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The Tor Browser
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XzIn.c (8729B)

      1 /* XzIn.c - Xz input
      2 2018-02-02 : Igor Pavlov : Public domain */
      3 
      4 #include "Precomp.h"
      5 
      6 #include <string.h>
      7 
      8 #include "7zCrc.h"
      9 #include "CpuArch.h"
     10 #include "Xz.h"
     11 
     12 /*
     13 #define XZ_FOOTER_SIG_CHECK(p) (memcmp((p), XZ_FOOTER_SIG, XZ_FOOTER_SIG_SIZE) == 0)
     14 */
     15 #define XZ_FOOTER_SIG_CHECK(p) ((p)[0] == XZ_FOOTER_SIG_0 && (p)[1] == XZ_FOOTER_SIG_1)
     16 
     17 
     18 SRes Xz_ReadHeader(CXzStreamFlags *p, ISeqInStream *inStream)
     19 {
     20  Byte sig[XZ_STREAM_HEADER_SIZE];
     21  RINOK(SeqInStream_Read2(inStream, sig, XZ_STREAM_HEADER_SIZE, SZ_ERROR_NO_ARCHIVE));
     22  if (memcmp(sig, XZ_SIG, XZ_SIG_SIZE) != 0)
     23    return SZ_ERROR_NO_ARCHIVE;
     24  return Xz_ParseHeader(p, sig);
     25 }
     26 
     27 #define READ_VARINT_AND_CHECK(buf, pos, size, res) \
     28  { unsigned s = Xz_ReadVarInt(buf + pos, size - pos, res); \
     29  if (s == 0) return SZ_ERROR_ARCHIVE; pos += s; }
     30 
     31 SRes XzBlock_ReadHeader(CXzBlock *p, ISeqInStream *inStream, Bool *isIndex, UInt32 *headerSizeRes)
     32 {
     33  Byte header[XZ_BLOCK_HEADER_SIZE_MAX];
     34  unsigned headerSize;
     35  *headerSizeRes = 0;
     36  RINOK(SeqInStream_ReadByte(inStream, &header[0]));
     37  headerSize = (unsigned)header[0];
     38  if (headerSize == 0)
     39  {
     40    *headerSizeRes = 1;
     41    *isIndex = True;
     42    return SZ_OK;
     43  }
     44 
     45  *isIndex = False;
     46  headerSize = (headerSize << 2) + 4;
     47  *headerSizeRes = headerSize;
     48  RINOK(SeqInStream_Read(inStream, header + 1, headerSize - 1));
     49  return XzBlock_Parse(p, header);
     50 }
     51 
     52 #define ADD_SIZE_CHECK(size, val) \
     53  { UInt64 newSize = size + (val); if (newSize < size) return XZ_SIZE_OVERFLOW; size = newSize; }
     54 
     55 UInt64 Xz_GetUnpackSize(const CXzStream *p)
     56 {
     57  UInt64 size = 0;
     58  size_t i;
     59  for (i = 0; i < p->numBlocks; i++)
     60    ADD_SIZE_CHECK(size, p->blocks[i].unpackSize);
     61  return size;
     62 }
     63 
     64 UInt64 Xz_GetPackSize(const CXzStream *p)
     65 {
     66  UInt64 size = 0;
     67  size_t i;
     68  for (i = 0; i < p->numBlocks; i++)
     69    ADD_SIZE_CHECK(size, (p->blocks[i].totalSize + 3) & ~(UInt64)3);
     70  return size;
     71 }
     72 
     73 /*
     74 SRes XzBlock_ReadFooter(CXzBlock *p, CXzStreamFlags f, ISeqInStream *inStream)
     75 {
     76  return SeqInStream_Read(inStream, p->check, XzFlags_GetCheckSize(f));
     77 }
     78 */
     79 
     80 static SRes Xz_ReadIndex2(CXzStream *p, const Byte *buf, size_t size, ISzAllocPtr alloc)
     81 {
     82  size_t numBlocks, pos = 1;
     83  UInt32 crc;
     84 
     85  if (size < 5 || buf[0] != 0)
     86    return SZ_ERROR_ARCHIVE;
     87 
     88  size -= 4;
     89  crc = CrcCalc(buf, size);
     90  if (crc != GetUi32(buf + size))
     91    return SZ_ERROR_ARCHIVE;
     92 
     93  {
     94    UInt64 numBlocks64;
     95    READ_VARINT_AND_CHECK(buf, pos, size, &numBlocks64);
     96    numBlocks = (size_t)numBlocks64;
     97    if (numBlocks != numBlocks64 || numBlocks * 2 > size)
     98      return SZ_ERROR_ARCHIVE;
     99  }
    100  
    101  Xz_Free(p, alloc);
    102  if (numBlocks != 0)
    103  {
    104    size_t i;
    105    p->numBlocks = numBlocks;
