Can't restore SSL_SESSION saved via i2d_SSL_SESSION using d2i_SSL_SESSION

[Klaus Thurnhofer]

Hi,

I'm trying to save a session to a buffer, like it is proposed in several
articles, using i2d_SSL_SESSION. However, when trying to restore the session
from the ASN1 buffer it immediately returns with an error.

from what I learned from the various articles and samples I feel that the
following code snippet should restore what is available in "sess" into
"sess2":

int len;
unsigned char *pp;
int rc;
SSL_SESSION *sess=NULL, *sess2=NULL;

sess = SSL_get1_session( ssl );
if( sess )
{
        len = i2d_SSL_SESSION( sess, NULL );
        fprintf( stderr, "SESS: len=%d\n", len );
        pp = (unsigned char *)malloc( len );
        rc = i2d_SSL_SESSION( sess, &pp );
        fprintf( stderr, "SESS: converted to asn1, rc=%d\n", rc );
       
        sess2 = d2i_SSL_SESSION( NULL, &pp, len );
        fprintf( stderr, "SESS: new sess2=%x\n", sess2 );
}


however, the result I keep getting is a NULL pointer and a the ssl error
message:

SSL error: 218525757 (error:0D06703D:asn1 encoding
routines:a2i_ASN1_STRING:expecting an asn1 sequence) in ssl_asn1.c line 242:
"address=135554540 offset=0".


there's not much comprehensive documentation about this topic and I'm sure I
misunderstand something ... but "WHAT" do I misunderstand is the question???

is there anyone out there who got this session saving stuff to work ... ???


Klaus.



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[Dr. Stephen Henson]

On Mon, Jul 04, 2005, Klaus Thurnhofer wrote:

> Hi,
>
> I'm trying to save a session to a buffer, like it is proposed in several
> articles, using i2d_SSL_SESSION. However, when trying to restore the session
> from the ASN1 buffer it immediately returns with an error.
>
> from what I learned from the various articles and samples I feel that the
> following code snippet should restore what is available in "sess" into
> "sess2":
>
> int len;
> unsigned char *pp;
> int rc;
> SSL_SESSION *sess=NULL, *sess2=NULL;
>
> sess = SSL_get1_session( ssl );
> if( sess )
> {
> len = i2d_SSL_SESSION( sess, NULL );
> fprintf( stderr, "SESS: len=%d\n", len );
> pp = (unsigned char *)malloc( len );
> rc = i2d_SSL_SESSION( sess, &pp );
> fprintf( stderr, "SESS: converted to asn1, rc=%d\n", rc );
>
> sess2 = d2i_SSL_SESSION( NULL, &pp, len );
> fprintf( stderr, "SESS: new sess2=%x\n", sess2 );
> }
>
>
> however, the result I keep getting is a NULL pointer and a the ssl error
> message:
>
>
> there's not much comprehensive documentation about this topic and I'm sure I
> misunderstand something ... but "WHAT" do I misunderstand is the question???
>
> is there anyone out there who got this session saving stuff to work ... ???
>

You aren't calling the i2d function correctly. This is dealt with in the FAQ.

Steve.
--
Dr Stephen N. Henson. Email, S/MIME and PGP keys: see homepage
OpenSSL project core developer and freelance consultant.
Funding needed! Details on homepage.
Homepage: http://www.drh-consultancy.demon.co.uk
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