Merge pull request #4330 from Silvertree2010/fix/h3008-rtf-import-decodes-a-plus-sign-a

Reject non-hex digits in RTF \'XX escapes

crates/engine/src/cmd/place/rtf.rs

@@ -108,7 +108,12 @@ pub(super) fn import(bytes: &[u8], cmd: &str) -> Result<Story> {
                 match next {
                     b'*' => starred = true,
                     b'\'' => {
-                        if let Some(v) = bytes.get(i..i + 2).and_then(|h| std::str::from_utf8(h).ok()).and_then(|h| u8::from_str_radix(h, 16).ok()) {
+                        if let Some(v) = bytes
+                            .get(i..i + 2)
+                            .filter(|h| h.iter().all(u8::is_ascii_hexdigit))
+                            .and_then(|h| std::str::from_utf8(h).ok())
+                            .and_then(|h| u8::from_str_radix(h, 16).ok())
+                        {
                             i += 2;
                             r.byte(v);
                         }
@@ -650,6 +655,13 @@ mod tests {
         assert_eq!(text_of(&mac), "é•", "Mac Roman");
     }
 
+    #[test]
+    fn hex_escapes_need_two_hex_digits() {
+        assert_eq!(text_of(&read(r"{\rtf1\ansi A\'+1B}")), "A+1B");
+        assert_eq!(text_of(&read(r"{\rtf1\ansi A\'-1B}")), "A-1B");
+        assert_eq!(text_of(&read(r"{\rtf1\ansi A\'g0B}")), "Ag0B");
+    }
+
     #[test]
     fn upr_groups_read_their_unicode_text() {
         let s = read(concat!(r"{\rtf1 a{\upr{\f0 b?}{\*\ud{\f0 c\u", "945", r"?}}}d}"));