/* * QEMU Block driver for DMG images * * Copyright (c) 2004 Johannes E. Schindelin * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu-common.h" #include "block/block_int.h" #include "qemu/bswap.h" #include "qemu/error-report.h" #include "qemu/module.h" #include <zlib.h> #ifdef CONFIG_BZIP2 #include <bzlib.h> #endif #include <glib.h> enum { /* Limit chunk sizes to prevent unreasonable amounts of memory being used * or truncating when converting to 32-bit types */ DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */ DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512, }; typedef struct BDRVDMGState { CoMutex lock; /* each chunk contains a certain number of sectors, * offsets[i] is the offset in the .dmg file, * lengths[i] is the length of the compressed chunk, * sectors[i] is the sector beginning at offsets[i], * sectorcounts[i] is the number of sectors in that chunk, * the sectors array is ordered * 0<=i<n_chunks */ uint32_t n_chunks; uint32_t* types; uint64_t* offsets; uint64_t* lengths; uint64_t* sectors; uint64_t* sectorcounts; uint32_t current_chunk; uint8_t *compressed_chunk; uint8_t *uncompressed_chunk; z_stream zstream; #ifdef CONFIG_BZIP2 bz_stream bzstream; #endif } BDRVDMGState; static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) { int len; if (!filename) { return 0; } len = strlen(filename); if (len > 4 && !strcmp(filename + len - 4, ".dmg")) { return 2; } return 0; } static int read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result) { uint64_t buffer; int ret; ret = bdrv_pread(bs->file->bs, offset, &buffer, 8); if (ret < 0) { return ret; } *result = be64_to_cpu(buffer); return 0; } static int read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result) { uint32_t buffer; int ret; ret = bdrv_pread(bs->file->bs, offset, &buffer, 4); if (ret < 0) { return ret; } *result = be32_to_cpu(buffer); return 0; } static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset) { return be64_to_cpu(*(uint64_t *)&buffer[offset]); } static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset) { return be32_to_cpu(*(uint32_t *)&buffer[offset]); } /* Increase max chunk sizes, if necessary. This function is used to calculate * the buffer sizes needed for compressed/uncompressed chunk I/O. */ static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk, uint32_t *max_compressed_size, uint32_t *max_sectors_per_chunk) { uint32_t compressed_size = 0; uint32_t uncompressed_sectors = 0; switch (s->types[chunk]) { case 0x80000005: /* zlib compressed */ case 0x80000006: /* bzip2 compressed */ compressed_size = s->lengths[chunk]; uncompressed_sectors = s->sectorcounts[chunk]; break; case 1: /* copy */ uncompressed_sectors = (s->lengths[chunk] + 511) / 512; break; case 2: /* zero */ /* as the all-zeroes block may be large, it is treated specially: the * sector is not copied from a large buffer, a simple memset is used * instead. Therefore uncompressed_sectors does not need to be set. */ break; } if (compressed_size > *max_compressed_size) { *max_compressed_size = compressed_size; } if (uncompressed_sectors > *max_sectors_per_chunk) { *max_sectors_per_chunk = uncompressed_sectors; } } static int64_t dmg_find_koly_offset(BlockDriverState *file_bs, Error **errp) { int64_t length; int64_t offset = 0; uint8_t buffer[515]; int i, ret; /* bdrv_getlength returns a multiple of block size (512), rounded up. Since * dmg images can have odd sizes, try to look for the "koly" magic which * marks the begin of the UDIF trailer (512 bytes). This magic can be found * in the last 511 bytes of the second-last sector or the first 4 bytes of * the last sector (search space: 515 bytes) */ length = bdrv_getlength(file_bs); if (length < 0) { error_setg_errno(errp, -length, "Failed to get file size while reading UDIF trailer"); return length; } else if (length < 512) { error_setg(errp, "dmg file must be at least 512 bytes long"); return -EINVAL; } if (length > 511 + 512) { offset = length - 511 - 512; } length = length < 515 ? length : 515; ret = bdrv_pread(file_bs, offset, buffer, length); if (ret < 0) { error_setg_errno(errp, -ret, "Failed while reading UDIF trailer"); return ret; } for (i = 0; i < length - 3; i++) { if (buffer[i] == 'k' && buffer[i+1] == 'o' && buffer[i+2] == 'l' && buffer[i+3] == 