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block: convert qcow/qcow2 to use generic cipher API
Switch the qcow/qcow2 block driver over to use the generic cipher API, this allows it to use the pluggable AES implementations, instead of being hardcoded to use QEMU's built-in impl. Signed-off-by: Daniel P. Berrange <berrange@redhat.com> Message-Id: <1435770638-25715-10-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Daniel P. Berrange
Paolo Bonzini
parent
8e9b0d24fb
commit
f6fa64f6d2
4 changed files with 165 additions and 91 deletions
102
block/qcow.c
102
block/qcow.c
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@ -26,7 +26,7 @@
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#include "qemu/module.h"
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#include <zlib.h>
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#include "qapi/qmp/qerror.h"
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#include "crypto/aes.h"
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#include "crypto/cipher.h"
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#include "migration/migration.h"
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/**************************************************************/
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@ -72,10 +72,8 @@ typedef struct BDRVQcowState {
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uint8_t *cluster_cache;
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uint8_t *cluster_data;
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uint64_t cluster_cache_offset;
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uint32_t crypt_method; /* current crypt method, 0 if no key yet */
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QCryptoCipher *cipher; /* NULL if no key yet */
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uint32_t crypt_method_header;
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AES_KEY aes_encrypt_key;
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AES_KEY aes_decrypt_key;
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CoMutex lock;
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Error *migration_blocker;
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} BDRVQcowState;
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@ -154,6 +152,11 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
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ret = -EINVAL;
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goto fail;
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}
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if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
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error_setg(errp, "AES cipher not available");
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ret = -EINVAL;
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goto fail;
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}
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s->crypt_method_header = header.crypt_method;
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if (s->crypt_method_header) {
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bs->encrypted = 1;
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@ -260,6 +263,7 @@ static int qcow_set_key(BlockDriverState *bs, const char *key)
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BDRVQcowState *s = bs->opaque;
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uint8_t keybuf[16];
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int len, i;
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Error *err;
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memset(keybuf, 0, 16);
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len = strlen(key);
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@ -271,38 +275,67 @@ static int qcow_set_key(BlockDriverState *bs, const char *key)
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keybuf[i] = key[i];
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}
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assert(bs->encrypted);
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s->crypt_method = s->crypt_method_header;
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if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
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return -1;
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if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
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qcrypto_cipher_free(s->cipher);
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s->cipher = qcrypto_cipher_new(
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QCRYPTO_CIPHER_ALG_AES_128,
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QCRYPTO_CIPHER_MODE_CBC,
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keybuf, G_N_ELEMENTS(keybuf),
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&err);
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if (!s->cipher) {
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/* XXX would be nice if errors in this method could
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* be properly propagate to the caller. Would need
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* the bdrv_set_key() API signature to be fixed. */
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error_free(err);
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return -1;
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}
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return 0;
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}
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/* The crypt function is compatible with the linux cryptoloop
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algorithm for < 4 GB images. NOTE: out_buf == in_buf is
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supported */
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static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
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uint8_t *out_buf, const uint8_t *in_buf,
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int nb_sectors, int enc,
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const AES_KEY *key)
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static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
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uint8_t *out_buf, const uint8_t *in_buf,
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int nb_sectors, bool enc, Error **errp)
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{
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union {
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uint64_t ll[2];
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uint8_t b[16];
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} ivec;
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int i;
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int ret;
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for(i = 0; i < nb_sectors; i++) {
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ivec.ll[0] = cpu_to_le64(sector_num);
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ivec.ll[1] = 0;
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AES_cbc_encrypt(in_buf, out_buf, 512, key,
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ivec.b, enc);
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if (qcrypto_cipher_setiv(s->cipher,
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ivec.b, G_N_ELEMENTS(ivec.b),
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errp) < 0) {
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return -1;
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}
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if (enc) {
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ret = qcrypto_cipher_encrypt(s->cipher,
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in_buf,
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out_buf,
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512,
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errp);
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} else {
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ret = qcrypto_cipher_decrypt(s->cipher,
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in_buf,
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out_buf,
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512,
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errp);
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}
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if (ret < 0) {
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return -1;
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}
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sector_num++;
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in_buf += 512;
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out_buf += 512;
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}
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return 0;
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}
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/* 'allocate' is:
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@ -416,15 +449,20 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
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if (bs->encrypted &&
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(n_end - n_start) < s->cluster_sectors) {
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uint64_t start_sect;
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assert(s->crypt_method);
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assert(s->cipher);
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start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
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memset(s->cluster_data + 512, 0x00, 512);
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for(i = 0; i < s->cluster_sectors; i++) {
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if (i < n_start || i >= n_end) {
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encrypt_sectors(s, start_sect + i,
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s->cluster_data,
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s->cluster_data + 512, 1, 1,
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&s->aes_encrypt_key);
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Error *err = NULL;
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if (encrypt_sectors(s, start_sect + i,
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s->cluster_data,
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s->cluster_data + 512, 1,
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true, &err) < 0) {
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error_free(err);
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errno = EIO;
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return -1;
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}
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if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
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s->cluster_data, 512) != 512)
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return -1;
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@ -464,7 +502,7 @@ static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
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if (!cluster_offset) {
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return 0;
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}
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if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) {
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if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) {
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return BDRV_BLOCK_DATA;
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}
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cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
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@ -531,6 +569,7 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
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QEMUIOVector hd_qiov;
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uint8_t *buf;
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void *orig_buf;
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Error *err = NULL;
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if (qiov->niov > 1) {
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buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
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@ -594,10 +633,11 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
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break;
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}
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if (bs->encrypted) {
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assert(s->crypt_method);
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encrypt_sectors(s, sector_num, buf, buf,
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n, 0,
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&s->aes_decrypt_key);
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assert(s->cipher);
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if (encrypt_sectors(s, sector_num, buf, buf,
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n, false, &err) < 0) {
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goto fail;
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}
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}
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}
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ret = 0;
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@ -618,6 +658,7 @@ done:
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return ret;
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fail:
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error_free(err);
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ret = -EIO;
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goto done;
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}
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@ -666,12 +707,17 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
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break;
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}
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if (bs->encrypted) {
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assert(s->crypt_method);
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Error *err = NULL;
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assert(s->cipher);
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if (!cluster_data) {
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cluster_data = g_malloc0(s->cluster_size);
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}
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encrypt_sectors(s, sector_num, cluster_data, buf,
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n, 1, &s->aes_encrypt_key);
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if (encrypt_sectors(s, sector_num, cluster_data, buf,
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n, true, &err) < 0) {
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error_free(err);
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ret = -EIO;
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break;
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}
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src_buf = cluster_data;
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} else {
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src_buf = buf;
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@ -708,6 +754,8 @@ static void qcow_close(BlockDriverState *bs)
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{
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BDRVQcowState *s = bs->opaque;
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qcrypto_cipher_free(s->cipher);
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s->cipher = NULL;
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g_free(s->l1_table);
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qemu_vfree(s->l2_cache);
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g_free(s->cluster_cache);
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