Merge branch 'fix-sha' into 'master'

fix: crypt_sha: bounds-check before slicing setting

See merge request redox-os/relibc!1440

src/header/crypt/sha.rs

@@ -77,7 +77,7 @@ pub fn crypt_sha(passw: &str, setting: &str, cipher: ShaType) -> Option<String>
 
     let has_round;
     // 7 is len("rounds=")
-    if &setting[cursor..cursor + 7] == RSTRING {
+    if setting.get(cursor..cursor + 7) == Some(RSTRING) {
         cursor += 7;
         has_round = true;
         if let Some(c_end) = setting[cursor..].chars().position(|r| r == '$') {