The Tor Browser: toolkit/components/url-classifier/ProtocolParser.cpp@925c144e1f1f (annotated)

toolkit/components/url-classifier/ProtocolParser.cpp@925c144e1f1f (annotated)

toolkit/components/url-classifier/ProtocolParser.cpp

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

 //* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "ProtocolParser.h"
 #include "LookupCache.h"
 #include "nsNetCID.h"
 #include "prlog.h"
 #include "prnetdb.h"
 #include "prprf.h"
 #include "nsUrlClassifierUtils.h"
 // NSPR_LOG_MODULES=UrlClassifierDbService:5
 extern PRLogModuleInfo *gUrlClassifierDbServiceLog;
 #if defined(PR_LOGGING)
 #define LOG(args) PR_LOG(gUrlClassifierDbServiceLog, PR_LOG_DEBUG, args)
 #define LOG_ENABLED() PR_LOG_TEST(gUrlClassifierDbServiceLog, 4)
 #else
 #define LOG(args)
 #define LOG_ENABLED() (false)
 #endif
 namespace mozilla {
 namespace safebrowsing {
 // Updates will fail if fed chunks larger than this
 const uint32_t MAX_CHUNK_SIZE = (1024 * 1024);
 const uint32_t DOMAIN_SIZE = 4;
 // Parse one stringified range of chunks of the form "n" or "n-m" from a
 // comma-separated list of chunks.  Upon return, 'begin' will point to the
 // next range of chunks in the list of chunks.
 static bool
 ParseChunkRange(nsACString::const_iterator& aBegin,
                 const nsACString::const_iterator& aEnd,
                 uint32_t* aFirst, uint32_t* aLast)
 {
   nsACString::const_iterator iter = aBegin;
   FindCharInReadable(',', iter, aEnd);
   nsAutoCString element(Substring(aBegin, iter));
   aBegin = iter;
   if (aBegin != aEnd)
     aBegin++;
   uint32_t numRead = PR_sscanf(element.get(), "%u-%u", aFirst, aLast);
   if (numRead == 2) {
     if (*aFirst > *aLast) {
       uint32_t tmp = *aFirst;
       *aFirst = *aLast;
       *aLast = tmp;
     }
     return true;
   }
   if (numRead == 1) {
     *aLast = *aFirst;
     return true;
   }
   return false;
 }
 ProtocolParser::ProtocolParser()
     : mState(PROTOCOL_STATE_CONTROL)
   , mUpdateStatus(NS_OK)
   , mUpdateWait(0)
   , mResetRequested(false)
 {
 }
 ProtocolParser::~ProtocolParser()
 {
   CleanupUpdates();
 }
 nsresult
 ProtocolParser::Init(nsICryptoHash* aHasher)
 {
   mCryptoHash = aHasher;
   return NS_OK;
 }
 void
 ProtocolParser::SetCurrentTable(const nsACString& aTable)
 {
   mTableUpdate = GetTableUpdate(aTable);
 }
 nsresult
 ProtocolParser::AppendStream(const nsACString& aData)
 {
   if (NS_FAILED(mUpdateStatus))
     return mUpdateStatus;
   nsresult rv;
   mPending.Append(aData);
   bool done = false;
   while (!done) {
     if (mState == PROTOCOL_STATE_CONTROL) {
       rv = ProcessControl(&done);
     } else if (mState == PROTOCOL_STATE_CHUNK) {
       rv = ProcessChunk(&done);
     } else {
       NS_ERROR("Unexpected protocol state");
       rv = NS_ERROR_FAILURE;
     }
     if (NS_FAILED(rv)) {
       mUpdateStatus = rv;
       return rv;
     }
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessControl(bool* aDone)
 {
   nsresult rv;
   nsAutoCString line;
   *aDone = true;
   while (NextLine(line)) {
     //LOG(("Processing %s\n", line.get()));
     if (StringBeginsWith(line, NS_LITERAL_CSTRING("i:"))) {
       // Set the table name from the table header line.
