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256 lines
8.7 KiB
C++
256 lines
8.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsCSPParser_h___
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#define nsCSPParser_h___
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#include "nsCSPUtils.h"
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#include "nsIURI.h"
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#include "nsString.h"
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/**
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* How does the parsing work?
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*
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* We generate tokens by splitting the policy-string by whitespace and semicolon.
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* Interally the tokens are represented as an array of string-arrays:
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*
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* [
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* [ name, src, src, src, ... ],
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* [ name, src, src, src, ... ],
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* [ name, src, src, src, ... ]
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* ]
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*
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* for example:
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* [
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* [ img-src, http://www.example.com, http:www.test.com ],
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* [ default-src, 'self'],
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* [ script-src, 'unsafe-eval', 'unsafe-inline' ],
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* ]
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*
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* The first element of each array has to be a valid directive-name, otherwise we can
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* ignore the remaining elements of the array. Also, if the
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* directive already exists in the current policy, we can ignore
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* the remaining elements of that array. (http://www.w3.org/TR/CSP/#parsing)
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*/
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typedef nsTArray< nsTArray<nsString> > cspTokens;
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class nsCSPTokenizer {
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public:
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static void tokenizeCSPPolicy(const nsAString &aPolicyString, cspTokens& outTokens);
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private:
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nsCSPTokenizer(const char16_t* aStart, const char16_t* aEnd);
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~nsCSPTokenizer();
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inline bool atEnd()
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{
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return mCurChar >= mEndChar;
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}
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inline void skipWhiteSpace()
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{
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while (mCurChar < mEndChar && *mCurChar == ' ') {
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mCurToken.Append(*mCurChar++);
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}
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mCurToken.Truncate();
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}
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inline void skipWhiteSpaceAndSemicolon()
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{
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while (mCurChar < mEndChar && (*mCurChar == ' ' || *mCurChar == ';')) {
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mCurToken.Append(*mCurChar++);
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}
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mCurToken.Truncate();
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}
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inline bool accept(char16_t aChar)
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{
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NS_ASSERTION(mCurChar < mEndChar, "Trying to dereference mEndChar");
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if (*mCurChar == aChar) {
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mCurToken.Append(*mCurChar++);
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return true;
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}
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return false;
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}
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void generateNextToken();
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void generateTokens(cspTokens& outTokens);
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const char16_t* mCurChar;
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const char16_t* mEndChar;
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nsString mCurToken;
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};
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class nsCSPParser {
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public:
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/**
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* The CSP parser only has one publicly accessible function, which is parseContentSecurityPolicy.
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* Internally the input string is separated into string tokens and policy() is called, which starts
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* parsing the policy. The parser calls one function after the other according the the source-list
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* from http://www.w3.org/TR/CSP11/#source-list. E.g., the parser can only call port() after the parser
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* has already processed any possible host in host(), similar to a finite state machine.
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*/
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static nsCSPPolicy* parseContentSecurityPolicy(const nsAString &aPolicyString,
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nsIURI *aSelfURI,
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bool aReportOnly,
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nsCSPContext* aCSPContext,
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bool aDeliveredViaMetaTag);
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private:
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nsCSPParser(cspTokens& aTokens,
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nsIURI* aSelfURI,
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nsCSPContext* aCSPContext,
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bool aDeliveredViaMetaTag);
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~nsCSPParser();
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// Parsing the CSP using the source-list from http://www.w3.org/TR/CSP11/#source-list
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nsCSPPolicy* policy();
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void directive();
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nsCSPDirective* directiveName();
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void directiveValue(nsTArray<nsCSPBaseSrc*>& outSrcs);
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void referrerDirectiveValue();
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void sourceList(nsTArray<nsCSPBaseSrc*>& outSrcs);
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nsCSPBaseSrc* sourceExpression();
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nsCSPSchemeSrc* schemeSource();
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nsCSPHostSrc* hostSource();
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nsCSPBaseSrc* keywordSource();
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nsCSPNonceSrc* nonceSource();
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nsCSPHashSrc* hashSource();
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nsCSPHostSrc* appHost(); // helper function to support app specific hosts
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nsCSPHostSrc* host();
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bool hostChar();
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bool schemeChar();
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bool port();
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bool path(nsCSPHostSrc* aCspHost);
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bool subHost(); // helper function to parse subDomains
