Remove the possibility to disable the UI module entirely

Instead, make it possible to disable the console reader that's part of
the UI module.  This makes it possible to use the UI API and other UI
methods in environments where the console reader isn't useful.

To disable the console reader, configure with 'no-ui-console' /
'disable-ui-console'.

'no-ui' / 'disable-ui' is now an alias for  'no-ui-console' /
'disable-ui-console'.

Fixes #3806

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3820)

1 files changed, 29 insertions, 19 deletions

diff --git a/apps/apps.c b/apps/apps.c
index a89d4eb5e6..8b1aab4c4d 100644
--- a/apps/apps.c
+++ b/apps/apps.c
@@ -56,9 +56,8 @@ typedef struct {
     unsigned long mask;
 } NAME_EX_TBL;
 
-#if !defined(OPENSSL_NO_UI) || !defined(OPENSSL_NO_ENGINE)
 static UI_METHOD *ui_method = NULL;
-#endif
+static const UI_METHOD *ui_fallback_method = NULL;
 
 static int set_table_opts(unsigned long *flags, const char *arg,
                           const NAME_EX_TBL * in_tbl);
@@ -176,14 +175,19 @@ int dump_cert_text(BIO *out, X509 *x)
     return 0;
 }
 
-#ifndef OPENSSL_NO_UI
 static int ui_open(UI *ui)
 {
-    return UI_method_get_opener(UI_OpenSSL())(ui);
+    int (*opener)(UI *ui) = UI_method_get_opener(ui_fallback_method);
+
+    if (opener)
+        return opener(ui);
+    return 1;
 }
 
 static int ui_read(UI *ui, UI_STRING *uis)
 {
+    int (*reader)(UI *ui, UI_STRING *uis) = NULL;
+
     if (UI_get_input_flags(uis) & UI_INPUT_FLAG_DEFAULT_PWD
         && UI_get0_user_data(ui)) {
         switch (UI_get_string_type(uis)) {
@@ -205,11 +209,17 @@ static int ui_read(UI *ui, UI_STRING *uis)
             break;
         }
     }
-    return UI_method_get_reader(UI_OpenSSL())(ui, uis);
+
+    reader = UI_method_get_reader(ui_fallback_method);
+    if (reader)
+        return reader(ui, uis);
+    return 1;
 }
 
 static int ui_write(UI *ui, UI_STRING *uis)
 {
+    int (*writer)(UI *ui, UI_STRING *uis) = NULL;
+
     if (UI_get_input_flags(uis) & UI_INPUT_FLAG_DEFAULT_PWD
         && UI_get0_user_data(ui)) {
         switch (UI_get_string_type(uis)) {
@@ -229,16 +239,28 @@ static int ui_write(UI *ui, UI_STRING *uis)
             break;
         }
     }
-    return UI_method_get_writer(UI_OpenSSL())(ui, uis);
+
+    writer = UI_method_get_reader(ui_fallback_method);
+    if (writer)
+        return writer(ui, uis);
+    return 1;
 }
 
 static int ui_close(UI *ui)
 {
-    return UI_method_get_closer(UI_OpenSSL())(ui);
+    int (*closer)(UI *ui) = UI_method_get_closer(ui_fallback_method);
+
+    if (closer)
+        return closer(ui);
+    return 1;
 }
 
 int setup_ui_method(void)
 {
+    ui_fallback_method = UI_null();
+#ifndef OPENSSL_NO_UI_CONSOLE
+    ui_fallback_method = UI_OpenSSL();
+#endif
     ui_method = UI_create_method("OpenSSL application user interface");
     UI_method_set_opener(ui_method, ui_open);
     UI_method_set_reader(ui_method, ui_read);
@@ -259,24 +281,13 @@ const UI_METHOD *get_ui_method(void)
 {
     return ui_method;
 }
-#endif
 
 int password_callback(char *buf, int bufsiz, int verify, PW_CB_DATA *cb_tmp)
 {
     int res = 0;
-#ifndef OPENSSL_NO_UI
     UI *ui = NULL;
-#endif
     PW_CB_DATA *cb_data = (PW_CB_DATA *)cb_tmp;
 
-#ifdef OPENSSL_NO_UI
-    if (cb_data != NULL && cb_data->password != NULL) {
-        res = strlen(cb_data->password);
-        if (res > bufsiz)
-            res = bufsiz;
-        memcpy(buf, cb_data->password, res);
-    }
-#else
     ui = UI_new_method(ui_method);
     if (ui) {
         int ok = 0;
@@ -331,7 +342,6 @@ int password_callback(char *buf, int bufsiz, int verify, PW_CB_DATA *cb_tmp)
         UI_free(ui);
         OPENSSL_free(prompt);
     }
-#endif
     return res;
 }