From: Arne Schwabe <arne@rfc2549.org>
Date: Fri, 23 Oct 2020 11:34:31 +0000 (+0200)
Subject: Remove NULL checks before calling free
X-Git-Tag: v2.6_beta1~662
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cb70cf51889ee96446ba77a406bb2ac0f01dc174;p=thirdparty%2Fopenvpn.git

Remove NULL checks before calling free

We (and OpenSSL) already use calling free on null pointers in a number
of places and also C99 standards says free(NULL) does nothing.

The if (x) free(x) calls more often make code harder to read, instead
of easier, remove these NULL checks in favour of directly calling
free(x).

The OpenSSL *_free methods are also safe to call with NULL and
pkcs11h_certificate_freeCertificateIdList is also safe to be called with
NULL.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20201023113431.26691-5-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21216.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
---

diff --git a/sample/sample-plugins/client-connect/sample-client-connect.c b/sample/sample-plugins/client-connect/sample-client-connect.c
index 6168076f0..7ed2f72ca 100644
--- a/sample/sample-plugins/client-connect/sample-client-connect.c
+++ b/sample/sample-plugins/client-connect/sample-client-connect.c
@@ -173,10 +173,7 @@ openvpn_plugin_open_v3(const int v3structver,
     return OPENVPN_PLUGIN_FUNC_SUCCESS;
 
 error:
-    if (context)
-    {
-        free(context);
-    }
+    free(context);
     return OPENVPN_PLUGIN_FUNC_ERROR;
 }
 
diff --git a/src/openvpn/buffer.c b/src/openvpn/buffer.c
index b32bc8b26..35d9ecdc0 100644
--- a/src/openvpn/buffer.c
+++ b/src/openvpn/buffer.c
@@ -184,10 +184,7 @@ buf_assign(struct buffer *dest, const struct buffer *src)
 void
 free_buf(struct buffer *buf)
 {
-    if (buf->data)
-    {
-        free(buf->data);
-    }
+    free(buf->data);
     CLEAR(*buf);
 }
 
diff --git a/src/openvpn/error.c b/src/openvpn/error.c
index d6247fec7..7d0fcb2df 100644
--- a/src/openvpn/error.c
+++ b/src/openvpn/error.c
@@ -488,11 +488,8 @@ close_syslog(void)
     {
         closelog();
         use_syslog = false;
-        if (pgmname_syslog)
-        {
-            free(pgmname_syslog);
-            pgmname_syslog = NULL;
-        }
+        free(pgmname_syslog);
+        pgmname_syslog = NULL;
     }
 #endif
 }
diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 034edba07..339e5c817 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -3597,14 +3597,9 @@ do_close_tls(struct context *c)
     }
 
     /* free options compatibility strings */
-    if (c->c2.options_string_local)
-    {
-        free(c->c2.options_string_local);
-    }
-    if (c->c2.options_string_remote)
-    {
-        free(c->c2.options_string_remote);
-    }
+    free(c->c2.options_string_local);
+    free(c->c2.options_string_remote);
+
     c->c2.options_string_local = c->c2.options_string_remote = NULL;
 
     if (c->c2.pulled_options_state)
diff --git a/src/openvpn/manage.c b/src/openvpn/manage.c
index ac142177f..85bd12273 100644
--- a/src/openvpn/manage.c
+++ b/src/openvpn/manage.c
@@ -826,14 +826,8 @@ man_pkcs11_id_get(struct management *man, const int index)
         msg(M_CLIENT, ">PKCS11ID-ENTRY:'%d'", index);
     }
 
-    if (id != NULL)
-    {
-        free(id);
-    }
-    if (base64 != NULL)
-    {
-        free(base64);
-    }
+    free(id);
+    free(base64);
 }
 
 #endif /* ifdef ENABLE_PKCS11 */
@@ -2613,10 +2607,7 @@ man_connection_close(struct management *man)
 {
     struct man_connection *mc = &man->connection;
 
