Make bsd_disklabel_le_enc calculate the checksum and fill it in.

(If there is a legitimate need to correctly encode and pack a
disklabel with an invalid checksum custom tools can be built for
that.)

Make bsd_disklabel_le_dec() validate the magics, number of partitions
(against a new parameter) and the checksum.

Vastly simplify the logic of the GEOM::BSD class implementation:

Let g_bsd_modify() always take a byte-stream label.

This simplifies all users, except the ioctl's which now have to
convert to a byte-stream first.  Their loss.

g_bsd_modify() is called with topology held now, and it returns
with it held.

Always update the md5sum in g_bsd_modify(), otherwise the check
is no use after the first modification of the label.  Make the
MD5 over the bytestream version of the label.

Move the rawoffset hack to g_bsd_modify() and remove all the
inram/ondisk conversions.

Don't configure hotspots in g_bsd_modify(), do it in taste instead,
we do not support moving the label to a different location on the
fly anyway.

This passes all current regression tests.
This commit is contained in:
Poul-Henning Kamp 2003-05-02 22:46:13 +00:00
parent 0477e337c2
commit 56dde750d5
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=114556
3 changed files with 150 additions and 269 deletions

View File

@ -58,6 +58,8 @@
#define ALPHA_LABEL_OFFSET 64
#define LABELSIZE (148 + 16 * MAXPARTITIONS)
static void g_bsd_hotwrite(void *arg, int flag);
/*
* Our private data about one instance. All the rest is handled by the
@ -69,123 +71,16 @@ struct g_bsd_softc {
off_t mbroffset;
off_t rawoffset;
struct disklabel ondisk;
struct disklabel inram;
u_char label[LABELSIZE];
u_char labelsum[16];
};
static int
g_bsd_ondisk_size(void)
{
return (148 + 16 * MAXPARTITIONS);
}
/*
* For reasons which were valid and just in their days, FreeBSD/i386 uses
* absolute disk-addresses in disklabels. The way it works is that the
* p_offset field of all partitions have the first sector number of the
* disk slice added to them. This was hidden kernel-magic, userland did
* not see these offsets. These two functions subtract and add them
* while converting from the "ondisk" to the "inram" labels and vice
* versa.
*/
static void
ondisk2inram(struct g_bsd_softc *sc)
{
struct partition *ppp;
struct disklabel *dl;
int i;
sc->inram = sc->ondisk;
dl = &sc->inram;
/* Basic sanity-check needed to avoid mistakes. */
if (dl->d_magic != DISKMAGIC || dl->d_magic2 != DISKMAGIC)
return;
if (dl->d_npartitions > MAXPARTITIONS)
return;
sc->rawoffset = dl->d_partitions[RAW_PART].p_offset;
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
if (ppp->p_size != 0 && ppp->p_offset < sc->rawoffset)
sc->rawoffset = 0;
}
if (sc->rawoffset > 0) {
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
if (ppp->p_offset != 0)
ppp->p_offset -= sc->rawoffset;
}
}
dl->d_checksum = 0;
dl->d_checksum = dkcksum(&sc->inram);
}
static void
inram2ondisk(struct g_bsd_softc *sc)
{
struct partition *ppp;
int i;
sc->ondisk = sc->inram;
if (sc->mbroffset != 0)
sc->rawoffset = sc->mbroffset / sc->inram.d_secsize;
if (sc->rawoffset != 0) {
for (i = 0; i < sc->inram.d_npartitions; i++) {
ppp = &sc->ondisk.d_partitions[i];
if (ppp->p_size > 0)
