1 /*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 // See imgdiff.c in this directory for a description of the patch file
18 // format.
19
20 #include <stdio.h>
21 #include <sys/cdefs.h>
22 #include <sys/stat.h>
23 #include <errno.h>
24 #include <unistd.h>
25 #include <string.h>
26
27 #include <vector>
28
29 #include "zlib.h"
30 #include "openssl/sha.h"
31 #include "applypatch.h"
32 #include "imgdiff.h"
33 #include "utils.h"
34
ApplyImagePatch(const unsigned char * old_data,ssize_t old_size,const unsigned char * patch_data,ssize_t patch_size,SinkFn sink,void * token)35 int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
36 const unsigned char* patch_data, ssize_t patch_size,
37 SinkFn sink, void* token) {
38 Value patch = {VAL_BLOB, patch_size,
39 reinterpret_cast<char*>(const_cast<unsigned char*>(patch_data))};
40 return ApplyImagePatch(
41 old_data, old_size, &patch, sink, token, nullptr, nullptr);
42 }
43
44 /*
45 * Apply the patch given in 'patch_filename' to the source data given
46 * by (old_data, old_size). Write the patched output to the 'output'
47 * file, and update the SHA context with the output data as well.
48 * Return 0 on success.
49 */
ApplyImagePatch(const unsigned char * old_data,ssize_t old_size,const Value * patch,SinkFn sink,void * token,SHA_CTX * ctx,const Value * bonus_data)50 int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
51 const Value* patch,
52 SinkFn sink, void* token, SHA_CTX* ctx,
53 const Value* bonus_data) {
54 ssize_t pos = 12;
55 char* header = patch->data;
56 if (patch->size < 12) {
57 printf("patch too short to contain header\n");
58 return -1;
59 }
60
61 // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW.
62 // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and
63 // CHUNK_GZIP.)
64 if (memcmp(header, "IMGDIFF2", 8) != 0) {
65 printf("corrupt patch file header (magic number)\n");
66 return -1;
67 }
68
69 int num_chunks = Read4(header+8);
70
71 int i;
72 for (i = 0; i < num_chunks; ++i) {
73 // each chunk's header record starts with 4 bytes.
74 if (pos + 4 > patch->size) {
75 printf("failed to read chunk %d record\n", i);
76 return -1;
77 }
78 int type = Read4(patch->data + pos);
79 pos += 4;
80
81 if (type == CHUNK_NORMAL) {
82 char* normal_header = patch->data + pos;
83 pos += 24;
84 if (pos > patch->size) {
85 printf("failed to read chunk %d normal header data\n", i);
86 return -1;
87 }
88
89 size_t src_start = Read8(normal_header);
90 size_t src_len = Read8(normal_header+8);
91 size_t patch_offset = Read8(normal_header+16);
92
93 if (src_start + src_len > static_cast<size_t>(old_size)) {
94 printf("source data too short\n");
95 return -1;
96 }
97 ApplyBSDiffPatch(old_data + src_start, src_len,
98 patch, patch_offset, sink, token, ctx);
99 } else if (type == CHUNK_RAW) {
100 char* raw_header = patch->data + pos;
101 pos += 4;
102 if (pos > patch->size) {
103 printf("failed to read chunk %d raw header data\n", i);
104 return -1;
105 }
106
107 ssize_t data_len = Read4(raw_header);
108
109 if (pos + data_len > patch->size) {
110 printf("failed to read chunk %d raw data\n", i);
111 return -1;
112 }
113 if (ctx) SHA1_Update(ctx, patch->data + pos, data_len);
114 if (sink((unsigned char*)patch->data + pos,
115 data_len, token) != data_len) {
116 printf("failed to write chunk %d raw data\n", i);
117 return -1;
118 }
119 pos += data_len;
120 } else if (type == CHUNK_DEFLATE) {
121 // deflate chunks have an additional 60 bytes in their chunk header.