    106    p->blocks = (CXzBlockSizes *)ISzAlloc_Alloc(alloc, sizeof(CXzBlockSizes) * numBlocks);
    107    if (!p->blocks)
    108      return SZ_ERROR_MEM;
    109    for (i = 0; i < numBlocks; i++)
    110    {
    111      CXzBlockSizes *block = &p->blocks[i];
    112      READ_VARINT_AND_CHECK(buf, pos, size, &block->totalSize);
    113      READ_VARINT_AND_CHECK(buf, pos, size, &block->unpackSize);
    114      if (block->totalSize == 0)
    115        return SZ_ERROR_ARCHIVE;
    116    }
    117  }
    118  while ((pos & 3) != 0)
    119    if (buf[pos++] != 0)
    120      return SZ_ERROR_ARCHIVE;
    121  return (pos == size) ? SZ_OK : SZ_ERROR_ARCHIVE;
    122 }
    123 
    124 static SRes Xz_ReadIndex(CXzStream *p, ILookInStream *stream, UInt64 indexSize, ISzAllocPtr alloc)
    125 {
    126  SRes res;
    127  size_t size;
    128  Byte *buf;
    129  if (indexSize > ((UInt32)1 << 31))
    130    return SZ_ERROR_UNSUPPORTED;
    131  size = (size_t)indexSize;
    132  if (size != indexSize)
    133    return SZ_ERROR_UNSUPPORTED;
    134  buf = (Byte *)ISzAlloc_Alloc(alloc, size);
    135  if (!buf)
    136    return SZ_ERROR_MEM;
    137  res = LookInStream_Read2(stream, buf, size, SZ_ERROR_UNSUPPORTED);
    138  if (res == SZ_OK)
    139    res = Xz_ReadIndex2(p, buf, size, alloc);
    140  ISzAlloc_Free(alloc, buf);
    141  return res;
    142 }
    143 
    144 static SRes LookInStream_SeekRead_ForArc(ILookInStream *stream, UInt64 offset, void *buf, size_t size)
    145 {
    146  RINOK(LookInStream_SeekTo(stream, offset));
    147  return LookInStream_Read(stream, buf, size);
    148  /* return LookInStream_Read2(stream, buf, size, SZ_ERROR_NO_ARCHIVE); */
    149 }
    150 
    151 static SRes Xz_ReadBackward(CXzStream *p, ILookInStream *stream, Int64 *startOffset, ISzAllocPtr alloc)
    152 {
    153  UInt64 indexSize;
    154  Byte buf[XZ_STREAM_FOOTER_SIZE];
    155  UInt64 pos = *startOffset;
    156 
    157  if ((pos & 3) != 0 || pos < XZ_STREAM_FOOTER_SIZE)
    158    return SZ_ERROR_NO_ARCHIVE;
    159 
    160  pos -= XZ_STREAM_FOOTER_SIZE;
    161  RINOK(LookInStream_SeekRead_ForArc(stream, pos, buf, XZ_STREAM_FOOTER_SIZE));
    162  
    163  if (!XZ_FOOTER_SIG_CHECK(buf + 10))
    164  {
    165    UInt32 total = 0;
    166    pos += XZ_STREAM_FOOTER_SIZE;
    167    
    168    for (;;)
    169    {
    170      size_t i;
    171      #define TEMP_BUF_SIZE (1 << 10)
    172      Byte temp[TEMP_BUF_SIZE];
    173      
    174      i = (pos > TEMP_BUF_SIZE) ? TEMP_BUF_SIZE : (size_t)pos;
    175      pos -= i;
    176      RINOK(LookInStream_SeekRead_ForArc(stream, pos, temp, i));
    177      total += (UInt32)i;
    178      for (; i != 0; i--)
    179        if (temp[i - 1] != 0)
    180          break;
    181      if (i != 0)
    182      {
    183        if ((i & 3) != 0)
    184          return SZ_ERROR_NO_ARCHIVE;
    185        pos += i;
    186        break;
    187      }
    188      if (pos < XZ_STREAM_FOOTER_SIZE || total > (1 << 16))
    189        return SZ_ERROR_NO_ARCHIVE;
    190    }
    191    
    192    if (pos < XZ_STREAM_FOOTER_SIZE)
    193      return SZ_ERROR_NO_ARCHIVE;
    194    pos -= XZ_STREAM_FOOTER_SIZE;
    195    RINOK(LookInStream_SeekRead_ForArc(stream, pos, buf, XZ_STREAM_FOOTER_SIZE));
    196    if (!XZ_FOOTER_SIG_CHECK(buf + 10))
    197      return SZ_ERROR_NO_ARCHIVE;
    198  }
    199  
    200  p->flags = (CXzStreamFlags)GetBe16(buf + 8);
    201 
    202  if (!XzFlags_IsSupported(p->flags))
    203    return SZ_ERROR_UNSUPPORTED;
    204 
    205  if (GetUi32(buf) != CrcCalc(buf + 4, 6))
    206    return SZ_ERROR_ARCHIVE;
