The Tor Browser: netwerk/protocol/http/Http2Compression.cpp@deefc01c0e14 (annotated)

netwerk/protocol/http/Http2Compression.cpp@deefc01c0e14 (annotated)

netwerk/protocol/http/Http2Compression.cpp

Thu, 15 Jan 2015 21:03:48 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 21:03:48 +0100
branch: TOR_BUG_9701
changeset 11: deefc01c0e14
permissions: -rw-r--r--

Integrate friendly tips from Tor colleagues to make (or not) 4.5 alpha 3;
This includes removal of overloaded (but unused) methods, and addition of
a overlooked call to DataStruct::SetData(nsISupports, uint32_t, bool.)

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=2 ts=8 et tw=80 : */
 /* 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/. */
 // HttpLog.h should generally be included first
 #include "HttpLog.h"
 // Log on level :5, instead of default :4.
 #undef LOG
 #define LOG(args) LOG5(args)
 #undef LOG_ENABLED
 #define LOG_ENABLED() LOG5_ENABLED()
 #include "Http2Compression.h"
 #include "Http2HuffmanIncoming.h"
 #include "Http2HuffmanOutgoing.h"
 extern PRThread *gSocketThread;
 namespace mozilla {
 namespace net {
 static nsDeque *gStaticHeaders = nullptr;
 void
 Http2CompressionCleanup()
 {
   // this happens after the socket thread has been destroyed
   delete gStaticHeaders;
   gStaticHeaders = nullptr;
 }
 static void
 AddStaticElement(const nsCString &name, const nsCString &value)
 {
   nvPair *pair = new nvPair(name, value);
   gStaticHeaders->Push(pair);
 }
 static void
 AddStaticElement(const nsCString &name)
 {
   AddStaticElement(name, EmptyCString());
 }
 static void
 InitializeStaticHeaders()
 {
   MOZ_ASSERT(PR_GetCurrentThread() == gSocketThread);
   if (!gStaticHeaders) {
     gStaticHeaders = new nsDeque();
     AddStaticElement(NS_LITERAL_CSTRING(":authority"));
     AddStaticElement(NS_LITERAL_CSTRING(":method"), NS_LITERAL_CSTRING("GET"));
     AddStaticElement(NS_LITERAL_CSTRING(":method"), NS_LITERAL_CSTRING("POST"));
     AddStaticElement(NS_LITERAL_CSTRING(":path"), NS_LITERAL_CSTRING("/"));
     AddStaticElement(NS_LITERAL_CSTRING(":path"), NS_LITERAL_CSTRING("/index.html"));
     AddStaticElement(NS_LITERAL_CSTRING(":scheme"), NS_LITERAL_CSTRING("http"));
     AddStaticElement(NS_LITERAL_CSTRING(":scheme"), NS_LITERAL_CSTRING("https"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("200"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("500"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("404"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("403"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("400"));
     AddStaticElement(NS_LITERAL_CSTRING(":status"), NS_LITERAL_CSTRING("401"));
     AddStaticElement(NS_LITERAL_CSTRING("accept-charset"));
     AddStaticElement(NS_LITERAL_CSTRING("accept-encoding"));
     AddStaticElement(NS_LITERAL_CSTRING("accept-language"));
     AddStaticElement(NS_LITERAL_CSTRING("accept-ranges"));
     AddStaticElement(NS_LITERAL_CSTRING("accept"));
     AddStaticElement(NS_LITERAL_CSTRING("access-control-allow-origin"));
     AddStaticElement(NS_LITERAL_CSTRING("age"));
     AddStaticElement(NS_LITERAL_CSTRING("allow"));
     AddStaticElement(NS_LITERAL_CSTRING("authorization"));
     AddStaticElement(NS_LITERAL_CSTRING("cache-control"));
     AddStaticElement(NS_LITERAL_CSTRING("content-disposition"));
     AddStaticElement(NS_LITERAL_CSTRING("content-encoding"));
     AddStaticElement(NS_LITERAL_CSTRING("content-language"));
     AddStaticElement(NS_LITERAL_CSTRING("content-length"));
     AddStaticElement(NS_LITERAL_CSTRING("content-location"));
     AddStaticElement(NS_LITERAL_CSTRING("content-range"));
     AddStaticElement(NS_LITERAL_CSTRING("content-type"));
     AddStaticElement(NS_LITERAL_CSTRING("cookie"));
     AddStaticElement(NS_LITERAL_CSTRING("date"));
     AddStaticElement(NS_LITERAL_CSTRING("etag"));
     AddStaticElement(NS_LITERAL_CSTRING("expect"));
     AddStaticElement(NS_LITERAL_CSTRING("expires"));
     AddStaticElement(NS_LITERAL_CSTRING("from"));
     AddStaticElement(NS_LITERAL_CSTRING("host"));
     AddStaticElement(NS_LITERAL_CSTRING("if-match"));
     AddStaticElement(NS_LITERAL_CSTRING("if-modified-since"));
     AddStaticElement(NS_LITERAL_CSTRING("if-none-match"));
     AddStaticElement(NS_LITERAL_CSTRING("if-range"));
     AddStaticElement(NS_LITERAL_CSTRING("if-unmodified-since"));
     AddStaticElement(NS_LITERAL_CSTRING("last-modified"));
     AddStaticElement(NS_LITERAL_CSTRING("link"));
     AddStaticElement(NS_LITERAL_CSTRING("location"));
     AddStaticElement(NS_LITERAL_CSTRING("max-forwards"));
     AddStaticElement(NS_LITERAL_CSTRING("proxy-authenticate"));
     AddStaticElement(NS_LITERAL_CSTRING("proxy-authorization"));
     AddStaticElement(NS_LITERAL_CSTRING("range"));
     AddStaticElement(NS_LITERAL_CSTRING("referer"));
     AddStaticElement(NS_LITERAL_CSTRING("refresh"));
     AddStaticElement(NS_LITERAL_CSTRING("retry-after"));
     AddStaticElement(NS_LITERAL_CSTRING("server"));
     AddStaticElement(NS_LITERAL_CSTRING("set-cookie"));
     AddStaticElement(NS_LITERAL_CSTRING("strict-transport-security"));
     AddStaticElement(NS_LITERAL_CSTRING("transfer-encoding"));
