fix(gw): 404 when a valid DAG is missing link

core/corehttp/gateway_handler.go

@@ -19,6 +19,7 @@ import (
 
 	cid "github.com/ipfs/go-cid"
 	files "github.com/ipfs/go-ipfs-files"
+	ipld "github.com/ipfs/go-ipld-format"
 	dag "github.com/ipfs/go-merkledag"
 	mfs "github.com/ipfs/go-mfs"
 	path "github.com/ipfs/go-path"
@@ -389,8 +390,7 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 			logger.Debugw("serve pretty 404 if present")
 			return
 		}
-
-		webError(w, "ipfs resolve -r "+debugStr(contentPath.String()), err, http.StatusNotFound)
+		webError(w, "ipfs resolve -r "+debugStr(contentPath.String()), err, http.StatusBadRequest)
 		return
 	}
 
@@ -782,6 +782,8 @@ func webError(w http.ResponseWriter, message string, err error, defaultCode int)
 		webErrorWithCode(w, message, err, http.StatusNotFound)
 	} else if err == routing.ErrNotFound {
 		webErrorWithCode(w, message, err, http.StatusNotFound)
+	} else if ipld.IsNotFound(err) {
+		webErrorWithCode(w, message, err, http.StatusNotFound)
 	} else if err == context.DeadlineExceeded {
 		webErrorWithCode(w, message, err, http.StatusRequestTimeout)
 	} else {

core/corehttp/gateway_handler_unixfs.go

@@ -22,7 +22,7 @@ func (i *gatewayHandler) serveUnixFS(ctx context.Context, w http.ResponseWriter,
 	// Handling UnixFS
 	dr, err := i.api.Unixfs().Get(ctx, resolvedPath)
 	if err != nil {
-		webError(w, "ipfs cat "+html.EscapeString(contentPath.String()), err, http.StatusNotFound)
+		webError(w, "ipfs cat "+html.EscapeString(contentPath.String()), err, http.StatusBadRequest)
 		return
 	}
 	defer dr.Close()

core/corehttp/gateway_test.go

@@ -235,17 +235,17 @@ func TestGatewayGet(t *testing.T) {
 		{"127.0.0.1:8080", "/", http.StatusNotFound, "404 page not found\n"},
 		{"127.0.0.1:8080", "/" + k.Cid().String(), http.StatusNotFound, "404 page not found\n"},
 		{"127.0.0.1:8080", k.String(), http.StatusOK, "fnord"},
-		{"127.0.0.1:8080", "/ipns/nxdomain.example.com", http.StatusNotFound, "ipfs resolve -r /ipns/nxdomain.example.com: " + namesys.ErrResolveFailed.Error() + "\n"},
-		{"127.0.0.1:8080", "/ipns/%0D%0A%0D%0Ahello", http.StatusNotFound, "ipfs resolve -r /ipns/\\r\\n\\r\\nhello: " + namesys.ErrResolveFailed.Error() + "\n"},
+		{"127.0.0.1:8080", "/ipns/nxdomain.example.com", http.StatusBadRequest, "ipfs resolve -r /ipns/nxdomain.example.com: " + namesys.ErrResolveFailed.Error() + "\n"},
+		{"127.0.0.1:8080", "/ipns/%0D%0A%0D%0Ahello", http.StatusBadRequest, "ipfs resolve -r /ipns/\\r\\n\\r\\nhello: " + namesys.ErrResolveFailed.Error() + "\n"},
 		{"127.0.0.1:8080", "/ipns/example.com", http.StatusOK, "fnord"},
 		{"example.com", "/", http.StatusOK, "fnord"},
 
 		{"working.example.com", "/", http.StatusOK, "fnord"},
 		{"double.example.com", "/", http.StatusOK, "fnord"},
 		{"triple.example.com", "/", http.StatusOK, "fnord"},
 		{"working.example.com", k.String(), http.StatusNotFound, "ipfs resolve -r /ipns/working.example.com" + k.String() + ": no link named \"ipfs\" under " + k.Cid().String() + "\n"},
-		{"broken.example.com", "/", http.StatusNotFound, "ipfs resolve -r /ipns/broken.example.com/: " + namesys.ErrResolveFailed.Error() + "\n"},
-		{"broken.example.com", k.String(), http.StatusNotFound, "ipfs resolve -r /ipns/broken.example.com" + k.String() + ": " + namesys.ErrResolveFailed.Error() + "\n"},
+		{"broken.example.com", "/", http.StatusBadRequest, "ipfs resolve -r /ipns/broken.example.com/: " + namesys.ErrResolveFailed.Error() + "\n"},
+		{"broken.example.com", k.String(), http.StatusBadRequest, "ipfs resolve -r /ipns/broken.example.com" + k.String() + ": " + namesys.ErrResolveFailed.Error() + "\n"},
 		// This test case ensures we don't treat the TLD as a file extension.
 		{"example.man", "/", http.StatusOK, "fnord"},
 	} {

test/sharness/t0110-gateway.sh

@@ -80,10 +80,14 @@ test_expect_success "GET IPFS directory with index.html and trailing slash retur
   test_should_contain \"hello i am a webpage\" response_with_slash
 "
 
-test_expect_success "GET IPFS nonexistent file returns code expected (404)" '
+test_expect_success "GET IPFS nonexistent file returns 404 (Not Found)" '
   test_curl_resp_http_code "http://127.0.0.1:$port/ipfs/$HASH2/pleaseDontAddMe" "HTTP/1.1 404 Not Found"
 '
 
+test_expect_success "GET IPFS invalid CID returns 400 (Bad Request)" '
+  test_curl_resp_http_code "http://127.0.0.1:$port/ipfs/QmInvalid/pleaseDontAddMe" "HTTP/1.1 400 Bad Request"
+'
+
 # https://github.com/ipfs/go-ipfs/issues/8230
 test_expect_success "GET IPFS inlined zero-length data object returns ok code (200)" '
   curl -sD - "http://127.0.0.1:$port/ipfs/bafkqaaa" > empty_ok_response &&
@@ -97,6 +101,10 @@ test_expect_success "GET /ipfs/ipfs/{cid} returns redirect to the valid path" '
   test_should_contain "<link rel=\"canonical\" href=\"/ipfs/bafkqaaa?query=to-remember\" />" response_with_double_ipfs_ns
 '
 
+test_expect_success "GET invalid IPNS root returns 400 (Bad Request)" '
+  test_curl_resp_http_code "http://127.0.0.1:$port/ipns/QmInvalid/pleaseDontAddMe" "HTTP/1.1 400 Bad Request"
+'
+
 test_expect_failure "GET IPNS path succeeds" '
   ipfs name publish --allow-offline "$HASH" &&
   PEERID=$(ipfs config Identity.PeerID) &&