/*- * Copyright (c) 2002 Poul-Henning Kamp * Copyright (c) 2002 Networks Associates Technology, Inc. * All rights reserved. * * This software was developed for the FreeBSD Project by Poul-Henning Kamp * and NAI Labs, the Security Research Division of Network Associates, Inc. * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the * DARPA CHATS research program. * * 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. * 3. The names of the authors may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. * * $FreeBSD$ * * This is the method for dealing with BSD disklabels. It has been * extensively (by my standards at least) commented, in the vain hope that * it will serve as the source in future copy&paste operations. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define BSD_CLASS_NAME "BSD" #define ALPHA_LABEL_OFFSET 64 /* * Our private data about one instance. All the rest is handled by the * slice code and stored in its softc, so this is just the stuff * specific to BSD disklabels. */ struct g_bsd_softc { off_t labeloffset; off_t mbroffset; off_t rawoffset; struct disklabel ondisk; struct disklabel inram; 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. */ static int g_bsd_modify(struct g_geom *gp, struct disklabel *dl) { int i, error; struct partition *ppp; struct g_slicer *gsp; struct g_consumer *cp; u_int secsize, u; off_t mediasize; /* Basic check that this is indeed a disklabel. */ error = g_bsd_checklabel(dl); if (error) 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 * initialized in many cases, and since we don't need it * for anything, we dont strictly need this test. * Preemptive action to avoid confusing people in disklabel(8) * may be in order. */ /* The label cannot claim a larger size than the media. */ if ((off_t)dl->d_secperunit * dl->d_secsize > mediasize) return (EINVAL); #endif /* ... or a smaller sector size. */ if (dl->d_secsize < secsize) return (EINVAL); /* ... or a non-multiple sector size. */ if (dl->d_secsize % secsize != 0) return (EINVAL); g_topology_lock(); /* Don't munge open partitions. */ gsp = gp->softc; for (i = 0; i < dl->d_npartitions; i++) { ppp = &dl->d_partitions[i]; 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, "%s%c", gp->name, 'a' + i); if (error) { g_topology_unlock(); return (error); } } /* Look good, go for it... */ for (u = 0; u < gsp->nslice; u++) { ppp = &dl->d_partitions[u]; 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, "%s%c", gp->name, 'a' + u); } 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 * will not need this, as there is only one possible place on disk to look * for the magic spot. */ static int g_bsd_try(struct g_geom *gp, struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd_softc *ms, off_t offset) { int error; u_char *buf; struct disklabel *dl; off_t secoff; /* * We need to read entire aligned sectors, and we assume that the * disklabel does not span sectors, so one sector is enough. */ error = 0; secoff = offset % secsize; buf = g_read_data(cp, offset - secoff, secsize, &error); if (buf == NULL || error != 0) return (ENOENT); /* 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; /* Remember to free the buffer g_read_data() gave us. */ g_free(buf); /* If we had a label, record it properly. */ if (error == 0) { ms->labeloffset = offset; g_topology_lock(); g_slice_conf_hot(gp, 0, offset, g_bsd_ondisk_size()); g_topology_unlock(); } return (error); } /* * Implement certain ioctls to modify disklabels with. This function * is called by the event handler thread with topology locked as result * of the g_call_me() in g_bsd_start(). It is not necessary to keep * topology locked all the time but make sure to return with topology * locked as well. */ static void g_bsd_ioctl(void *arg, int flag) { struct bio *bp; 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; off_t secoff; u_int secsize; int error, i; uint64_t sum; 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; /* The disklabel to set is the ioctl argument. */ dl = 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(); 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; secoff = ms->labeloffset % secsize; buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error); if (buf == NULL || error != 0) { g_io_deliver(bp, error); return; } dl = &ms->ondisk; bsd_disklabel_le_enc(buf + secoff, dl); 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, ms->labeloffset - secoff, buf, secsize); g_free(buf); g_io_deliver(bp, error); } /* * Rewrite the bootblock, which is BBSIZE bytes from the start of the disk. * We punch down the disklabel where we expect it to be before writing. */ static int g_bsd_diocbsdbb(dev_t dev, u_long cmd __unused, caddr_t data, int fflag __unused, struct thread *td __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; u_int secsize; int error, i; uint64_t sum; /* Get hold of the interesting bits from the bio. */ gp = (void *)dev; gsp = gp->softc; ms = gsp->softc; /* The disklabel to set is the ioctl argument. */ 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); } error = g_write_data(cp, 0, buf, BBSIZE); g_topology_unlock(); } g_free(buf); PICKUP_GIANT(); return (error); } /* * If the user tries to overwrite our disklabel through an open partition * or via a magicwrite config call, we end up here and try to prevent * footshooting as best we can. */ static void g_bsd_hotwrite(void *arg, int flag) { struct bio *bp; struct g_geom *gp; struct g_slicer *gsp; struct g_slice *gsl; struct g_bsd_softc *ms; struct g_bsd_softc fake; u_char *p; int error; KASSERT(flag != EV_CANCEL, ("g_bsd_hotwrite cancelled")); bp = arg; gp = bp->bio_to->geom; gsp = gp->softc; ms = gsp->softc; 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. */ 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); } /*- * This start routine is only called for non-trivial requests, all the * trivial ones are handled autonomously by the slice code. * For requests we handle here, we must call the g_io_deliver() on the * bio, and return non-zero to indicate to the slice code that we did so. * This code executes in the "DOWN" I/O path, this means: * * No sleeping. * * Don't grab the topology lock. * * Don't call biowait, g_getattr(), g_setattr() or g_read_data() */ static int g_bsd_start(struct bio *bp) { struct g_geom *gp; struct g_bsd_softc *ms; struct g_slicer *gsp; struct g_ioctl *gio; int error; gp = bp->bio_to->geom; gsp = gp->softc; ms = gsp->softc; switch(bp->bio_cmd) { case BIO_READ: /* We allow reading of our hot spots */ return (0); case BIO_DELETE: /* We do not allow deleting our hot spots */ return (EPERM); case BIO_WRITE: g_call_me(g_bsd_hotwrite, bp, gp, NULL); return (EJUSTRETURN); case BIO_GETATTR: if (g_handleattr(bp, "BSD::labelsum", ms->labelsum, sizeof(ms->labelsum))) return (1); break; default: KASSERT(0 == 1, ("Unknown bio_cmd in g_bsd_start (%d)", bp->bio_cmd)); } /* We only handle ioctl(2) requests of the right format. */ if (strcmp(bp->bio_attribute, "GEOM::ioctl")) return (0); else if (bp->bio_length != sizeof(*gio)) return (0); /* Get hold of the ioctl parameters. */ gio = (struct g_ioctl *)bp->bio_data; switch (gio->cmd) { case DIOCGDINFO: /* Return a copy of the disklabel to userland. */ bcopy(&ms->inram, gio->data, sizeof(ms->inram)); g_io_deliver(bp, 0); return (1); case DIOCBSDBB: gio->func = g_bsd_diocbsdbb; gio->dev = (void *)gp; g_io_deliver(bp, EDIRIOCTL); return (1); case DIOCSDINFO: case DIOCWDINFO: /* * These we cannot do without the topology lock and some * some I/O requests. Ask the event-handler to schedule * us in a less restricted environment. */ error = g_call_me(g_bsd_ioctl, bp, gp, NULL); if (error) g_io_deliver(bp, error); /* * We must return non-zero to indicate that we will deal * with this bio, even though we have not done so yet. */ return (1); default: return (0); } } /* * Dump configuration information in XML format. * Notice that the function is called once for the geom and once for each * consumer and provider. We let g_slice_dumpconf() do most of the work. */ static void g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp) { struct g_bsd_softc *ms; struct g_slicer *gsp; gsp = gp->softc; ms = gsp->softc; g_slice_dumpconf(sb, indent, gp, cp, pp); if (indent != NULL && pp == NULL && cp == NULL) { sbuf_printf(sb, "%s%jd\n", indent, (intmax_t)ms->labeloffset); sbuf_printf(sb, "%s%jd\n", indent, (intmax_t)ms->rawoffset); sbuf_printf(sb, "%s%jd\n", indent, (intmax_t)ms->mbroffset); } else if (pp != NULL) { if (indent == NULL) sbuf_printf(sb, " ty %d", ms->inram.d_partitions[pp->index].p_fstype); else sbuf_printf(sb, "%s%d\n", indent, ms->inram.d_partitions[pp->index].p_fstype); } } /* * The taste function is called from the event-handler, with the topology * lock already held and a provider to examine. The flags are unused. * * If flags == G_TF_NORMAL, the idea is to take a bite of the provider and * if we find valid, consistent magic on it, build a geom on it. * any magic bits which indicate that we should automatically put a BSD * geom on it. * * There may be cases where the operator would like to put a BSD-geom on * providers which do not meet all of the requirements. This can be done * by instead passing the G_TF_INSIST flag, which will override these * checks. * * The final flags value is G_TF_TRANSPARENT, which instructs the method * to put a geom on top of the provider and configure it to be as transparent * as possible. This is not really relevant to the BSD method and therefore * not implemented here. */ static struct g_geom * g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags) { struct g_geom *gp; 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]; g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name); g_topology_assert(); /* We don't implement transparent inserts. */ if (flags == G_TF_TRANSPARENT) return (NULL); /* * BSD labels are a subclass of the general "slicing" topology so * a lot of the work can be done by the common "slice" code. * Create a geom with space for MAXPARTITIONS providers, one consumer * and a softc structure for us. Specify the provider to attach * the consumer to and our "start" routine for special requests. * The provider is opened with mode (1,0,0) so we can do reads * from it. */ gp = g_slice_new(mp, MAXPARTITIONS, pp, &cp, &ms, sizeof(*ms), g_bsd_start); 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 */ gp->dumpconf = g_bsd_dumpconf; /* Get the geom_slicer softc from the geom. */ gsp = gp->softc; /* * The do...while loop here allows us to have multiple escapes * using a simple "break". This improves code clarity without * ending up in deep nesting and without using goto or come from. */ do { /* * If the provider is an MBR we will only auto attach * to type 165 slices in the G_TF_NORMAL case. We will * attach to any other type. */ error = g_getattr("MBR::type", cp, &i); if (!error) { if (i != 165 && flags == G_TF_NORMAL) break; error = g_getattr("MBR::offset", cp, &ms->mbroffset); if (error) break; } /* Same thing if we are inside a PC98 */ error = g_getattr("PC98::type", cp, &i); if (!error) { if (i != 0xc494 && flags == G_TF_NORMAL) break; error = g_getattr("PC98::offset", cp, &ms->mbroffset); if (error) break; } /* Get sector size, we need it to read data. */ secsize = cp->provider->sectorsize; if (secsize < 512) break; /* First look for a label at the start of the second sector. */ error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize); /* Next, look for alpha labels */ if (error) error = g_bsd_try(gp, gsp, cp, secsize, ms, ALPHA_LABEL_OFFSET); /* If we didn't find a label, punt. */ if (error) break; /* * 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. */ dl = &ms->inram; MD5Init(&md5sum); MD5Update(&md5sum, (u_char *)dl, sizeof(dl)); MD5Final(ms->labelsum, &md5sum); error = g_getattr("BSD::labelsum", cp, &hash); if (!error && !strncmp(ms->labelsum, hash, sizeof(hash))) break; /* * 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; } 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) return (gp); /* * ...else push the "self-destruct" button, by spoiling our own * consumer. This triggers a call to g_std_spoiled which will * dismantle what was setup. */ g_std_spoiled(cp); return (NULL); } /* Finally, register with GEOM infrastructure. */ static struct g_class g_bsd_class = { .name = BSD_CLASS_NAME, .taste = g_bsd_taste, G_CLASS_INITIALIZER }; DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);