1 /* XzIn.c - Xz input
2 2018-07-04 : 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 
Xz_ReadHeader(CXzStreamFlags * p,ISeqInStream * inStream)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 
XzBlock_ReadHeader(CXzBlock * p,ISeqInStream * inStream,BoolInt * isIndex,UInt32 * headerSizeRes)31 SRes XzBlock_ReadHeader(CXzBlock *p, ISeqInStream *inStream, BoolInt *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 
Xz_GetUnpackSize(const CXzStream * p)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 
Xz_GetPackSize(const CXzStream * p)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 
Xz_ReadIndex2(CXzStream * p,const Byte * buf,size_t size,ISzAllocPtr alloc)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 
Xz_ReadIndex(CXzStream * p,ILookInStream * stream,UInt64 indexSize,ISzAllocPtr alloc)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 
LookInStream_SeekRead_ForArc(ILookInStream * stream,UInt64 offset,void * buf,size_t size)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 
Xz_ReadBackward(CXzStream * p,ILookInStream * stream,Int64 * startOffset,ISzAllocPtr alloc)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 
Xzs_Construct(CXzs * p)241 void Xzs_Construct(CXzs *p)
242 {
243   p->num = p->numAllocated = 0;
244   p->streams = 0;
245 }
246 
Xzs_Free(CXzs * p,ISzAllocPtr alloc)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 
Xzs_GetNumBlocks(const CXzs * p)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 
Xzs_GetUnpackSize(const CXzs * p)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 
Xzs_ReadBackward(CXzs * p,ILookInStream * stream,Int64 * startOffset,ICompressProgress * progress,ISzAllocPtr alloc)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 }
320