     AddStaticElement(NS_LITERAL_CSTRING("user-agent"));
     AddStaticElement(NS_LITERAL_CSTRING("vary"));
     AddStaticElement(NS_LITERAL_CSTRING("via"));
     AddStaticElement(NS_LITERAL_CSTRING("www-authenticate"));
   }
 }
 nvFIFO::nvFIFO()
   : mByteCount(0)
   , mTable()
 {
   InitializeStaticHeaders();
 }
 nvFIFO::~nvFIFO()
 {
   Clear();
 }
 void
 nvFIFO::AddElement(const nsCString &name, const nsCString &value)
 {
   mByteCount += name.Length() + value.Length() + 32;
   nvPair *pair = new nvPair(name, value);
   mTable.PushFront(pair);
 }
 void
 nvFIFO::AddElement(const nsCString &name)
 {
   AddElement(name, EmptyCString());
 }
 void
 nvFIFO::RemoveElement()
 {
   nvPair *pair = static_cast<nvPair *>(mTable.Pop());
   if (pair) {
     mByteCount -= pair->Size();
     delete pair;
   }
 }
 uint32_t
 nvFIFO::ByteCount() const
 {
   return mByteCount;
 }
 uint32_t
 nvFIFO::Length() const
 {
   return mTable.GetSize() + gStaticHeaders->GetSize();
 }
 uint32_t
 nvFIFO::VariableLength() const
 {
   return mTable.GetSize();
 }
 void
 nvFIFO::Clear()
 {
   mByteCount = 0;
   while (mTable.GetSize())
     delete static_cast<nvPair *>(mTable.Pop());
 }
 const nvPair *
 nvFIFO::operator[] (int32_t index) const
 {
   if (index >= (mTable.GetSize() + gStaticHeaders->GetSize())) {
     MOZ_ASSERT(false);
     NS_WARNING("nvFIFO Table Out of Range");
     return nullptr;
   }
   if (index >= mTable.GetSize()) {
     return static_cast<nvPair *>(gStaticHeaders->ObjectAt(index - mTable.GetSize()));
   }
   return static_cast<nvPair *>(mTable.ObjectAt(index));
 }
 Http2BaseCompressor::Http2BaseCompressor()
   : mOutput(nullptr)
   , mMaxBuffer(kDefaultMaxBuffer)
 {
 }
 void
 Http2BaseCompressor::ClearHeaderTable()
 {
   uint32_t dynamicCount = mHeaderTable.VariableLength();
   mHeaderTable.Clear();
   for (int32_t i = mReferenceSet.Length() - 1; i >= 0; --i) {
     if (mReferenceSet[i] < dynamicCount) {
       mReferenceSet.RemoveElementAt(i);
     } else {
       mReferenceSet[i] -= dynamicCount;
     }
   }
   for (int32_t i = mAlternateReferenceSet.Length() - 1; i >= 0; --i) {
     if (mAlternateReferenceSet[i] < dynamicCount) {
       mAlternateReferenceSet.RemoveElementAt(i);
     } else {
       mAlternateReferenceSet[i] -= dynamicCount;
     }
   }
 }
 void
 Http2BaseCompressor::UpdateReferenceSet(int32_t delta)
 {
   if (!delta)
     return;
   uint32_t headerTableSize = mHeaderTable.VariableLength();
   uint32_t oldHeaderTableSize = headerTableSize + delta;
   for (int32_t i = mReferenceSet.Length() - 1; i >= 0; --i) {
     uint32_t indexRef = mReferenceSet[i];
     if (indexRef >= headerTableSize) {
       if (indexRef < oldHeaderTableSize) {
         // This one got dropped
         LOG3(("HTTP base compressor reference to index %u removed.\n",
               indexRef));
         mReferenceSet.RemoveElementAt(i);
       } else {
         // This pointed to the static table, need to adjust
         uint32_t newRef = indexRef - delta;
         LOG3(("HTTP base compressor reference to index %u changed to %d (%s)\n",
               mReferenceSet[i], newRef, mHeaderTable[newRef]->mName.get()));
         mReferenceSet[i] = newRef;
       }
     }
   }
   for (int32_t i = mAlternateReferenceSet.Length() - 1; i >= 0; --i) {
     uint32_t indexRef = mAlternateReferenceSet[i];
     if (indexRef >= headerTableSize) {
       if (indexRef < oldHeaderTableSize) {
         // This one got dropped
         LOG3(("HTTP base compressor new reference to index %u removed.\n",
               indexRef));
         mAlternateReferenceSet.RemoveElementAt(i);
       } else {
         // This pointed to the static table, need to adjust
         uint32_t newRef = indexRef - delta;
         LOG3(("HTTP base compressor new reference to index %u changed to %d (%s)\n",
               mAlternateReferenceSet[i], newRef, mHeaderTable[newRef]->mName.get()));
         mAlternateReferenceSet[i] = newRef;
       }
     }
   }
 }
 void
 Http2BaseCompressor::IncrementReferenceSetIndices()
 {
   for (int32_t i = mReferenceSet.Length() - 1; i >= 0; --i) {
     mReferenceSet[i] = mReferenceSet[i] + 1;
   }
   for (int32_t i = mAlternateReferenceSet.Length() - 1; i >= 0; --i) {
     mAlternateReferenceSet[i] = mAlternateReferenceSet[i] + 1;
   }
 }
 nsresult
 Http2Decompressor::DecodeHeaderBlock(const uint8_t *data, uint32_t datalen,
                                      nsACString &output)
 {
   mAlternateReferenceSet.Clear();
   mOffset = 0;
   mData = data;
   mDataLen = datalen;
   mOutput = &output;
   mOutput->Truncate();
   mHeaderStatus.Truncate();
   mHeaderHost.Truncate();
   mHeaderScheme.Truncate();
   mHeaderPath.Truncate();
   mHeaderMethod.Truncate();
   nsresult rv = NS_OK;
   while (NS_SUCCEEDED(rv) && (mOffset < datalen)) {
     if (mData[mOffset] & 0x80) {
       rv = DoIndexed();
     } else if (mData[mOffset] & 0x40) {
       rv = DoLiteralWithoutIndex();
     } else {
       rv = DoLiteralWithIncremental();
     }
   }
   // after processing the input the decompressor comapres the alternate
   // set to the inherited reference set and generates headers for
   // anything implicit in reference - alternate.