ppp->p_offset += sc->rawoffset;
else
ppp->p_offset = 0;
}
}
sc->ondisk.d_checksum = 0;
sc->ondisk.d_checksum = dkcksum(&sc->ondisk);
}
/*
* Check that this looks like a valid disklabel, but be prepared
* to get any kind of junk. The checksum must be checked only
* after this function returns success to prevent a bogus d_npartitions
* value from tripping us up.
*/
static int
g_bsd_checklabel(struct disklabel *dl)
{
struct partition *ppp;
int i;
if (dl->d_magic != DISKMAGIC || dl->d_magic2 != DISKMAGIC)
return (EINVAL);
/*
* If the label specifies more partitions than we can handle
* we have to reject it: If people updated the label they would
* trash it, and that would break the checksum.
*/
if (dl->d_npartitions > MAXPARTITIONS)
return (EINVAL);
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
/* Cannot extend past unit. */
if (ppp->p_size != 0 &&
ppp->p_offset + ppp->p_size > dl->d_secperunit) {
return (EINVAL);
}
}
return (0);
}
/*
* Modify our slicer to match proposed disklabel, if possible.
* First carry out all the simple checks, then lock topology
* and check that no open providers are affected negatively
* then carry out all the changes.
*
* NB: Returns with topology held only if successful return.
* This is where we make sure we don't do something stupid.
*/
static int
g_bsd_modify(struct g_geom *gp, struct disklabel *dl)
g_bsd_modify(struct g_geom *gp, u_char *label)
{
int i, error;
struct partition *ppp;
@ -193,33 +88,25 @@ g_bsd_modify(struct g_geom *gp, struct disklabel *dl)
struct g_consumer *cp;
struct g_bsd_softc *ms;
u_int secsize, u;
off_t mediasize;
off_t mediasize, rawoffset, o;
struct disklabel dl;
MD5_CTX md5sum;
/* Basic check that this is indeed a disklabel. */
error = g_bsd_checklabel(dl);
if (error)
g_topology_assert();
gsp = gp->softc;
ms = gsp->softc;
error = bsd_disklabel_le_dec(label, &dl, MAXPARTITIONS);
if (error) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return (error);
/* Make sure the checksum is OK. */
if (dkcksum(dl) != 0)
return (EINVAL);
}
/* Get dimensions of our device. */
cp = LIST_FIRST(&gp->consumer);
secsize = cp->provider->sectorsize;
mediasize = cp->provider->mediasize;
#ifdef nolonger
/*
* The raw-partition must start at zero. We do not check that the
* size == mediasize because this is overly restrictive. We have
* already tested in g_bsd_checklabel() that it is not longer.
* XXX: RAW_PART is archaic anyway, and we should drop it.
*/
if (dl->d_partitions[RAW_PART].p_offset != 0)
return (EINVAL);
#endif
#ifdef notyet
/*
* Indications are that the d_secperunit is not correctly
@ -229,73 +116,82 @@ g_bsd_modify(struct g_geom *gp, struct disklabel *dl)
* may be in order.
*/
/* The label cannot claim a larger size than the media. */
if ((off_t)dl->d_secperunit * dl->d_secsize > mediasize)
if ((off_t)dl.d_secperunit * dl.d_secsize > mediasize)
return (EINVAL);
#endif
/* ... or a smaller sector size. */
if (dl->d_secsize < secsize)
if (dl.d_secsize < secsize) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return (EINVAL);
}
/* ... or a non-multiple sector size. */
if (dl->d_secsize % secsize != 0)
if (dl.d_secsize % secsize != 0) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return (EINVAL);
}
g_topology_lock();
