diff --git a/netwerk/protocol/http/src/nsHttpChannel.cpp b/netwerk/protocol/http/src/nsHttpChannel.cpp
index fe8ff66e6d06..5f267ea883cf 100644
--- a/netwerk/protocol/http/src/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/src/nsHttpChannel.cpp
@@ -69,6 +69,7 @@ nsHttpChannel::nsHttpChannel()
     , mCachedContentIsValid(PR_FALSE)
     , mResponseHeadersModified(PR_FALSE)
     , mCanceled(PR_FALSE)
+    , mUploadStreamHasHeaders(PR_FALSE)
 {
     LOG(("Creating nsHttpChannel @%x\n", this));
 
@@ -435,7 +436,7 @@ nsHttpChannel::SetupTransaction()
         mRequestHead.SetHeader(nsHttp::Cache_Control, "max-age=0");
     }
 
-    return mTransaction->SetupRequest(&mRequestHead, mUploadStream);
+    return mTransaction->SetupRequest(&mRequestHead, mUploadStream, mUploadStreamHasHeaders);
 }
 
 void
@@ -2171,11 +2172,38 @@ nsHttpChannel::GetUploadStream(nsIInputStream **stream)
 NS_IMETHODIMP
 nsHttpChannel::SetUploadStream(nsIInputStream *stream, const char* contentType, PRInt32 contentLength)
 {
+    // NOTE: for backwards compatibility and for compatibility with old style
+    // plugins, |stream| may include headers, specifically Content-Type and
+    // Content-Length headers.  in this case, |contentType| and |contentLength|
+    // would be unspecified.  this is traditionally the case of a POST request,
+    // and so we select POST as the request method if contentType and
+    // contentLength are unspecified.
+    
+    if (mUploadStream) {
+        if (contentType) {
+            if (contentLength < 0) {
+                stream->Available((PRUint32 *) &contentLength);
+                if (contentLength < 0) {
+                    NS_ERROR("unable to determine content length");
+                    return NS_ERROR_FAILURE;
+                }
+            }
+            nsCAutoString buf; buf.AppendInt(contentLength);
+            mRequestHead.SetHeader(nsHttp::Content_Length, buf.get());
+            mRequestHead.SetHeader(nsHttp::Content_Type, contentType);
+            mUploadStreamHasHeaders = PR_FALSE;
+            mRequestHead.SetMethod(nsHttp::Put); // PUT request
+        }
+        else {
+            mUploadStreamHasHeaders = PR_TRUE;
+            mRequestHead.SetMethod(nsHttp::Post); // POST request
+        }
+    }
+    else {
+        mUploadStreamHasHeaders = PR_FALSE;
+        mRequestHead.SetMethod(nsHttp::Get); // revert to GET request
+    }
     mUploadStream = stream;
-    if (mUploadStream)
-        mRequestHead.SetMethod(nsHttp::Post);
-    else
-        mRequestHead.SetMethod(nsHttp::Get);
     return NS_OK;
 }
 
diff --git a/netwerk/protocol/http/src/nsHttpChannel.h b/netwerk/protocol/http/src/nsHttpChannel.h
index 6e260d68a8e3..cedb79bba599 100644
--- a/netwerk/protocol/http/src/nsHttpChannel.h
+++ b/netwerk/protocol/http/src/nsHttpChannel.h
@@ -172,6 +172,7 @@ private:
     PRPackedBool                      mCachedContentIsValid;
     PRPackedBool                      mResponseHeadersModified;
     PRPackedBool                      mCanceled;
+    PRPackedBool                      mUploadStreamHasHeaders;
 };
 
 #endif // nsHttpChannel_h__
diff --git a/netwerk/protocol/http/src/nsHttpResponseHead.h b/netwerk/protocol/http/src/nsHttpResponseHead.h
index 346736359cb5..ea6c831da891 100644
--- a/netwerk/protocol/http/src/nsHttpResponseHead.h
+++ b/netwerk/protocol/http/src/nsHttpResponseHead.h
@@ -62,7 +62,7 @@ public:
     nsresult GetHeader(nsHttpAtom h, char **v)      { return mHeaders.GetHeader(h, v); }
     void     ClearHeaders()                         { mHeaders.Clear(); }
 
-    void     SetContentType(const char *s) { CRTFREEIF(mContentType); mContentType = (s ? nsCRT::strdup(s) : 0); }
+    void     SetContentType(const char *s) { CRTFREEIF(mContentType); mContentType = strdup_if(s); }
     void     SetContentLength(PRInt32);
 
     // write out the response status line and headers as a single text block,
diff --git a/netwerk/protocol/http/src/nsHttpTransaction.cpp b/netwerk/protocol/http/src/nsHttpTransaction.cpp
index 48492a79ad3f..3739278414aa 100644
--- a/netwerk/protocol/http/src/nsHttpTransaction.cpp
+++ b/netwerk/protocol/http/src/nsHttpTransaction.cpp
@@ -118,7 +118,8 @@ nsHttpTransaction::~nsHttpTransaction()
 
 nsresult
 nsHttpTransaction::SetupRequest(nsHttpRequestHead *requestHead,
-                                nsIInputStream *requestStream)
+                                nsIInputStream *requestBody,
+                                PRBool requestBodyHasHeaders)
 {
     nsresult rv;
 
@@ -164,9 +165,11 @@ nsHttpTransaction::SetupRequest(nsHttpRequestHead *requestHead,
     }
 #endif
 
-    mReqUploadStream = requestStream;
-    if (!mReqUploadStream)
-        // Write out end-of-headers sequence if NOT uploading data:
+    mReqUploadStream = requestBody;
+
+    // If the request body does not include headers or if there is no request
+    // body, then we must add the header/body separator manually.
+    if (!requestBodyHasHeaders || !requestBody)
         mReqHeaderBuf.Append("\r\n");
 
     // Create a string stream for the request header buf
diff --git a/netwerk/protocol/http/src/nsHttpTransaction.h b/netwerk/protocol/http/src/nsHttpTransaction.h
index 9e59aea1bb6c..cfb47b237eb0 100644
--- a/netwerk/protocol/http/src/nsHttpTransaction.h
+++ b/netwerk/protocol/http/src/nsHttpTransaction.h
@@ -60,7 +60,9 @@ public:
     virtual ~nsHttpTransaction();
 
     // Called to initialize the transaction
-    nsresult SetupRequest(nsHttpRequestHead *, nsIInputStream *);
+    nsresult SetupRequest(nsHttpRequestHead *requestHeaders,
+                          nsIInputStream    *requestBody,
+                          PRBool             requestBodyIncludesHeaders);
 
     nsIStreamListener     *Listener()       { return mListener; }
     nsAHttpConnection     *Connection()     { return mConnection; }