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freebsd-dev/sys/geom/eli/g_eli_privacy.c
John Baldwin 9c0e3d3a53 Add support for optional separate output buffers to in-kernel crypto. 
Some crypto consumers such as GELI and KTLS for file-backed sendfile
need to store their output in a separate buffer from the input.
Currently these consumers copy the contents of the input buffer into
the output buffer and queue an in-place crypto operation on the output
buffer.  Using a separate output buffer avoids this copy.

- Create a new 'struct crypto_buffer' describing a crypto buffer
  containing a type and type-specific fields.  crp_ilen is gone,
  instead buffers that use a flat kernel buffer have a cb_buf_len
  field for their length.  The length of other buffer types is
  inferred from the backing store (e.g. uio_resid for a uio).
  Requests now have two such structures: crp_buf for the input buffer,
  and crp_obuf for the output buffer.

- Consumers now use helper functions (crypto_use_*,
  e.g. crypto_use_mbuf()) to configure the input buffer.  If an output
  buffer is not configured, the request still modifies the input
  buffer in-place.  A consumer uses a second set of helper functions
  (crypto_use_output_*) to configure an output buffer.

- Consumers must request support for separate output buffers when
  creating a crypto session via the CSP_F_SEPARATE_OUTPUT flag and are
  only permitted to queue a request with a separate output buffer on
  sessions with this flag set.  Existing drivers already reject
  sessions with unknown flags, so this permits drivers to be modified
  to support this extension without requiring all drivers to change.

- Several data-related functions now have matching versions that
  operate on an explicit buffer (e.g. crypto_apply_buf,
  crypto_contiguous_subsegment_buf, bus_dma_load_crp_buf).

- Most of the existing data-related functions operate on the input
  buffer.  However crypto_copyback always writes to the output buffer
  if a request uses a separate output buffer.

- For the regions in input/output buffers, the following conventions
  are followed:
  - AAD and IV are always present in input only and their
    fields are offsets into the input buffer.
  - payload is always present in both buffers.  If a request uses a
    separate output buffer, it must set a new crp_payload_start_output
    field to the offset of the payload in the output buffer.
  - digest is in the input buffer for verify operations, and in the
    output buffer for compute operations.  crp_digest_start is relative
    to the appropriate buffer.

- Add a crypto buffer cursor abstraction.  This is a more general form
  of some bits in the cryptosoft driver that tried to always use uio's.
  However, compared to the original code, this avoids rewalking the uio
  iovec array for requests with multiple vectors.  It also avoids
  allocate an iovec array for mbufs and populating it by instead walking
  the mbuf chain directly.

- Update the cryptosoft(4) driver to support separate output buffers
  making use of the cursor abstraction.

Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D24545
2020-05-25 22:12:04 +00:00