-    if (mc->es)
-    {
-        event_free(mc->es);
-    }
+    event_free(mc->es);
 #ifdef _WIN32
     net_event_win32_close(&mc->ne32);
 #endif
@@ -2629,14 +2620,10 @@ man_connection_close(struct management *man)
     {
         man_close_socket(man, mc->sd_cli);
     }
-    if (mc->in)
-    {
-        command_line_free(mc->in);
-    }
-    if (mc->out)
-    {
-        buffer_list_free(mc->out);
-    }
+
+    command_line_free(mc->in);
+    buffer_list_free(mc->out);
+
     in_extra_reset(&man->connection, IER_RESET);
     buffer_list_free(mc->ext_key_input);
     man_connection_clear(mc);
@@ -3896,6 +3883,10 @@ command_line_reset(struct command_line *cl)
 void
 command_line_free(struct command_line *cl)
 {
+    if (!cl)
+    {
+        return;
+    }
     command_line_reset(cl);
     free_buf(&cl->buf);
     free_buf(&cl->residual);
@@ -4015,10 +4006,8 @@ log_entry_print(const struct log_entry *e, unsigned int flags, struct gc_arena *
 static void
 log_entry_free_contents(struct log_entry *e)
 {
-    if (e->string)
-    {
-        free((char *)e->string);
-    }
+    /* Cast away constness of const char* */
+    free((char *)e->string);
     CLEAR(*e);
 }
 
diff --git a/src/openvpn/mtcp.c b/src/openvpn/mtcp.c
index 458e6e4cf..22c824aaa 100644
--- a/src/openvpn/mtcp.c
+++ b/src/openvpn/mtcp.c
@@ -229,10 +229,7 @@ multi_tcp_free(struct multi_tcp *mtcp)
     if (mtcp)
     {
         event_free(mtcp->es);
-        if (mtcp->esr)
-        {
-            free(mtcp->esr);
-        }
+        free(mtcp->esr);
         free(mtcp);
     }
 }
diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c
index 009b46fa1..ad4ec1c21 100644
--- a/src/openvpn/multi.c
+++ b/src/openvpn/multi.c
@@ -73,10 +73,7 @@ id(struct multi_instance *mi)
 static void
 set_cc_config(struct multi_instance *mi, struct buffer_list *cc_config)
 {
-    if (mi->cc_config)
-    {
-        buffer_list_free(mi->cc_config);
-    }
+    buffer_list_free(mi->cc_config);
     mi->cc_config = cc_config;
 }
 #endif
@@ -4016,10 +4013,7 @@ management_client_pf(void *arg,
         ret = pf_load_from_buffer_list(&mi->context, pf_config);
     }
 
-    if (pf_config)
-    {
-        buffer_list_free(pf_config);
-    }
+    buffer_list_free(pf_config);
     return ret;
 }
 #endif /* ifdef MANAGEMENT_PF */
diff --git a/src/openvpn/packet_id.c b/src/openvpn/packet_id.c
index 0c7448751..2b9ef0791 100644
--- a/src/openvpn/packet_id.c
+++ b/src/openvpn/packet_id.c
@@ -103,10 +103,7 @@ packet_id_free(struct packet_id *p)
     if (p)
     {
         dmsg(D_PID_DEBUG, "PID packet_id_free");
-        if (p->rec.seq_list)
-        {
-            free(p->rec.seq_list);
-        }
+        free(p->rec.seq_list);
         CLEAR(*p);
     }
 }
diff --git a/src/openvpn/pkcs11.c b/src/openvpn/pkcs11.c
index d40ca458d..524229180 100644
--- a/src/openvpn/pkcs11.c
+++ b/src/openvpn/pkcs11.c
@@ -461,11 +461,8 @@ pkcs11_management_id_count(void)
 
 cleanup:
 
-    if (id_list != NULL)
-    {
-        pkcs11h_certificate_freeCertificateIdList(id_list);
-        id_list = NULL;
-    }
+    pkcs11h_certificate_freeCertificateIdList(id_list);
+    id_list = NULL;
 
     dmsg(
         D_PKCS11_DEBUG,
@@ -630,29 +627,17 @@ pkcs11_management_id_get(
 
 cleanup:
 
-    if (id_list != NULL)
-    {
-        pkcs11h_certificate_freeCertificateIdList(id_list);
-        id_list = NULL;
-    }
+    pkcs11h_certificate_freeCertificateIdList(id_list);
+    id_list = NULL;
 
-    if (internal_id != NULL)
-    {
-        free(internal_id);
-        internal_id = NULL;
-    }
+    free(internal_id);
+    internal_id = NULL;
 
