/* * Block driver for the QCOW format * * Copyright (c) 2004-2006 Fabrice Bellard * * 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_int.h"#include <zlib.h>#include "aes.h"/**************************************************************//* QEMU COW block driver with compression and encryption support */#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)#define QCOW_VERSION 1#define QCOW_CRYPT_NONE 0#define QCOW_CRYPT_AES  1#define QCOW_OFLAG_COMPRESSED (1LL << 63)typedef struct QCowHeader {    uint32_t magic;    uint32_t version;    uint64_t backing_file_offset;    uint32_t backing_file_size;    uint32_t mtime;    uint64_t size; /* in bytes */    uint8_t cluster_bits;    uint8_t l2_bits;    uint32_t crypt_method;    uint64_t l1_table_offset;} QCowHeader;#define L2_CACHE_SIZE 16typedef struct BDRVQcowState {    BlockDriverState *hd;    int cluster_bits;    int cluster_size;    int cluster_sectors;    int l2_bits;    int l2_size;    int l1_size;    uint64_t cluster_offset_mask;    uint64_t l1_table_offset;    uint64_t *l1_table;    uint64_t *l2_cache;    uint64_t l2_cache_offsets[L2_CACHE_SIZE];    uint32_t l2_cache_counts[L2_CACHE_SIZE];    uint8_t *cluster_cache;    uint8_t *cluster_data;    uint64_t cluster_cache_offset;    uint32_t crypt_method; /* current crypt method, 0 if no key yet */    uint32_t crypt_method_header;    AES_KEY aes_encrypt_key;    AES_KEY aes_decrypt_key;} BDRVQcowState;static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename){    const QCowHeader *cow_header = (const void *)buf;    if (buf_size >= sizeof(QCowHeader) &&        be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&        be32_to_cpu(cow_header->version) == QCOW_VERSION)        return 100;    else        return 0;}static int qcow_open(BlockDriverState *bs, const char *filename, int flags){    BDRVQcowState *s = bs->opaque;    int len, i, shift, ret;    QCowHeader header;    ret = bdrv_file_open(&s->hd, filename, flags);    if (ret < 0)        return ret;    if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))        goto fail;    be32_to_cpus(&header.magic);    be32_to_cpus(&header.version);    be64_to_cpus(&header.backing_file_offset);    be32_to_cpus(&header.backing_file_size);    be32_to_cpus(&header.mtime);    be64_to_cpus(&header.size);    be32_to_cpus(&header.crypt_method);    be64_to_cpus(&header.l1_table_offset);    if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)        goto fail;    if (header.size <= 1 || header.cluster_bits < 9)        goto fail;    if (header.crypt_method > QCOW_CRYPT_AES)        goto fail;    s->crypt_method_header = header.crypt_method;    if (s->crypt_method_header)        bs->encrypted = 1;    s->cluster_bits = header.cluster_bits;    s->cluster_size = 1 << s->cluster_bits;    s->cluster_sectors = 1 << (s->cluster_bits - 9);    s->l2_bits = header.l2_bits;    s->l2_size = 1 << s->l2_bits;    bs->total_sectors = header.size / 512;    s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;    /* read the level 1 table */    shift = s->cluster_bits + s->l2_bits;    s->l1_size = (header.size + (1LL << shift) - 1) >> shift;    s->l1_table_offset = header.l1_table_offset;    s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));    if (!s->l1_table)        goto fail;    if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=        s->l1_size * sizeof(uint64_t))        goto fail;    for(i = 0;i < s->l1_size; i++) {        be64_to_cpus(&s->l1_table[i]);    }    /* alloc L2 cache */    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));    if (!s->l2_cache)        goto fail;    s->cluster_cache = qemu_malloc(s->cluster_size);    if (!s->cluster_cache)        goto fail;    s->cluster_data = qemu_malloc(s->cluster_size);    if (!s->cluster_data)        goto fail;    s->cluster_cache_offset = -1;    /* read the backing file name */    if (header.backing_file_offset != 0) {        len = header.backing_file_size;        if (len > 1023)            len = 1023;        if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)            goto fail;        bs->backing_file[len] = '\0';    }    return 0; fail:    qemu_free(s->l1_table);    qemu_free(s->l2_cache);    qemu_free(s->cluster_cache);    qemu_free(s->cluster_data);    bdrv_delete(s->hd);    return -1;}static int qcow_set_key(BlockDriverState *bs, const char *key){    BDRVQcowState *s = bs->opaque;    uint8_t keybuf[16];    