/* Historical braindamage... */
rawoffset = (off_t)dl.d_partitions[RAW_PART].p_offset * dl.d_secsize;
for (i = 0; i < dl.d_npartitions; i++) {
ppp = &dl.d_partitions[i];
if (ppp->p_size == 0)
continue;
o = (off_t)ppp->p_offset * dl.d_secsize;
if (o < rawoffset)
rawoffset = 0;
}
/* Don't munge open partitions. */
gsp = gp->softc;
ms = gsp->softc;
for (i = 0; i < dl->d_npartitions; i++) {
ppp = &dl->d_partitions[i];
for (i = 0; i < dl.d_npartitions; i++) {
ppp = &dl.d_partitions[i];
o = (off_t)ppp->p_offset * dl.d_secsize;
if (o == 0)
o = rawoffset;
error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
(off_t)ppp->p_offset * dl->d_secsize,
(off_t)ppp->p_size * dl->d_secsize,
dl->d_secsize,
o - rawoffset,
(off_t)ppp->p_size * dl.d_secsize,
dl.d_secsize,
"%s%c", gp->name, 'a' + i);
if (error) {
g_topology_unlock();
if (error)
return (error);
}
}
/* Look good, go for it... */
for (u = 0; u < gsp->nslice; u++) {
ppp = &dl->d_partitions[u];
ppp = &dl.d_partitions[u];
o = (off_t)ppp->p_offset * dl.d_secsize;
if (o == 0)
o = rawoffset;
g_slice_config(gp, u, G_SLICE_CONFIG_SET,
(off_t)ppp->p_offset * dl->d_secsize,
(off_t)ppp->p_size * dl->d_secsize,
dl->d_secsize,
o - rawoffset,
(off_t)ppp->p_size * dl.d_secsize,
dl.d_secsize,
"%s%c", gp->name, 'a' + u);
}
g_slice_conf_hot(gp, 0, ms->labeloffset, g_bsd_ondisk_size(),
G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
gsp->hot = g_bsd_hotwrite;
/* Update our softc */
ms->ondisk = dl;
if (label != ms->label)
bcopy(label, ms->label, LABELSIZE);
ms->rawoffset = rawoffset;
/*
* In order to avoid recursively attaching to the same
* on-disk label (it's usually visible through the 'c'
* partition) we calculate an MD5 and ask if other BSD's
* below us love that label. If they do, we don't.
*/
MD5Init(&md5sum);
MD5Update(&md5sum, ms->label, sizeof(ms->label));
MD5Final(ms->labelsum, &md5sum);
return (0);
}
/*
* Calculate a disklabel checksum for a little-endian byte-stream.
* We need access to the decoded disklabel because the checksum only
* covers the partition data for the first d_npartitions.
*/
static int
g_bsd_lesum(struct disklabel *dl, u_char *p)
{
u_char *pe;
uint16_t sum;
pe = p + 148 + 16 * dl->d_npartitions;
sum = 0;
while (p < pe) {
sum ^= le16dec(p);
p += 2;
}
return (sum);
}
/*
* This is an internal helper function, called multiple times from the taste
* function to try to locate a disklabel on the disk. More civilized formats
@ -323,17 +219,9 @@ g_bsd_try(struct g_geom *gp, struct g_slicer *gsp, struct g_consumer *cp, int se
/* Decode into our native format. */
dl = &ms->ondisk;
bsd_disklabel_le_dec(buf + secoff, dl);
ondisk2inram(ms);
dl = &ms->inram;
/* Does it look like a label at all? */
if (g_bsd_checklabel(dl))
error = ENOENT;
/* ... and does the raw data have a good checksum? */
if (error == 0 && g_bsd_lesum(dl, buf + secoff) != 0)
error = ENOENT;
error = bsd_disklabel_le_dec(buf + secoff, dl, MAXPARTITIONS);
if (!error)
bcopy(buf + secoff, ms->label, LABELSIZE);
/* Remember to free the buffer g_read_data() gave us. */
g_free(buf);
@ -357,47 +245,41 @@ g_bsd_ioctl(void *arg, int flag)
struct g_geom *gp;
struct g_slicer *gsp;
struct g_bsd_softc *ms;
struct disklabel *dl;
struct g_ioctl *gio;
