1 /* XzIn.c - Xz input
2 2021-09-04 : 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; \
30 pos += s; }
31
XzBlock_ReadHeader(CXzBlock * p,ISeqInStream * inStream,BoolInt * isIndex,UInt32 * headerSizeRes)32 SRes XzBlock_ReadHeader(CXzBlock *p, ISeqInStream *inStream, BoolInt *isIndex, UInt32 *headerSizeRes)
33 {
34 Byte header[XZ_BLOCK_HEADER_SIZE_MAX];
35 unsigned headerSize;
36 *headerSizeRes = 0;
37 RINOK(SeqInStream_ReadByte(inStream, &header[0]));
38 headerSize = (unsigned)header[0];
39 if (headerSize == 0)
40 {
41 *headerSizeRes = 1;
42 *isIndex = True;
43 return SZ_OK;
44 }
45
46 *isIndex = False;
47 headerSize = (headerSize << 2) + 4;
48 *headerSizeRes = headerSize;
49 RINOK(SeqInStream_Read(inStream, header + 1, headerSize - 1));
50 return XzBlock_Parse(p, header);
51 }
52
53 #define ADD_SIZE_CHECK(size, val) \
54 { UInt64 newSize = size + (val); if (newSize < size) return XZ_SIZE_OVERFLOW; size = newSize; }
55
Xz_GetUnpackSize(const CXzStream * p)56 UInt64 Xz_GetUnpackSize(const CXzStream *p)
57 {
58 UInt64 size = 0;
59 size_t i;
60 for (i = 0; i < p->numBlocks; i++)
61 ADD_SIZE_CHECK(size, p->blocks[i].unpackSize);
62 return size;
63 }
64
Xz_GetPackSize(const CXzStream * p)65 UInt64 Xz_GetPackSize(const CXzStream *p)
66 {
67 UInt64 size = 0;
68 size_t i;
69 for (i = 0; i < p->numBlocks; i++)
70 ADD_SIZE_CHECK(size, (p->blocks[i].totalSize + 3) & ~(UInt64)3);
71 return size;
72 }
73
74 /*
75 SRes XzBlock_ReadFooter(CXzBlock *p, CXzStreamFlags f, ISeqInStream *inStream)
76 {
77 return SeqInStream_Read(inStream, p->check, XzFlags_GetCheckSize(f));
78 }
79 */
80
Xz_ReadIndex2(CXzStream * p,const Byte * buf,size_t size,ISzAllocPtr alloc)81 static SRes Xz_ReadIndex2(CXzStream *p, const Byte *buf, size_t size, ISzAllocPtr alloc)
82 {
83 size_t numBlocks, pos = 1;
84 UInt32 crc;
85
86 if (size < 5 || buf[0] != 0)
87 return SZ_ERROR_ARCHIVE;
88
89 size -= 4;
90 crc = CrcCalc(buf, size);
91 if (crc != GetUi32(buf + size))
92 return SZ_ERROR_ARCHIVE;
93
94 {
95 UInt64 numBlocks64;
96 READ_VARINT_AND_CHECK(buf, pos, size, &numBlocks64);
97 numBlocks = (size_t)numBlocks64;
98 if (numBlocks != numBlocks64 || numBlocks * 2 > size)
99 return SZ_ERROR_ARCHIVE;
100 }
101
102 Xz_Free(p, alloc);
103 if (numBlocks != 0)
104 {
105 size_t i;
106 p->numBlocks = numBlocks;
107 p->blocks = (CXzBlockSizes *)ISzAlloc_Alloc(alloc, sizeof(CXzBlockSizes) * numBlocks);
108 if (!p->blocks)
109 return SZ_ERROR_MEM;
110 for (i = 0; i < numBlocks; i++)
111 {
112 CXzBlockSizes *block = &p->blocks[i];
113 READ_VARINT_AND_CHECK(buf, pos, size, &block->totalSize);
114 READ_VARINT_AND_CHECK(buf, pos, size, &block->unpackSize);
115 if (block->totalSize == 0)
116 return SZ_ERROR_ARCHIVE;
117 }
118 }
119 while ((pos & 3) != 0)
120 if (buf[pos++] != 0)
121 return SZ_ERROR_ARCHIVE;
122 return (pos == size) ? SZ_OK : SZ_ERROR_ARCHIVE;
123 }
124
Xz_ReadIndex(CXzStream * p,ILookInStream * stream,UInt64 indexSize,ISzAllocPtr alloc)125 static SRes Xz_ReadIndex(CXzStream *p, ILookInStream *stream, UInt64 indexSize, ISzAllocPtr alloc)
