tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

SinfParser.cpp (2549B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 #include "SinfParser.h"
      6 
      7 #include "AtomType.h"
      8 #include "Box.h"
      9 #include "ByteStream.h"
     10 #include "mozilla/Try.h"
     11 
     12 namespace mozilla {
     13 
     14 Sinf::Sinf(const Box& aBox) : mDefaultIVSize(0) {
     15  SinfParser parser(aBox);
     16  if (parser.GetSinf().IsValid()) {
     17    *this = parser.GetSinf();
     18  }
     19 }
     20 
     21 SinfParser::SinfParser(const Box& aBox) {
     22  for (Box box = aBox.FirstChild(); box.IsAvailable(); box = box.Next()) {
     23    if (box.IsType("schm")) {
     24      (void)ParseSchm(box);
     25    } else if (box.IsType("schi")) {
     26      (void)ParseSchi(box);
     27    }
     28  }
     29 }
     30 
     31 Result<Ok, nsresult> SinfParser::ParseSchm(const Box& aBox) {
     32  BoxReader reader(aBox);
     33 
     34  if (reader->Remaining() < 8) {
     35    return Err(NS_ERROR_FAILURE);
     36  }
     37 
     38  MOZ_TRY(reader->ReadU32());  // flags -- ignore
     39  mSinf.mDefaultEncryptionType = MOZ_TRY(reader->ReadU32());
     40  return Ok();
     41 }
     42 
     43 Result<Ok, nsresult> SinfParser::ParseSchi(const Box& aBox) {
     44  for (Box box = aBox.FirstChild(); box.IsAvailable(); box = box.Next()) {
     45    if (box.IsType("tenc") && ParseTenc(box).isErr()) {
     46      return Err(NS_ERROR_FAILURE);
     47    }
     48  }
     49  return Ok();
     50 }
     51 
     52 Result<Ok, nsresult> SinfParser::ParseTenc(const Box& aBox) {
     53  BoxReader reader(aBox);
     54 
     55  if (reader->Remaining() < 24) {
     56    return Err(NS_ERROR_FAILURE);
     57  }
     58 
     59  uint32_t flags = MOZ_TRY(reader->ReadU32());
     60  uint8_t version = flags >> 24;
     61 
     62  // Skip reserved byte
     63  MOZ_TRY(reader->ReadU8());
     64  if (version >= 1) {
     65    uint8_t pattern = MOZ_TRY(reader->ReadU8());
     66    mSinf.mDefaultCryptByteBlock = pattern >> 4;
     67    mSinf.mDefaultSkipByteBlock = pattern & 0x0f;
     68  } else {
     69    // Reserved if version is less than 1
     70    MOZ_TRY(reader->ReadU8());
     71    mSinf.mDefaultCryptByteBlock = 0;
     72    mSinf.mDefaultSkipByteBlock = 0;
     73  }
     74 
     75  uint8_t isEncrypted = MOZ_TRY(reader->ReadU8());
     76  mSinf.mDefaultIVSize = MOZ_TRY(reader->ReadU8());
     77  memcpy(mSinf.mDefaultKeyID, reader->Read(16), 16);
     78 
     79  if (isEncrypted && mSinf.mDefaultIVSize == 0) {
     80    uint8_t defaultConstantIVSize = MOZ_TRY(reader->ReadU8());
     81    if (!mSinf.mDefaultConstantIV.SetLength(defaultConstantIVSize,
     82                                            mozilla::fallible)) {
     83      return Err(NS_ERROR_FAILURE);
     84    }
     85    for (uint8_t i = 0; i < defaultConstantIVSize; i++) {
     86      mSinf.mDefaultConstantIV.ElementAt(i) = MOZ_TRY(reader->ReadU8());
     87    }
     88  }
     89  return Ok();
     90 }
     91 
     92 }  // namespace mozilla