       SetCurrentTable(Substring(line, 2));
     } else if (StringBeginsWith(line, NS_LITERAL_CSTRING("n:"))) {
       if (PR_sscanf(line.get(), "n:%d", &mUpdateWait) != 1) {
         LOG(("Error parsing n: '%s' (%d)", line.get(), mUpdateWait));
         mUpdateWait = 0;
       }
     } else if (line.EqualsLiteral("r:pleasereset")) {
       mResetRequested = true;
     } else if (StringBeginsWith(line, NS_LITERAL_CSTRING("u:"))) {
       rv = ProcessForward(line);
       NS_ENSURE_SUCCESS(rv, rv);
     } else if (StringBeginsWith(line, NS_LITERAL_CSTRING("a:")) ||
                StringBeginsWith(line, NS_LITERAL_CSTRING("s:"))) {
       rv = ProcessChunkControl(line);
       NS_ENSURE_SUCCESS(rv, rv);
       *aDone = false;
       return NS_OK;
     } else if (StringBeginsWith(line, NS_LITERAL_CSTRING("ad:")) ||
                StringBeginsWith(line, NS_LITERAL_CSTRING("sd:"))) {
       rv = ProcessExpirations(line);
       NS_ENSURE_SUCCESS(rv, rv);
     }
   }
   *aDone = true;
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessExpirations(const nsCString& aLine)
 {
   if (!mTableUpdate) {
     NS_WARNING("Got an expiration without a table.");
     return NS_ERROR_FAILURE;
   }
   const nsCSubstring &list = Substring(aLine, 3);
   nsACString::const_iterator begin, end;
   list.BeginReading(begin);
   list.EndReading(end);
   while (begin != end) {
     uint32_t first, last;
     if (ParseChunkRange(begin, end, &first, &last)) {
       for (uint32_t num = first; num <= last; num++) {
         if (aLine[0] == 'a')
           mTableUpdate->NewAddExpiration(num);
         else
           mTableUpdate->NewSubExpiration(num);
       }
     } else {
       return NS_ERROR_FAILURE;
     }
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessChunkControl(const nsCString& aLine)
 {
   if (!mTableUpdate) {
     NS_WARNING("Got a chunk before getting a table.");
     return NS_ERROR_FAILURE;
   }
   mState = PROTOCOL_STATE_CHUNK;
   char command;
   mChunkState.Clear();
   if (PR_sscanf(aLine.get(),
                 "%c:%d:%d:%d",
                 &command,
                 &mChunkState.num, &mChunkState.hashSize, &mChunkState.length)
       != 4)
   {
     return NS_ERROR_FAILURE;
   }
   if (mChunkState.length > MAX_CHUNK_SIZE) {
     return NS_ERROR_FAILURE;
   }
   if (!(mChunkState.hashSize == PREFIX_SIZE || mChunkState.hashSize == COMPLETE_SIZE)) {
     NS_WARNING("Invalid hash size specified in update.");
     return NS_ERROR_FAILURE;
   }
   if (StringEndsWith(mTableUpdate->TableName(),
                      NS_LITERAL_CSTRING("-shavar")) ||
       StringEndsWith(mTableUpdate->TableName(),
                      NS_LITERAL_CSTRING("-simple"))) {
     // Accommodate test tables ending in -simple for now.
     mChunkState.type = (command == 'a') ? CHUNK_ADD : CHUNK_SUB;
   } else if (StringEndsWith(mTableUpdate->TableName(),
     NS_LITERAL_CSTRING("-digest256"))) {
     LOG(("Processing digest256 data"));
     mChunkState.type = (command == 'a') ? CHUNK_ADD_DIGEST : CHUNK_SUB_DIGEST;
   }
   switch (mChunkState.type) {
     case CHUNK_ADD:
       mTableUpdate->NewAddChunk(mChunkState.num);
       break;
     case CHUNK_SUB:
       mTableUpdate->NewSubChunk(mChunkState.num);
       break;
     case CHUNK_ADD_DIGEST:
       mTableUpdate->NewAddChunk(mChunkState.num);
       break;
     case CHUNK_SUB_DIGEST:
       mTableUpdate->NewSubChunk(mChunkState.num);
       break;
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessForward(const nsCString& aLine)
 {
   const nsCSubstring &forward = Substring(aLine, 2);
   return AddForward(forward);
 }
 nsresult
 ProtocolParser::AddForward(const nsACString& aUrl)
 {
   if (!mTableUpdate) {
     NS_WARNING("Forward without a table name.");
     return NS_ERROR_FAILURE;
   }
   ForwardedUpdate *forward = mForwards.AppendElement();
   forward->table = mTableUpdate->TableName();
   forward->url.Assign(aUrl);
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessChunk(bool* aDone)
 {
   if (!mTableUpdate) {
     NS_WARNING("Processing chunk without an active table.");
     return NS_ERROR_FAILURE;
   }
   NS_ASSERTION(mChunkState.num != 0, "Must have a chunk number.");
   if (mPending.Length() < mChunkState.length) {
     *aDone = true;
     return NS_OK;
   }
   // Pull the chunk out of the pending stream data.
