Commit 603fbd07 authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Max Reitz
Browse files

block/qcow2: refactor encryption code 



* Change the qcow2_co_{encrypt|decrypt} to just receive full host and
  guest offsets and use this function directly instead of calling
  do_perform_cow_encrypt (which is removed by that patch).

* Adjust qcow2_co_encdec to take full host and guest offsets as well.

* Document the qcow2_co_{encrypt|decrypt} arguments
  to prevent the bug fixed in former commit from hopefully
  happening again.

Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-id: 20190915203655.21638-3-mlevitsk@redhat.com
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[mreitz: Let perform_cow() return the error value returned by
         qcow2_co_encrypt(), as proposed by Vladimir]
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 38e7d54b

block/qcow2-cluster.c

+13 −28
Original line number Diff line number Diff line
@@ -462,28 +462,6 @@ static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, 
    return 0;

}



static bool coroutine_fn do_perform_cow_encrypt(BlockDriverState *bs,

                                                uint64_t src_cluster_offset,

                                                uint64_t cluster_offset,

                                                unsigned offset_in_cluster,

                                                uint8_t *buffer,

                                                unsigned bytes)

{

    if (bytes && bs->encrypted) {

        BDRVQcow2State *s = bs->opaque;

        assert(QEMU_IS_ALIGNED(offset_in_cluster, BDRV_SECTOR_SIZE));

        assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));

        assert(s->crypto);

        if (qcow2_co_encrypt(bs,

                start_of_cluster(s, cluster_offset + offset_in_cluster),

                src_cluster_offset + offset_in_cluster,

                buffer, bytes) < 0) {

            return false;

        }

    }

    return true;

}



static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,

                                             uint64_t cluster_offset,

                                             unsigned offset_in_cluster,
@@ -891,12 +869,19 @@ static int perform_cow(BlockDriverState *bs, QCowL2Meta *m) 


    /* Encrypt the data if necessary before writing it */

    if (bs->encrypted) {

        if (!do_perform_cow_encrypt(bs, m->offset, m->alloc_offset,

                                    start->offset, start_buffer,

                                    start->nb_bytes) ||

            !do_perform_cow_encrypt(bs, m->offset, m->alloc_offset,

                                    end->offset, end_buffer, end->nb_bytes)) {

            ret = -EIO;

        ret = qcow2_co_encrypt(bs,

                               m->alloc_offset + start->offset,

                               m->offset + start->offset,

                               start_buffer, start->nb_bytes);

        if (ret < 0) {

            goto fail;

        }



        ret = qcow2_co_encrypt(bs,

                               m->alloc_offset + end->offset,

                               m->offset + end->offset,

                               end_buffer, end->nb_bytes);

        if (ret < 0) {

            goto fail;

        }

    }

block/qcow2-threads.c

+49 −14
Original line number Diff line number Diff line
@@ -234,35 +234,70 @@ static int qcow2_encdec_pool_func(void *opaque) 
}



static int coroutine_fn

qcow2_co_encdec(BlockDriverState *bs, uint64_t file_cluster_offset,

                  uint64_t offset, void *buf, size_t len, Qcow2EncDecFunc func)

qcow2_co_encdec(BlockDriverState *bs, uint64_t host_offset,

                uint64_t guest_offset, void *buf, size_t len,

                Qcow2EncDecFunc func)

{

    BDRVQcow2State *s = bs->opaque;

    Qcow2EncDecData arg = {

        .block = s->crypto,

        .offset = s->crypt_physical_offset ?

                      file_cluster_offset + offset_into_cluster(s, offset) :

                      offset,

        .offset = s->crypt_physical_offset ? host_offset : guest_offset,

        .buf = buf,

        .len = len,

        .func = func,

    };



    return qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);

    assert(QEMU_IS_ALIGNED(guest_offset, BDRV_SECTOR_SIZE));

    assert(QEMU_IS_ALIGNED(host_offset, BDRV_SECTOR_SIZE));

    assert(QEMU_IS_ALIGNED(len, BDRV_SECTOR_SIZE));

    assert(s->crypto);



    return len == 0 ? 0 : qcow2_co_process(bs, qcow2_encdec_pool_func, &arg);

