Don't need to copy the challenge data before calling DER_Encode because

DER_Encode will copy it.  Document the GenKeyAndSignChallenge function.

R=mattm,davidben
BUG=148
TEST=none
Review URL: http://codereview.chromium.org/2866011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50682 0039d316-1c4b-4281-b951-d872f2087c98

net/third_party/mozilla_security_manager/nsKeygenHandler.cpp

@@ -123,7 +123,6 @@ std::string GenKeyAndSignChallenge(int key_size_in_bits,
   SECItem signedItem;
   CERTPublicKeyAndChallenge pkac;
   void *keyGenParams;
-  pkac.challenge.data = NULL;
   bool isSuccess = true;  // Set to false as soon as a step fails.
 
   std::string result_blob;  // the result.
@@ -208,13 +207,9 @@ std::string GenKeyAndSignChallenge(int key_size_in_bits,
 
   // Set up the PublicKeyAndChallenge data structure, then DER encode it.
   pkac.spki = spkiItem;
+  pkac.challenge.type = siBuffer;
   pkac.challenge.len = challenge.length();
-  pkac.challenge.data = (unsigned char *)strdup(challenge.c_str());
-  if (!pkac.challenge.data) {
-    LOG(ERROR) << "Out of memory while making a copy of challenge data";
-    isSuccess = false;
-    goto failure;
-  }
+  pkac.challenge.data = (unsigned char *)challenge.data();
   sec_rv = DER_Encode(arena, &pkacItem, CERTPublicKeyAndChallengeTemplate,
                       &pkac);
   if (SECSuccess != sec_rv) {
@@ -275,9 +270,6 @@ std::string GenKeyAndSignChallenge(int key_size_in_bits,
   if (slot != NULL) {
     PK11_FreeSlot(slot);
   }
-  if (pkac.challenge.data) {
-    free(pkac.challenge.data);
-  }
 
   return (isSuccess ? result_blob : std::string());
 }

net/third_party/mozilla_security_manager/nsKeygenHandler.h

@@ -47,6 +47,12 @@ namespace mozilla_security_manager {
 #define DEFAULT_RSA_KEYGEN_PE 65537L
 #define DEFAULT_RSA_KEYGEN_ALG SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION
 
+// Generates the key pair and the cert request (SPKAC), and returns a
+// base64-encoded string suitable for use as the form value of <keygen>.
+// Parameters:
+//   key_size_in_bits: key size in bits (usually 2048)
+//   challenge: challenge string sent by server
+//   stores_key: should the generated key pair be stored persistently?
 std::string GenKeyAndSignChallenge(int key_size_in_bits,
                                    const std::string& challenge,
                                    bool stores_key);