    207 
    208  indexSize = ((UInt64)GetUi32(buf + 4) + 1) << 2;
    209 
    210  if (pos < indexSize)
    211    return SZ_ERROR_ARCHIVE;
    212 
    213  pos -= indexSize;
    214  RINOK(LookInStream_SeekTo(stream, pos));
    215  RINOK(Xz_ReadIndex(p, stream, indexSize, alloc));
    216 
    217  {
    218    UInt64 totalSize = Xz_GetPackSize(p);
    219    if (totalSize == XZ_SIZE_OVERFLOW
    220        || totalSize >= ((UInt64)1 << 63)
    221        || pos < totalSize + XZ_STREAM_HEADER_SIZE)
    222      return SZ_ERROR_ARCHIVE;
    223    pos -= (totalSize + XZ_STREAM_HEADER_SIZE);
    224    RINOK(LookInStream_SeekTo(stream, pos));
    225    *startOffset = pos;
    226  }
    227  {
    228    CXzStreamFlags headerFlags;
    229    CSecToRead secToRead;
    230    SecToRead_CreateVTable(&secToRead);
    231    secToRead.realStream = stream;
    232 
    233    RINOK(Xz_ReadHeader(&headerFlags, &secToRead.vt));
    234    return (p->flags == headerFlags) ? SZ_OK : SZ_ERROR_ARCHIVE;
    235  }
    236 }
    237 
    238 
    239 /* ---------- Xz Streams ---------- */
    240 
    241 void Xzs_Construct(CXzs *p)
    242 {
    243  p->num = p->numAllocated = 0;
    244  p->streams = 0;
    245 }
    246 
    247 void Xzs_Free(CXzs *p, ISzAllocPtr alloc)
    248 {
    249  size_t i;
    250  for (i = 0; i < p->num; i++)
    251    Xz_Free(&p->streams[i], alloc);
    252  ISzAlloc_Free(alloc, p->streams);
    253  p->num = p->numAllocated = 0;
    254  p->streams = 0;
    255 }
    256 
    257 UInt64 Xzs_GetNumBlocks(const CXzs *p)
    258 {
    259  UInt64 num = 0;
    260  size_t i;
    261  for (i = 0; i < p->num; i++)
    262    num += p->streams[i].numBlocks;
    263  return num;
    264 }
    265 
    266 UInt64 Xzs_GetUnpackSize(const CXzs *p)
    267 {
    268  UInt64 size = 0;
    269  size_t i;
    270  for (i = 0; i < p->num; i++)
    271    ADD_SIZE_CHECK(size, Xz_GetUnpackSize(&p->streams[i]));
    272  return size;
    273 }
    274 
    275 /*
    276 UInt64 Xzs_GetPackSize(const CXzs *p)
    277 {
    278  UInt64 size = 0;
    279  size_t i;
    280  for (i = 0; i < p->num; i++)
    281    ADD_SIZE_CHECK(size, Xz_GetTotalSize(&p->streams[i]));
    282  return size;
    283 }
    284 */
    285 
    286 SRes Xzs_ReadBackward(CXzs *p, ILookInStream *stream, Int64 *startOffset, ICompressProgress *progress, ISzAllocPtr alloc)
    287 {
    288  Int64 endOffset = 0;
    289  RINOK(ILookInStream_Seek(stream, &endOffset, SZ_SEEK_END));
    290  *startOffset = endOffset;
    291  for (;;)
    292  {
    293    CXzStream st;
    294    SRes res;
    295    Xz_Construct(&st);
    296    res = Xz_ReadBackward(&st, stream, startOffset, alloc);
    297    st.startOffset = *startOffset;
    298    RINOK(res);
    299    if (p->num == p->numAllocated)
    300    {
    301      size_t newNum = p->num + p->num / 4 + 1;
    302      Byte *data = (Byte *)ISzAlloc_Alloc(alloc, newNum * sizeof(CXzStream));
    303      if (!data)
    304        return SZ_ERROR_MEM;
    305      p->numAllocated = newNum;
    306      if (p->num != 0)
    307        memcpy(data, p->streams, p->num * sizeof(CXzStream));
    308      ISzAlloc_Free(alloc, p->streams);
    309      p->streams = (CXzStream *)data;
    310    }
    311    p->streams[p->num++] = st;
    312    if (*startOffset == 0)
    313      break;
    314    RINOK(LookInStream_SeekTo(stream, *startOffset));
    315    if (progress && ICompressProgress_Progress(progress, endOffset - *startOffset, (UInt64)(Int64)-1) != SZ_OK)
    316      return SZ_ERROR_PROGRESS;
    317  }
    318  return SZ_OK;
    319 }