geom_mbr.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2002 Poul-Henning Kamp
    5  * Copyright (c) 2002 Networks Associates Technology, Inc.
    6  * All rights reserved.
    7  *
    8  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    9  * and NAI Labs, the Security Research Division of Network Associates, Inc.
   10  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   11  * DARPA CHATS research program.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/12.0/sys/geom/geom_mbr.c 332387 2018-04-10 19:18:16Z kevans $");
   37 
   38 #include <sys/param.h>
   39 #include <sys/errno.h>
   40 #include <sys/endian.h>
   41 #include <sys/systm.h>
   42 #include <sys/sysctl.h>
   43 #include <sys/kernel.h>
   44 #include <sys/fcntl.h>
   45 #include <sys/malloc.h>
   46 #include <sys/bio.h>
   47 #include <sys/lock.h>
   48 #include <sys/mutex.h>
   49 #include <sys/md5.h>
   50 #include <sys/proc.h>
   51 
   52 #include <sys/diskmbr.h>
   53 #include <sys/sbuf.h>
   54 #include <geom/geom.h>
   55 #include <geom/geom_slice.h>
   56 
   57 FEATURE(geom_mbr, "GEOM DOS/MBR partitioning support");
   58 
   59 #define MBR_CLASS_NAME "MBR"
   60 #define MBREXT_CLASS_NAME "MBREXT"
   61 
   62 static int g_mbr_once = 0;
   63 
   64 static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
   65         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   66         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   67         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   68         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
   69 };
   70 
   71 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
   72         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   73         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   74         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   75         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
   76 };
   77 
   78 static void
   79 g_mbr_print(int i, struct dos_partition *dp)
   80 {
   81 
   82         printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
   83         printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
   84             dp->dp_shd, DPSECT(dp->dp_ssect));
   85         printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
   86             dp->dp_ehd, DPSECT(dp->dp_esect));
   87         printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
   88 }
   89 
   90 struct g_mbr_softc {
   91         int             type [NDOSPART];
   92         u_int           sectorsize;
   93         u_char          sec0[512];
   94         u_char          slicesum[16];
   95 };
   96 
   97 /*
   98  * XXX: Add gctl_req arg and give good error msgs.
   99  * XXX: Check that length argument does not bring boot code inside any slice.
  100  */
  101 static int
  102 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0, int len __unused)
  103 {
  104         int i, error;
  105         off_t l[NDOSPART];
  106         struct dos_partition ndp[NDOSPART], *dp;
  107         MD5_CTX md5sum;
  108 
  109         g_topology_assert();
  110 
  111         if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
  112                 return (EBUSY);
  113 
  114         dp = ndp;
  115         for (i = 0; i < NDOSPART; i++) {
  116                 dos_partition_dec(
  117                     sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
  118                     dp + i);
  119         }
  120         if ((!bcmp(dp, historical_bogus_partition_table,
  121             sizeof historical_bogus_partition_table)) ||
  122             (!bcmp(dp, historical_bogus_partition_table_fixed,
  123             sizeof historical_bogus_partition_table_fixed))) {
  124                 /*
  125                  * We will not allow people to write these from "the inside",
  126                  * Since properly selfdestructing takes too much code.  If 
  127                  * people really want to do this, they cannot have any
  128                  * providers of this geom open, and in that case they can just
  129                  * as easily overwrite the MBR in the parent device.
  130                  */
  131                 return(EBUSY);
  132         }
  133         for (i = 0; i < NDOSPART; i++) {
  134                 /* 
  135                  * A Protective MBR (PMBR) has a single partition of
  136                  * type 0xEE spanning the whole disk. Such a MBR
  137                  * protects a GPT on the disk from MBR tools that
  138                  * don't know anything about GPT. We're interpreting
  139                  * it a bit more loosely: any partition of type 0xEE
  140                  * is to be skipped as it doesn't contain any data
  141                  * that we should care about. We still allow other
  142                  * partitions to be present in the MBR. A PMBR will
  143                  * be handled correctly anyway.
  144                  */
  145                 if (dp[i].dp_typ == DOSPTYP_PMBR)
  146                         l[i] = 0;
  147                 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
  148                         l[i] = 0;
  149                 else if (dp[i].dp_typ == 0)
  150                         l[i] = 0;
  151                 else
  152                         l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
  153                 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
  154                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  155                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  156                 if (error)
  157                         return (error);
  158         }
  159         for (i = 0; i < NDOSPART; i++) {
  160                 ms->type[i] = dp[i].dp_typ;
  161                 g_slice_config(gp, i, G_SLICE_CONFIG_SET,
  162                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  163                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  164         }
  165         bcopy(sec0, ms->sec0, 512);
  166 
  167         /*
  168          * Calculate MD5 from the first sector and use it for avoiding
  169          * recursive slices creation.
