Increment SSL_CTX's reference count in Ssl::get_ssl_context()

Without this, whenever the returned SslContext is released,
the refcount of the underlying SSL_CTX will decrease and it
will be freed too soon

openssl-sys-extras/src/lib.rs

@@ -69,4 +69,6 @@ extern {
     pub fn SSL_CTX_set_tlsext_servername_callback(ssl: *mut SSL_CTX, callback: Option<extern fn()>);
     #[link_name = "SSL_CTX_set_tlsext_servername_arg_shim"]
     pub fn SSL_CTX_set_tlsext_servername_arg(ssl: *mut SSL_CTX, arg: *const c_void);
+    #[link_name = "SSL_CTX_increment_refcount_shim"]
+    pub fn SSL_CTX_increment_refcount(ssl: *mut SSL_CTX) -> c_long;
 }

openssl-sys-extras/src/openssl_shim.c

@@ -123,6 +123,11 @@ long SSL_CTX_set_tlsext_servername_arg_shim(SSL_CTX *ctx, void* arg) {
     return SSL_CTX_set_tlsext_servername_arg(ctx, arg);
 }
 
+long SSL_CTX_increment_refcount_shim(SSL_CTX *ctx) {
+    int i = CRYPTO_add(&ctx->references,1,CRYPTO_LOCK_SSL_CTX);
+    return i;
+}
+
 #if OPENSSL_VERSION_NUMBER >= 0x10002000L
 int SSL_CTX_set_ecdh_auto_shim(SSL_CTX *ctx, int onoff) {
     return SSL_CTX_set_ecdh_auto(ctx, onoff);

openssl/src/ssl/mod.rs

@@ -995,6 +995,7 @@ impl Ssl {
     /// obtain the context corresponding to the current connection
     pub fn get_ssl_context(&self) -> SslContext {
         let ssl_ctx = unsafe { ffi::SSL_get_SSL_CTX(self.ssl) };
+        let count = unsafe { ffi_extras::SSL_CTX_increment_refcount(ssl_ctx) };
         SslContext { ctx: ssl_ctx }
     }
 }