126 {
127 SRes res;
128 size_t size;
129 Byte *buf;
130 if (indexSize > ((UInt32)1 << 31))
131 return SZ_ERROR_UNSUPPORTED;
132 size = (size_t)indexSize;
133 if (size != indexSize)
134 return SZ_ERROR_UNSUPPORTED;
135 buf = (Byte *)ISzAlloc_Alloc(alloc, size);
136 if (!buf)
137 return SZ_ERROR_MEM;
138 res = LookInStream_Read2(stream, buf, size, SZ_ERROR_UNSUPPORTED);
139 if (res == SZ_OK)
140 res = Xz_ReadIndex2(p, buf, size, alloc);
141 ISzAlloc_Free(alloc, buf);
142 return res;
143 }
144
LookInStream_SeekRead_ForArc(ILookInStream * stream,UInt64 offset,void * buf,size_t size)145 static SRes LookInStream_SeekRead_ForArc(ILookInStream *stream, UInt64 offset, void *buf, size_t size)
146 {
147 RINOK(LookInStream_SeekTo(stream, offset));
148 return LookInStream_Read(stream, buf, size);
149 /* return LookInStream_Read2(stream, buf, size, SZ_ERROR_NO_ARCHIVE); */
150 }
151
Xz_ReadBackward(CXzStream * p,ILookInStream * stream,Int64 * startOffset,ISzAllocPtr alloc)152 static SRes Xz_ReadBackward(CXzStream *p, ILookInStream *stream, Int64 *startOffset, ISzAllocPtr alloc)
153 {
154 UInt64 indexSize;
155 Byte buf[XZ_STREAM_FOOTER_SIZE];
156 UInt64 pos = (UInt64)*startOffset;
157
158 if ((pos & 3) != 0 || pos < XZ_STREAM_FOOTER_SIZE)
159 return SZ_ERROR_NO_ARCHIVE;
160
161 pos -= XZ_STREAM_FOOTER_SIZE;
162 RINOK(LookInStream_SeekRead_ForArc(stream, pos, buf, XZ_STREAM_FOOTER_SIZE));
163
164 if (!XZ_FOOTER_SIG_CHECK(buf + 10))
165 {
166 UInt32 total = 0;
167 pos += XZ_STREAM_FOOTER_SIZE;
168
169 for (;;)
170 {
171 size_t i;
172 #define TEMP_BUF_SIZE (1 << 10)
173 Byte temp[TEMP_BUF_SIZE];
174
175 i = (pos > TEMP_BUF_SIZE) ? TEMP_BUF_SIZE : (size_t)pos;
176 pos -= i;
177 RINOK(LookInStream_SeekRead_ForArc(stream, pos, temp, i));
178 total += (UInt32)i;
179 for (; i != 0; i--)
180 if (temp[i - 1] != 0)
181 break;
182 if (i != 0)
183 {
184 if ((i & 3) != 0)
185 return SZ_ERROR_NO_ARCHIVE;
186 pos += i;
187 break;
188 }
189 if (pos < XZ_STREAM_FOOTER_SIZE || total > (1 << 16))
190 return SZ_ERROR_NO_ARCHIVE;
191 }
192
193 if (pos < XZ_STREAM_FOOTER_SIZE)
194 return SZ_ERROR_NO_ARCHIVE;
195 pos -= XZ_STREAM_FOOTER_SIZE;
196 RINOK(LookInStream_SeekRead_ForArc(stream, pos, buf, XZ_STREAM_FOOTER_SIZE));
197 if (!XZ_FOOTER_SIG_CHECK(buf + 10))
198 return SZ_ERROR_NO_ARCHIVE;
199 }
200
201 p->flags = (CXzStreamFlags)GetBe16(buf + 8);
202
203 if (!XzFlags_IsSupported(p->flags))
204 return SZ_ERROR_UNSUPPORTED;
205
206 {
207 /* to eliminate GCC 6.3 warning:
208 dereferencing type-punned pointer will break strict-aliasing rules */
209 const Byte *buf_ptr = buf;
210 if (GetUi32(buf_ptr) != CrcCalc(buf + 4, 6))
211 return SZ_ERROR_ARCHIVE;
212 }
213
214 indexSize = ((UInt64)GetUi32(buf + 4) + 1) << 2;
215
216 if (pos < indexSize)
217 return SZ_ERROR_ARCHIVE;
218
219 pos -= indexSize;
220 RINOK(LookInStream_SeekTo(stream, pos));
221 RINOK(Xz_ReadIndex(p, stream, indexSize, alloc));
222