  170          */
  171         MD5Init(&md5sum);
  172         MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
  173         MD5Final(ms->slicesum, &md5sum);
  174 
  175         return (0);
  176 }
  177 
  178 static int
  179 g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
  180 {
  181         struct g_geom *gp;
  182         struct g_mbr_softc *ms;
  183         struct g_slicer *gsp;
  184         struct g_consumer *cp;
  185         int error, opened;
  186 
  187         gp = pp->geom;
  188         gsp = gp->softc;
  189         ms = gsp->softc;
  190 
  191         opened = 0;
  192         error = 0;
  193         switch(cmd) {
  194         case DIOCSMBR: {
  195                 if (!(fflag & FWRITE))
  196                         return (EPERM);
  197                 g_topology_lock();
  198                 cp = LIST_FIRST(&gp->consumer);
  199                 if (cp->acw == 0) {
  200                         error = g_access(cp, 0, 1, 0);
  201                         if (error == 0)
  202                                 opened = 1;
  203                 }
  204                 if (!error)
  205                         error = g_mbr_modify(gp, ms, data, 512);
  206                 if (!error)
  207                         error = g_write_data(cp, 0, data, 512);
  208                 if (opened)
  209                         g_access(cp, 0, -1 , 0);
  210                 g_topology_unlock();
  211                 return(error);
  212         }
  213         default:
  214                 return (ENOIOCTL);
  215         }
  216 }
  217 
  218 static int
  219 g_mbr_start(struct bio *bp)
  220 {
  221         struct g_provider *pp;
  222         struct g_geom *gp;
  223         struct g_mbr_softc *mp;
  224         struct g_slicer *gsp;
  225         int idx;
  226 
  227         pp = bp->bio_to;
  228         idx = pp->index;
  229         gp = pp->geom;
  230         gsp = gp->softc;
  231         mp = gsp->softc;
  232         if (bp->bio_cmd == BIO_GETATTR) {
  233                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  234                         return (1);
  235                 if (g_handleattr_off_t(bp, "MBR::offset",
  236                     gsp->slices[idx].offset))
  237                         return (1);
  238                 if (g_handleattr(bp, "MBR::slicesum", mp->slicesum,
  239                     sizeof(mp->slicesum)))
  240                         return (1);
  241         }
  242 
  243         return (0);
  244 }
  245 
  246 static void
  247 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  248 {
  249         struct g_mbr_softc *mp;
  250         struct g_slicer *gsp;
  251 
  252         gsp = gp->softc;
  253         mp = gsp->softc;
  254         g_slice_dumpconf(sb, indent, gp, cp, pp);
  255         if (pp != NULL) {
  256                 if (indent == NULL)
  257                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  258                 else
  259                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  260                             mp->type[pp->index]);
  261         }
  262 }
  263 
  264 static struct g_geom *
  265 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
  266 {
  267         struct g_geom *gp;
  268         struct g_consumer *cp;
  269         int error;
  270         struct g_mbr_softc *ms;
  271         u_int fwsectors, sectorsize;
  272         u_char *buf;
  273         u_char hash[16];
  274         MD5_CTX md5sum;
  275 
  276         g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
  277         g_topology_assert();
  278         if (!strcmp(pp->geom->class->name, MBR_CLASS_NAME))
  279                 return (NULL);
  280         gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
  281         if (gp == NULL)
  282                 return (NULL);
  283         g_topology_unlock();
  284         do {
  285                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  286                 if (error)
  287                         fwsectors = 17;
  288                 sectorsize = cp->provider->sectorsize;
  289                 if (sectorsize < 512)
  290                         break;
  291                 ms->sectorsize = sectorsize;
  292                 buf = g_read_data(cp, 0, sectorsize, NULL);
  293                 if (buf == NULL)
  294                         break;
  295 
  296                 /*
  297                  * Calculate MD5 from the first sector and use it for avoiding
  298                  * recursive slices creation.