297 lines
8.5 KiB
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2005-2011 Pawel Jakub Dawidek <pawel@dawidek.net>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/bio.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/kthread.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/vnode.h>
#include <vm/uma.h>
#include <geom/geom.h>
#include <geom/geom_dbg.h>
#include <geom/eli/g_eli.h>
#include <geom/eli/pkcs5v2.h>
/*
* Code paths:
* BIO_READ:
* g_eli_start -> g_eli_crypto_read -> g_io_request -> g_eli_read_done -> g_eli_crypto_run -> g_eli_crypto_read_done -> g_io_deliver
* BIO_WRITE:
* g_eli_start -> g_eli_crypto_run -> g_eli_crypto_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
*/
MALLOC_DECLARE(M_ELI);
/*
* The function is called after we read and decrypt data.
*
* g_eli_start -> g_eli_crypto_read -> g_io_request -> g_eli_read_done -> g_eli_crypto_run -> G_ELI_CRYPTO_READ_DONE -> g_io_deliver
*/
static int
g_eli_crypto_read_done(struct cryptop *crp)
{
struct g_eli_softc *sc;
struct bio *bp;
if (crp->crp_etype == EAGAIN) {
if (g_eli_crypto_rerun(crp) == 0)
return (0);
}
bp = (struct bio *)crp->crp_opaque;
bp->bio_inbed++;
if (crp->crp_etype == 0) {
G_ELI_DEBUG(3, "Crypto READ request done (%d/%d).",
bp->bio_inbed, bp->bio_children);
bp->bio_completed += crp->crp_payload_length;
} else {
G_ELI_DEBUG(1, "Crypto READ request failed (%d/%d) error=%d.",
bp->bio_inbed, bp->bio_children, crp->crp_etype);
if (bp->bio_error == 0)
bp->bio_error = crp->crp_etype;
}
sc = bp->bio_to->geom->softc;
if (sc != NULL && crp->crp_cipher_key != NULL)
g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
crypto_freereq(crp);
/*
* Do we have all sectors already?
*/
if (bp->bio_inbed < bp->bio_children)
return (0);
free(bp->bio_driver2, M_ELI);
bp->bio_driver2 = NULL;
if (bp->bio_error != 0) {
G_ELI_LOGREQ(0, bp, "Crypto READ request failed (error=%d).",
bp->bio_error);
bp->bio_completed = 0;
}
/*
* Read is finished, send it up.
*/
g_io_deliver(bp, bp->bio_error);
if (sc != NULL)
atomic_subtract_int(&sc->sc_inflight, 1);
return (0);
}
/*
* The function is called after data encryption.
*
* g_eli_start -> g_eli_crypto_run -> G_ELI_CRYPTO_WRITE_DONE -> g_io_request -> g_eli_write_done -> g_io_deliver
*/
static int
g_eli_crypto_write_done(struct cryptop *crp)
{
struct g_eli_softc *sc;
struct g_geom *gp;
struct g_consumer *cp;
struct bio *bp, *cbp;
if (crp->crp_etype == EAGAIN) {
if (g_eli_crypto_rerun(crp) == 0)
return (0);
}
bp = (struct bio *)crp->crp_opaque;
bp->bio_inbed++;
if (crp->crp_etype == 0) {
G_ELI_DEBUG(3, "Crypto WRITE request done (%d/%d).",
bp->bio_inbed, bp->bio_children);
} else {
G_ELI_DEBUG(1, "Crypto WRITE request failed (%d/%d) error=%d.",
bp->bio_inbed, bp->bio_children, crp->crp_etype);
if (bp->bio_error == 0)
bp->bio_error = crp->crp_etype;
}
gp = bp->bio_to->geom;
sc = gp->softc;
if (crp->crp_cipher_key != NULL)
g_eli_key_drop(sc, __DECONST(void *, crp->crp_cipher_key));
crypto_freereq(crp);
/*
* All sectors are already encrypted?
*/
if (bp->bio_inbed < bp->bio_children)
return (0);
bp->bio_inbed = 0;
bp->bio_children = 1;
cbp = bp->bio_driver1;
bp->bio_driver1 = NULL;
if (bp->bio_error != 0) {
G_ELI_LOGREQ(0, bp, "Crypto WRITE request failed (error=%d).",
bp->bio_error);
free(bp->bio_driver2, M_ELI);
bp->bio_driver2 = NULL;
g_destroy_bio(cbp);
g_io_deliver(bp, bp->bio_error);
atomic_subtract_int(&sc->sc_inflight, 1);
