrypted message, and openssl able to decrypt it and it is wrting client_hello into the buffer, but i am getting zero bytes from BIO_read and getting error saying that "Failed to read possible Application Data error:00000000:lib(0):func(0):reason(0)" the ultimate issue which i am seeing is that once if it received finish then BIO_read simply return zero. what could be the issue ? – Anbazhakan Anbu Nov 11 '14 at 7:13

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