   uint32_t setLen = mReferenceSet.Length();
   for (uint32_t index = 0; index < setLen; ++index) {
     if (!mAlternateReferenceSet.Contains(mReferenceSet[index])) {
       LOG3(("HTTP decompressor carryover in reference set with index %u %s %s\n",
             mReferenceSet[index],
             mHeaderTable[mReferenceSet[index]]->mName.get(),
             mHeaderTable[mReferenceSet[index]]->mValue.get()));
       OutputHeader(mReferenceSet[index]);
     }
   }
   mAlternateReferenceSet.Clear();
   return rv;
 }
 nsresult
 Http2Decompressor::DecodeInteger(uint32_t prefixLen, uint32_t &accum)
 {
   accum = 0;
   if (prefixLen) {
     uint32_t mask = (1 << prefixLen) - 1;
     accum = mData[mOffset] & mask;
     ++mOffset;
     if (accum != mask) {
       // the simple case for small values
       return NS_OK;
     }
   }
   uint32_t factor = 1; // 128 ^ 0
   // we need a series of bytes. The high bit signifies if we need another one.
   // The first one is a a factor of 128 ^ 0, the next 128 ^1, the next 128 ^2, ..
   if (mOffset >= mDataLen) {
     NS_WARNING("Ran out of data to decode integer");
     return NS_ERROR_ILLEGAL_VALUE;
   }
   bool chainBit = mData[mOffset] & 0x80;
   accum += (mData[mOffset] & 0x7f) * factor;
   ++mOffset;
   factor = factor * 128;
   while (chainBit) {
     // really big offsets are just trawling for overflows
     if (accum >= 0x800000) {
       NS_WARNING("Decoding integer >= 0x800000");
       return NS_ERROR_ILLEGAL_VALUE;
     }
     if (mOffset >= mDataLen) {
       NS_WARNING("Ran out of data to decode integer");
       return NS_ERROR_ILLEGAL_VALUE;
     }
     chainBit = mData[mOffset] & 0x80;
     accum += (mData[mOffset] & 0x7f) * factor;
     ++mOffset;
     factor = factor * 128;
   }
   return NS_OK;
 }
 nsresult
 Http2Decompressor::OutputHeader(const nsACString &name, const nsACString &value)
 {
     // exclusions
   if (name.Equals(NS_LITERAL_CSTRING("connection")) ||
       name.Equals(NS_LITERAL_CSTRING("host")) ||
       name.Equals(NS_LITERAL_CSTRING("keep-alive")) ||
       name.Equals(NS_LITERAL_CSTRING("proxy-connection")) ||
       name.Equals(NS_LITERAL_CSTRING("te")) ||
       name.Equals(NS_LITERAL_CSTRING("transfer-encoding")) ||
       name.Equals(NS_LITERAL_CSTRING("upgrade")) ||
       name.Equals(("accept-encoding"))) {
     nsCString toLog(name);
     LOG3(("HTTP Decompressor illegal response header found : %s",
           toLog.get()));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   // Look for upper case characters in the name.
   for (const char *cPtr = name.BeginReading();
        cPtr && cPtr < name.EndReading();
        ++cPtr) {
     if (*cPtr <= 'Z' && *cPtr >= 'A') {
       nsCString toLog(name);
       LOG3(("HTTP Decompressor upper case response header found. [%s]\n",
             toLog.get()));
       return NS_ERROR_ILLEGAL_VALUE;
     }
   }
   // Look for CR OR LF in value - could be smuggling Sec 10.3
   // can map to space safely
   for (const char *cPtr = value.BeginReading();
        cPtr && cPtr < value.EndReading();
        ++cPtr) {
     if (*cPtr == '\r' || *cPtr== '\n') {
       char *wPtr = const_cast<char *>(cPtr);
       *wPtr = ' ';
     }
   }
   // Status comes first
   if (name.Equals(NS_LITERAL_CSTRING(":status"))) {
     nsAutoCString status(NS_LITERAL_CSTRING("HTTP/2.0 "));
     status.Append(value);
     status.Append(NS_LITERAL_CSTRING("\r\n"));
     mOutput->Insert(status, 0);
     mHeaderStatus = value;
   } else if (name.Equals(NS_LITERAL_CSTRING(":authority"))) {
     mHeaderHost = value;
   } else if (name.Equals(NS_LITERAL_CSTRING(":scheme"))) {
     mHeaderScheme = value;
   } else if (name.Equals(NS_LITERAL_CSTRING(":path"))) {
     mHeaderPath = value;
   } else if (name.Equals(NS_LITERAL_CSTRING(":method"))) {
     mHeaderMethod = value;
   }
   // http/2 transport level headers shouldn't be gatewayed into http/1
   if(*(name.BeginReading()) == ':') {
     LOG3(("HTTP Decompressor not gatewaying %s into http/1",
           name.BeginReading()));
     return NS_OK;
   }
   mOutput->Append(name);
   mOutput->Append(NS_LITERAL_CSTRING(": "));
   // Special handling for set-cookie according to the spec
   bool isSetCookie = name.Equals(NS_LITERAL_CSTRING("set-cookie"));
   int32_t valueLen = value.Length();
   for (int32_t i = 0; i < valueLen; ++i) {
     if (value[i] == '\0') {
       if (isSetCookie) {
         mOutput->Append(NS_LITERAL_CSTRING("\r\n"));
         mOutput->Append(name);
         mOutput->Append(NS_LITERAL_CSTRING(": "));
       } else {
         mOutput->Append(NS_LITERAL_CSTRING(", "));
       }
     } else {
       mOutput->Append(value[i]);
     }
   }
   mOutput->Append(NS_LITERAL_CSTRING("\r\n"));
   return NS_OK;
 }
 nsresult
 Http2Decompressor::OutputHeader(uint32_t index)
 {
   // bounds check
   if (mHeaderTable.Length() <= index)
     return NS_ERROR_ILLEGAL_VALUE;
   return OutputHeader(mHeaderTable[index]->mName,
                       mHeaderTable[index]->mValue);
 }
 nsresult
 Http2Decompressor::CopyHeaderString(uint32_t index, nsACString &name)
 {
   // bounds check
   if (mHeaderTable.Length() <= index)
     return NS_ERROR_ILLEGAL_VALUE;
   name = mHeaderTable[index]->mName;
   return NS_OK;
 }
 nsresult
 Http2Decompressor::CopyStringFromInput(uint32_t bytes, nsACString &val)
 {
   if (mOffset + bytes > mDataLen)
     return NS_ERROR_ILLEGAL_VALUE;
   val.Assign(reinterpret_cast<const char *>(mData) + mOffset, bytes);
   mOffset += bytes;
   return NS_OK;
 }
 nsresult
 Http2Decompressor::DecodeFinalHuffmanCharacter(HuffmanIncomingTable *table,
                                                uint8_t &c, uint8_t &bitsLeft)
 {
   uint8_t mask = (1 << bitsLeft) - 1;
   uint8_t idx = mData[mOffset - 1] & mask;
   idx <<= (8 - bitsLeft);
   // Don't update bitsLeft yet, because we need to check that value against the
   // number of bits used by our encoding later on. We'll update when we are sure
   // how many bits we've actually used.
