Fix a bug in handling of 128 byte long PSK identity in
psk_client_callback.
OpenSSL supports PSK identities of up to (and including) 128 bytes in
length. PSK identity is obtained via the psk_client_callback,
implementors of which are expected to provide a NULL-terminated
identity. However, the callback is invoked with only 128 bytes of
storage thus making it impossible to return a 128 byte long identity and
the required additional NULL byte.
This CL fixes the issue by passing in a 129 byte long buffer into the
psk_client_callback. As a safety precaution, this CL also zeroes out the
buffer before passing it into the callback, uses strnlen for obtaining
the length of the identity returned by the callback, and aborts the
handshake if the identity (without the NULL terminator) is longer than
128 bytes.
PSK identity hint can be stored in SSL_CTX and in SSL/SSL_SESSION,
similar to other TLS parameters, with the value in SSL/SSL_SESSION
taking precedence over the one in SSL_CTX. The value in SSL_CTX is
shared (used as the default) between all SSL instances associated
with that SSL_CTX, whereas the value in SSL/SSL_SESSION is confined
to that particular TLS/SSL connection/session.
The existing implementation of TLS-PSK does not correctly distinguish
between PSK identity hint in SSL_CTX and in SSL/SSL_SESSION. This
change fixes these issues:
1. SSL_use_psk_identity_hint does nothing and returns "success" when
the SSL object does not have an associated SSL_SESSION.
2. On the client, the hint in SSL_CTX (which is shared between
multiple SSL instances) is overwritten with the hint received from
server or reset to NULL if no hint was received.
3. On the client, psk_client_callback is invoked with the hint from
SSL_CTX rather than from current SSL/SSL_SESSION (i.e., the one
received from the server). Issue #2 above masks this issue.
4. On the server, the hint in SSL/SSL_SESSION is ignored and the hint
from SSL_CTX is sent to the client.
5. On the server, the hint in SSL/SSL_SESSION is reset to the one in
SSL_CTX after the ClientKeyExchange message step.
This change fixes the issues by:
* Adding storage for the hint in the SSL object. The idea being that
the hint in the associated SSL_SESSION takes precedence.
* Reading the hint during the handshake only from the associated
SSL_SESSION object.
* Initializing the hint in SSL object with the one from the SSL_CTX
object.
* Initializing the hint in SSL_SESSION object with the one from the
SSL object.
* Making SSL_use_psk_identity_hint and SSL_get_psk_identity_hint
set/get the hint to/from SSL_SESSION associated with the provided
SSL object, or, if no SSL_SESSION is available, set/get the hint
to/from the provided SSL object.
* Removing code which resets the hint during handshake.
Fix limit checks in ssl_add_clienthello_tlsext and
ssl_add_serverhello_tlsext.
Some of the limit checks reference p rather than ret. p is the original
buffer position, not the current one. Fix those and rename p to orig so
it's clearer.
(Called "cut through" for historical reasons in this patch.)
Enables SSL3+ clients to send application data immediately following the
Finished message even when negotiating full-handshakes. With this
patch, clients can negotiate SSL connections in 1-RTT even when
performing full-handshakes.
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)
