Add fuzzers for import of WebCrypto DER-encoded keys.

components/webcrypto/BUILD.gn

Index: components/webcrypto/BUILD.gn
diff --git a/components/webcrypto/BUILD.gn b/components/webcrypto/BUILD.gn
index 94a251d380e56431a0d69ff35cde9309e0a9c265..0db4ccc072d1427006d819e342e7fba4452ce563 100644
--- a/components/webcrypto/BUILD.gn
+++ b/components/webcrypto/BUILD.gn
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import("//testing/test.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 
 source_set("webcrypto") {
   sources = [
@@ -93,3 +94,76 @@ source_set("unit_tests") {
     "//third_party/re2",
   ]
 }
+
+# Shared functionality for writing WebCrypto fuzzers at this layer (several
+# things need to be done to initialize Blink and pull in the right
+# dependencies).
+source_set("fuzzer_support") {
+  testonly = true
+
+  sources = [
+    "fuzzer_support.cc",
+    "fuzzer_support.h",
+  ]
+  deps = [
+    ":webcrypto",
+    "//crypto",
+    "//crypto:platform",
+
+    # The "blink_for_unittests" includes a dependency on Mojo, which otherwise
+    # public:blink lacks and would result in a linker error.
+    "//third_party/WebKit/public:blink_for_unittests",
+
+    # This contains a helper function for initializing Blink (needed for
+    # PartitionAlloc initialization).
+    "//components/test_runner:test_runner",
+  ]
+}
+
+# Tests the import of PKCS8 formatted EC keys.
+fuzzer_test("ec_import_key_pkcs8_fuzzer") {
+  sources = [
+    "ec_import_key_pkcs8_fuzzer.cc",
+  ]
+  deps = [
+    ":fuzzer_support",
+    ":webcrypto",
+    "//third_party/WebKit/public:blink_headers",
+  ]
+}
+
+# Tests the import of SPKI formatted EC keys.
+fuzzer_test("ec_import_key_spki_fuzzer") {
+  sources = [
+    "ec_import_key_spki_fuzzer.cc",
+  ]
+  deps = [
+    ":fuzzer_support",
+    ":webcrypto",
+    "//third_party/WebKit/public:blink_headers",
+  ]
+}
+
+# Tests the import of PKCS8 formatted RSA keys.
+fuzzer_test("rsa_import_key_pkcs8_fuzzer") {
+  sources = [
+    "rsa_import_key_pkcs8_fuzzer.cc",
+  ]
+  deps = [
+    ":fuzzer_support",
+    ":webcrypto",
+    "//third_party/WebKit/public:blink_headers",
+  ]
+}
+
+# Tests the import of SPKI formatted RSA keys.
+fuzzer_test("rsa_import_key_spki_fuzzer") {
+  sources = [
+    "rsa_import_key_pkcs8_fuzzer.cc",

[Nico, 2017/03/26 03:14:39]

You copied rsa_import_key_pkcs8_fuzzer here and forgot to change the sources
line. None of your fuzzers uses rsa_import_key_spki_fuzzer.cc but two use
rsa_import_key_pkcs8_fuzzer.cc. Whoops! :-)

[eroman, 2017/03/30 17:02:56]

Ugh, I am terrible :(

Thanks for pointing this out!

+  ]
+  deps = [
+    ":fuzzer_support",
+    ":webcrypto",
+    "//third_party/WebKit/public:blink_headers",
+  ]
+}