int len, i;    memset(keybuf, 0, 16);    len = strlen(key);    if (len > 16)        len = 16;    /* XXX: we could compress the chars to 7 bits to increase       entropy */    for(i = 0;i < len;i++) {        keybuf[i] = key[i];    }    s->crypt_method = s->crypt_method_header;    if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)        return -1;    if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)        return -1;#if 0    /* test */    {        uint8_t in[16];        uint8_t out[16];        uint8_t tmp[16];        for(i=0;i<16;i++)            in[i] = i;        AES_encrypt(in, tmp, &s->aes_encrypt_key);        AES_decrypt(tmp, out, &s->aes_decrypt_key);        for(i = 0; i < 16; i++)            printf(" %02x", tmp[i]);        printf("\n");        for(i = 0; i < 16; i++)            printf(" %02x", out[i]);        printf("\n");    }#endif    return 0;}/* The crypt function is compatible with the linux cryptoloop   algorithm for < 4 GB images. NOTE: out_buf == in_buf is   supported */static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,                            uint8_t *out_buf, const uint8_t *in_buf,                            int nb_sectors, int enc,                            const AES_KEY *key){    union {        uint64_t ll[2];        uint8_t b[16];    } ivec;    int i;    for(i = 0; i < nb_sectors; i++) {        ivec.ll[0] = cpu_to_le64(sector_num);        ivec.ll[1] = 0;        AES_cbc_encrypt(in_buf, out_buf, 512, key,                        ivec.b, enc);        sector_num++;        in_buf += 512;        out_buf += 512;    }}/* 'allocate' is: * * 0 to not allocate. * * 1 to allocate a normal cluster (for sector indexes 'n_start' to * 'n_end') * * 2 to allocate a compressed cluster of size * 'compressed_size'. 'compressed_size' must be > 0 and < * cluster_size * * return 0 if not allocated. */static uint64_t get_cluster_offset(BlockDriverState *bs,                                   uint64_t offset, int allocate,                                   int compressed_size,                                   int n_start, int n_end){    BDRVQcowState *s = bs->opaque;    int min_index, i, j, l1_index, l2_index;    uint64_t l2_offset, *l2_table, cluster_offset, tmp;    uint32_t min_count;    int new_l2_table;    l1_index = offset >> (s->l2_bits + s->cluster_bits);    l2_offset = s->l1_table[l1_index];    new_l2_table = 0;    if (!l2_offset) {        if (!allocate)            return 0;        /* allocate a new l2 entry */        l2_offset = bdrv_getlength(s->hd);        /* round to cluster size */        l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);        /* update the L1 entry */        s->l1_table[l1_index] = l2_offset;        tmp = cpu_to_be64(l2_offset);        if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),                        &tmp, sizeof(tmp)) != sizeof(tmp))            return 0;        new_l2_table = 1;    }    for(i = 0; i < L2_CACHE_SIZE; i++) {        if (l2_offset == s->l2_cache_offsets[i]) {            /* increment the hit count */            if (++s->l2_cache_counts[i] == 0xffffffff) {                for(j = 0; j < L2_CACHE_SIZE; j++) {                    s->l2_cache_counts[j] >>= 1;                }            }            l2_table = s->l2_cache + (i << s->l2_bits);            goto found;        }    }    /* not found: load a new entry in the least used one */    min_index = 0;    min_count = 0xffffffff;    for(i = 0; i < L2_CACHE_SIZE; i++) {        if (s->l2_cache_counts[i] < min_count) {            min_count = s->l2_cache_counts[i];            min_index = i;        }    }    l2_table = s->l2_cache + (min_index << s->l2_bits);    if (new_l2_table) {        memset(l2_table, 0, s->l2_size * sizeof(uint64_t));        if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=            s->l2_size * sizeof(uint64_t))            return 0;    } else {        if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=            s->l2_size * sizeof(uint64_t))            return 0;    }    s->l2_cache_offsets[min_index] = l2_offset;    s->l2_cache_counts[min_index] = 1; found:    l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);    cluster_offset = be64_to_cpu(l2_table[l2_index]);    if (!cluster_offset ||        ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {        if (!allocate)            return 0;        /* allocate a new cluster */        