'y') { return offset + i; } } error_setg(errp, "Could not locate UDIF trailer in dmg file"); return -EINVAL; } /* used when building the sector table */ typedef struct DmgHeaderState { /* used internally by dmg_read_mish_block to remember offsets of blocks * across calls */ uint64_t data_fork_offset; /* exported for dmg_open */ uint32_t max_compressed_size; uint32_t max_sectors_per_chunk; } DmgHeaderState; static bool dmg_is_known_block_type(uint32_t entry_type) { switch (entry_type) { case 0x00000001: /* uncompressed */ case 0x00000002: /* zeroes */ case 0x80000005: /* zlib */ #ifdef CONFIG_BZIP2 case 0x80000006: /* bzip2 */ #endif return true; default: return false; } } static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds, uint8_t *buffer, uint32_t count) { uint32_t type, i; int ret; size_t new_size; uint32_t chunk_count; int64_t offset = 0; uint64_t data_offset; uint64_t in_offset = ds->data_fork_offset; uint64_t out_offset; type = buff_read_uint32(buffer, offset); /* skip data that is not a valid MISH block (invalid magic or too small) */ if (type != 0x6d697368 || count < 244) { /* assume success for now */ return 0; } /* chunk offsets are relative to this sector number */ out_offset = buff_read_uint64(buffer, offset + 8); /* location in data fork for (compressed) blob (in bytes) */ data_offset = buff_read_uint64(buffer, offset + 0x18); in_offset += data_offset; /* move to begin of chunk entries */ offset += 204; chunk_count = (count - 204) / 40; new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); s->types = g_realloc(s->types, new_size / 2); s->offsets = g_realloc(s->offsets, new_size); s->lengths = g_realloc(s->lengths, new_size); s->sectors = g_realloc(s->sectors, new_size); s->sectorcounts = g_realloc(s->sectorcounts, new_size); for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) { s->types[i] = buff_read_uint32(buffer, offset); if (!dmg_is_known_block_type(s->types[i])) { chunk_count--; i--; offset += 40; continue; } /* sector number */ s->sectors[i] = buff_read_uint64(buffer, offset + 8); s->sectors[i] += out_offset; /* sector count */ s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10); /* all-zeroes sector (type 2) does not need to be "uncompressed" and can * therefore be unbounded. */ if (s->types[i] != 2 && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) { error_report("sector count %" PRIu64 " for chunk %" PRIu32 " is larger than max (%u)", s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX); ret = -EINVAL; goto fail; } /* offset in (compressed) data fork */ s->offsets[i] = buff_read_uint64(buffer, offset + 0x18); s->offsets[i] += in_offset; /* length in (compressed) data fork */ s->lengths[i] = buff_read_uint64(buffer, offset + 0x20); if (s->lengths[i] > DMG_LENGTHS_MAX) { error_report("length %" PRIu64 " for chunk %" PRIu32 " is larger than max (%u)", s->lengths[i], i, DMG_LENGTHS_MAX); ret = -EINVAL; goto fail; } update_max_chunk_size(s, i, &ds->max_compressed_size, &ds->max_sectors_per_chunk); offset += 40; } s->n_chunks += chunk_count; return 0; fail: return ret; } static int dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds, uint64_t info_begin, uint64_t info_length) { BDRVDMGState *s = bs->opaque; int ret; uint32_t count, rsrc_data_offset; uint8_t *buffer = NULL; uint64_t info_end; uint64_t offset; /* read offset from begin of resource fork (info_begin) to resource data */ ret = read_uint32(bs, info_begin, &rsrc_data_offset); if (ret < 0) { goto fail; } else if (rsrc_data_offset > info_length) { ret = -EINVAL; goto fail; } /* read length of resource data */ ret = read_uint32(bs, info_begin + 8, &count); if (ret < 0) { goto fail; } else if (count == 0 || rsrc_data_offset + count > info_length) { ret = -EINVAL; goto fail; } /* begin of resource data (consisting of one or more resources) */ offset = info_begin + rsrc_data_offset; /* end of resource data (there is possibly a following resource map * which will be ignored). */ info_end = offset + count; /* read offsets (mish blocks) from one or more resources in resource data */ while (offset < info_end) { /* size of following resource */ ret = read_uint32(bs, offset, &count); if (ret < 0) { goto fail; } else if (count == 0 || count > info_end - offset) { ret = -EINVAL; goto fail; } offset += 4; buffer = g_realloc(buffer, count); ret = bdrv_pread(bs->file->bs, offset, buffer, count); if (ret < 0) { goto fail; } ret = dmg_read_mish_block(s, ds, buffer, count); if (ret < 0) { goto fail; } /* advance offset by size of resource */ offset += count; } ret = 0; fail: g_free(buffer); return ret; } static int dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds, uint64_t info_begin, uint64_t info_length) { BDRVDMGState *s = bs->opaque; int ret; uint8_t *buffer = NULL; char *data_begin, *data_end; /* Have at least some length to avoid NULL for g_malloc. Attempt to set a * safe upper cap on the data length. A test sample had a XML length of * about 1 MiB. */ if (info_length == 0 || info_length > 16 * 1024 * 1024) { ret = -EINVAL; goto fail; } buffer = g_malloc(info_length + 1); buffer[info_length] = '\0'; ret = bdrv_pread(bs->file->bs, info_begin, buffer, info_length); if (ret != info_length) { ret = -EINVAL; goto fail; } /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64 * decode. The actual data element has 431 (0x1af) bytes which includes tabs * and line feeds. */ data_end = (char *)buffer; while ((data_begin = strstr(data_end, "<data>")) != NULL) { guchar *mish; gsize out_len = 0; data_begin += 6; data_end = strstr(data_begin, "</data>"); /* malformed XML? */ if (data_end == NULL) { ret = -EINVAL; goto fail; } *data_end++ = '\0'; mish = g_base64_decode(data_begin, &out_len); ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len); g_free(mish); if (ret < 0) { goto fail; } } ret = 0; fail: g_free(buffer); return ret; } static int dmg_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVDMGState *s = bs->opaque; DmgHeaderState ds; uint64_t rsrc_fork_offset, rsrc_fork_length; uint64_t plist_xml_offset, plist_xml_length; int64_t offset; int ret; bs->read_only = 1; s->n_chunks = 0; s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL; /* used by dmg_read_mish_block to keep track of the current I/O position */ ds.data_fork_offset = 0; ds.max_compressed_size = 1; ds.max_sectors_per_chunk = 1; /* locate the UDIF trailer */ offset = dmg_find_koly_offset(bs->file->bs, errp); if (offset < 0) { ret = offset; goto fail; } /* offset of data fork (DataForkOffset) */ ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset); if (ret < 0) { goto fail; } else if (ds.data_fork_offset > offset) { ret = -EINVAL; goto fail; } /* offset of resource fork (RsrcForkOffset) */ ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset); if (ret < 0) { goto fail; } ret = read_uint64(bs, offset + 0x30, &rsrc_fork_length); if (ret < 0) { goto fail; } if (rsrc_fork_offset >= offset || rsrc_fork_length > offset - rsrc_fork_offset) { ret = -EINVAL; goto fail; } /* offset of property list (XMLOffset) */ ret = read_uint64(bs, offset + 0xd8, &plist_xml_offset); if (ret < 0) { goto fail; } ret = read_uint64(bs, offset + 0xe0, &plist_xml_length); if (ret < 0) { goto fail; } if (plist_xml_offset >= offset || plist_xml_length > offset - plist_xml_offset) { ret = -EINVAL; goto fail; } ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors); if (ret < 0) { goto fail; } if (bs->total_sectors < 0) { ret = -EINVAL; goto fail; } if (rsrc_fork_length != 0) { ret = dmg_read_resource_fork(bs, &ds, rsrc_fork_offset, rsrc_fork_length); if (ret < 0) { goto fail; } } else if (plist_xml_length != 0) { ret = dmg_read_plist_xml(bs, &ds, plist_xml_offset, plist_xml_length); if (ret < 0) { goto fail; } } else { ret = -EINVAL; goto fail; } /* initialize zlib engine */ s->compressed_chunk = qemu_try_blockalign(bs->file->bs, ds.max_compressed_size + 1); s->uncompressed_chunk = qemu_try_blockalign(bs->file->bs, 512 * ds.max_sectors_per_chunk); if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) { ret = -ENOMEM; goto fail; } if (inflateInit(&s->zstream) != Z_OK) { ret = -EINVAL; goto fail; } s->current_chunk = s->n_chunks; qemu_co_mutex_init(&s->lock); return 0; fail: g_free(s->types); g_free(s->offsets); g_free(s->lengths); g_free(s->sectors); g_free(s->sectorcounts); qemu_vfree(s->compressed_chunk); qemu_vfree(s->uncompressed_chunk); return ret; } static inline int is_sector_in_chunk(BDRVDMGState* s, uint32_t chunk_num, uint64_t sector_num) { if (chunk_num >= s->n_chunks || s->sectors[chunk_num] > sector_num || s->sectors[chunk_num] + s->sectorcounts[chunk_num] <= sector_num) { return 0; } else { return -1; } } static inline uint32_t search_chunk(BDRVDMGState *s, uint64_t sector_num) { /* binary search */ uint32_t chunk1 = 0, chunk2 = s->n_chunks, chunk3; while (chunk1 != chunk2) { chunk3 = (chunk1 + chunk2) / 2; if (s->sectors[chunk3] > sector_num) { chunk2 = chunk3; } else if (s->sectors[chunk3] + s->sectorcounts[chunk3] > sector_num) { return chunk3; } else { chunk1 = chunk3; } } return s->n_chunks; /* error */ } static inline int dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num) { BDRVDMGState *s = bs->opaque; if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) { int ret; uint32_t chunk = search_chunk(s, sector_num); #ifdef CONFIG_BZIP2 uint64_t total_out; #endif if (chunk >= s->n_chunks) { return -1; } s->current_chunk = s->n_chunks; switch (s->types[chunk]) { /* block entry type */ case 0x80000005: { /* zlib compressed */ /* we need to buffer, because only the chunk as whole can be * inflated. */ ret = bdrv_pread(bs->file->bs, s->offsets[chunk], s->compressed_chunk, s->lengths[chunk]); if (ret != s->lengths[chunk]) { return -1; } s->zstream.next_in = s->compressed_chunk; s->zstream.avail_in = s->lengths[chunk]; s->zstream.next_out = s->uncompressed_chunk; s->zstream.avail_out = 512 * s->sectorcounts[chunk]; ret = inflateReset(&s->zstream); if (ret != Z_OK) { return -1; } ret = inflate(&s->zstream, Z_FINISH); if (ret != Z_STREAM_END || s->zstream.total_out != 512 * s->sectorcounts[chunk]) { return -1; } break; } #ifdef CONFIG_BZIP2 case 0x80000006: /* bzip2 compressed */ /* we need to buffer, because only the chunk as whole can be * inflated. */ ret = bdrv_pread(bs->file->bs, s->offsets[chunk], s->compressed_chunk, s->lengths[chunk]); if (ret != s->lengths[chunk]) { return -1; } ret = BZ2_bzDecompressInit(&s->bzstream, 0, 0); if (ret != BZ_OK) { return -1; } s->bzstream.next_in = (char *)s->compressed_chunk; s->bzstream.avail_in = (unsigned int) s->lengths[chunk]; s->bzstream.next_out = (char *)s->uncompressed_chunk; s->bzstream.avail_out = (unsigned int) 512 * s->sectorcounts[chunk]; ret = BZ2_bzDecompress(&s->bzstream); total_out = ((uint64_t)s->bzstream.total_out_hi32 << 32) + s->bzstream.total_out_lo32; BZ2_bzDecompressEnd(&s->bzstream); if (ret != BZ_STREAM_END || total_out != 512 * s->sectorcounts[chunk]) { return -1; } break; #endif /* CONFIG_BZIP2 */ case 1: /* copy */ ret = bdrv_pread(bs->file->bs, s->offsets[chunk], s->uncompressed_chunk, s->lengths[chunk]); if (ret != s->lengths[chunk]) { return -1; } break; case 2: /* zero */ /* see dmg_read, it is treated specially. No buffer needs to be * pre-filled, the zeroes can be set directly. */ break; } s->current_chunk = chunk; } return 0; } static int dmg_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { BDRVDMGState *s = bs->opaque; int i; for (i = 0; i < nb_sectors; i++) { uint32_t sector_offset_in_chunk; if (dmg_read_chunk(bs, sector_num + i) != 0) { return -1; } /* Special case: current chunk is all zeroes. Do not perform a memcpy as * s->uncompressed_chunk may be too small to cover the large all-zeroes * section. dmg_read_chunk is called to find s->current_chunk */ if (s->types[s->current_chunk] == 2) { /* all zeroes block entry */ memset(buf + i * 512, 0, 512); continue; } sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk]; memcpy(buf + i * 512, s->uncompressed_chunk + sector_offset_in_chunk * 512, 512); } return 0; } static coroutine_fn int dmg_co_read(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, int nb_sectors) { int ret; BDRVDMGState *s = bs->opaque; qemu_co_mutex_lock(&s->lock); ret = dmg_read(bs, sector_num, buf, nb_sectors); qemu_co_mutex_unlock(&s->lock); return ret; } static void dmg_close(BlockDriverState *bs) { BDRVDMGState *s = bs->opaque; g_free(s->types); g_free(s->offsets); g_free(s->lengths); g_free(s->sectors); g_free(s->sectorcounts); qemu_vfree(s->compressed_chunk); qemu_vfree(s->uncompressed_chunk); inflateEnd(&s->zstream); } static BlockDriver bdrv_dmg = { .format_name = "dmg", .instance_size = sizeof(BDRVDMGState), .bdrv_probe = dmg_probe, .bdrv_open = dmg_open, .bdrv_read = dmg_co_read, .bdrv_close = dmg_close, }; static void bdrv_dmg_init(void) { bdrv_register(&bdrv_dmg); } block_init(bdrv_dmg_init);