Fix bugs in ImapResponseParser

mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/ImapResponseParser.java

@@ -339,7 +339,18 @@ class ImapResponseParser {
      */
     private Object parseLiteral() throws IOException {
         expect('{');
-        int size = Integer.parseInt(readStringUntil('}'));
+
+        int size;
+        try {
+            size = Integer.parseInt(readStringUntil('}'));
+        } catch (NumberFormatException e) {
+            throw new ImapResponseParserException("Invalid value for size of literal string", e);
+        }
+
+        if (size < 0) {
+            throw new ImapResponseParserException("Invalid value for size of literal string");
+        }
+
         expect('\r');
         expect('\n');
 
@@ -479,9 +490,9 @@ class ImapResponseParser {
 
     }
 
-    private void checkTokenIsString(Object token) throws IOException {
+    private void checkTokenIsString(Object token) {
         if (!(token instanceof String)) {
-            throw new IOException("Unexpected non-string token: " + token.getClass().getSimpleName() + " - " + token);
+            throw new ImapResponseParserException("Unexpected non-string token");
         }
     }
 }

mail/protocols/imap/src/main/java/com/fsck/k9/mail/store/imap/ImapResponseParserException.java

@@ -2,6 +2,10 @@ package com.fsck.k9.mail.store.imap;
 
 
 public class ImapResponseParserException extends RuntimeException {
+    public ImapResponseParserException(String message) {
+        super(message);
+    }
+
     public ImapResponseParserException(String message, Throwable cause) {
         super(message, cause);
     }

mail/protocols/imap/src/test/java/com/fsck/k9/mail/store/imap/ImapResponseParserTest.kt

@@ -236,6 +236,39 @@ class ImapResponseParserTest {
         assertThatAllInputWasConsumed()
     }
 
+    @Test
+    fun `readResponse() with literal containing negative size`() {
+        val parser = createParserWithResponses("* {-1}")
+
+        assertThat {
+            parser.readResponse()
+        }.isFailure()
+            .isInstanceOf(ImapResponseParserException::class)
+            .hasMessage("Invalid value for size of literal string")
+    }
+
+    @Test
+    fun `readResponse() with literal size exceeding Int`() {
+        val parser = createParserWithResponses("* {2147483648}")
+
+        assertThat {
+            parser.readResponse()
+        }.isFailure()
+            .isInstanceOf(ImapResponseParserException::class)
+            .hasMessage("Invalid value for size of literal string")
+    }
+
+    @Test
+    fun `readResponse() with invalid characters for literal size`() {
+        val parser = createParserWithResponses("* {invalid}")
+
+        assertThat {
+            parser.readResponse()
+        }.isFailure()
+            .isInstanceOf(ImapResponseParserException::class)
+            .hasMessage("Invalid value for size of literal string")
+    }
+
     @Test
     fun `readResponse() should throw when end of stream is reached while reading literal`() {
         val parser = createParserWithData("* {4}\r\nabc")
@@ -452,6 +485,17 @@ class ImapResponseParserTest {
         assertThatAllInputWasConsumed()
     }
 
+    @Test
+    fun `readResponse() with tagged response missing completion code should throw`() {
+        val parser = createParserWithResponses("tag ")
+
+        assertThat {
+            parser.readResponse()
+        }.isFailure()
+            .isInstanceOf(ImapResponseParserException::class)
+            .hasMessage("Unexpected non-string token")
+    }
+
     @Test
     fun `readResponse() with list as first token should throw`() {
         val parser = createParserWithResponses("* [1 2] 3")
@@ -459,8 +503,8 @@ class ImapResponseParserTest {
         assertThat {
             parser.readResponse()
         }.isFailure()
-            .isInstanceOf(IOException::class)
-            .hasMessage("Unexpected non-string token: ImapList - [1, 2]")
+            .isInstanceOf(ImapResponseParserException::class)
+            .hasMessage("Unexpected non-string token")
     }
 
     @Test