bug 597706 - response header smuggling r=honzab

reject responses with multiple non identical or invalid
content-length headers

netwerk/base/public/nsNetError.h

@@ -144,6 +144,14 @@
 #define NS_ERROR_INVALID_CONTENT_ENCODING \
     NS_ERROR_GENERATE_FAILURE(NS_ERROR_MODULE_NETWORK, 27)
 
+/**
+ * A transport level corruption was found in the source document. for example
+ * a document with a calculated checksum that does not match the Content-MD5
+ * http header.
+ */
+#define NS_ERROR_CORRUPTED_CONTENT \
+    NS_ERROR_GENERATE_FAILURE(NS_ERROR_MODULE_NETWORK, 29)
+
 /******************************************************************************
  * Connectivity error codes:
  */

netwerk/protocol/http/nsHttpChunkedDecoder.cpp

@@ -137,7 +137,8 @@ nsHttpChunkedDecoder::ParseChunkRemaining(char *buf,
                 LOG(("got trailer: %s\n", buf));
                 // allocate a header array for the trailers on demand
                 if (!mTrailers) {
-                    mTrailers = new nsHttpHeaderArray();
+                    mTrailers = new nsHttpHeaderArray
+                        (nsHttpHeaderArray::HTTP_RESPONSE_HEADERS);
                     if (!mTrailers)
                         return NS_ERROR_OUT_OF_MEMORY;
                 }

netwerk/protocol/http/nsHttpHeaderArray.cpp

@@ -85,8 +85,11 @@ nsHttpHeaderArray::SetHeader(nsHttpAtom header,
         entry->value.Append(value);
     }
     // Replace the existing string with the new value
-    else
+    else if (CanOverwriteHeader(header))
         entry->value = value;
+    else if (!entry->value.Equals(value))
+        return NS_ERROR_CORRUPTED_CONTENT;
+
     return NS_OK;
 }
 
@@ -129,7 +132,7 @@ nsHttpHeaderArray::VisitHeaders(nsIHttpHeaderVisitor *visitor)
     return NS_OK;
 }
 
-void
+nsresult
 nsHttpHeaderArray::ParseHeaderLine(const char *line,
                                    nsHttpAtom *hdr,
                                    char **val)
@@ -151,13 +154,13 @@ nsHttpHeaderArray::ParseHeaderLine(const char *line,
     char *p = (char *) strchr(line, ':');
     if (!p) {
         LOG(("malformed header [%s]: no colon\n", line));
-        return;
+        return NS_OK;
     }
 
     // make sure we have a valid token for the field-name
     if (!nsHttp::IsValidToken(line, p)) {
         LOG(("malformed header [%s]: field-name not a token\n", line));
-        return;
+        return NS_OK;
     }
     
     *p = 0; // null terminate field-name
@@ -165,7 +168,7 @@ nsHttpHeaderArray::ParseHeaderLine(const char *line,
     nsHttpAtom atom = nsHttp::ResolveAtom(line);
     if (!atom) {
         LOG(("failed to resolve atom [%s]\n", line));
-        return;
+        return NS_OK;
     }
 
     // skip over whitespace
@@ -183,7 +186,7 @@ nsHttpHeaderArray::ParseHeaderLine(const char *line,
     if (val) *val = p;
 
     // assign response header
-    SetHeader(atom, nsDependentCString(p, p2 - p), PR_TRUE);
+    return SetHeader(atom, nsDependentCString(p, p2 - p), PR_TRUE);
 }
 
 void
@@ -247,3 +250,11 @@ nsHttpHeaderArray::CanAppendToHeader(nsHttpAtom header)
            header != nsHttp::Location            &&
            header != nsHttp::Max_Forwards;
 }
+
+PRBool
+nsHttpHeaderArray::CanOverwriteHeader(nsHttpAtom header)
+{
+    if (mType != HTTP_RESPONSE_HEADERS)
+        return PR_TRUE;
+    return header != nsHttp::Content_Length;
+}

netwerk/protocol/http/nsHttpHeaderArray.h

@@ -49,7 +49,12 @@
 class nsHttpHeaderArray
 {
 public:
-    nsHttpHeaderArray() {}
+    enum nsHttpHeaderType {
+        HTTP_REQUEST_HEADERS,
+        HTTP_RESPONSE_HEADERS
+    };
+
+    nsHttpHeaderArray(nsHttpHeaderType headerType) : mType(headerType) {}
    ~nsHttpHeaderArray() { Clear(); }
 
     const char *PeekHeader(nsHttpAtom header);
@@ -73,9 +78,9 @@ public:
 
     // parse a header line, return the header atom and a pointer to the 
     // header value (the substring of the header line -- do not free).
-    void ParseHeaderLine(const char *line,
+    nsresult ParseHeaderLine(const char *line,
-                         nsHttpAtom *header=nsnull,
+                             nsHttpAtom *header=nsnull,
-                         char **value=nsnull);
+                             char **value=nsnull);
 
     void Flatten(nsACString &, PRBool pruneProxyHeaders=PR_FALSE);
 
@@ -104,8 +109,10 @@ public:
 private:
     PRInt32 LookupEntry(nsHttpAtom header, nsEntry **);
     PRBool  CanAppendToHeader(nsHttpAtom header);
+    PRBool  CanOverwriteHeader(nsHttpAtom header);
 
     nsTArray<nsEntry> mHeaders;
+    nsHttpHeaderType  mType;
 };
 
