/* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // See imgdiff.c in this directory for a description of the patch file // format. #include #include #include #include #include #include #include #include "zlib.h" #include "mincrypt/sha.h" #include "applypatch.h" #include "imgdiff.h" #include "utils.h" /* * Apply the patch given in 'patch_filename' to the source data given * by (old_data, old_size). Write the patched output to the 'output' * file, and update the SHA context with the output data as well. * Return 0 on success. */ int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size __unused, const Value* patch, SinkFn sink, void* token, SHA_CTX* ctx, const Value* bonus_data) { ssize_t pos = 12; char* header = patch->data; if (patch->size < 12) { printf("patch too short to contain header\n"); return -1; } // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW. // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and // CHUNK_GZIP.) if (memcmp(header, "IMGDIFF2", 8) != 0) { printf("corrupt patch file header (magic number)\n"); return -1; } int num_chunks = Read4(header+8); int i; for (i = 0; i < num_chunks; ++i) { // each chunk's header record starts with 4 bytes. if (pos + 4 > patch->size) { printf("failed to read chunk %d record\n", i); return -1; } int type = Read4(patch->data + pos); pos += 4; if (type == CHUNK_NORMAL) { char* normal_header = patch->data + pos; pos += 24; if (pos > patch->size) { printf("failed to read chunk %d normal header data\n", i); return -1; } size_t src_start = Read8(normal_header); size_t src_len = Read8(normal_header+8); size_t patch_offset = Read8(normal_header+16); ApplyBSDiffPatch(old_data + src_start, src_len, patch, patch_offset, sink, token, ctx); } else if (type == CHUNK_RAW) { char* raw_header = patch->data + pos; pos += 4; if (pos > patch->size) { printf("failed to read chunk %d raw header data\n", i); return -1; } ssize_t data_len = Read4(raw_header); if (pos + data_len > patch->size) { printf("failed to read chunk %d raw data\n", i); return -1; } if (ctx) SHA_update(ctx, patch->data + pos, data_len); if (sink((unsigned char*)patch->data + pos, data_len, token) != data_len) { printf("failed to write chunk %d raw data\n", i); return -1; } pos += data_len; } else if (type == CHUNK_DEFLATE) { // deflate chunks have an additional 60 bytes in their chunk header. char* deflate_header = patch->data + pos; pos += 60; if (pos > patch->size) { printf("failed to read chunk %d deflate header data\n", i); return -1; } size_t src_start = Read8(deflate_header); size_t src_len = Read8(deflate_header+8); size_t patch_offset = Read8(deflate_header+16); size_t expanded_len = Read8(deflate_header+24); size_t target_len = Read8(deflate_header+32); int level = Read4(deflate_header+40); int method = Read4(deflate_header+44); int windowBits = Read4(deflate_header+48); int memLevel = Read4(deflate_header+52); int strategy = Read4(deflate_header+56); // Decompress the source data; the chunk header tells us exactly // how big we expect it to be when decompressed. // Note: expanded_len will include the bonus data size if // the patch was constructed with bonus data. The // deflation will come up 'bonus_size' bytes short; these // must be appended from the bonus_data value. size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0; unsigned char* expanded_source = malloc(expanded_len); if (expanded_source == NULL) { printf("failed to allocate %zu bytes for expanded_source\n", expanded_len); return -1; } z_stream strm; strm.zalloc = Z_NULL; strm.zfree = Z_NULL; strm.opaque = Z_NULL; strm.avail_in = src_len; strm.next_in = (unsigned char*)(old_data + src_start); strm.avail_out = expanded_len; strm.next_out = expanded_source; int ret; ret = inflateInit2(&strm, -15); if (ret != Z_OK) { printf("failed to init source inflation: %d\n", ret); return -1; } // Because we've provided enough room to accommodate the output // data, we expect one call to inflate() to suffice. ret = inflate(&strm, Z_SYNC_FLUSH); if (ret != Z_STREAM_END) { printf("source inflation returned %d\n", ret); return -1; } // We should have filled the output buffer exactly, except // for the bonus_size. if (strm.avail_out != bonus_size) { printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size); return -1; } inflateEnd(&strm); if (bonus_size) { memcpy(expanded_source + (expanded_len - bonus_size), bonus_data->data, bonus_size); } // Next, apply the bsdiff patch (in memory) to the uncompressed // data. unsigned char* uncompressed_target_data; ssize_t uncompressed_target_size; if (ApplyBSDiffPatchMem(expanded_source, expanded_len, patch, patch_offset, &uncompressed_target_data, &uncompressed_target_size) != 0) { return -1; } // Now compress the target data and append it to the output. // we're done with the expanded_source data buffer, so we'll // reuse that memory to receive the output of deflate. unsigned char* temp_data = expanded_source; ssize_t temp_size = expanded_len; if (temp_size < 32768) { // ... unless the buffer is too small, in which case we'll // allocate a fresh one. free(temp_data); temp_data = malloc(32768); temp_size = 32768; } // now the deflate stream strm.zalloc = Z_NULL; strm.zfree = Z_NULL; strm.opaque = Z_NULL; strm.avail_in = uncompressed_target_size; strm.next_in = uncompressed_target_data; ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy); do { strm.avail_out = temp_size; strm.next_out = temp_data; ret = deflate(&strm, Z_FINISH); ssize_t have = temp_size - strm.avail_out; if (sink(temp_data, have, token) != have) { printf("failed to write %ld compressed bytes to output\n", (long)have); return -1; } if (ctx) SHA_update(ctx, temp_data, have); } while (ret != Z_STREAM_END); deflateEnd(&strm); free(temp_data); free(uncompressed_target_data); } else { printf("patch chunk %d is unknown type %d\n", i, type); return -1; } } return 0; }