Instead of just printing the contents of the flags variable, try to
convert it to a human-readable error string and print that instead.
This will for example print "The certificate is signed with an
unacceptable key (eg bad curve, RSA too short).", instead of
"flags=10000".
Signed-off-by: Steffan Karger <stef...@karger.me>
---
Changes.rst | 5 ++++-
src/openvpn/ssl_verify_mbedtls.c | 20 +++++++++++++++++---
2 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/Changes.rst b/Changes.rst
index 5034b15..dc9131b 100644
--- a/Changes.rst
+++ b/Changes.rst
@@ -91,10 +91,13 @@ User-visible Changes
* Non-ephemeral key exchange using static (EC)DH keys
* DSS private keys
-- PolarSSL builds: changed the tls_digest_N values exported to the script
+- mbed TLS builds: changed the tls_digest_N values exported to the script
environment to be equal to the ones exported by OpenSSL builds, namely
the certificate fingerprint (was the hash of the 'to be signed' data).
+- mbed TLS builds: minimum RSA key size is now 2048 bits. Shorter keys will
+ not be accepted, both local and from the peer.
+
Maintainer-visible changes
--------------------------
diff --git a/src/openvpn/ssl_verify_mbedtls.c b/src/openvpn/ssl_verify_mbedtls.c
index ffe196e..e59dedb 100644
--- a/src/openvpn/ssl_verify_mbedtls.c
+++ b/src/openvpn/ssl_verify_mbedtls.c
@@ -65,13 +65,27 @@ verify_callback (void *session_obj, mbedtls_x509_crt *cert,
int cert_depth,
/* did peer present cert which was signed by our root cert? */
if (*flags != 0)
{
+ int ret = 0;
+ char errstr[512] = { 0 };
char *subject = x509_get_subject(cert, &gc);
+ ret = mbedtls_x509_crt_verify_info (errstr, sizeof(errstr)-1, "",
*flags);
+ if (ret <= 0 && !openvpn_snprintf(errstr, sizeof(errstr),
+ "Could not retrieve error string, flags=%"PRIx32, *flags))
+ {
+ errstr[0] = '\0';
+ }
+
if (subject)
- msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, flags=%x, %s", cert_depth,
*flags, subject);
+ {
+ msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, subject=%s: %s",
+ cert_depth, subject, errstr);
+ }
else
- msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, flags=%x, could not extract
X509 "
- "subject string from certificate", *flags, cert_depth);
+ {
+ msg (D_TLS_ERRORS, "VERIFY ERROR: depth=%d, (could not extract X509 "
+ "subject string from certificate): %s", cert_depth, errstr);
+ }
/* Leave flags set to non-zero to indicate that the cert is not ok */
}
--
2.7.4