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bool atValidUnreservedChar(); // helper function to parse unreserved
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bool atValidSubDelimChar(); // helper function to parse sub-delims
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bool atValidPctEncodedChar(); // helper function to parse pct-encoded
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bool subPath(nsCSPHostSrc* aCspHost); // helper function to parse paths
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void reportURIList(nsTArray<nsCSPBaseSrc*>& outSrcs); // helper function to parse report-uris
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void percentDecodeStr(const nsAString& aEncStr, // helper function to percent-decode
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nsAString& outDecStr);
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inline bool atEnd()
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{
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return mCurChar >= mEndChar;
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}
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inline bool accept(char16_t aSymbol)
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{
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if (atEnd()) { return false; }
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return (*mCurChar == aSymbol) && advance();
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}
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inline bool accept(bool (*aClassifier) (char16_t))
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{
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if (atEnd()) { return false; }
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return (aClassifier(*mCurChar)) && advance();
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}
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inline bool peek(char16_t aSymbol)
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{
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if (atEnd()) { return false; }
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return *mCurChar == aSymbol;
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}
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inline bool peek(bool (*aClassifier) (char16_t))
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{
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if (atEnd()) { return false; }
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return aClassifier(*mCurChar);
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}
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inline bool advance()
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{
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if (atEnd()) { return false; }
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mCurValue.Append(*mCurChar++);
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return true;
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}
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inline void resetCurValue()
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{
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mCurValue.Truncate();
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}
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bool atEndOfPath();
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bool atValidPathChar();
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void resetCurChar(const nsAString& aToken);
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void logWarningErrorToConsole(uint32_t aSeverityFlag,
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const char* aProperty,
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const char16_t* aParams[],
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uint32_t aParamsLength);
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/**
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* When parsing the policy, the parser internally uses the following helper
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* variables/members which are used/reset during parsing. The following
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* example explains how they are used.
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* The tokenizer separats all input into arrays of arrays of strings, which
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* are stored in mTokens, for example:
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* mTokens = [ [ script-src, http://www.example.com, 'self' ], ... ]
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*
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* When parsing starts, mCurdir always holds the currently processed array of strings.
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* In our example:
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* mCurDir = [ script-src, http://www.example.com, 'self' ]
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*
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* During parsing, we process/consume one string at a time of that array.
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* We set mCurToken to the string we are currently processing; in the first case
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* that would be:
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* mCurToken = script-src
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* which allows to do simple string comparisons to see if mCurToken is a valid directive.
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*
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* Continuing parsing, the parser consumes the next string of that array, resetting:
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* mCurToken = "http://www.example.com"
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* ^ ^
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* mCurChar mEndChar (points *after* the 'm')
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* mCurValue = ""
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*
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* After calling advance() the first time, helpers would hold the following values:
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* mCurToken = "http://www.example.com"
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* ^ ^
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* mCurChar mEndChar (points *after* the 'm')
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* mCurValue = "h"
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*
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* We continue parsing till all strings of one directive are consumed, then we reset
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* mCurDir to hold the next array of strings and start the process all over.
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*/
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const char16_t* mCurChar;
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const char16_t* mEndChar;
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nsString mCurValue;
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nsString mCurToken;
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nsTArray<nsString> mCurDir;
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// cache variables to ignore unsafe-inline if hash or nonce is specified
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bool mHasHashOrNonce; // false, if no hash or nonce is defined
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nsCSPKeywordSrc* mUnsafeInlineKeywordSrc; // null, otherwise invlidate()
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// cache variables for child-src and frame-src directive handling.
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// frame-src is deprecated in favor of child-src, however if we
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// see a frame-src directive, it takes precedence for frames and iframes.
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// At the end of parsing, if we have a child-src directive, we need to
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// decide whether it will handle frames, or if there is a frame-src we
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// should honor instead.
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nsCSPChildSrcDirective* mChildSrc;
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nsCSPDirective* mFrameSrc;
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cspTokens mTokens;
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nsIURI* mSelfURI;
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nsCSPPolicy* mPolicy;
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nsCSPContext* mCSPContext; // used for console logging
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bool mDeliveredViaMetaTag;
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};
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#endif /* nsCSPParser_h___ */
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