   nsAutoCString chunk;
   chunk.Assign(Substring(mPending, 0, mChunkState.length));
   mPending = Substring(mPending, mChunkState.length);
   *aDone = false;
   mState = PROTOCOL_STATE_CONTROL;
   //LOG(("Handling a %d-byte chunk", chunk.Length()));
   if (StringEndsWith(mTableUpdate->TableName(),
                      NS_LITERAL_CSTRING("-shavar"))) {
     return ProcessShaChunk(chunk);
   }
   if (StringEndsWith(mTableUpdate->TableName(),
              NS_LITERAL_CSTRING("-digest256"))) {
     return ProcessDigestChunk(chunk);
   }
   return ProcessPlaintextChunk(chunk);
 }
 /**
  * Process a plaintext chunk (currently only used in unit tests).
  */
 nsresult
 ProtocolParser::ProcessPlaintextChunk(const nsACString& aChunk)
 {
   if (!mTableUpdate) {
     NS_WARNING("Chunk received with no table.");
     return NS_ERROR_FAILURE;
   }
   nsTArray<nsCString> lines;
   ParseString(PromiseFlatCString(aChunk), '\n', lines);
   // non-hashed tables need to be hashed
   for (uint32_t i = 0; i < lines.Length(); i++) {
     nsCString& line = lines[i];
     if (mChunkState.type == CHUNK_ADD) {
       if (mChunkState.hashSize == COMPLETE_SIZE) {
         Completion hash;
         hash.FromPlaintext(line, mCryptoHash);
         mTableUpdate->NewAddComplete(mChunkState.num, hash);
       } else {
         NS_ASSERTION(mChunkState.hashSize == 4, "Only 32- or 4-byte hashes can be used for add chunks.");
         Prefix hash;
         hash.FromPlaintext(line, mCryptoHash);
         mTableUpdate->NewAddPrefix(mChunkState.num, hash);
       }
     } else {
       nsCString::const_iterator begin, iter, end;
       line.BeginReading(begin);
       line.EndReading(end);
       iter = begin;
       uint32_t addChunk;
       if (!FindCharInReadable(':', iter, end) ||
           PR_sscanf(lines[i].get(), "%d:", &addChunk) != 1) {
         NS_WARNING("Received sub chunk without associated add chunk.");
         return NS_ERROR_FAILURE;
       }
       iter++;
       if (mChunkState.hashSize == COMPLETE_SIZE) {
         Completion hash;
         hash.FromPlaintext(Substring(iter, end), mCryptoHash);
         mTableUpdate->NewSubComplete(addChunk, hash, mChunkState.num);
       } else {
         NS_ASSERTION(mChunkState.hashSize == 4, "Only 32- or 4-byte hashes can be used for add chunks.");
         Prefix hash;
         hash.FromPlaintext(Substring(iter, end), mCryptoHash);
         mTableUpdate->NewSubPrefix(addChunk, hash, mChunkState.num);
       }
     }
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessShaChunk(const nsACString& aChunk)
 {
   uint32_t start = 0;
   while (start < aChunk.Length()) {
     // First four bytes are the domain key.
     Prefix domain;
     domain.Assign(Substring(aChunk, start, DOMAIN_SIZE));
     start += DOMAIN_SIZE;
     // Then a count of entries.