   HuffmanIncomingEntry *entry = &(table->mEntries[idx]);
   if (entry->mPtr) {
     // Can't chain to another table when we're all out of bits in the encoding
     LOG3(("DecodeFinalHuffmanCharacter trying to chain when we're out of bits"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   if (bitsLeft < entry->mPrefixLen) {
     // We don't have enough bits to actually make a match, this is some sort of
     // invalid coding
     LOG3(("DecodeFinalHuffmanCharacter does't have enough bits to match"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   // This is a character!
   if (entry->mValue == 256) {
     // EOS
     LOG3(("DecodeFinalHuffmanCharacter actually decoded an EOS"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   c = static_cast<uint8_t>(entry->mValue & 0xFF);
   bitsLeft -= entry->mPrefixLen;
   return NS_OK;
 }
 uint8_t
 Http2Decompressor::ExtractByte(uint8_t bitsLeft, uint32_t &bytesConsumed)
 {
   uint8_t rv;
   if (bitsLeft) {
     // Need to extract bitsLeft bits from the previous byte, and 8 - bitsLeft
     // bits from the current byte
     uint8_t mask = (1 << bitsLeft) - 1;
     rv = (mData[mOffset - 1] & mask) << (8 - bitsLeft);
     rv |= (mData[mOffset] & ~mask) >> bitsLeft;
   } else {
     rv = mData[mOffset];
   }
   // We always update these here, under the assumption that all 8 bits we got
   // here will be used. These may be re-adjusted later in the case that we don't
   // use up all 8 bits of the byte.
   ++mOffset;
   ++bytesConsumed;
   return rv;
 }
 nsresult
 Http2Decompressor::DecodeHuffmanCharacter(HuffmanIncomingTable *table,
                                           uint8_t &c, uint32_t &bytesConsumed,
                                           uint8_t &bitsLeft)
 {
   uint8_t idx = ExtractByte(bitsLeft, bytesConsumed);
   HuffmanIncomingEntry *entry = &(table->mEntries[idx]);
   if (entry->mPtr) {
     if (bytesConsumed >= mDataLen) {
       if (!bitsLeft || (bytesConsumed > mDataLen)) {
         // TODO - does this get me into trouble in the new world?
         // No info left in input to try to consume, we're done
         LOG3(("DecodeHuffmanCharacter all out of bits to consume, can't chain"));
         return NS_ERROR_ILLEGAL_VALUE;
       }
       // We might get lucky here!
       return DecodeFinalHuffmanCharacter(entry->mPtr, c, bitsLeft);
     }
     // We're sorry, Mario, but your princess is in another castle
     return DecodeHuffmanCharacter(entry->mPtr, c, bytesConsumed, bitsLeft);
   }
   if (entry->mValue == 256) {
     LOG3(("DecodeHuffmanCharacter found an actual EOS"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   c = static_cast<uint8_t>(entry->mValue & 0xFF);
   // Need to adjust bitsLeft (and possibly other values) because we may not have
   // consumed all of the bits of the byte we extracted.
   if (entry->mPrefixLen <= bitsLeft) {
     bitsLeft -= entry->mPrefixLen;
     --mOffset;
     --bytesConsumed;
   } else {
     bitsLeft = 8 - (entry->mPrefixLen - bitsLeft);
   }
   MOZ_ASSERT(bitsLeft < 8);
   return NS_OK;
 }
 nsresult
 Http2Decompressor::CopyHuffmanStringFromInput(uint32_t bytes, nsACString &val)
 {
   if (mOffset + bytes > mDataLen) {
     LOG3(("CopyHuffmanStringFromInput not enough data"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   uint32_t bytesRead = 0;
   uint8_t bitsLeft = 0;
   nsAutoCString buf;
   nsresult rv;
   uint8_t c;
   while (bytesRead < bytes) {
     uint32_t bytesConsumed = 0;
     rv = DecodeHuffmanCharacter(&HuffmanIncomingRoot, c, bytesConsumed,
                                 bitsLeft);
     if (NS_FAILED(rv)) {
       LOG3(("CopyHuffmanStringFromInput failed to decode a character"));
       return rv;
     }
     bytesRead += bytesConsumed;
     buf.Append(c);
   }
   if (bytesRead > bytes) {
     LOG3(("CopyHuffmanStringFromInput read more bytes than was allowed!"));
     return NS_ERROR_ILLEGAL_VALUE;
   }
   if (bitsLeft) {
     // The shortest valid code is 4 bits, so we know there can be at most one
     // character left that our loop didn't decode. Check to see if that's the
     // case, and if so, add it to our output.
