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qcow: make encrypt_sectors encrypt in place

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Instead of requiring separate input/output buffers for
encrypting data, change encrypt_sectors() to assume
use of a single buffer, encrypting in place. One current
caller uses the same buffer for input/output already
and the other two callers are easily converted to do so.

Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-9-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Daniel P. Berrange 2017-06-23 17:24:07 +01:00 committed by Max Reitz
parent 0cb8d47ba9
commit 1fad1f9400
1 changed files with 15 additions and 30 deletions
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45
block/qcow.c
View file

@ -322,11 +322,10 @@ static int qcow_set_key(BlockDriverState *bs, const char *key)
}
/* The crypt function is compatible with the linux cryptoloop
algorithm for < 4 GB images. NOTE: out_buf == in_buf is
supported */
algorithm for < 4 GB images. */
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)
uint8_t *buf, int nb_sectors, bool enc,
Error **errp)
{
union {
uint64_t ll[2];
@ -345,14 +344,12 @@ static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
}
if (enc) {
ret = qcrypto_cipher_encrypt(s->cipher,
in_buf,
out_buf,
buf, buf,
512,
errp);
} else {
ret = qcrypto_cipher_decrypt(s->cipher,
in_buf,
out_buf,
buf, buf,
512,
errp);
}
@ -360,8 +357,7 @@ static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
return -1;
}
sector_num++;
in_buf += 512;
out_buf += 512;
buf += 512;
}
return 0;
}
@ -481,13 +477,12 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t start_sect;
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) {
Error *err = NULL;
memset(s->cluster_data, 0x00, 512);
if (encrypt_sectors(s, start_sect + i,
s->cluster_data,
s->cluster_data + 512, 1,
s->cluster_data, 1,
true, &err) < 0) {
error_free(err);
errno = EIO;
@ -665,7 +660,7 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
}
if (bs->encrypted) {
assert(s->cipher);
if (encrypt_sectors(s, sector_num, buf, buf,
if (encrypt_sectors(s, sector_num, buf,
n, false, &err) < 0) {
goto fail;
}
@ -700,9 +695,7 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
BDRVQcowState *s = bs->opaque;
int index_in_cluster;
uint64_t cluster_offset;
const uint8_t *src_buf;
int ret = 0, n;
uint8_t *cluster_data = NULL;
struct iovec hd_iov;
QEMUIOVector hd_qiov;
uint8_t *buf;
@ -710,7 +703,9 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
s->cluster_cache_offset = -1; /* disable compressed cache */
if (qiov->niov > 1) {
/* We must always copy the iov when encrypting, so we
* don't modify the original data buffer during encryption */
if (bs->encrypted || qiov->niov > 1) {
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
@ -740,21 +735,14 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
if (bs->encrypted) {
Error *err = NULL;
assert(s->cipher);
if (!cluster_data) {
cluster_data = g_malloc0(s->cluster_size);
}
if (encrypt_sectors(s, sector_num, cluster_data, buf,
n, true, &err) < 0) {
if (encrypt_sectors(s, sector_num, buf, n, true, &err) < 0) {
error_free(err);
ret = -EIO;
break;
}
src_buf = cluster_data;
} else {
src_buf = buf;
}
hd_iov.iov_base = (void *)src_buf;
hd_iov.iov_base = (void *)buf;
hd_iov.iov_len = n * 512;
qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
qemu_co_mutex_unlock(&s->lock);
@ -773,10 +761,7 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
}
qemu_co_mutex_unlock(&s->lock);
if (qiov->niov > 1) {
qemu_vfree(orig_buf);
}
g_free(cluster_data);
qemu_vfree(orig_buf);
return ret;
}