/*- * 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. */ /* * 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include FEATURE(geom_bsd, "GEOM BSD disklabels support"); #define BSD_CLASS_NAME "BSD" #define ALPHA_LABEL_OFFSET 64 #define HISTORIC_LABEL_OFFSET 512 #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 * 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; u_char label[LABELSIZE]; u_char labelsum[16]; }; /* * Modify our slicer to match proposed disklabel, if possible. * This is where we make sure we don't do something stupid. */ static int g_bsd_modify(struct g_geom *gp, u_char *label) { int i, error; struct partition *ppp; struct g_slicer *gsp; struct g_consumer *cp; struct g_bsd_softc *ms; u_int secsize, u; off_t rawoffset, o; struct disklabel dl; MD5_CTX md5sum; g_topology_assert(); gsp = gp->softc; ms = gsp->softc; error = bsd_disklabel_le_dec(label, &dl, MAXPARTITIONS); if (error) { return (error); } /* Get dimensions of our device. */ cp = LIST_FIRST(&gp->consumer); secsize = cp->provider->sectorsize; /* ... 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); } /* 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; } if (rawoffset != 0 && (off_t)rawoffset != ms->mbroffset) printf("WARNING: %s expected rawoffset %jd, found %jd\n", gp->name, (intmax_t)ms->mbroffset/dl.d_secsize, (intmax_t)rawoffset/dl.d_secsize); /* Don't munge open partitions. */ 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, o - rawoffset, (off_t)ppp->p_size * dl.d_secsize, dl.d_secsize, "%s%c", gp->name, 'a' + i); if (error) return (error); } /* Look good, go for it... */ for (u = 0; u < gsp->nslice; 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, o - rawoffset, (off_t)ppp->p_size * dl.d_secsize, dl.d_secsize, "%s%c", gp->name, 'a' + u); } /* 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); } /* * 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. */ secoff = offset % secsize; buf = g_read_data(cp, offset - secoff, secsize, NULL); if (buf == NULL) return (ENOENT); /* Decode into our native format. */ dl = &ms->ondisk; 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); ms->labeloffset = offset; return (error); } /* * This function writes the current label to disk, possibly updating * the alpha SRM checksum. */ static int g_bsd_writelabel(struct g_geom *gp, u_char *bootcode) { off_t secoff; u_int secsize; struct g_consumer *cp; struct g_slicer *gsp; struct g_bsd_softc *ms; u_char *buf; uint64_t sum; int error, i; gsp = gp->softc; ms = gsp->softc; cp = LIST_FIRST(&gp->consumer); /* Get sector size, we need it to read data. */ secsize = cp->provider->sectorsize; secoff = ms->labeloffset % secsize; if (bootcode == NULL) { buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error); if (buf == NULL) return (error); bcopy(ms->label, buf + secoff, sizeof(ms->label)); } else { buf = bootcode; bcopy(ms->label, buf + ms->labeloffset, sizeof(ms->label)); } if (ms->labeloffset == ALPHA_LABEL_OFFSET) { sum = 0; for (i = 0; i < 63; i++) sum += le64dec(buf + i * 8); le64enc(buf + 504, sum); } if (bootcode == NULL) { error = g_write_data(cp, ms->labeloffset - secoff, buf, secsize); g_free(buf); } else { error = g_write_data(cp, 0, bootcode, BBSIZE); } 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; 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. */ 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); error = g_bsd_modify(gp, p); if (error) { g_io_deliver(bp, EPERM); return; } 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_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td) { struct g_geom *gp; struct g_bsd_softc *ms; struct g_slicer *gsp; u_char *label; int error; gp = pp->geom; gsp = gp->softc; ms = gsp->softc; switch(cmd) { case DIOCGDINFO: /* Return a copy of the disklabel to userland. */ bsd_disklabel_le_dec(ms->label, data, MAXPARTITIONS); return(0); case DIOCBSDBB: { struct g_consumer *cp; u_char *buf; void *p; int error, i; uint64_t sum; if (!(fflag & FWRITE)) return (EPERM); /* The disklabel to set is the ioctl argument. */ buf = g_malloc(BBSIZE, M_WAITOK); p = *(void **)data; error = copyin(p, buf, BBSIZE); if (!error) { /* XXX: Rude, but supposedly safe */ 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); 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(); PICKUP_GIANT(); } g_free(buf); return (error); } case DIOCSDINFO: case DIOCWDINFO: { if (!