     rv = DecodeFinalHuffmanCharacter(&HuffmanIncomingRoot, c, bitsLeft);
     if (NS_SUCCEEDED(rv)) {
       buf.Append(c);
     }
   }
   if (bitsLeft) {
     // Any bits left at this point must belong to the EOS symbol, so make sure
     // they make sense (ie, are all ones)
     uint8_t mask = (1 << bitsLeft) - 1;
     uint8_t bits = mData[mOffset - 1] & mask;
     if (bits != mask) {
       LOG3(("CopyHuffmanStringFromInput ran out of data but found possible "
             "non-EOS symbol"));
       return NS_ERROR_ILLEGAL_VALUE;
     }
   }
   val = buf;
   LOG3(("CopyHuffmanStringFromInput decoded a full string!"));
   return NS_OK;
 }
 void
 Http2Decompressor::MakeRoom(uint32_t amount)
 {
   // make room in the header table
   uint32_t removedCount = 0;
   while (mHeaderTable.VariableLength() && ((mHeaderTable.ByteCount() + amount) > mMaxBuffer)) {
     uint32_t index = mHeaderTable.VariableLength() - 1;
     mHeaderTable.RemoveElement();
     ++removedCount;
     LOG3(("HTTP decompressor header table index %u removed for size.\n",
           index));
   }
   // adjust references to header table
   UpdateReferenceSet(removedCount);
 }
 nsresult
 Http2Decompressor::DoIndexed()
 {
   // this starts with a 1 bit pattern
   MOZ_ASSERT(mData[mOffset] & 0x80);
   // Indexed entries toggle the reference set
   // This is a 7 bit prefix
   uint32_t index;
   nsresult rv = DecodeInteger(7, index);
   if (NS_FAILED(rv))
     return rv;
   LOG3(("HTTP decompressor indexed entry %u\n", index));
   if (index == 0) {
     // Index 0 is a special case - it has extra data tacked on the end to
     // determine what kind of change to make to the encoding context.
     //
     if (mData[mOffset] & 0x80) {
       // This means we have to clear out the reference set
       mReferenceSet.Clear();
       mAlternateReferenceSet.Clear();
       ++mOffset;
       return NS_OK;
     }
     // Getting here means we have to adjust the max table size
     uint32_t newMaxSize;
     rv = DecodeInteger(7, newMaxSize);
     if (NS_FAILED(rv))
       return rv;
     return mCompressor->SetMaxBufferSizeInternal(newMaxSize);
   }
   index--; // Internally, we 0-index everything, since this is, y'know, C++
   // Toggle this in the reference set..
   // if its not currently in the reference set then add it and
   // also emit it. If it is currently in the reference set then just
   // remove it from there.
   if (mReferenceSet.RemoveElement(index)) {
     mAlternateReferenceSet.RemoveElement(index);
     return NS_OK;
   }
   rv = OutputHeader(index);
   if (index >= mHeaderTable.VariableLength()) {
     const nvPair *pair = mHeaderTable[index];
     uint32_t room = pair->Size();
     if (room > mMaxBuffer) {
       ClearHeaderTable();
       LOG3(("HTTP decompressor index not referenced due to size %u %s\n",
             room, pair->mName.get()));
       return rv;
     }
     MakeRoom(room);
     mHeaderTable.AddElement(pair->mName, pair->mValue);
     IncrementReferenceSetIndices();
     index = 0;
   }
   mReferenceSet.AppendElement(index);
   mAlternateReferenceSet.AppendElement(index);
   return rv;
 }
 nsresult
 Http2Decompressor::DoLiteralInternal(nsACString &name, nsACString &value)
 {
   // guts of doliteralwithoutindex and doliteralwithincremental
   MOZ_ASSERT(((mData[mOffset] & 0xC0) == 0x40) ||  // withoutindex
              ((mData[mOffset] & 0xC0) == 0x00));   // withincremental
   // first let's get the name
   uint32_t index;
   nsresult rv = DecodeInteger(6, index);
   if (NS_FAILED(rv))
     return rv;
   bool isHuffmanEncoded;
   if (!index) {
     // name is embedded as a literal
     uint32_t nameLen;
     isHuffmanEncoded = mData[mOffset] & (1 << 7);
     rv = DecodeInteger(7, nameLen);
     if (NS_SUCCEEDED(rv)) {
       if (isHuffmanEncoded) {
         rv = CopyHuffmanStringFromInput(nameLen, name);
       } else {
         rv = CopyStringFromInput(nameLen, name);
       }
     }
   } else {
     // name is from headertable
     rv = CopyHeaderString(index - 1, name);
   }
   if (NS_FAILED(rv))
     return rv;
   // now the value
   uint32_t valueLen;
   isHuffmanEncoded = mData[mOffset] & (1 << 7);
   rv = DecodeInteger(7, valueLen);
   if (NS_SUCCEEDED(rv)) {
     if (isHuffmanEncoded) {
       rv = CopyHuffmanStringFromInput(valueLen, value);
     } else {
       rv = CopyStringFromInput(valueLen, value);
     }
   }
   if (NS_FAILED(rv))
     return rv;
   return NS_OK;
 }
 nsresult
 Http2Decompressor::DoLiteralWithoutIndex()
 {
   // this starts with 01 bit pattern
   MOZ_ASSERT((mData[mOffset] & 0xC0) == 0x40);
   // This is not indexed so there is no adjustment to the
   // persistent reference set
   nsAutoCString name, value;
   nsresult rv = DoLiteralInternal(name, value);
   LOG3(("HTTP decompressor literal without index %s %s\n",
         name.get(), value.get()));
   // Output the header now because we don't keep void
   // indicies in the reference set
   if (NS_SUCCEEDED(rv))
     rv = OutputHeader(name, value);
   return rv;
 }
 nsresult
 Http2Decompressor::DoLiteralWithIncremental()
 {
   // this starts with 00 bit pattern
   MOZ_ASSERT((mData[mOffset] & 0xC0) == 0x00);
   nsAutoCString name, value;
   nsresult rv = DoLiteralInternal(name, value);
   if (NS_SUCCEEDED(rv))
     rv = OutputHeader(name, value);
   if (NS_FAILED(rv))
     return rv;
   uint32_t room = nvPair(name, value).Size();
   if (room > mMaxBuffer) {
     ClearHeaderTable();
     LOG3(("HTTP decompressor literal with index not referenced due to size %u %s\n",
           room, name.get()));
     return NS_OK;
   }
   MakeRoom(room);
   // Incremental Indexing implicitly adds a row to the header table.