     uint8_t numEntries = static_cast<uint8_t>(aChunk[start]);
     start++;
     nsresult rv;
     if (mChunkState.type == CHUNK_ADD && mChunkState.hashSize == PREFIX_SIZE) {
       rv = ProcessHostAdd(domain, numEntries, aChunk, &start);
     } else if (mChunkState.type == CHUNK_ADD && mChunkState.hashSize == COMPLETE_SIZE) {
       rv = ProcessHostAddComplete(numEntries, aChunk, &start);
     } else if (mChunkState.type == CHUNK_SUB && mChunkState.hashSize == PREFIX_SIZE) {
       rv = ProcessHostSub(domain, numEntries, aChunk, &start);
     } else if (mChunkState.type == CHUNK_SUB && mChunkState.hashSize == COMPLETE_SIZE) {
       rv = ProcessHostSubComplete(numEntries, aChunk, &start);
     } else {
       NS_WARNING("Unexpected chunk type/hash size!");
       LOG(("Got an unexpected chunk type/hash size: %s:%d",
            mChunkState.type == CHUNK_ADD ? "add" : "sub",
            mChunkState.hashSize));
       return NS_ERROR_FAILURE;
     }
     NS_ENSURE_SUCCESS(rv, rv);
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessDigestChunk(const nsACString& aChunk)
 {
   if (mChunkState.type == CHUNK_ADD_DIGEST) {
     return ProcessDigestAdd(aChunk);
   }
   if (mChunkState.type == CHUNK_SUB_DIGEST) {
     return ProcessDigestSub(aChunk);
   }
   return NS_ERROR_UNEXPECTED;
 }
 nsresult
 ProtocolParser::ProcessDigestAdd(const nsACString& aChunk)
 {
   // The ABNF format for add chunks is (HASH)+, where HASH is 32 bytes.
   MOZ_ASSERT(aChunk.Length() % 32 == 0,
              "Chunk length in bytes must be divisible by 4");
   uint32_t start = 0;
   while (start < aChunk.Length()) {
     Completion hash;
     hash.Assign(Substring(aChunk, start, COMPLETE_SIZE));
     start += COMPLETE_SIZE;
     mTableUpdate->NewAddComplete(mChunkState.num, hash);
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessDigestSub(const nsACString& aChunk)
 {
   // The ABNF format for sub chunks is (ADDCHUNKNUM HASH)+, where ADDCHUNKNUM
   // is a 4 byte chunk number, and HASH is 32 bytes.
   MOZ_ASSERT(aChunk.Length() % 36 == 0,
              "Chunk length in bytes must be divisible by 36");
   uint32_t start = 0;
   while (start < aChunk.Length()) {
     // Read ADDCHUNKNUM
     const nsCSubstring& addChunkStr = Substring(aChunk, start, 4);
     start += 4;
     uint32_t addChunk;
     memcpy(&addChunk, addChunkStr.BeginReading(), 4);
     addChunk = PR_ntohl(addChunk);
     // Read the hash
     Completion hash;
     hash.Assign(Substring(aChunk, start, COMPLETE_SIZE));
     start += COMPLETE_SIZE;
     mTableUpdate->NewSubComplete(addChunk, hash, mChunkState.num);
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessHostAdd(const Prefix& aDomain, uint8_t aNumEntries,
                                const nsACString& aChunk, uint32_t* aStart)
 {
   NS_ASSERTION(mChunkState.hashSize == PREFIX_SIZE,
                "ProcessHostAdd should only be called for prefix hashes.");
   if (aNumEntries == 0) {
     mTableUpdate->NewAddPrefix(mChunkState.num, aDomain);
     return NS_OK;
   }
   if (*aStart + (PREFIX_SIZE * aNumEntries) > aChunk.Length()) {
     NS_WARNING("Chunk is not long enough to contain the expected entries.");
     return NS_ERROR_FAILURE;
   }
   for (uint8_t i = 0; i < aNumEntries; i++) {
     Prefix hash;
     hash.Assign(Substring(aChunk, *aStart, PREFIX_SIZE));
     mTableUpdate->NewAddPrefix(mChunkState.num, hash);
     *aStart += PREFIX_SIZE;
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessHostSub(const Prefix& aDomain, uint8_t aNumEntries,
                                const nsACString& aChunk, uint32_t *aStart)
 {
   NS_ASSERTION(mChunkState.hashSize == PREFIX_SIZE,
                "ProcessHostSub should only be called for prefix hashes.");
   if (aNumEntries == 0) {
     if ((*aStart) + 4 > aChunk.Length()) {
       NS_WARNING("Received a zero-entry sub chunk without an associated add.");
       return NS_ERROR_FAILURE;
     }
     const nsCSubstring& addChunkStr = Substring(aChunk, *aStart, 4);
     *aStart += 4;
     uint32_t addChunk;
     memcpy(&addChunk, addChunkStr.BeginReading(), 4);
     addChunk = PR_ntohl(addChunk);
     mTableUpdate->NewSubPrefix(addChunk, aDomain, mChunkState.num);
     return NS_OK;
   }
   if (*aStart + ((PREFIX_SIZE + 4) * aNumEntries) > aChunk.Length()) {
     NS_WARNING("Chunk is not long enough to contain the expected entries.");
     return NS_ERROR_FAILURE;
   }
   for (uint8_t i = 0; i < aNumEntries; i++) {
     const nsCSubstring& addChunkStr = Substring(aChunk, *aStart, 4);
     *aStart += 4;
     uint32_t addChunk;
     memcpy(&addChunk, addChunkStr.BeginReading(), 4);
     addChunk = PR_ntohl(addChunk);
     Prefix prefix;
     prefix.Assign(Substring(aChunk, *aStart, PREFIX_SIZE));
     *aStart += PREFIX_SIZE;
     mTableUpdate->NewSubPrefix(addChunk, prefix, mChunkState.num);
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessHostAddComplete(uint8_t aNumEntries,
                                        const nsACString& aChunk, uint32_t* aStart)
 {
   NS_ASSERTION(mChunkState.hashSize == COMPLETE_SIZE,
                "ProcessHostAddComplete should only be called for complete hashes.");
   if (aNumEntries == 0) {
     // this is totally comprehensible.