 #endif

netwerk/protocol/http/nsHttpRequestHead.h

@@ -52,8 +52,10 @@
 class nsHttpRequestHead
 {
 public:
-    nsHttpRequestHead() : mMethod(nsHttp::Get), mVersion(NS_HTTP_VERSION_1_1) {}
+    nsHttpRequestHead() : mHeaders(nsHttpHeaderArray::HTTP_REQUEST_HEADERS)
-   ~nsHttpRequestHead() {}
+                        , mMethod(nsHttp::Get)
+                        , mVersion(NS_HTTP_VERSION_1_1) {}
+    ~nsHttpRequestHead() {}
 
     void SetMethod(nsHttpAtom method) { mMethod = method; }
     void SetVersion(nsHttpVersion version) { mVersion = version; }

netwerk/protocol/http/nsHttpResponseHead.cpp

@@ -197,23 +197,30 @@ nsHttpResponseHead::ParseStatusLine(const char *line)
         PRUintn(mVersion), PRUintn(mStatus), mStatusText.get()));
 }
 
-void
+nsresult
 nsHttpResponseHead::ParseHeaderLine(const char *line)
 {
     nsHttpAtom hdr = {0};
     char *val;
-
+    nsresult rv;
-    mHeaders.ParseHeaderLine(line, &hdr, &val);
+    
+    rv = mHeaders.ParseHeaderLine(line, &hdr, &val);
+    if (NS_FAILED(rv))
+        return rv;
+    
     // leading and trailing LWS has been removed from |val|
 
     // handle some special case headers...
     if (hdr == nsHttp::Content_Length) {
         PRInt64 len;
         // permit only a single value here.
-        if (nsHttp::ParseInt64(val, &len))
+        if (nsHttp::ParseInt64(val, &len)) {
             mContentLength = len;
-        else
+        }
+        else {
             LOG(("invalid content-length!\n"));
+            return NS_ERROR_CORRUPTED_CONTENT;
+        }
     }
     else if (hdr == nsHttp::Content_Type) {
         LOG(("ParseContentType [type=%s]\n", val));
@@ -225,6 +232,7 @@ nsHttpResponseHead::ParseHeaderLine(const char *line)
         ParseCacheControl(val);
     else if (hdr == nsHttp::Pragma)
         ParsePragma(val);
+    return NS_OK;
 }
 
 // From section 13.2.3 of RFC2616, we compute the current age of a cached

netwerk/protocol/http/nsHttpResponseHead.h

@@ -51,13 +51,14 @@
 class nsHttpResponseHead
 {
 public:
-    nsHttpResponseHead() : mVersion(NS_HTTP_VERSION_1_1)
+    nsHttpResponseHead() : mHeaders(nsHttpHeaderArray::HTTP_RESPONSE_HEADERS)
+                         , mVersion(NS_HTTP_VERSION_1_1)
                          , mStatus(200)
                          , mContentLength(LL_MAXUINT)
                          , mCacheControlNoStore(PR_FALSE)
                          , mCacheControlNoCache(PR_FALSE)
                          , mPragmaNoCache(PR_FALSE) {}
-   ~nsHttpResponseHead() 
+    ~nsHttpResponseHead() 
     {
         Reset();
     }
@@ -104,7 +105,7 @@ public:
     void     ParseStatusLine(const char *line);
 
     // parse a header line. line must be null terminated. parsing is destructive.
-    void     ParseHeaderLine(const char *line);
+    nsresult ParseHeaderLine(const char *line);
 
     // cache validation support methods
     nsresult ComputeFreshnessLifetime(PRUint32 *);

netwerk/protocol/http/nsHttpTransaction.cpp

@@ -784,12 +784,12 @@ nsHttpTransaction::LocateHttpStart(char *buf, PRUint32 len,
     return 0;
 }
 
-
+nsresult
-void
 nsHttpTransaction::ParseLine(char *line)
 {
     LOG(("nsHttpTransaction::ParseLine [%s]\n", line));
-
+    nsresult rv = NS_OK;
+    
     if (!mHaveStatusLine) {
         mResponseHead->ParseStatusLine(line);
         mHaveStatusLine = PR_TRUE;
@@ -797,8 +797,10 @@ nsHttpTransaction::ParseLine(char *line)
         if (mResponseHead->Version() == NS_HTTP_VERSION_0_9)
             mHaveAllHeaders = PR_TRUE;
     }
-    else
+    else {
-        mResponseHead->ParseHeaderLine(line);
+        rv = mResponseHead->ParseHeaderLine(line);
+    }
+    return rv;
 }
 
 nsresult
@@ -813,8 +815,11 @@ nsHttpTransaction::ParseLineSegment(char *segment, PRUint32 len)
         // of mLineBuf.
         mLineBuf.Truncate(mLineBuf.Length() - 1);
         if (!mHaveStatusLine || (*segment != ' ' && *segment != '\t')) {
-            ParseLine(mLineBuf.BeginWriting());
+            nsresult rv = ParseLine(mLineBuf.BeginWriting());
             mLineBuf.Truncate();
+            if (NS_FAILED(rv)) {
+                return rv;
+            }
         }
     }
 

netwerk/protocol/http/nsHttpTransaction.h

@@ -141,7 +141,7 @@ private:
     nsresult Restart();
     char    *LocateHttpStart(char *buf, PRUint32 len,
                              PRBool aAllowPartialMatch);
-    void     ParseLine(char *line);
+    nsresult ParseLine(char *line);
     nsresult ParseLineSegment(char *seg, PRUint32 len);
     nsresult ParseHead(char *, PRUint32 count, PRUint32 *countRead);
     nsresult HandleContentStart();