   // It also adds the new row to the Reference Set
   mHeaderTable.AddElement(name, value);
   IncrementReferenceSetIndices();
   mReferenceSet.AppendElement(0);
   mAlternateReferenceSet.AppendElement(0);
   LOG3(("HTTP decompressor literal with index 0 %s %s\n",
         name.get(), value.get()));
   return NS_OK;
 }
 /////////////////////////////////////////////////////////////////
 nsresult
 Http2Compressor::EncodeHeaderBlock(const nsCString &nvInput,
                                    const nsACString &method, const nsACString &path,
                                    const nsACString &host, const nsACString &scheme,
                                    nsACString &output)
 {
   mAlternateReferenceSet.Clear();
   mImpliedReferenceSet.Clear();
   mOutput = &output;
   output.SetCapacity(1024);
   output.Truncate();
   mParsedContentLength = -1;
   // colon headers first
   ProcessHeader(nvPair(NS_LITERAL_CSTRING(":method"), method));
   ProcessHeader(nvPair(NS_LITERAL_CSTRING(":path"), path));
   ProcessHeader(nvPair(NS_LITERAL_CSTRING(":authority"), host));
   ProcessHeader(nvPair(NS_LITERAL_CSTRING(":scheme"), scheme));
   // now the non colon headers
   const char *beginBuffer = nvInput.BeginReading();
   int32_t crlfIndex = nvInput.Find("\r\n");
   while (true) {
     int32_t startIndex = crlfIndex + 2;
     crlfIndex = nvInput.Find("\r\n", false, startIndex);
     if (crlfIndex == -1)
       break;
     int32_t colonIndex = nvInput.Find(":", false, startIndex,
                                       crlfIndex - startIndex);
     if (colonIndex == -1)
       break;
     nsDependentCSubstring name = Substring(beginBuffer + startIndex,
                                            beginBuffer + colonIndex);
     // all header names are lower case in http/2
     ToLowerCase(name);
     // exclusions
     if (name.Equals("connection") ||
         name.Equals("host") ||
         name.Equals("keep-alive") ||
         name.Equals("proxy-connection") ||
         name.Equals("te") ||
         name.Equals("transfer-encoding") ||
         name.Equals("upgrade") ||
         name.Equals("accept-encoding")) {
       continue;
     }
     // colon headers are for http/2 and this is http/1 input, so that
     // is probably a smuggling attack of some kind
     if(*(name.BeginReading()) == ':') {
       continue;
     }
     int32_t valueIndex = colonIndex + 1;
     // if we have Expect: *100-continue,*" redact the 100-continue
     // as we don't have a good mechanism for clients to make use of it
     // anyhow
     if (name.Equals("expect")) {
       const char *continueHeader =
         nsHttp::FindToken(beginBuffer + valueIndex, "100-continue",
                           HTTP_HEADER_VALUE_SEPS);
       if (continueHeader) {
         char *writableVal = const_cast<char *>(continueHeader);
         memset(writableVal, 0, 12);
         writableVal += 12;
         // this will terminate safely because CRLF EOL has been confirmed
         while ((*writableVal == ' ') || (*writableVal == '\t') ||
                (*writableVal == ',')) {
           *writableVal = ' ';
           ++writableVal;
         }
       }
     }
     while (valueIndex < crlfIndex && beginBuffer[valueIndex] == ' ')
       ++valueIndex;
     nsDependentCSubstring value = Substring(beginBuffer + valueIndex,
                                             beginBuffer + crlfIndex);
     if (name.Equals("content-length")) {
       int64_t len;
       nsCString tmp(value);
       if (nsHttp::ParseInt64(tmp.get(), nullptr, &len))
         mParsedContentLength = len;
     }
     if (name.Equals("cookie")) {
       // cookie crumbling
       bool haveMoreCookies = true;
       int32_t nextCookie = valueIndex;
       while (haveMoreCookies) {
         int32_t semiSpaceIndex = nvInput.Find("; ", false, nextCookie,
                                               crlfIndex - nextCookie);
         if (semiSpaceIndex == -1) {
           haveMoreCookies = false;
           semiSpaceIndex = crlfIndex;
         }
         nsDependentCSubstring cookie = Substring(beginBuffer + nextCookie,
                                                  beginBuffer + semiSpaceIndex);
         ProcessHeader(nvPair(name, cookie));
         nextCookie = semiSpaceIndex + 2;
       }
     } else {
       ProcessHeader(nvPair(name, value));
     }
   }
   // iterate mreference set and if !alternate.contains(old[i])
   // toggle off
   uint32_t setLen = mReferenceSet.Length();
   for (uint32_t index = 0; index < setLen; ++index) {
     if (!mAlternateReferenceSet.Contains(mReferenceSet[index])) {
       DoOutput(kToggleOff, mHeaderTable[mReferenceSet[index]],
                mReferenceSet[index]);
     }
   }
   mReferenceSet = mAlternateReferenceSet;
   mAlternateReferenceSet.Clear();
   mImpliedReferenceSet.Clear();
   mOutput = nullptr;
   return NS_OK;
 }
 void
 Http2Compressor::DoOutput(Http2Compressor::outputCode code,
                           const class nvPair *pair, uint32_t index)
 {
   // start Byte needs to be calculated from the offset after
   // the opcode has been written out in case the output stream
   // buffer gets resized/relocated
   uint32_t offset = mOutput->Length();
   uint8_t *startByte;
   switch (code) {
   case kPlainLiteral:
     LOG3(("HTTP compressor %p noindex literal with name reference %u %s: %s\n",
           this, index, pair->mName.get(), pair->mValue.get()));
     // In this case, the index will have already been adjusted to be 1-based
     // instead of 0-based.