return (0);
}
cbp->bio_data = bp->bio_driver2;
cbp->bio_done = g_eli_write_done;
cp = LIST_FIRST(&gp->consumer);
cbp->bio_to = cp->provider;
G_ELI_LOGREQ(2, cbp, "Sending request.");
/*
* Send encrypted data to the provider.
*/
g_io_request(cbp, cp);
return (0);
}
/*
* The function is called to read encrypted data.
*
* g_eli_start -> G_ELI_CRYPTO_READ -> g_io_request -> g_eli_read_done -> g_eli_crypto_run -> g_eli_crypto_read_done -> g_io_deliver
*/
void
g_eli_crypto_read(struct g_eli_softc *sc, struct bio *bp, boolean_t fromworker)
{
struct g_consumer *cp;
struct bio *cbp;
if (!fromworker) {
/*
* We are not called from the worker thread, so check if
* device is suspended.
*/
mtx_lock(&sc->sc_queue_mtx);
if (sc->sc_flags & G_ELI_FLAG_SUSPEND) {
/*
* If device is suspended, we place the request onto
* the queue, so it can be handled after resume.
*/
G_ELI_DEBUG(0, "device suspended, move onto queue");
bioq_insert_tail(&sc->sc_queue, bp);
mtx_unlock(&sc->sc_queue_mtx);
wakeup(sc);
return;
}
atomic_add_int(&sc->sc_inflight, 1);
mtx_unlock(&sc->sc_queue_mtx);
}
bp->bio_pflags = 0;
bp->bio_driver2 = NULL;
cbp = bp->bio_driver1;
cbp->bio_done = g_eli_read_done;
cp = LIST_FIRST(&sc->sc_geom->consumer);
cbp->bio_to = cp->provider;
G_ELI_LOGREQ(2, cbp, "Sending request.");
/*
* Read encrypted data from provider.
*/
g_io_request(cbp, cp);
}
/*
* This is the main function responsible for cryptography (ie. communication
* with crypto(9) subsystem).
*
* BIO_READ:
* g_eli_start -> g_eli_crypto_read -> g_io_request -> g_eli_read_done -> G_ELI_CRYPTO_RUN -> g_eli_crypto_read_done -> g_io_deliver
* BIO_WRITE:
* g_eli_start -> G_ELI_CRYPTO_RUN -> g_eli_crypto_write_done -> g_io_request -> g_eli_write_done -> g_io_deliver
*/
void
g_eli_crypto_run(struct g_eli_worker *wr, struct bio *bp)
{
struct g_eli_softc *sc;
struct cryptop *crp;
u_int i, nsec, secsize;
off_t dstoff;
u_char *data;
int error;
G_ELI_LOGREQ(3, bp, "%s", __func__);
bp->bio_pflags = wr->w_number;
sc = wr->w_softc;
secsize = LIST_FIRST(&sc->sc_geom->provider)->sectorsize;
nsec = bp->bio_length / secsize;
bp->bio_inbed = 0;
bp->bio_children = nsec;
/*
* If we write the data we cannot destroy current bio_data content,
* so we need to allocate more memory for encrypted data.
*/
if (bp->bio_cmd == BIO_WRITE) {
data = malloc(bp->bio_length, M_ELI, M_WAITOK);
bp->bio_driver2 = data;
bcopy(bp->bio_data, data, bp->bio_length);
} else
data = bp->bio_data;
for (i = 0, dstoff = bp->bio_offset; i < nsec; i++, dstoff += secsize) {
crp = crypto_getreq(wr->w_sid, M_WAITOK);
crypto_use_buf(crp, data, secsize);
crp->crp_opaque = (void *)bp;
data += secsize;
if (bp->bio_cmd == BIO_WRITE) {
crp->crp_op = CRYPTO_OP_ENCRYPT;
crp->crp_callback = g_eli_crypto_write_done;
} else /* if (bp->bio_cmd == BIO_READ) */ {
crp->crp_op = CRYPTO_OP_DECRYPT;
crp->crp_callback = g_eli_crypto_read_done;
}
crp->crp_flags = CRYPTO_F_CBIFSYNC;
if (g_eli_batch)
crp->crp_flags |= CRYPTO_F_BATCH;
crp->crp_payload_start = 0;
crp->crp_payload_length = secsize;
crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
if ((sc->sc_flags & G_ELI_FLAG_SINGLE_KEY) == 0) {
crp->crp_cipher_key = g_eli_key_hold(sc, dstoff,
secsize);
}
g_eli_crypto_ivgen(sc, dstoff, crp->crp_iv,
sizeof(crp->crp_iv));
error = crypto_dispatch(crp);
KASSERT(error == 0, ("crypto_dispatch() failed (error=%d)",
error));
}
}
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