struct g_consumer *cp;
u_char *buf;
u_char *buf, *label;
off_t secoff;
u_int secsize;
int error, i;
uint64_t sum;
g_topology_assert();
bp = arg;
if (flag == EV_CANCEL) {
g_io_deliver(bp, ENXIO);
return;
}
/* We don't need topology for now. */
g_topology_unlock();
gp = bp->bio_to->geom;
gsp = gp->softc;
ms = gsp->softc;
gio = (struct g_ioctl *)bp->bio_data;
label = g_malloc(LABELSIZE, M_WAITOK);
/* The disklabel to set is the ioctl argument. */
dl = gio->data;
bsd_disklabel_le_enc(label, gio->data);
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, dl); /* Picks up topology lock on success. */
if (error) {
g_topology_lock();
error = g_bsd_modify(gp, label); /* Picks up topology lock on success. */
g_free(label);
if (error || gio->cmd == DIOCSDINFO) {
g_io_deliver(bp, error);
return;
}
/* Update our copy of the disklabel. */
ms->inram = *dl;
inram2ondisk(ms);
if (gio->cmd == DIOCSDINFO) {
g_io_deliver(bp, 0);
return;
}
KASSERT(gio->cmd == DIOCWDINFO, ("Unknown ioctl in g_bsd_ioctl"));
cp = LIST_FIRST(&gp->consumer);
/* Get sector size, we need it to read data. */
secsize = cp->provider->sectorsize;
@ -407,8 +289,7 @@ g_bsd_ioctl(void *arg, int flag)
g_io_deliver(bp, error);
return;
}
dl = &ms->ondisk;
bsd_disklabel_le_enc(buf + secoff, dl);
bcopy(ms->label, buf + secoff, sizeof(ms->label));
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
@ -430,7 +311,6 @@ g_bsd_diocbsdbb(dev_t dev, u_long cmd __unused, caddr_t data, int fflag __unused
struct g_geom *gp;
struct g_slicer *gsp;
struct g_bsd_softc *ms;
struct disklabel *dl;
struct g_consumer *cp;
u_char *buf;
void *p;
@ -447,33 +327,26 @@ g_bsd_diocbsdbb(dev_t dev, u_long cmd __unused, caddr_t data, int fflag __unused
buf = g_malloc(BBSIZE, M_WAITOK);
p = *(void **)data;
error = copyin(p, buf, BBSIZE);
if (error) {
g_free(buf);
return (error);
}
/* The disklabel to set is the ioctl argument. */
dl = (void *)(buf + ms->labeloffset);
DROP_GIANT();
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, dl); /* Picks up topology lock on success. */
if (!error) {
cp = LIST_FIRST(&gp->consumer);
secsize = cp->provider->sectorsize;
dl = &ms->ondisk;
bsd_disklabel_le_enc(buf + ms->labeloffset, dl);
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
sum += le64dec(buf + i * 8);
le64enc(buf + 504, sum);
DROP_GIANT();
g_topology_lock();
/* Validate and modify our slice instance to match. */
error = g_bsd_modify(gp, buf + ms->labeloffset);
if (!error) {
cp = LIST_FIRST(&gp->consumer);
secsize = cp->provider->sectorsize;
if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
sum = 0;
for (i = 0; i < 63; i++)
sum += le64dec(buf + i * 8);
le64enc(buf + 504, sum);
}
error = g_write_data(cp, 0, buf, BBSIZE);
}
error = g_write_data(cp, 0, buf, BBSIZE);
g_topology_unlock();
PICKUP_GIANT();
}
g_free(buf);
PICKUP_GIANT();
return (error);
}
@ -490,10 +363,10 @@ g_bsd_hotwrite(void *arg, int flag)
struct g_slicer *gsp;
struct g_slice *gsl;
struct g_bsd_softc *ms;
struct g_bsd_softc fake;
u_char *p;
int error;
g_topology_assert();
/*
* We should never get canceled, because that would amount to a removal
* of the geom while there was outstanding I/O requests.
@ -506,28 +379,11 @@ g_bsd_hotwrite(void *arg, int flag)