     EncodeInteger(6, index); // 01 2 bit prefix
     startByte = reinterpret_cast<unsigned char *>(mOutput->BeginWriting()) + offset;
     *startByte = (*startByte & 0x3f) | 0x40;
     if (!index) {
       HuffmanAppend(pair->mName);
     }
     HuffmanAppend(pair->mValue);
     break;
   case kIndexedLiteral:
     LOG3(("HTTP compressor %p literal with name reference %u %s: %s\n",
           this, index, pair->mName.get(), pair->mValue.get()));
     // In this case, the index will have already been adjusted to be 1-based
     // instead of 0-based.
     EncodeInteger(6, index); // 00 2 bit prefix
     startByte = reinterpret_cast<unsigned char *>(mOutput->BeginWriting()) + offset;
     *startByte = *startByte & 0x3f;
     if (!index) {
       HuffmanAppend(pair->mName);
     }
     HuffmanAppend(pair->mValue);
     break;
   case kToggleOff:
   case kToggleOn:
     LOG3(("HTTP compressor %p toggle %s index %u %s\n",
           this, (code == kToggleOff) ? "off" : "on",
           index, pair->mName.get()));
     // In this case, we are passed the raw 0-based C index, and need to
     // increment to make it 1-based and comply with the spec
     EncodeInteger(7, index + 1);
     startByte = reinterpret_cast<unsigned char *>(mOutput->BeginWriting()) + offset;
     *startByte = *startByte | 0x80; // 1 1 bit prefix
     break;
   case kNop:
     LOG3(("HTTP compressor %p implied in reference set index %u %s\n",
           this, index, pair->mName.get()));
     break;
   }
 }
 // writes the encoded integer onto the output
 void
 Http2Compressor::EncodeInteger(uint32_t prefixLen, uint32_t val)
 {
   uint32_t mask = (1 << prefixLen) - 1;
   uint8_t tmp;
   if (val < mask) {
     // 1 byte encoding!
     tmp = val;
     mOutput->Append(reinterpret_cast<char *>(&tmp), 1);
     return;
   }
   if (mask) {
     val -= mask;
     tmp = mask;
     mOutput->Append(reinterpret_cast<char *>(&tmp), 1);
   }
   uint32_t q, r;
   do {
     q = val / 128;
     r = val % 128;
     tmp = r;
     if (q)
       tmp |= 0x80; // chain bit
     val = q;
     mOutput->Append(reinterpret_cast<char *>(&tmp), 1);
   } while (q);
 }
 void
 Http2Compressor::ClearHeaderTable()
 {
   uint32_t dynamicCount = mHeaderTable.VariableLength();
   Http2BaseCompressor::ClearHeaderTable();
   for (int32_t i = mImpliedReferenceSet.Length() - 1; i >= 0; --i) {
     if (mImpliedReferenceSet[i] < dynamicCount) {
       mImpliedReferenceSet.RemoveElementAt(i);
     } else {
       mImpliedReferenceSet[i] -= dynamicCount;
     }
   }
 }
 void
 Http2Compressor::UpdateReferenceSet(int32_t delta)
 {
   if (!delta)
     return;
   Http2BaseCompressor::UpdateReferenceSet(delta);
   uint32_t headerTableSize = mHeaderTable.VariableLength();
   uint32_t oldHeaderTableSize = headerTableSize + delta;
   for (int32_t i = mImpliedReferenceSet.Length() - 1; i >= 0; --i) {
     uint32_t indexRef = mImpliedReferenceSet[i];
     if (indexRef >= headerTableSize) {
       if (indexRef < oldHeaderTableSize) {
         // This one got dropped
         LOG3(("HTTP compressor implied reference to index %u removed.\n",
               indexRef));
         mImpliedReferenceSet.RemoveElementAt(i);
       } else {
         // This pointed to the static table, need to adjust
         uint32_t newRef = indexRef - delta;
         LOG3(("HTTP compressor implied reference to index %u changed to %d (%s)\n",
               mImpliedReferenceSet[i], newRef, mHeaderTable[newRef]->mName.get()));
         mImpliedReferenceSet[i] = newRef;
       }
     }
   }
 }
 void
 Http2Compressor::IncrementReferenceSetIndices()
 {
   Http2BaseCompressor::IncrementReferenceSetIndices();
   for (int32_t i = mImpliedReferenceSet.Length() - 1; i >= 0; --i) {
     mImpliedReferenceSet[i] = mImpliedReferenceSet[i] + 1;
   }
 }
 void
 Http2Compressor::MakeRoom(uint32_t amount)
 {
   // make room in the header table
   uint32_t removedCount = 0;
   while (mHeaderTable.VariableLength() && ((mHeaderTable.ByteCount() + amount) > mMaxBuffer)) {
     // if there is a reference to removedCount (~0) in the implied reference set we need,
     // to toggle it off/on so that the implied reference is not lost when the
     // table is trimmed
     uint32_t index = mHeaderTable.VariableLength() - 1;
     if (mImpliedReferenceSet.Contains(index) ) {
       LOG3(("HTTP compressor header table index %u %s about to be "
             "removed for size but has an implied reference. Will Toggle.\n",
             index, mHeaderTable[index]->mName.get()));
       DoOutput(kToggleOff, mHeaderTable[index], index);
       DoOutput(kToggleOn, mHeaderTable[index], index);
     }
     LOG3(("HTTP compressor header table index %u %s removed for size.\n",
           index, mHeaderTable[index]->mName.get()));
     mHeaderTable.RemoveElement();
     ++removedCount;
   }
   // adjust references to header table
   UpdateReferenceSet(removedCount);
 }
 void
 Http2Compressor::HuffmanAppend(const nsCString &value)
 {
   nsAutoCString buf;
   uint8_t bitsLeft = 8;
   uint32_t length = value.Length();
   uint32_t offset;
   uint8_t *startByte;
   for (uint32_t i = 0; i < length; ++i) {