-    if (internal_base64 != NULL)
-    {
-        free(internal_base64);
-        internal_base64 = NULL;
-    }
+    free(internal_base64);
+    internal_base64 = NULL;
 
-    if (certificate_blob != NULL)
-    {
-        free(certificate_blob);
-        certificate_blob = NULL;
-    }
+    free(certificate_blob);
+    certificate_blob = NULL;
 
     dmsg(
         D_PKCS11_DEBUG,
@@ -1005,19 +990,13 @@ cleanup1:
             certificate = NULL;
         }
 
-        if (ser != NULL)
-        {
-            free(ser);
-            ser = NULL;
-        }
+        free(ser);
+        ser = NULL;
     }
 
 cleanup:
-    if (user_certificates != NULL)
-    {
-        pkcs11h_certificate_freeCertificateIdList(user_certificates);
-        user_certificates = NULL;
-    }
+    pkcs11h_certificate_freeCertificateIdList(user_certificates);
+    user_certificates = NULL;
 
     pkcs11h_terminate();
     gc_free(&gc);
diff --git a/src/openvpn/pkcs11_openssl.c b/src/openvpn/pkcs11_openssl.c
index 642769cc5..a84bc6359 100644
--- a/src/openvpn/pkcs11_openssl.c
+++ b/src/openvpn/pkcs11_openssl.c
@@ -102,17 +102,11 @@ cleanup:
      * openssl objects have reference
      * count, so release them
      */
-    if (x509 != NULL)
-    {
-        X509_free(x509);
-        x509 = NULL;
-    }
+    X509_free(x509);
+    x509 = NULL;
 
-    if (evp != NULL)
-    {
-        EVP_PKEY_free(evp);
-        evp = NULL;
-    }
+    EVP_PKEY_free(evp);
+    evp = NULL;
 
     if (openssl_session != NULL)
     {
@@ -138,11 +132,8 @@ pkcs11_certificate_dn(pkcs11h_certificate_t certificate, struct gc_arena *gc)
     dn = x509_get_subject(x509, gc);
 
 cleanup:
-    if (x509 != NULL)
-    {
-        X509_free(x509);
-        x509 = NULL;
-    }
+    X509_free(x509);
+    x509 = NULL;
 
     return dn;
 }
@@ -183,12 +174,9 @@ pkcs11_certificate_serial(pkcs11h_certificate_t certificate, char *serial,
     ret = 0;
 
 cleanup:
+    X509_free(x509);
+    x509 = NULL;
 
-    if (x509 != NULL)
-    {
-        X509_free(x509);
-        x509 = NULL;
-    }
     return ret;
 }
 #endif /* defined(ENABLE_PKCS11) && defined(ENABLE_OPENSSL) */
diff --git a/src/openvpn/proxy.c b/src/openvpn/proxy.c
index 9998623a0..f390daedf 100644
--- a/src/openvpn/proxy.c
+++ b/src/openvpn/proxy.c
@@ -366,10 +366,7 @@ get_proxy_authenticate(socket_descriptor_t sd,
 static void
 store_proxy_authenticate(struct http_proxy_info *p, char *data)
 {
-    if (p->proxy_authenticate)
-    {
-        free(p->proxy_authenticate);
-    }
+    free(p->proxy_authenticate);
     p->proxy_authenticate = data;
 }
 
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 7a3eb146a..97e2c6194 100644
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -1105,10 +1105,7 @@ tls_session_free(struct tls_session *session, bool clear)
         key_state_free(&session->key[i], false);
     }
 
-    if (session->common_name)
-    {
-        free(session->common_name);
-    }
+    free(session->common_name);
 
     cert_hash_free(session->cert_hash_set);
 
