fuzzing request parsing

fuzz/Cargo.toml

@@ -22,3 +22,7 @@ members = ["."]
 [[bin]]
 name = "parse_filter"
 path = "fuzz_targets/parse_filter.rs"
+
+[[bin]]
+name = "parse_request"
+path = "fuzz_targets/parse_request.rs"

fuzz/fuzz_targets/parse_request.rs

@@ -0,0 +1,13 @@
+#![no_main]
+use libfuzzer_sys::fuzz_target;
+use adblock::request::Request;
+
+fuzz_target!(|data: &[u8]| {
+    if let Ok(url) = std::str::from_utf8(data) {
+        Request::from_url(&format!("https://{}", url));
+        Request::from_urls(url, "https://example.com", "script");
+        Request::from_urls(url, "", "");
+        Request::from_urls(url, url, "");
+        Request::from_urls(url, url, url);
+    }
+});

src/request.rs

@@ -534,4 +534,17 @@ mod tests {
             assert_eq!(parsed.is_third_party, Some(false));
         }
     }
+
+    #[test]
+    fn fuzzing_errors() {
+        {
+            let parsed = Request::from_url("https://߶");
+            assert!(parsed.is_ok());
+        }
+        {
+            let parsed = Request::from_url(
+                &format!("https://{}", std::str::from_utf8(&[9, 9, 64]).unwrap()));
+            assert!(parsed.is_err());
+        }
+    }
 }

src/url_parser/mod.rs

@@ -40,7 +40,7 @@ impl UrlParser for Request {
                     url: h.url_str().to_owned(),
                     schema_end: h.scheme_end,
                     hostname_pos: (h.host_start, h.host_end),
-                    domain: get_host_domain(&url[h.host_start..h.host_end])
+                    domain: get_host_domain(&h.url_str()[h.host_start..h.host_end])
                 }),
                 _ => None
             }

src/url_parser/parser.rs

@@ -189,6 +189,7 @@ simple_enum_error! {
     // SetHostOnCannotBeABaseUrl => "a cannot-be-a-base URL doesn’t have a host to set",
     // Overflow => "URLs more than 4 GB are not supported",
     FileUrlNotSupported => "file URLs are not supported",
+    ExpectedMoreChars => "Expected more characters",
 }
 
 #[cfg(feature = "heapsize")]
@@ -454,7 +455,7 @@ impl Parser {
         let mut has_password = false;
         let mut has_username = false;
         while userinfo_char_count > 0 {
-            let (c, utf8_c) = input.next_utf8().unwrap();
+            let (c, utf8_c) = input.next_utf8().ok_or(ParseError::ExpectedMoreChars)?;
             userinfo_char_count -= 1;
             if c == ':' && username_end.is_none() {
                 // Start parsing password