Fix stack corruption in ui_read

This is an alternative to #20893 Additionally this fixes also a possible issue in UI_UTIL_read_pw: When UI_new returns NULL, the result code would still be zero as if UI_UTIL_read_pw succeeded, but the password buffer is left uninitialized, with subsequent possible stack corruption or worse. Reviewed-by: Richard Levitte <levitte@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from #20957) (cherry picked from commit a64c48c)
openssl · May 17, 2023 · 0f90c4d · 0f90c4d
1 parent 8ddacec
commit 0f90c4d
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Showing 2 changed files with 5 additions and 3 deletions.
diff --git a/crypto/ui/ui_lib.c b/crypto/ui/ui_lib.c
@@ -529,6 +529,10 @@ int UI_process(UI *ui)
                 ok = 0;
                 break;
             }
+        } else {
+            ui->flags &= ~UI_FLAG_REDOABLE;
+            ok = -2;
+            goto err;
         }
     }
 

diff --git a/crypto/ui/ui_util.c b/crypto/ui/ui_util.c
@@ -32,7 +32,7 @@ int UI_UTIL_read_pw_string(char *buf, int length, const char *prompt,
 int UI_UTIL_read_pw(char *buf, char *buff, int size, const char *prompt,
                     int verify)
 {
-    int ok = 0;
+    int ok = -2;
     UI *ui;
 
     if (size < 1)
@@ -47,8 +47,6 @@ int UI_UTIL_read_pw(char *buf, char *buff, int size, const char *prompt,
             ok = UI_process(ui);
         UI_free(ui);
     }
-    if (ok > 0)
-        ok = 0;
     return ok;
 }