@@ -1300,16 +1297,8 @@ tls_multi_free(struct tls_multi *multi, bool clear)
     auth_set_client_reason(multi, NULL);
 
     free(multi->peer_info);
-
-    if (multi->locked_cn)
-    {
-        free(multi->locked_cn);
-    }
-
-    if (multi->locked_username)
-    {
-        free(multi->locked_username);
-    }
+    free(multi->locked_cn);
+    free(multi->locked_username);
 
     cert_hash_free(multi->locked_cert_hash_set);
 
diff --git a/src/openvpn/ssl_mbedtls.c b/src/openvpn/ssl_mbedtls.c
index 11fbeae47..b30b6b9db 100644
--- a/src/openvpn/ssl_mbedtls.c
+++ b/src/openvpn/ssl_mbedtls.c
@@ -138,53 +138,31 @@ tls_ctx_free(struct tls_root_ctx *ctx)
     if (ctx)
     {
         mbedtls_pk_free(ctx->priv_key);
-        if (ctx->priv_key)
-        {
-            free(ctx->priv_key);
-        }
+        free(ctx->priv_key);
 
         mbedtls_x509_crt_free(ctx->ca_chain);
-        if (ctx->ca_chain)
-        {
-            free(ctx->ca_chain);
-        }
+        free(ctx->ca_chain);
 
         mbedtls_x509_crt_free(ctx->crt_chain);
-        if (ctx->crt_chain)
-        {
-            free(ctx->crt_chain);
-        }
+        free(ctx->crt_chain);
 
         mbedtls_dhm_free(ctx->dhm_ctx);
-        if (ctx->dhm_ctx)
-        {
-            free(ctx->dhm_ctx);
-        }
+        free(ctx->dhm_ctx);
 
         mbedtls_x509_crl_free(ctx->crl);
-        if (ctx->crl)
-        {
-            free(ctx->crl);
-        }
+        free(ctx->crl);
 
 #if defined(ENABLE_PKCS11)
         pkcs11h_certificate_freeCertificate(ctx->pkcs11_cert);
 #endif
 
-        if (ctx->allowed_ciphers)
-        {
-            free(ctx->allowed_ciphers);
-        }
+        free(ctx->allowed_ciphers);
 
-        if (ctx->groups)
-        {
-            free(ctx->groups);
-        }
+        free(ctx->groups);
 
         CLEAR(*ctx);
 
         ctx->initialised = false;
-
     }
 }
 
diff --git a/src/openvpn/ssl_openssl.c b/src/openvpn/ssl_openssl.c
index 122083a8e..d161f48b8 100644
--- a/src/openvpn/ssl_openssl.c
+++ b/src/openvpn/ssl_openssl.c
@@ -144,10 +144,7 @@ void
 tls_ctx_free(struct tls_root_ctx *ctx)
 {
     ASSERT(NULL != ctx);
-    if (NULL != ctx->ctx)
-    {
-        SSL_CTX_free(ctx->ctx);
-    }
+    SSL_CTX_free(ctx->ctx);
     ctx->ctx = NULL;
 }
 
@@ -978,14 +975,8 @@ end:
         crypto_print_openssl_errors(M_DEBUG);
     }
 
-    if (in != NULL)
-    {
-        BIO_free(in);
-    }
-    if (x)
-    {
-        X509_free(x);
-    }
+    BIO_free(in);
+    X509_free(x);
 }
 
 int
@@ -1044,14 +1035,8 @@ tls_ctx_load_priv_file(struct tls_root_ctx *ctx, const char *priv_key_file,
     ret = 0;
 
 end:
-    if (pkey)
-    {
-        EVP_PKEY_free(pkey);
-    }
-    if (in)
-    {
-        BIO_free(in);
-    }
+    EVP_PKEY_free(pkey);
+    BIO_free(in);
     return ret;
 }
 
@@ -1312,12 +1297,9 @@ err:
     {
         RSA_free(rsa);
     }
-    else
+    else if (rsa_meth)
     {
-        if (rsa_meth)
-        {
-            RSA_meth_free(rsa_meth);
-        }
+        RSA_meth_free(rsa_meth);
     }
     return 0;
 }
@@ -1441,14 +1423,8 @@ tls_ctx_use_external_ec_key(struct tls_root_ctx *ctx, EVP_PKEY *pkey)
 
 err:
     /* Reach here only when ec and privkey can be independenly freed */
-    if (privkey)
-    {
-        EVP_PKEY_free(privkey);
-    }
-    if (ec)
-    {
-        EC_KEY_free(ec);
-    }
+    EVP_PKEY_free(privkey);
+    EC_KEY_free(ec);
     return 0;
 }
 #endif /* OPENSSL_VERSION_NUMBER > 1.1.0 dev && !defined(OPENSSL_NO_EC) */
@@ -1645,10 +1621,7 @@ tls_ctx_load_ca(struct tls_root_ctx *ctx, const char *ca_file,
             }
         }
 
