Provide a different mechanism to indicate that the application wants
to retry the verification. The negative result of the callback function
now indicates an error again.
Instead the SSL_set_retry_verify() can be called from the callback
to indicate that the handshake should be suspended.
Fixes#17568
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17825)
- Make clear the callback is called whenever a peer certificate has been received,
which is independent of the verification mode.
- Make clear that a return value > 1 always leads to handshake failure.
- Make clear that in server mode also return values <= 0 lead to handshake failure.
- For client mode replace the incorrect formulation "if B<SSL_VERIFY_PEER> is set"
by what is actually implemented: "if the verification mode is not B<SSL_VERIFY_NONE>".
- Refer to X509_STORE_CTX_set_error() rather than to internal error variable.
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13937)
The client-side cert verification callback function may not only return
as usual for success or 0 for failure, but also -1,
typically on failure verifying the server certificate.
This makes the handshake suspend and return control to the calling application
with SSL_ERROR_WANT_RETRY_VERIFY.
The app can for instance fetch further certificates or cert status information
needed for the verification.
Calling SSL_connect() again resumes the connection attempt
by retrying the server certificate verification step.
This process may even be repeated if need be.
The core implementation of the feature is in ssl/statem/statem_clnt.c,
splitting tls_process_server_certificate() into a preparation step
that just copies the certificates received from the server to s->session->peer_chain
(rather than having them in a local variable at first) and returns to the state machine,
and a post-processing step in tls_post_process_server_certificate() that can be repeated:
Try verifying the current contents of s->session->peer_chain basically as before,
but give the verification callback function the chance to pause connecting and
make the TLS state machine later call tls_post_process_server_certificate() again.
Otherwise processing continues as usual.
The documentation of the new feature is added to SSL_CTX_set_cert_verify_callback.pod
and SSL_want.pod.
This adds two tests:
* A generic test in test/helpers/handshake.c
on the usability of the new server cert verification retry feature.
It is triggered via test/ssl-tests/03-custom_verify.cnf.in (while the bulky auto-
generated changes to test/ssl-tests/03-custom_verify.cnf can be basically ignored).
* A test in test/sslapitest.c that demonstrates the effectiveness of the approach
for augmenting the cert chain provided by the server in between SSL_connect() calls.
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13906)
Because the related PR/commits are merged in 2018...
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4976)
All missing sections are added.
Reviewed-by: Andy Polyakov <appro@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4976)
I tried hard to keep the lines at 80 characters or less, but in a few
cases I had to punt and just indented the subsequent lines by 4 spaces.
A few well-placed typedefs for callback functions would really help, but
these would be part of the API, so that's probably for later.
I also took the liberty of inserting empty lines in overlong blocks to
provide some visual space.
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1956)
Move manpages to manX directories
Add Windows/VMS install fix from Richard Levitte
Update README
Fix typo's
Remove some duplicates
Reviewed-by: Richard Levitte <levitte@openssl.org>
