This fixes a null-pointer dereference in tls_ctx_cert_time(), which will
occur on clients that do not use a client certificate (ie that only have
auth-user-pass in the config, but no key and cert). This bug was
introduced by commit 091edd8e on the master branch, and commit dfd940bb
on the release/2.3 branch (which is part of 2.3.9).
While touching this function, I also made this function conform to the
openvpn coding style.
Signed-off-by: Steffan Karger <stef...@karger.me>
---
src/openvpn/ssl_openssl.c | 15 +++++++++++----
src/openvpn/ssl_polarssl.c | 6 ++++++
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 0a7f14b..5cf6d7f 100644
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -356,15 +356,22 @@ tls_ctx_check_cert_time (const struct tls_root_ctx *ctx)
int ret;
const X509 *cert;
+ ASSERT (ctx);
+
#if OPENSSL_VERSION_NUMBER >= 0x10002000L
/* OpenSSL 1.0.2 and up */
- cert = SSL_CTX_get0_certificate(ctx->ctx);
+ cert = SSL_CTX_get0_certificate (ctx->ctx);
#else
/* OpenSSL 1.0.1 and earlier need an SSL object to get at the certificate */
- SSL *ssl = SSL_new(ctx->ctx);
- cert = SSL_get_certificate(ssl);
+ SSL *ssl = SSL_new (ctx->ctx);
+ cert = SSL_get_certificate (ssl);
#endif
+ if (cert == NULL)
+ {
+ return; /* Nothing to check if there is no certificate */
+ }
+
ret = X509_cmp_time (X509_get_notBefore (cert), NULL);
if (ret == 0)
{
@@ -385,7 +392,7 @@ tls_ctx_check_cert_time (const struct tls_root_ctx *ctx)
msg (M_WARN, "WARNING: Your certificate has expired!");
}
#if OPENSSL_VERSION_NUMBER < 0x10002000L
- SSL_free(ssl);
+ SSL_free (ssl);
#endif
}
diff --git a/src/openvpn/ssl_polarssl.c b/src/openvpn/ssl_polarssl.c
index 4782469..58b2116 100644
--- a/src/openvpn/ssl_polarssl.c
+++ b/src/openvpn/ssl_polarssl.c
@@ -219,6 +219,12 @@ tls_ctx_restrict_ciphers(struct tls_root_ctx *ctx, const
char *ciphers)
void
tls_ctx_check_cert_time (const struct tls_root_ctx *ctx)
{
+ ASSERT (ctx);
+ if (ctx->crt_chain == NULL)
+ {
+ return; /* Nothing to check if there is no certificate */
+ }
+
if (x509_time_future (&ctx->crt_chain->valid_from))
{
msg (M_WARN, "WARNING: Your certificate is not yet valid!");
--
2.5.0
