Allow fuzzing libCUPS on linux and chromeos

Relaxed use_cups rules to just require a copy of libCUPS to allow
fuzzing.

Bug: chromium:831914
Test: ran fuzz test
Change-Id: I190eab4f7de3bbb4d096a39cabb4bb7fb9e3de3b
Reviewed-on: https://chromium-review.googlesource.com/c/1479899
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Commit-Queue: Luum Habtemariam <luum@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635339}

BUILD.gn

@@ -723,6 +723,7 @@ group("gn_all") {
   if ((is_linux && !is_chromecast) ||
       (is_win && (use_drfuzz || use_libfuzzer)) || (use_libfuzzer && is_mac)) {
     deps += [
+      "//chrome/services/cups_ipp_parser/public/cpp:fuzzers",
       "//testing/libfuzzer/fuzzers",
       "//third_party/grpc:fuzzers",
       "//third_party/icu/fuzzers",

chrome/app/chrome_packaged_service_manifests.cc

@@ -26,7 +26,7 @@
 #include "ash/components/tap_visualizer/public/cpp/manifest.h"
 #include "ash/public/cpp/manifest.h"
 #include "chrome/browser/chromeos/prefs/ash_pref_connector_manifest.h"
-#include "chrome/services/cups_ipp_parser/public/cpp/manifest.h"
+#include "chrome/services/cups_ipp_parser/public/cpp/manifest.h"  // nogncheck
 #include "chromeos/services/ime/public/cpp/manifest.h"
 #include "chromeos/services/secure_channel/public/cpp/manifest.h"
 #include "services/ws/public/mojom/input_devices/input_device_controller.mojom.h"

chrome/services/cups_ipp_parser/public/cpp/BUILD.gn

@@ -22,15 +22,18 @@ if (use_cups) {
     configs += [ "//printing:cups" ]
   }
 
-  fuzzer_test("ipp_message_parser_fuzzer") {
-    sources = [
-      "ipp_message_parser_fuzzer.cc",
-    ]
-    deps = [
-      ":cpp",
-    ]
+  # Fuzzer target only available on fuzzing builds.
+  if (use_fuzzing_engine) {
+    fuzzer_test("ipp_message_parser_fuzzer") {
+      sources = [
+        "ipp_message_parser_fuzzer.cc",
+      ]
+      deps = [
+        ":cpp",
+      ]
 
-    dict = "ipp_message_parser_fuzzer.dict"
+      dict = "ipp_message_parser_fuzzer.dict"
+    }
   }
 }
 
@@ -46,3 +49,7 @@ source_set("manifest") {
     "//services/service_manager/public/cpp",
   ]
 }
+
+# A dummy group to make fuzz targets discoverable.
+group("fuzzers") {
+}

printing/BUILD.gn

@@ -208,6 +208,14 @@ component("printing") {
         "backend/print_backend_cups.cc",
         "backend/print_backend_cups.h",
       ]
+
+      # We still build the utils for fuzzing.
+      if (use_fuzzing_engine) {
+        sources += [
+          "backend/cups_ipp_util.cc",
+          "backend/cups_ipp_util.h",
+        ]
+      }
     }
   }
 

printing/buildflags/buildflags.gni

@@ -4,6 +4,7 @@
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/features.gni")
+import("//build/config/sanitizers/sanitizers.gni")
 
 declare_args() {
   # Enable basic printing support and UI.
@@ -15,5 +16,10 @@ declare_args() {
   # enable_basic_printing within the same declare_args() block.
   enable_print_preview = !is_android && !is_chromecast && !is_ios && !is_fuchsia
 
-  use_cups = (is_desktop_linux || is_mac) && !is_chromecast && !is_fuchsia
+  if (use_fuzzing_engine) {
+    # For fuzzing, just restrict to chromeos and linux.
+    use_cups = is_linux
+  } else {
+    use_cups = (is_desktop_linux || is_mac) && !is_chromecast && !is_fuchsia
+  }
 }