From 7e2c89b1b36d79694a74cdbc7a413694eb7a9843 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Thu, 20 May 2021 12:40:12 +0200
Subject: [PATCH] Trim passphrases

---
 .../java/org/pgpainless/util/Passphrase.java  | 43 ++++++++++++++++++-
 .../key/protection/PassphraseTest.java        | 31 +++++++++++++
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/pgpainless-core/src/main/java/org/pgpainless/util/Passphrase.java b/pgpainless-core/src/main/java/org/pgpainless/util/Passphrase.java
index 6aa89e91..31bb867e 100644
--- a/pgpainless-core/src/main/java/org/pgpainless/util/Passphrase.java
+++ b/pgpainless-core/src/main/java/org/pgpainless/util/Passphrase.java
@@ -32,7 +32,48 @@ public class Passphrase {
      * @param chars may be null for empty passwords.
      */
     public Passphrase(@Nullable char[] chars) {
-        this.chars = chars;
+        if (chars == null) {
+            this.chars = null;
+        } else {
+            char[] trimmed = removeTrailingAndLeadingWhitespace(chars);
+            if (trimmed.length == 0) {
+                this.chars = null;
+            } else {
+                this.chars = trimmed;
+            }
+        }
+    }
+
+    /**
+     * Return a copy of the passed in char array, with leading and trailing whitespace characters removed.
+     *
+     * @param chars char array
+     * @return copy of char array with leading and trailing whitespace characters removed
+     */
+    private static char[] removeTrailingAndLeadingWhitespace(char[] chars) {
+        int i = 0;
+        while (i < chars.length && isWhitespace(chars[i])) {
+            i++;
+        }
+        int j = chars.length - 1;
+        while (j >= i && isWhitespace(chars[j])) {
+            j--;
+        }
+
+        char[] trimmed = new char[chars.length - i - (chars.length - 1 - j)];
+        System.arraycopy(chars, i, trimmed, 0, trimmed.length);
+
+        return trimmed;
+    }
+
+    /**
+     * Return true, if the passed in char is a whitespace symbol (space, newline, tab).
+     *
+     * @param xar char
+     * @return true if whitespace
+     */
+    private static boolean isWhitespace(char xar) {
+        return xar == ' ' || xar == '\n' || xar == '\t';
     }
 
     /**
diff --git a/pgpainless-core/src/test/java/org/pgpainless/key/protection/PassphraseTest.java b/pgpainless-core/src/test/java/org/pgpainless/key/protection/PassphraseTest.java
index 637162c6..1aa1b80c 100644
--- a/pgpainless-core/src/test/java/org/pgpainless/key/protection/PassphraseTest.java
+++ b/pgpainless-core/src/test/java/org/pgpainless/key/protection/PassphraseTest.java
@@ -17,6 +17,7 @@ package org.pgpainless.key.protection;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -37,4 +38,34 @@ public class PassphraseTest {
         assertFalse(passphrase.isValid());
         assertThrows(IllegalStateException.class, passphrase::getChars);
     }
+
+    @Test
+    public void testTrimming() {
+        Passphrase leadingSpace = Passphrase.fromPassword(" space");
+        assertArrayEquals("space".toCharArray(), leadingSpace.getChars());
+        assertFalse(leadingSpace.isEmpty());
+
+        Passphrase trailingSpace = Passphrase.fromPassword("space ");
+        assertArrayEquals("space".toCharArray(), trailingSpace.getChars());
+        assertFalse(trailingSpace.isEmpty());
+
+        Passphrase leadingTrailingWhitespace = new Passphrase("\t Such whitespace, much wow\n ".toCharArray());
+        assertArrayEquals("Such whitespace, much wow".toCharArray(), leadingTrailingWhitespace.getChars());
+        assertFalse(leadingTrailingWhitespace.isEmpty());
+
+        Passphrase fromEmptyChars = new Passphrase("     ".toCharArray());
+        assertNull(fromEmptyChars.getChars());
+        assertTrue(fromEmptyChars.isEmpty());
+    }
+
+    @Test
+    public void testEmptyPassphrase() {
+        Passphrase empty = Passphrase.emptyPassphrase();
+        assertNull(empty.getChars());
+        assertTrue(empty.isEmpty());
+
+        Passphrase trimmedEmpty = Passphrase.fromPassword("    ");
+        assertNull(trimmedEmpty.getChars());
+        assertTrue(trimmedEmpty.isEmpty());
+    }
 }