-        if (in)
-        {
-            BIO_free(in);
-        }
+        BIO_free(in);
     }
 
     /* Set a store for certs (CA & CRL) with a lookup on the "capath" hash directory */
diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c
index 2d7abdde4..95d8c918c 100644
--- a/src/openvpn/ssl_verify.c
+++ b/src/openvpn/ssl_verify.c
@@ -841,11 +841,9 @@ cleanup:
 void
 auth_set_client_reason(struct tls_multi *multi, const char *client_reason)
 {
-    if (multi->client_reason)
-    {
-        free(multi->client_reason);
-        multi->client_reason = NULL;
-    }
+    free(multi->client_reason);
+    multi->client_reason = NULL;
+
     if (client_reason && strlen(client_reason))
     {
         multi->client_reason = string_alloc(client_reason, NULL);
diff --git a/src/openvpn/ssl_verify_openssl.c b/src/openvpn/ssl_verify_openssl.c
index 39d381a17..d063aeda4 100644
--- a/src/openvpn/ssl_verify_openssl.c
+++ b/src/openvpn/ssl_verify_openssl.c
@@ -372,11 +372,7 @@ x509_get_subject(X509 *cert, struct gc_arena *gc)
     subject[subject_mem->length] = '\0';
 
 err:
-    if (subject_bio)
-    {
-        BIO_free(subject_bio);
-    }
-
+    BIO_free(subject_bio);
     return subject;
 }
 
diff --git a/src/openvpn/status.c b/src/openvpn/status.c
index e8dcf7cd6..11e24ae48 100644
--- a/src/openvpn/status.c
+++ b/src/openvpn/status.c
@@ -203,10 +203,8 @@ status_close(struct status_output *so)
                 ret = false;
             }
         }
-        if (so->filename)
-        {
-            free(so->filename);
-        }
+        free(so->filename);
+
         if (buf_defined(&so->read_buf))
         {
             free_buf(&so->read_buf);
diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c
index 8315a4264..400a50cac 100644
--- a/src/openvpn/tun.c
+++ b/src/openvpn/tun.c
@@ -1835,10 +1835,8 @@ close_tun_generic(struct tuntap *tt)
     {
         close(tt->fd);
     }
-    if (tt->actual_name)
-    {
-        free(tt->actual_name);
-    }
+
+    free(tt->actual_name);
     clear_tuntap(tt);
 }
 #endif /* !_WIN32 */
@@ -2522,10 +2520,7 @@ close_tun(struct tuntap *tt, openvpn_net_ctx_t *ctx)
 
     solaris_close_tun(tt);
 
-    if (tt->actual_name)
-    {
-        free(tt->actual_name);
-    }
+    free(tt->actual_name);
 
     clear_tuntap(tt);
     free(tt);
@@ -6901,10 +6896,7 @@ close_tun(struct tuntap *tt, openvpn_net_ctx_t *ctx)
         }
     }
 
-    if (tt->actual_name)
-    {
-        free(tt->actual_name);
-    }
+    free(tt->actual_name);
 
     if (tt->windows_driver == WINDOWS_DRIVER_WINTUN)
     {
diff --git a/src/plugins/auth-pam/auth-pam.c b/src/plugins/auth-pam/auth-pam.c
index f537652ea..3d167233f 100644
--- a/src/plugins/auth-pam/auth-pam.c
+++ b/src/plugins/auth-pam/auth-pam.c
@@ -506,10 +506,7 @@ openvpn_plugin_open_v3(const int v3structver,
     }
 
 error:
-    if (context)
-    {
-        free(context);
-    }
+    free(context);
     return OPENVPN_PLUGIN_FUNC_ERROR;
 }
 
diff --git a/src/plugins/down-root/down-root.c b/src/plugins/down-root/down-root.c
index da445c618..7a3d34a03 100644
--- a/src/plugins/down-root/down-root.c
+++ b/src/plugins/down-root/down-root.c
@@ -238,10 +238,7 @@ free_context(struct down_root_context *context)
 {
     if (context)
     {
-        if (context->command)
-        {
-            free(context->command);
-        }
+        free(context->command);
         free(context);
     }
 }