(fflag & FWRITE)) return (EPERM); label = g_malloc(LABELSIZE, M_WAITOK); /* The disklabel to set is the ioctl argument. */ bsd_disklabel_le_enc(label, data); DROP_GIANT(); g_topology_lock(); /* Validate and modify our slice instance to match. */ error = g_bsd_modify(gp, label); if (error == 0 && cmd == DIOCWDINFO) error = g_bsd_writelabel(gp, NULL); g_topology_unlock(); PICKUP_GIANT(); g_free(label); return(error); } default: return (ENOIOCTL); } } static int g_bsd_start(struct bio *bp) { struct g_geom *gp; struct g_bsd_softc *ms; struct g_slicer *gsp; gp = bp->bio_to->geom; gsp = gp->softc; ms = gsp->softc; if (bp->bio_cmd == BIO_GETATTR) { if (g_handleattr(bp, "BSD::labelsum", ms->labelsum, sizeof(ms->labelsum))) return (1); } 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->ondisk.d_partitions[pp->index].p_fstype); else sbuf_printf(sb, "%s%d\n", indent, ms->ondisk.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. * * 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 uuid freebsd_slice = GPT_ENT_TYPE_FREEBSD; 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; u_int secsize; struct g_slicer *gsp; u_char hash[16]; MD5_CTX md5sum; struct uuid uuid; 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); /* 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; } /* Same thing if we are inside a GPT */ error = g_getattr("GPT::type", cp, &uuid); if (!error) { if (memcmp(&uuid, &freebsd_slice, sizeof(uuid)) != 0 && flags == G_TF_NORMAL) 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); /* * If sector size is not 512 the label still can be at * offset 512, not at the start of the second sector. At least * it's true for labels created by the FreeBSD's bsdlabel(8). */ if (error && secsize != HISTORIC_LABEL_OFFSET) error = g_bsd_try(gp, gsp, cp, secsize, ms, HISTORIC_LABEL_OFFSET); /* 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. */ MD5Init(&md5sum); MD5Update(&md5sum, ms->label, sizeof(ms->label)); MD5Final(ms->labelsum, &md5sum); error = g_getattr("BSD::labelsum", cp, &hash); if (!error && !bcmp(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, ms->label); } while (0); /* Success or failure, we can close our provider now. */ g_access(cp, -1, 0, 0); /* If we have configured any providers, return the new geom. */ 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 * dismantle what was setup. */ g_slice_spoiled(cp); return (NULL); } struct h0h0 { struct g_geom *gp; struct g_bsd_softc *ms; u_char *label; int error; }; static void g_bsd_callconfig(void *arg, int flag) { struct h0h0 *hp; hp = arg; hp->error = g_bsd_modify(hp->gp, hp->label); if (!hp->error) hp->error = g_bsd_writelabel(hp->gp, NULL); } /* * NB! curthread is user process which GCTL'ed. */ static void g_bsd_config(struct gctl_req *req, struct g_class *mp, char const *verb) { u_char *label; int error; struct h0h0 h0h0; struct g_geom *gp; struct g_slicer *gsp; struct g_consumer *cp; struct g_bsd_softc *ms; g_topology_assert(); gp = gctl_get_geom(req, mp, "geom"); if (gp == NULL) return; cp = LIST_FIRST(&gp->consumer); gsp = gp->softc; ms = gsp->softc; if (!strcmp(verb, "read mbroffset")) { gctl_set_param_err(req, "mbroffset", &ms->mbroffset, sizeof(ms->mbroffset)); return; } else if (!strcmp(verb, "write label")) { label = gctl_get_paraml(req, "label", LABELSIZE); if (label == NULL) return; h0h0.gp = gp; h0h0.ms = gsp->softc; h0h0.label = label; h0h0.error = -1; /* XXX: Does this reference register with our selfdestruct code ? */ error = g_access(cp, 1, 1, 1); if (error) { gctl_error(req, "could not access consumer"); return; } g_bsd_callconfig(&h0h0, 0); error = h0h0.error; g_access(cp, -1, -1, -1); } else if (!strcmp(verb, "write bootcode")) { label = gctl_get_paraml(req, "bootcode", BBSIZE); if (label == NULL) return; /* XXX: Does this reference register with our selfdestruct code ? */ error = g_access(cp, 1, 1, 1); if (error) { gctl_error(req, "could not access consumer"); return; } error = g_bsd_writelabel(gp, label); g_access(cp, -1, -1, -1); } else { gctl_error(req, "Unknown verb parameter"); } return; } /* Finally, register with GEOM infrastructure. */ static struct g_class g_bsd_class = { .name = BSD_CLASS_NAME, .version = G_VERSION, .taste = g_bsd_taste, .ctlreq = g_bsd_config, .dumpconf = g_bsd_dumpconf, .ioctl = g_bsd_ioctl, }; DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);