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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 2015-07-01 18:10:37 +01:00 committed by Paolo Bonzini
parent 8e9b0d24fb
commit f6fa64f6d2
4 changed files with 165 additions and 91 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

102
block/qcow.c
View File

@ -26,7 +26,7 @@
#include "qemu/module.h"
#include <zlib.h>
#include "qapi/qmp/qerror.h"
#include "crypto/aes.h"
#include "crypto/cipher.h"
#include "migration/migration.h"
/**************************************************************/
@ -72,10 +72,8 @@ typedef struct BDRVQcowState {
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 */
QCryptoCipher *cipher; /* NULL if no key yet */
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
CoMutex lock;
Error *migration_blocker;
} BDRVQcowState;
@ -154,6 +152,11 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
ret = -EINVAL;
goto fail;
}
if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
error_setg(errp, "AES cipher not available");
ret = -EINVAL;
goto fail;
}
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header) {
bs->encrypted = 1;
@ -260,6 +263,7 @@ static int qcow_set_key(BlockDriverState *bs, const char *key)
BDRVQcowState *s = bs->opaque;
uint8_t keybuf[16];
int len, i;
Error *err;
memset(keybuf, 0, 16);
len = strlen(key);
@ -271,38 +275,67 @@ static int qcow_set_key(BlockDriverState *bs, const char *key)
keybuf[i] = key[i];
}
assert(bs->encrypted);
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)
qcrypto_cipher_free(s->cipher);
s->cipher = qcrypto_cipher_new(
QCRYPTO_CIPHER_ALG_AES_128,
QCRYPTO_CIPHER_MODE_CBC,
keybuf, G_N_ELEMENTS(keybuf),
&err);
if (!s->cipher) {
/* XXX would be nice if errors in this method could
* be properly propagate to the caller. Would need
* the bdrv_set_key() API signature to be fixed. */
error_free(err);
return -1;
}
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)
static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
uint8_t *out_buf, const uint8_t *in_buf,
int nb_sectors, bool enc, Error **errp)
{
union {
uint64_t ll[2];
uint8_t b[16];
} ivec;
int i;
int ret;
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);
if (qcrypto_cipher_setiv(s->cipher,
ivec.b, G_N_ELEMENTS(ivec.b),
errp) < 0) {
return -1;
}
if (enc) {
ret = qcrypto_cipher_encrypt(s->cipher,
in_buf,
out_buf,
512,
errp);
} else {
ret = qcrypto_cipher_decrypt(s->cipher,
in_buf,
out_buf,
512,
errp);
}
if (ret < 0) {
return -1;
}
sector_num++;
in_buf += 512;
out_buf += 512;
}
return 0;
}
/* 'allocate' is:
@ -416,15 +449,20 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
if (bs->encrypted &&
(n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
assert(s->crypt_method);
assert(s->cipher);
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);
Error *err = NULL;
if (encrypt_sectors(s, start_sect + i,
s->cluster_data,
s->cluster_data + 512, 1,
true, &err) < 0) {
error_free(err);
errno = EIO;
return -1;
}
if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
s->cluster_data, 512) != 512)
return -1;
@ -464,7 +502,7 @@ static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
if (!cluster_offset) {
return 0;
}
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) {
if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) {
return BDRV_BLOCK_DATA;
}
cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
@ -531,6 +569,7 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
QEMUIOVector hd_qiov;
uint8_t *buf;
void *orig_buf;
Error *err = NULL;
if (qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
@ -594,10 +633,11 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
break;
}
if (bs->encrypted) {
assert(s->crypt_method);
encrypt_sectors(s, sector_num, buf, buf,
n, 0,
&s->aes_decrypt_key);
assert(s->cipher);
if (encrypt_sectors(s, sector_num, buf, buf,
n, false, &err) < 0) {
goto fail;
}
}
}
ret = 0;
@ -618,6 +658,7 @@ done:
return ret;
fail:
error_free(err);
ret = -EIO;
goto done;
}
@ -666,12 +707,17 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
break;
}
if (bs->encrypted) {
assert(s->crypt_method);
Error *err = NULL;
assert(s->cipher);
if (!cluster_data) {
cluster_data = g_malloc0(s->cluster_size);
}
encrypt_sectors(s, sector_num, cluster_data, buf,
n, 1, &s->aes_encrypt_key);
if (encrypt_sectors(s, sector_num, cluster_data, buf,
n, true, &err) < 0) {
error_free(err);
ret = -EIO;
break;
}
src_buf = cluster_data;
} else {
src_buf = buf;
@ -708,6 +754,8 @@ static void qcow_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
qcrypto_cipher_free(s->cipher);
s->cipher = NULL;
g_free(s->l1_table);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);