223 {
224 UInt64 totalSize = Xz_GetPackSize(p);
225 if (totalSize == XZ_SIZE_OVERFLOW
226 || totalSize >= ((UInt64)1 << 63)
227 || pos < totalSize + XZ_STREAM_HEADER_SIZE)
228 return SZ_ERROR_ARCHIVE;
229 pos -= (totalSize + XZ_STREAM_HEADER_SIZE);
230 RINOK(LookInStream_SeekTo(stream, pos));
231 *startOffset = (Int64)pos;
232 }
233 {
234 CXzStreamFlags headerFlags;
235 CSecToRead secToRead;
236 SecToRead_CreateVTable(&secToRead);
237 secToRead.realStream = stream;
238
239 RINOK(Xz_ReadHeader(&headerFlags, &secToRead.vt));
240 return (p->flags == headerFlags) ? SZ_OK : SZ_ERROR_ARCHIVE;
241 }
242 }
243
244
245 /* ---------- Xz Streams ---------- */
246
Xzs_Construct(CXzs * p)247 void Xzs_Construct(CXzs *p)
248 {
249 p->num = p->numAllocated = 0;
250 p->streams = 0;
251 }
252
Xzs_Free(CXzs * p,ISzAllocPtr alloc)253 void Xzs_Free(CXzs *p, ISzAllocPtr alloc)
254 {
255 size_t i;
256 for (i = 0; i < p->num; i++)
257 Xz_Free(&p->streams[i], alloc);
258 ISzAlloc_Free(alloc, p->streams);
259 p->num = p->numAllocated = 0;
260 p->streams = 0;
261 }
262
Xzs_GetNumBlocks(const CXzs * p)263 UInt64 Xzs_GetNumBlocks(const CXzs *p)
264 {
265 UInt64 num = 0;
266 size_t i;
267 for (i = 0; i < p->num; i++)
268 num += p->streams[i].numBlocks;
269 return num;
270 }
271
Xzs_GetUnpackSize(const CXzs * p)272 UInt64 Xzs_GetUnpackSize(const CXzs *p)
273 {
274 UInt64 size = 0;
275 size_t i;
276 for (i = 0; i < p->num; i++)
277 ADD_SIZE_CHECK(size, Xz_GetUnpackSize(&p->streams[i]));
278 return size;
279 }
280
281 /*
282 UInt64 Xzs_GetPackSize(const CXzs *p)
283 {
284 UInt64 size = 0;
285 size_t i;
286 for (i = 0; i < p->num; i++)
287 ADD_SIZE_CHECK(size, Xz_GetTotalSize(&p->streams[i]));
288 return size;
289 }
290 */
291
Xzs_ReadBackward(CXzs * p,ILookInStream * stream,Int64 * startOffset,ICompressProgress * progress,ISzAllocPtr alloc)292 SRes Xzs_ReadBackward(CXzs *p, ILookInStream *stream, Int64 *startOffset, ICompressProgress *progress, ISzAllocPtr alloc)
293 {
294 Int64 endOffset = 0;
295 RINOK(ILookInStream_Seek(stream, &endOffset, SZ_SEEK_END));
296 *startOffset = endOffset;
297 for (;;)
298 {
299 CXzStream st;
300 SRes res;
301 Xz_Construct(&st);
302 res = Xz_ReadBackward(&st, stream, startOffset, alloc);
303 st.startOffset = (UInt64)*startOffset;
304 RINOK(res);
305 if (p->num == p->numAllocated)
306 {
307 const size_t newNum = p->num + p->num / 4 + 1;
308 void *data = ISzAlloc_Alloc(alloc, newNum * sizeof(CXzStream));
309 if (!data)
310 return SZ_ERROR_MEM;
311 p->numAllocated = newNum;
312 if (p->num != 0)
313 memcpy(data, p->streams, p->num * sizeof(CXzStream));
314 ISzAlloc_Free(alloc, p->streams);
315 p->streams = (CXzStream *)data;
316 }
317 p->streams[p->num++] = st;
318 if (*startOffset == 0)
319 break;
320 RINOK(LookInStream_SeekTo(stream, (UInt64)*startOffset));
321 if (progress && ICompressProgress_Progress(progress, (UInt64)(endOffset - *startOffset), (UInt64)(Int64)-1) != SZ_OK)
322 return SZ_ERROR_PROGRESS;
323 }
324 return SZ_OK;
325 }
326