     // My sarcasm detector is going off!
     NS_WARNING("Expected > 0 entries for a 32-byte hash add.");
     return NS_OK;
   }
   if (*aStart + (COMPLETE_SIZE * aNumEntries) > aChunk.Length()) {
     NS_WARNING("Chunk is not long enough to contain the expected entries.");
     return NS_ERROR_FAILURE;
   }
   for (uint8_t i = 0; i < aNumEntries; i++) {
     Completion hash;
     hash.Assign(Substring(aChunk, *aStart, COMPLETE_SIZE));
     mTableUpdate->NewAddComplete(mChunkState.num, hash);
     *aStart += COMPLETE_SIZE;
   }
   return NS_OK;
 }
 nsresult
 ProtocolParser::ProcessHostSubComplete(uint8_t aNumEntries,
                                        const nsACString& aChunk, uint32_t* aStart)
 {
   NS_ASSERTION(mChunkState.hashSize == COMPLETE_SIZE,
                "ProcessHostSubComplete should only be called for complete hashes.");
   if (aNumEntries == 0) {
     // this is totally comprehensible.
     NS_WARNING("Expected > 0 entries for a 32-byte hash sub.");
     return NS_OK;
   }
   if (*aStart + ((COMPLETE_SIZE + 4) * aNumEntries) > aChunk.Length()) {
     NS_WARNING("Chunk is not long enough to contain the expected entries.");
     return NS_ERROR_FAILURE;
   }
   for (uint8_t i = 0; i < aNumEntries; i++) {
     Completion hash;
     hash.Assign(Substring(aChunk, *aStart, COMPLETE_SIZE));
     *aStart += COMPLETE_SIZE;
     const nsCSubstring& addChunkStr = Substring(aChunk, *aStart, 4);
     *aStart += 4;
     uint32_t addChunk;
     memcpy(&addChunk, addChunkStr.BeginReading(), 4);
     addChunk = PR_ntohl(addChunk);
     mTableUpdate->NewSubComplete(addChunk, hash, mChunkState.num);
   }
   return NS_OK;
 }
 bool
 ProtocolParser::NextLine(nsACString& line)
 {
   int32_t newline = mPending.FindChar('\n');
   if (newline == kNotFound) {
     return false;
   }
   line.Assign(Substring(mPending, 0, newline));
   mPending = Substring(mPending, newline + 1);
   return true;
 }
 void
 ProtocolParser::CleanupUpdates()
 {
   for (uint32_t i = 0; i < mTableUpdates.Length(); i++) {
     delete mTableUpdates[i];
   }
   mTableUpdates.Clear();
 }
 TableUpdate *
 ProtocolParser::GetTableUpdate(const nsACString& aTable)
 {
   for (uint32_t i = 0; i < mTableUpdates.Length(); i++) {
     if (aTable.Equals(mTableUpdates[i]->TableName())) {
       return mTableUpdates[i];
     }
   }
   // We free automatically on destruction, ownership of these
   // updates can be transferred to DBServiceWorker, which passes
   // them back to Classifier when doing the updates, and that
   // will free them.
   TableUpdate *update = new TableUpdate(aTable);
   mTableUpdates.AppendElement(update);
   return update;
 }
 } // namespace safebrowsing
 } // namespace mozilla

The Tor Browser / annotate

toolkit/components/url-classifier/ProtocolParser.cpp@925c144e1f1f (annotated)

toolkit/components/url-classifier/ProtocolParser.cpp