46
block/qcow2-cluster.c
View File

@ -339,26 +339,47 @@ static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_tab
/* The crypt function is compatible with the linux cryptoloop
algorithm for < 4 GB images. NOTE: out_buf == in_buf is
supported */
void qcow2_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)
int qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
uint8_t *out_buf, const uint8_t *in_buf,
int nb_sectors, bool enc,
Error **errp)
{
union {
uint64_t ll[2];
uint8_t b[16];
} ivec;
int i;
int ret;
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);
if (qcrypto_cipher_setiv(s->cipher,
ivec.b, G_N_ELEMENTS(ivec.b),
errp) < 0) {
return -1;
}
if (enc) {
ret = qcrypto_cipher_encrypt(s->cipher,
in_buf,
out_buf,
512,
errp);
} else {
ret = qcrypto_cipher_decrypt(s->cipher,
in_buf,
out_buf,
512,
errp);
}
if (ret < 0) {
return -1;
}
sector_num++;
in_buf += 512;
out_buf += 512;
}
return 0;
}
static int coroutine_fn copy_sectors(BlockDriverState *bs,
@ -401,10 +422,15 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
}
if (bs->encrypted) {
assert(s->crypt_method);
qcow2_encrypt_sectors(s, start_sect + n_start,
iov.iov_base, iov.iov_base, n, 1,
&s->aes_encrypt_key);
Error *err = NULL;
assert(s->cipher);
if (qcow2_encrypt_sectors(s, start_sect + n_start,
iov.iov_base, iov.iov_base, n,
true, &err) < 0) {
ret = -EIO;
error_free(err);
goto out;
}
}
ret = qcow2_pre_write_overlap_check(bs, 0,

