Hi there,

I believe the following memcmp call is vulnerable to a remote timing
attack.

https://github.com/openssl/openssl/blob/master/ssl/ssl_lib.c#L1974

static int ssl_session_cmp(const SSL_SESSION *a,const SSL_SESSION *b)
        {
        if (a->ssl_version != b->ssl_version)
                return(1);
        if (a->session_id_length != b->session_id_length)
                return(1);
        return(memcmp(a->session_id,b->session_id,a->session_id_length));
        }

For more information on memcmp timing attacks please see:
http://rdist.root.org/2010/08/05/optimized-memcmp-leaks-useful-timing-differences/
&&
https://lkml.org/lkml/2013/2/10/131

Regards,
Peter.

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