gsl = &gsp->slices[bp->bio_to->index];
p = (u_char*)bp->bio_data + ms->labeloffset
- (bp->bio_offset + gsl->offset);
bsd_disklabel_le_dec(p, &fake.ondisk);
ondisk2inram(&fake);
if (g_bsd_checklabel(&fake.inram)) {
g_io_deliver(bp, EPERM);
return;
}
if (g_bsd_lesum(&fake.ondisk, p) != 0) {
g_io_deliver(bp, EPERM);
return;
}
g_topology_unlock();
error = g_bsd_modify(gp, &fake.inram); /* May pick up topology. */
error = g_bsd_modify(gp, p);
if (error) {
g_io_deliver(bp, EPERM);
g_topology_lock();
return;
}
/* Update our copy of the disklabel. */
ms->inram = fake.inram;
inram2ondisk(ms);
bsd_disklabel_le_enc(p, &ms->ondisk);
g_slice_finish_hot(bp);
}
@ -577,7 +433,7 @@ g_bsd_start(struct bio *bp)
switch (gio->cmd) {
case DIOCGDINFO:
/* Return a copy of the disklabel to userland. */
bcopy(&ms->inram, gio->data, sizeof(ms->inram));
bsd_disklabel_le_dec(ms->label, gio->data, MAXPARTITIONS);
g_io_deliver(bp, 0);
return (1);
case DIOCBSDBB:
@ -629,10 +485,10 @@ g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_
} else if (pp != NULL) {
if (indent == NULL)
sbuf_printf(sb, " ty %d",
ms->inram.d_partitions[pp->index].p_fstype);
ms->ondisk.d_partitions[pp->index].p_fstype);
else
sbuf_printf(sb, "%s<type>%d</type>\n", indent,
ms->inram.d_partitions[pp->index].p_fstype);
ms->ondisk.d_partitions[pp->index].p_fstype);
}
}
@ -663,11 +519,10 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
struct g_consumer *cp;
int error, i;
struct g_bsd_softc *ms;
struct disklabel *dl;
u_int secsize;
struct g_slicer *gsp;
MD5_CTX md5sum;
u_char hash[16];
MD5_CTX md5sum;
g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
@ -690,13 +545,6 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
if (gp == NULL)
return (NULL);
/*
* Now that we have attached to and opened our provider, we do
* not need the topology lock until we change the topology again
* next time.
*/
g_topology_unlock();
/*
* Fill in the optional details, in our case we have a dumpconf
* routine which the "slice" code should call at the right time
@ -759,10 +607,8 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
* partition) we calculate an MD5 and ask if other BSD's
* below us love that label. If they do, we don't.
*/
dl = &ms->inram;
MD5Init(&md5sum);
MD5Update(&md5sum, (u_char *)dl, sizeof(dl));
MD5Update(&md5sum, ms->label, sizeof(ms->label));
MD5Final(ms->labelsum, &md5sum);
error = g_getattr("BSD::labelsum", cp, &hash);
@ -773,19 +619,19 @@ g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
* Process the found disklabel, and modify our "slice"
* instance to match it, if possible.
*/
error = g_bsd_modify(gp, dl); /* Picks up topology lock. */
if (!error)
g_topology_unlock();
break;
error = g_bsd_modify(gp, ms->label);
} while (0);
/* Success or failure, we can close our provider now. */
g_topology_lock();
error = g_access_rel(cp, -1, 0, 0);
/* If we have configured any providers, return the new geom. */
if (gsp->nprovider > 0)
if (gsp->nprovider > 0) {
g_slice_conf_hot(gp, 0, ms->labeloffset, LABELSIZE,
G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
gsp->hot = g_bsd_hotwrite;
return (gp);
}
/*
* ...else push the "self-destruct" button, by spoiling our own
* consumer. This triggers a call to g_slice_spoiled which will