95
block/qcow2.c
View File

@ -698,6 +698,11 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
ret = -EINVAL;
goto fail;
}
if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
error_setg(errp, "AES cipher not available");
ret = -EINVAL;
goto fail;
}
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header) {
bs->encrypted = 1;
@ -1031,6 +1036,7 @@ static int qcow2_set_key(BlockDriverState *bs, const char *key)
BDRVQcowState *s = bs->opaque;
uint8_t keybuf[16];
int len, i;
Error *err = NULL;
memset(keybuf, 0, 16);
len = strlen(key);
@ -1042,30 +1048,21 @@ static int qcow2_set_key(BlockDriverState *bs, const char *key)
keybuf[i] = key[i];
}
assert(bs->encrypted);
s->crypt_method = s->crypt_method_header;
if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
qcrypto_cipher_free(s->cipher);
s->cipher = qcrypto_cipher_new(
QCRYPTO_CIPHER_ALG_AES_128,
QCRYPTO_CIPHER_MODE_CBC,
keybuf, G_N_ELEMENTS(keybuf),
&err);
if (!s->cipher) {
/* XXX would be nice if errors in this method could
* be properly propagate to the caller. Would need
* the bdrv_set_key() API signature to be fixed. */
error_free(err);
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;
}
@ -1108,7 +1105,7 @@ static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
}
if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
!s->crypt_method) {
!s->cipher) {
index_in_cluster = sector_num & (s->cluster_sectors - 1);
cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
@ -1158,7 +1155,7 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
/* prepare next request */
cur_nr_sectors = remaining_sectors;
if (s->crypt_method) {
if (s->cipher) {
cur_nr_sectors = MIN(cur_nr_sectors,
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
}
@ -1230,7 +1227,7 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
}
if (bs->encrypted) {
assert(s->crypt_method);
assert(s->cipher);
/*
* For encrypted images, read everything into a temporary
@ -1263,9 +1260,15 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
goto fail;
}
if (bs->encrypted) {
assert(s->crypt_method);
qcow2_encrypt_sectors(s, sector_num, cluster_data,
cluster_data, cur_nr_sectors, 0, &s->aes_decrypt_key);
assert(s->cipher);
Error *err = NULL;
if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
cluster_data, cur_nr_sectors, false,
&err) < 0) {
error_free(err);
ret = -EIO;
goto fail;
}
qemu_iovec_from_buf(qiov, bytes_done,
cluster_data, 512 * cur_nr_sectors);
}
@ -1343,7 +1346,8 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
cur_nr_sectors * 512);
if (bs->encrypted) {
assert(s->crypt_method);
Error *err = NULL;
assert(s->cipher);
if (!cluster_data) {
cluster_data = qemu_try_blockalign(bs->file,
QCOW_MAX_CRYPT_CLUSTERS
@ -1358,8 +1362,13 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
qcow2_encrypt_sectors(s, sector_num, cluster_data,
cluster_data, cur_nr_sectors, 1, &s->aes_encrypt_key);
if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
cluster_data, cur_nr_sectors,
true, &err) < 0) {
error_free(err);
ret = -EIO;
goto fail;
}
qemu_iovec_reset(&hd_qiov);
qemu_iovec_add(&hd_qiov, cluster_data,
@ -1465,6 +1474,9 @@ static void qcow2_close(BlockDriverState *bs)
qcow2_cache_destroy(bs, s->l2_table_cache);
qcow2_cache_destroy(bs, s->refcount_block_cache);
qcrypto_cipher_free(s->cipher);
s->cipher = NULL;
g_free(s->unknown_header_fields);
cleanup_unknown_header_ext(bs);
@ -1481,9 +1493,7 @@ static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
{
BDRVQcowState *s = bs->opaque;
int flags = s->flags;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
uint32_t crypt_method = 0;
QCryptoCipher *cipher = NULL;
QDict *options;
Error *local_err = NULL;
int ret;
@ -1493,12 +1503,8 @@ static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
* that means we don't have to worry about reopening them here.
*/
if (bs->encrypted) {
assert(s->crypt_method);
crypt_method = s->crypt_method;
memcpy(&aes_encrypt_key, &s->aes_encrypt_key, sizeof(aes_encrypt_key));
memcpy(&aes_decrypt_key, &s->aes_decrypt_key, sizeof(aes_decrypt_key));
}
cipher = s->cipher;
s->cipher = NULL;
qcow2_close(bs);
@ -1523,11 +1529,7 @@ static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
return;
}
if (bs->encrypted) {
s->crypt_method = crypt_method;
memcpy(&s->aes_encrypt_key, &aes_encrypt_key, sizeof(aes_encrypt_key));
memcpy(&s->aes_decrypt_key, &aes_decrypt_key, sizeof(aes_decrypt_key));
}
s->cipher = cipher;
}
static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
@ -2728,8 +2730,9 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
} else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
s->crypt_method);
if (encrypt != !!s->crypt_method) {
!!s->cipher);
if (encrypt != !!s->cipher) {
fprintf(stderr, "Changing the encryption flag is not "
"supported.\n");
return -ENOTSUP;

13
block/qcow2.h
View File

@ -25,7 +25,7 @@
#ifndef BLOCK_QCOW2_H
#define BLOCK_QCOW2_H
#include "crypto/aes.h"
#include "crypto/cipher.h"
#include "block/coroutine.h"
//#define DEBUG_ALLOC
@ -253,10 +253,8 @@ typedef struct BDRVQcowState {
CoMutex lock;
uint32_t crypt_method; /* current crypt method, 0 if no key yet */
QCryptoCipher *cipher; /* current cipher, NULL if no key yet */
uint32_t crypt_method_header;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
uint64_t snapshots_offset;
int snapshots_size;
unsigned int nb_snapshots;
@ -536,10 +534,9 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
void qcow2_l2_cache_reset(BlockDriverState *bs);
int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
void qcow2_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);
int qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
uint8_t *out_buf, const uint8_t *in_buf,
int nb_sectors, bool enc, Error **errp);
int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
int *num, uint64_t *cluster_offset);