     uint8_t idx = static_cast<uint8_t>(value[i]);
     uint8_t huffLength = HuffmanOutgoing[idx].mLength;
     uint32_t huffValue = HuffmanOutgoing[idx].mValue;
     if (bitsLeft < 8) {
       // Fill in the least significant <bitsLeft> bits of the previous byte
       // first
       uint32_t val;
       if (huffLength >= bitsLeft) {
         val = huffValue & ~((1 << (huffLength - bitsLeft)) - 1);
         val >>= (huffLength - bitsLeft);
       } else {
         val = huffValue << (bitsLeft - huffLength);
       }
       val &= ((1 << bitsLeft) - 1);
       offset = buf.Length() - 1;
       startByte = reinterpret_cast<unsigned char *>(buf.BeginWriting()) + offset;
       *startByte = *startByte | static_cast<uint8_t>(val & 0xFF);
       if (huffLength >= bitsLeft) {
         huffLength -= bitsLeft;
         bitsLeft = 8;
       } else {
         bitsLeft -= huffLength;
         huffLength = 0;
       }
     }
     while (huffLength > 8) {
       uint32_t mask = ~((1 << (huffLength - 8)) - 1);
       uint8_t val = ((huffValue & mask) >> (huffLength - 8)) & 0xFF;
       buf.Append(reinterpret_cast<char *>(&val), 1);
       huffLength -= 8;
     }
     if (huffLength) {
       // Fill in the most significant <huffLength> bits of the next byte
       bitsLeft = 8 - huffLength;
       uint8_t val = (huffValue & ((1 << huffLength) - 1)) << bitsLeft;
       buf.Append(reinterpret_cast<char *>(&val), 1);
     }
   }
   if (bitsLeft != 8) {
     // Pad the last <bitsLeft> bits with ones, which corresponds to the EOS
     // encoding
     uint8_t val = (1 << bitsLeft) - 1;
     offset = buf.Length() - 1;
     startByte = reinterpret_cast<unsigned char *>(buf.BeginWriting()) + offset;
     *startByte = *startByte | val;
   }
   // Now we know how long our encoded string is, we can fill in our length
   uint32_t bufLength = buf.Length();
   offset = mOutput->Length();
   EncodeInteger(7, bufLength);
   startByte = reinterpret_cast<unsigned char *>(mOutput->BeginWriting()) + offset;
   *startByte = *startByte | 0x80;
   // Finally, we can add our REAL data!
   mOutput->Append(buf);
 }
 void
 Http2Compressor::ProcessHeader(const nvPair inputPair)
 {
   uint32_t newSize = inputPair.Size();
   uint32_t headerTableSize = mHeaderTable.Length();
   uint32_t matchedIndex;
   uint32_t nameReference = 0;
   bool match = false;
   for (uint32_t index = 0; index < headerTableSize; ++index) {
     if (mHeaderTable[index]->mName.Equals(inputPair.mName)) {
       nameReference = index + 1;
       if (mHeaderTable[index]->mValue.Equals(inputPair.mValue)) {
         match = true;
         matchedIndex = index;
         break;
       }
     }
   }
   // We need to emit a new literal
   if (!match) {
     if ((newSize > (mMaxBuffer / 2)) || (mMaxBuffer < 128)) {
       DoOutput(kPlainLiteral, &inputPair, nameReference);
       return;
     }
     // make sure to makeroom() first so that any implied items
     // get preserved.
     MakeRoom(newSize);
     DoOutput(kIndexedLiteral, &inputPair, nameReference);
     mHeaderTable.AddElement(inputPair.mName, inputPair.mValue);
     IncrementReferenceSetIndices();
     LOG3(("HTTP compressor %p new literal placed at index 0\n",
           this));
     mAlternateReferenceSet.AppendElement(0);
     return;
   }
   // It is in the reference set. just check to see if it is
   // a duplicate for output purposes
   if (mReferenceSet.Contains(matchedIndex)) {
     if (mAlternateReferenceSet.Contains(matchedIndex)) {
       DoOutput(kToggleOff, &inputPair, matchedIndex);
       DoOutput(kToggleOn, &inputPair, matchedIndex);
     } else {
       DoOutput(kNop, &inputPair, matchedIndex);
       if (!mImpliedReferenceSet.Contains(matchedIndex))
         mImpliedReferenceSet.AppendElement(matchedIndex);
       mAlternateReferenceSet.AppendElement(matchedIndex);
     }
     return;
   }
   // emit an index to add to reference set
   DoOutput(kToggleOn, &inputPair, matchedIndex);
   if (matchedIndex >= mHeaderTable.VariableLength()) {
     MakeRoom(newSize);
     mHeaderTable.AddElement(inputPair.mName, inputPair.mValue);
     IncrementReferenceSetIndices();
     mAlternateReferenceSet.AppendElement(0);
   } else {
     mAlternateReferenceSet.AppendElement(matchedIndex);
   }
   return;
 }
 void
 Http2Compressor::SetMaxBufferSize(uint32_t maxBufferSize)
 {
   mMaxBufferSetting = maxBufferSize;
   SetMaxBufferSizeInternal(maxBufferSize);
 }
 nsresult
 Http2Compressor::SetMaxBufferSizeInternal(uint32_t maxBufferSize)
 {
   if (maxBufferSize > mMaxBufferSetting) {
     return NS_ERROR_ILLEGAL_VALUE;
   }
   uint32_t removedCount = 0;
   LOG3(("Http2Compressor::SetMaxBufferSizeInternal %u called", maxBufferSize));
   while (mHeaderTable.VariableLength() && (mHeaderTable.ByteCount() > maxBufferSize)) {
     mHeaderTable.RemoveElement();
     ++removedCount;
   }
   UpdateReferenceSet(removedCount);
   mMaxBuffer = maxBufferSize;
   return NS_OK;
 }
 } // namespace mozilla::net
 } // namespace mozilla

The Tor Browser / annotate

netwerk/protocol/http/Http2Compression.cpp@deefc01c0e14 (annotated)

netwerk/protocol/http/Http2Compression.cpp