if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&            (n_end - n_start) < s->cluster_sectors) {            /* if the cluster is already compressed, we must               decompress it in the case it is not completely               overwritten */            if (decompress_cluster(s, cluster_offset) < 0)                return 0;            cluster_offset = bdrv_getlength(s->hd);            cluster_offset = (cluster_offset + s->cluster_size - 1) &                ~(s->cluster_size - 1);            /* write the cluster content */            if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=                s->cluster_size)                return -1;        } else {            cluster_offset = bdrv_getlength(s->hd);            if (allocate == 1) {                /* round to cluster size */                cluster_offset = (cluster_offset + s->cluster_size - 1) &                    ~(s->cluster_size - 1);                bdrv_truncate(s->hd, cluster_offset + s->cluster_size);                /* if encrypted, we must initialize the cluster                   content which won't be written */                if (s->crypt_method &&                    (n_end - n_start) < s->cluster_sectors) {                    uint64_t start_sect;                    start_sect = (offset & ~(s->cluster_size - 1)) >> 9;                    memset(s->cluster_data + 512, 0x00, 512);                    for(i = 0; i < s->cluster_sectors; i++) {                        if (i < n_start || i >= n_end) {                            encrypt_sectors(s, start_sect + i,                                            s->cluster_data,                                            s->cluster_data + 512, 1, 1,                                            &s->aes_encrypt_key);                            if (bdrv_pwrite(s->hd, cluster_offset + i * 512,                                            s->cluster_data, 512) != 512)                                return -1;                        }                    }                }            } else {                cluster_offset |= QCOW_OFLAG_COMPRESSED |                    (uint64_t)compressed_size << (63 - s->cluster_bits);            }        }        /* update L2 table */        tmp = cpu_to_be64(cluster_offset);        l2_table[l2_index] = tmp;        if (bdrv_pwrite(s->hd,                        l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))            return 0;    }    return cluster_offset;}static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,                             int nb_sectors, int *pnum){    BDRVQcowState *s = bs->opaque;    int index_in_cluster, n;    uint64_t cluster_offset;    cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);    index_in_cluster = sector_num & (s->cluster_sectors - 1);    n = s->cluster_sectors - index_in_cluster;    if (n > nb_sectors)        n = nb_sectors;    *pnum = n;    return (cluster_offset != 0);}static int decompress_buffer(uint8_t *out_buf, int out_buf_size,                             const uint8_t *buf, int buf_size){    z_stream strm1, *strm = &strm1;    int ret, out_len;    memset(strm, 0, sizeof(*strm));    strm->next_in = (uint8_t *)buf;    strm->avail_in = buf_size;    strm->next_out = out_buf;    strm->avail_out = out_buf_size;    ret = inflateInit2(strm, -12);    if (ret != Z_OK)        return -1;    ret = inflate(strm, Z_FINISH);    out_len = strm->next_out - out_buf;    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||        out_len != out_buf_size) {        inflateEnd(strm);        return -1;    }    inflateEnd(strm);    return 0;}static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset){    int ret, csize;    uint64_t coffset;    coffset = cluster_offset & s->cluster_offset_mask;    if (s->cluster_cache_offset != coffset) {        csize = cluster_offset >> (63 - s->cluster_bits);        csize &= (s->cluster_size - 1);        ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);        if (ret != csize)            return -1;        if (decompress_buffer(s->cluster_cache, s->cluster_size,                              s->cluster_data, csize) < 0) {            return -1;        }        s->cluster_cache_offset = coffset;    }    return 0;}#if 0static int qcow_read(BlockDriverState *bs, int64_t sector_num,                     uint8_t *buf, int nb_sectors){    BDRVQcowState *s = bs->opaque;    int ret, index_in_cluster, n;    uint64_t cluster_offset;