122 char* deflate_header = patch->data + pos;
123 pos += 60;
124 if (pos > patch->size) {
125 printf("failed to read chunk %d deflate header data\n", i);
126 return -1;
127 }
128
129 size_t src_start = Read8(deflate_header);
130 size_t src_len = Read8(deflate_header+8);
131 size_t patch_offset = Read8(deflate_header+16);
132 size_t expanded_len = Read8(deflate_header+24);
133 int level = Read4(deflate_header+40);
134 int method = Read4(deflate_header+44);
135 int windowBits = Read4(deflate_header+48);
136 int memLevel = Read4(deflate_header+52);
137 int strategy = Read4(deflate_header+56);
138
139 if (src_start + src_len > static_cast<size_t>(old_size)) {
140 printf("source data too short\n");
141 return -1;
142 }
143
144 // Decompress the source data; the chunk header tells us exactly
145 // how big we expect it to be when decompressed.
146
147 // Note: expanded_len will include the bonus data size if
148 // the patch was constructed with bonus data. The
149 // deflation will come up 'bonus_size' bytes short; these
150 // must be appended from the bonus_data value.
151 size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0;
152
153 std::vector<unsigned char> expanded_source(expanded_len);
154
155 // inflate() doesn't like strm.next_out being a nullptr even with
156 // avail_out being zero (Z_STREAM_ERROR).
157 if (expanded_len != 0) {
158 z_stream strm;
159 strm.zalloc = Z_NULL;
160 strm.zfree = Z_NULL;
161 strm.opaque = Z_NULL;
162 strm.avail_in = src_len;
163 strm.next_in = (unsigned char*)(old_data + src_start);
164 strm.avail_out = expanded_len;
165 strm.next_out = expanded_source.data();
166
167 int ret;
168 ret = inflateInit2(&strm, -15);
169 if (ret != Z_OK) {
170 printf("failed to init source inflation: %d\n", ret);
171 return -1;
172 }
173
174 // Because we've provided enough room to accommodate the output
175 // data, we expect one call to inflate() to suffice.
176 ret = inflate(&strm, Z_SYNC_FLUSH);
177 if (ret != Z_STREAM_END) {
178 printf("source inflation returned %d\n", ret);
179 return -1;
180 }
181 // We should have filled the output buffer exactly, except
182 // for the bonus_size.
183 if (strm.avail_out != bonus_size) {
184 printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size);
185 return -1;
186 }
187 inflateEnd(&strm);
188
189 if (bonus_size) {
190 memcpy(expanded_source.data() + (expanded_len - bonus_size),
191 bonus_data->data, bonus_size);
192 }
193 }
194
195 // Next, apply the bsdiff patch (in memory) to the uncompressed
196 // data.
197 std::vector<unsigned char> uncompressed_target_data;
198 if (ApplyBSDiffPatchMem(expanded_source.data(), expanded_len,
199 patch, patch_offset,
200 &uncompressed_target_data) != 0) {
201 return -1;
202 }
203
204 // Now compress the target data and append it to the output.
205
206 // we're done with the expanded_source data buffer, so we'll
207 // reuse that memory to receive the output of deflate.
208 if (expanded_source.size() < 32768U) {
209 expanded_source.resize(32768U);
210 }
211
212 {
213 std::vector<unsigned char>& temp_data = expanded_source;
214
215 // now the deflate stream
216 z_stream strm;
217 strm.zalloc = Z_NULL;
218 strm.zfree = Z_NULL;
219 strm.opaque = Z_NULL;
220 strm.avail_in = uncompressed_target_data.size();
221 strm.next_in = uncompressed_target_data.data();
222 int ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy);
223 if (ret != Z_OK) {
224 printf("failed to init uncompressed data deflation: %d\n", ret);
225 return -1;
226 }
227 do {
228 strm.avail_out = temp_data.size();
229 strm.next_out = temp_data.data();
230 ret = deflate(&strm, Z_FINISH);
231 ssize_t have = temp_data.size() - strm.avail_out;
232
233 if (sink(temp_data.data(), have, token) != have) {
234 printf("failed to write %ld compressed bytes to output\n",
235 (long)have);
236 return -1;
237 }
238 if (ctx) SHA1_Update(ctx, temp_data.data(), have);
239 } while (ret != Z_STREAM_END);
240 deflateEnd(&strm);
241 }
242 } else {
243 printf("patch chunk %d is unknown type %d\n", i, type);
244 return -1;
245 }
246 }
247
248 return 0;
249 }
250