}



/*

 * qcow2_co_encrypt()

 *

 * Encrypts one or more contiguous aligned sectors

 *

 * @host_offset - underlying storage offset of the first sector of the

 * data to be encrypted

 *

 * @guest_offset - guest (virtual) offset of the first sector of the

 * data to be encrypted

 *

 * @buf - buffer with the data to encrypt, that after encryption

 *        will be written to the underlying storage device at

 *        @host_offset

 *

 * @len - length of the buffer (must be a BDRV_SECTOR_SIZE multiple)

 *

 * Depending on the encryption method, @host_offset and/or @guest_offset

 * may be used for generating the initialization vector for

 * encryption.

 *

 * Note that while the whole range must be aligned on sectors, it

 * does not have to be aligned on clusters and can also cross cluster

 * boundaries

 */

int coroutine_fn

qcow2_co_encrypt(BlockDriverState *bs, uint64_t file_cluster_offset,

                 uint64_t offset, void *buf, size_t len)

qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,

                 uint64_t guest_offset, void *buf, size_t len)

{

    return qcow2_co_encdec(bs, file_cluster_offset, offset, buf, len,

    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,

                           qcrypto_block_encrypt);

}



/*

 * qcow2_co_decrypt()

 *

 * Decrypts one or more contiguous aligned sectors

 * Similar to qcow2_co_encrypt

 */

int coroutine_fn

qcow2_co_decrypt(BlockDriverState *bs, uint64_t file_cluster_offset,

                 uint64_t offset, void *buf, size_t len)

qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,

                 uint64_t guest_offset, void *buf, size_t len)

{

    return qcow2_co_encdec(bs, file_cluster_offset, offset, buf, len,

    return qcow2_co_encdec(bs, host_offset, guest_offset, buf, len,

                           qcrypto_block_decrypt);

}

block/qcow2.c

+3 −2
Original line number Diff line number Diff line
@@ -2069,7 +2069,8 @@ static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs, 


                assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));

                assert(QEMU_IS_ALIGNED(cur_bytes, BDRV_SECTOR_SIZE));

                if (qcow2_co_decrypt(bs, cluster_offset, offset,

                if (qcow2_co_decrypt(bs, cluster_offset + offset_in_cluster,

                                     offset,

                                     cluster_data, cur_bytes) < 0) {

                    ret = -EIO;

                    goto fail;
@@ -2288,7 +2289,7 @@ static coroutine_fn int qcow2_co_pwritev_part( 
            qemu_iovec_to_buf(qiov, qiov_offset + bytes_done,

                              cluster_data, cur_bytes);



            if (qcow2_co_encrypt(bs, cluster_offset, offset,

            if (qcow2_co_encrypt(bs, cluster_offset + offset_in_cluster, offset,

                                 cluster_data, cur_bytes) < 0) {

                ret = -EIO;

                goto out_unlocked;

block/qcow2.h

+4 −4
Original line number Diff line number Diff line
@@ -758,10 +758,10 @@ ssize_t coroutine_fn 
qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,

                    const void *src, size_t src_size);

int coroutine_fn

qcow2_co_encrypt(BlockDriverState *bs, uint64_t file_cluster_offset,

                 uint64_t offset, void *buf, size_t len);

qcow2_co_encrypt(BlockDriverState *bs, uint64_t host_offset,

                 uint64_t guest_offset, void *buf, size_t len);

int coroutine_fn

qcow2_co_decrypt(BlockDriverState *bs, uint64_t file_cluster_offset,

                 uint64_t offset, void *buf, size_t len);

qcow2_co_decrypt(BlockDriverState *bs, uint64_t host_offset,

                 uint64_t guest_offset, void *buf, size_t len);



#endif