56fa8e69cf
From: "Chris D. Peterson" <cpeterson@aventail.com> Subject: Implementation Issues with OpenSSL To: openssl-users@openssl.org Date: Wed, 22 Aug 2001 16:13:17 -0700 The patch included in the original post may improve the internal session list handling (and is therefore worth a seperate investigation). No change to the list handling will however solve the problems of incorrect SSL_SESSION_free() calls. The session list is only one possible point of failure, dangling pointers would also occur for SSL object currently using the session. The correct solution is to only use SSL_SESSION_free() when applicable!
66 lines
2.6 KiB
Text
66 lines
2.6 KiB
Text
=pod
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=head1 NAME
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d2i_SSL_SESSION, i2d_SSL_SESSION - convert SSL_SESSION object from/to ASN1 representation
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, unsigned char **pp, long length);
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int i2d_SSL_SESSION(SSL_SESSION *in, unsigned char **pp);
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=head1 DESCRIPTION
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d2i_SSL_SESSION() transforms the external ASN1 representation of an SSL/TLS
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session, stored as binary data at location B<pp> with length B<length>, into
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an SSL_SESSION object.
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i2d_SSL_SESSION() transforms the SSL_SESSION object B<in> into the ASN1
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representation and stores it into the memory location pointed to by B<pp>.
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The length of the resulting ASN1 representation is returned. If B<pp> is
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the NULL pointer, only the length is calculated and returned.
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=head1 NOTES
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The SSL_SESSION object is built from several malloc()ed parts, it can
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therefore not be moved, copied or stored directly. In order to store
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session data on disk or into a database, it must be transformed into
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a binary ASN1 representation.
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When using d2i_SSL_SESSION(), the SSL_SESSION object is automatically
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allocated. The reference count is 1, so that the session must be
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explicitly removed using L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>,
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unless the SSL_SESSION object is completely taken over, when being called
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inside the get_session_cb() (see
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L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>).
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SSL_SESSION objects keep internal link information about the session cache
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list, when being inserted into one SSL_CTX object's session cache.
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One SSL_SESSION object, regardless of its reference count, must therefore
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only be used with one SSL_CTX object (and the SSL objects created
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from this SSL_CTX object).
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When using i2d_SSL_SESSION(), the memory location pointed to by B<pp> must be
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large enough to hold the binary representation of the session. There is no
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known limit on the size of the created ASN1 representation, so the necessary
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amount of space should be obtained by first calling i2d_SSL_SESSION() with
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B<pp=NULL>, and obtain the size needed, then allocate the memory and
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call i2d_SSL_SESSION() again.
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=head1 RETURN VALUES
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d2i_SSL_SESSION() returns a pointer to the newly allocated SSL_SESSION
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object. In case of failure the NULL-pointer is returned and the error message
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can be retrieved from the error stack.
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i2d_SSL_SESSION() returns the size of the ASN1 representation in bytes.
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When the session is not valid, B<0> is returned and no operation is performed.
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=head1 SEE ALSO
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L<ssl(3)|ssl(3)>, L<SSL_SESSION_free(3)|SSL_SESSION_free(3)>,
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L<SSL_CTX_sess_set_get_cb(3)|SSL_CTX_sess_set_get_cb(3)>
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=cut
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