freebsd-skq/sys/geom/eli/g_eli_privacy.c
pjd d5e7511690 Bring in geli suspend/resume functionality (finally).
Before this change if you wanted to suspend your laptop and be sure that your
encryption keys are safe, you had to stop all processes that use file system
stored on encrypted device, unmount the file system and detach geli provider.

This isn't very handy. If you are a lucky user of a laptop where suspend/resume
actually works with FreeBSD (I'm not!) you most likely want to suspend your
laptop, because you don't want to start everything over again when you turn
your laptop back on.

And this is where geli suspend/resume steps in. When you execute:

	# geli suspend -a

geli will wait for all in-flight I/O requests, suspend new I/O requests, remove
all geli sensitive data from the kernel memory (like encryption keys) and will
wait for either 'geli resume' or 'geli detach'.

Now with no keys in memory you can suspend your laptop without stopping any
processes or unmounting any file systems.

When you resume your laptop you have to resume geli devices using 'geli resume'
command. You need to provide your passphrase, etc. again so the keys can be
restored and suspended I/O requests released.

Of course you need to remember that 'geli suspend' won't clear file system
cache and other places where data from your geli-encrypted file system might be
present. But to get rid of those stopping processes and unmounting file system
won't help either - you have to turn your laptop off. Be warned.

Also note, that suspending geli device which contains file system with geli
utility (or anything used by 'geli resume') is not very good idea, as you won't
be able to resume it - when you execute geli(8), the kernel will try to read it
and this read I/O request will be suspended.
2010-10-20 20:50:55 +00:00

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9.3 KiB
C

/*-
* Copyright (c) 2005-2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* 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/uio.h>
#include <sys/vnode.h>
#include <vm/uma.h>
#include <geom/geom.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_olen;
} 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;
}
/*
* 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.
*/
sc = bp->bio_to->geom->softc;
g_io_deliver(bp, bp->bio_error);
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;
}
/*
* 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;
gp = bp->bio_to->geom;
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);
sc = gp->softc;
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;
struct cryptodesc *crd;
struct uio *uio;
struct iovec *iov;
u_int i, nsec, secsize;
int err, error;
off_t dstoff;
size_t size;
u_char *p, *data;
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;
/*
* Calculate how much memory do we need.
* We need separate crypto operation for every single sector.
* It is much faster to calculate total amount of needed memory here and
* do the allocation once instead of allocating memory in pieces (many,
* many pieces).
*/
size = sizeof(*crp) * nsec;
size += sizeof(*crd) * nsec;
size += sizeof(*uio) * nsec;
size += sizeof(*iov) * 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)
size += bp->bio_length;
p = malloc(size, M_ELI, M_WAITOK);
bp->bio_inbed = 0;
bp->bio_children = nsec;
bp->bio_driver2 = p;
if (bp->bio_cmd == BIO_READ)
data = bp->bio_data;
else {
data = p;
p += bp->bio_length;
bcopy(bp->bio_data, data, bp->bio_length);
}
error = 0;
for (i = 0, dstoff = bp->bio_offset; i < nsec; i++, dstoff += secsize) {
crp = (struct cryptop *)p; p += sizeof(*crp);
crd = (struct cryptodesc *)p; p += sizeof(*crd);
uio = (struct uio *)p; p += sizeof(*uio);
iov = (struct iovec *)p; p += sizeof(*iov);
iov->iov_len = secsize;
iov->iov_base = data;
data += secsize;
uio->uio_iov = iov;
uio->uio_iovcnt = 1;
uio->uio_segflg = UIO_SYSSPACE;
uio->uio_resid = secsize;
crp->crp_sid = wr->w_sid;
crp->crp_ilen = secsize;
crp->crp_olen = secsize;
crp->crp_opaque = (void *)bp;
crp->crp_buf = (void *)uio;
if (bp->bio_cmd == BIO_WRITE)
crp->crp_callback = g_eli_crypto_write_done;
else /* if (bp->bio_cmd == BIO_READ) */
crp->crp_callback = g_eli_crypto_read_done;
crp->crp_flags = CRYPTO_F_IOV | CRYPTO_F_CBIFSYNC | CRYPTO_F_REL;
if (g_eli_batch)
crp->crp_flags |= CRYPTO_F_BATCH;
crp->crp_desc = crd;
crd->crd_skip = 0;
crd->crd_len = secsize;
crd->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT;
if (sc->sc_nekeys > 1)
crd->crd_flags |= CRD_F_KEY_EXPLICIT;
if (bp->bio_cmd == BIO_WRITE)
crd->crd_flags |= CRD_F_ENCRYPT;
crd->crd_alg = sc->sc_ealgo;
crd->crd_key = g_eli_crypto_key(sc, dstoff, secsize);
crd->crd_klen = sc->sc_ekeylen;
if (sc->sc_ealgo == CRYPTO_AES_XTS)
crd->crd_klen <<= 1;
g_eli_crypto_ivgen(sc, dstoff, crd->crd_iv,
sizeof(crd->crd_iv));
crd->crd_next = NULL;
crp->crp_etype = 0;
err = crypto_dispatch(crp);
if (error == 0)
error = err;
}
if (bp->bio_error == 0)
bp->bio_error = error;
}