View File

@ -44,10 +44,12 @@
#include <sys/types.h>
#include <sys/endian.h>
#include <sys/disklabel.h>
#include <sys/errno.h>
#ifdef _KERNEL
#include <sys/systm.h>
#else
#include <string.h>
#include <stdio.h>
#endif
void
@ -61,12 +63,38 @@ bsd_partition_le_dec(u_char *ptr, struct partition *d)
d->p_cpg = le16dec(ptr + 14);
}
void
bsd_disklabel_le_dec(u_char *ptr, struct disklabel *d)
int
bsd_disklabel_le_dec(u_char *ptr, struct disklabel *d, int maxpart)
{
int i;
u_char *p, *pe;
uint16_t sum;
d->d_magic = le32dec(ptr + 0);
if (d->d_magic != DISKMAGIC)
return(EINVAL);
d->d_magic2 = le32dec(ptr + 132);
if (d->d_magic2 != DISKMAGIC) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return(EINVAL);
}
d->d_npartitions = le16dec(ptr + 138);
if (d->d_npartitions > maxpart) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return(EINVAL);
}
pe = ptr + 148 + 16 * d->d_npartitions;
sum = 0;
for (p = ptr; p < pe; p += 2)
sum ^= le16dec(p);
if (sum != 0) {
printf("HERE %s %d\n", __FILE__, __LINE__);
return(EINVAL);
}
d->d_type = le16dec(ptr + 4);
d->d_subtype = le16dec(ptr + 6);
bcopy(ptr + 8, d->d_typename, 16);
@ -97,13 +125,13 @@ bsd_disklabel_le_dec(u_char *ptr, struct disklabel *d)
d->d_spare[2] = le32dec(ptr + 120);
d->d_spare[3] = le32dec(ptr + 124);
d->d_spare[4] = le32dec(ptr + 128);
d->d_magic2 = le32dec(ptr + 132);
d->d_checksum = le16dec(ptr + 136);
d->d_npartitions = le16dec(ptr + 138);
d->d_bbsize = le32dec(ptr + 140);
d->d_sbsize = le32dec(ptr + 144);
for (i = 0; i < MAXPARTITIONS; i++)
bsd_partition_le_dec(ptr + 148 + 16 * i, &d->d_partitions[i]);
return(0);
}
void
@ -121,6 +149,8 @@ void
bsd_disklabel_le_enc(u_char *ptr, struct disklabel *d)
{
int i;
u_char *p, *pe;
uint16_t sum;
le32enc(ptr + 0, d->d_magic);
le16enc(ptr + 4, d->d_type);
@ -154,10 +184,15 @@ bsd_disklabel_le_enc(u_char *ptr, struct disklabel *d)
le32enc(ptr + 124, d->d_spare[3]);
le32enc(ptr + 128, d->d_spare[4]);
le32enc(ptr + 132, d->d_magic2);
le16enc(ptr + 136, d->d_checksum);
le16enc(ptr + 136, 0);
le16enc(ptr + 138, d->d_npartitions);
le32enc(ptr + 140, d->d_bbsize);
le32enc(ptr + 144, d->d_sbsize);
for (i = 0; i < MAXPARTITIONS; i++)
for (i = 0; i < d->d_npartitions; i++)
bsd_partition_le_enc(ptr + 148 + 16 * i, &d->d_partitions[i]);
pe = ptr + 148 + 16 * d->d_npartitions;
sum = 0;
for (p = ptr; p < pe; p += 2)
sum ^= le16dec(p);
le16enc(ptr + 136, sum);
}

View File

@ -305,7 +305,7 @@ static const char *fstypenames[] = {
* bytestring.
*/
void bsd_partition_le_dec(u_char *ptr, struct partition *d);
void bsd_disklabel_le_dec(u_char *ptr, struct disklabel *d);
int bsd_disklabel_le_dec(u_char *ptr, struct disklabel *d, int maxpart);
void bsd_partition_le_enc(u_char *ptr, struct partition *d);
void bsd_disklabel_le_enc(u_char *ptr, struct disklabel *d);