  299                  */
  300                 bcopy(buf, ms->sec0, 512);
  301                 MD5Init(&md5sum);
  302                 MD5Update(&md5sum, ms->sec0, sizeof(ms->sec0));
  303                 MD5Final(ms->slicesum, &md5sum);
  304 
  305                 error = g_getattr("MBR::slicesum", cp, &hash);
  306                 if (!error && !bcmp(ms->slicesum, hash, sizeof(hash))) {
  307                         g_free(buf);
  308                         break;
  309                 }
  310 
  311                 g_topology_lock();
  312                 g_mbr_modify(gp, ms, buf, 512);
  313                 g_topology_unlock();
  314                 g_free(buf);
  315                 break;
  316         } while (0);
  317         g_topology_lock();
  318         g_access(cp, -1, 0, 0);
  319         if (LIST_EMPTY(&gp->provider)) {
  320                 g_slice_spoiled(cp);
  321                 return (NULL);
  322         }
  323         if (!g_mbr_once) {
  324                 g_mbr_once = 1;
  325                 printf(
  326                     "WARNING: geom_mbr (geom %s) is deprecated, "
  327                     "use gpart instead.\n", gp->name);
  328         }
  329         return (gp);
  330 }
  331 
  332 static void
  333 g_mbr_config(struct gctl_req *req, struct g_class *mp, const char *verb)
  334 {
  335         struct g_geom *gp;
  336         struct g_consumer *cp;
  337         struct g_mbr_softc *ms;
  338         struct g_slicer *gsp;
  339         int opened = 0, error = 0;
  340         void *data;
  341         int len;
  342 
  343         g_topology_assert();
  344         gp = gctl_get_geom(req, mp, "geom");
  345         if (gp == NULL)
  346                 return;
  347         if (strcmp(verb, "write MBR")) {
  348                 gctl_error(req, "Unknown verb");
  349                 return;
  350         }
  351         gsp = gp->softc;
  352         ms = gsp->softc;
  353         data = gctl_get_param(req, "data", &len);
  354         if (data == NULL)
  355                 return;
  356         if (len < 512 || (len % 512)) {
  357                 gctl_error(req, "Wrong request length");
  358                 return;
  359         }
  360         cp = LIST_FIRST(&gp->consumer);
  361         if (cp->acw == 0) {
  362                 error = g_access(cp, 0, 1, 0);
  363                 if (error == 0)
  364                         opened = 1;
  365         }
  366         if (!error)
  367                 error = g_mbr_modify(gp, ms, data, len);
  368         if (error)
  369                 gctl_error(req, "conflict with open slices");
  370         if (!error)
  371                 error = g_write_data(cp, 0, data, len);
  372         if (error)
  373                 gctl_error(req, "sector zero write failed");
  374         if (opened)
  375                 g_access(cp, 0, -1 , 0);
  376         return;
  377 }
  378 
  379 static struct g_class g_mbr_class       = {
  380         .name = MBR_CLASS_NAME,
  381         .version = G_VERSION,
  382         .taste = g_mbr_taste,
  383         .dumpconf = g_mbr_dumpconf,
  384         .ctlreq = g_mbr_config,
  385         .ioctl = g_mbr_ioctl,
  386 };
  387 
  388 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
  389 
  390 #define NDOSEXTPART             32
  391 struct g_mbrext_softc {
  392         int             type [NDOSEXTPART];
  393 };
  394 
  395 static int
  396 g_mbrext_start(struct bio *bp)
  397 {
  398         struct g_provider *pp;
  399         struct g_geom *gp;
  400         struct g_mbrext_softc *mp;
  401         struct g_slicer *gsp;
  402         int idx;
  403 
  404         pp = bp->bio_to;
  405         idx = pp->index;
  406         gp = pp->geom;
  407         gsp = gp->softc;
  408         mp = gsp->softc;
  409         if (bp->bio_cmd == BIO_GETATTR) {
  410                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  411                         return (1);
  412         }
  413         return (0);
  414 }
  415 
  416 static void
  417 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  418 {
  419         struct g_mbrext_softc *mp;
  420         struct g_slicer *gsp;
  421 
  422         g_slice_dumpconf(sb, indent, gp, cp, pp);
  423         gsp = gp->softc;
  424         mp = gsp->softc;
  425         if (pp != NULL) {
  426                 if (indent == NULL)
  427                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  428                 else
  429                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  430                             mp->type[pp->index]);
  431         }
  432 }
  433 
  434 static struct g_geom *
  435 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
  436 {
  437         struct g_geom *gp;
  438         struct g_consumer *cp;
  439         int error, i, slice;
  440         struct g_mbrext_softc *ms;
  441         off_t off;
  442         u_char *buf;
  443         struct dos_partition dp[4];
  444         u_int fwsectors, sectorsize;
  445 
  446         g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
  447         g_topology_assert();
  448         if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
  449                 return (NULL);
  450         gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
  451             g_mbrext_start);
  452         if (gp == NULL)
  453                 return (NULL);
  454         g_topology_unlock();
  455         off = 0;
  456         slice = 0;
  457         do {
  458                 error = g_getattr("MBR::type", cp, &i);
  459                 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
  460                         break;
  461                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  462                 if (error)
  463                         fwsectors = 17;
  464                 sectorsize = cp->provider->sectorsize;
  465                 if (sectorsize != 512)
  466                         break;
  467                 for (;;) {
  468                         buf = g_read_data(cp, off, sectorsize, NULL);
  469                         if (buf == NULL)
  470                                 break;
  471                         if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
  472                                 g_free(buf);
  473                                 break;
  474                         }
  475                         for (i = 0; i < NDOSPART; i++) 
  476                                 dos_partition_dec(
  477                                     buf + DOSPARTOFF + 
  478                                     i * sizeof(struct dos_partition), dp + i);
  479                         g_free(buf);
  480                         if (0 && bootverbose) {
  481                                 printf("MBREXT Slice %d on %s:\n",
  482                                     slice + 5, gp->name);
  483                                 g_mbr_print(0, dp);
  484                                 g_mbr_print(1, dp + 1);
  485                         }
  486                         if ((dp[0].dp_flag & 0x7f) == 0 &&
  487                              dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
  488                                 g_topology_lock();
  489                                 g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
  490                                     (((off_t)dp[0].dp_start) << 9ULL) + off,
  491                                     ((off_t)dp[0].dp_size) << 9ULL,
  492                                     sectorsize,
  493                                     "%*.*s%d",
  494                                     (int)strlen(gp->name) - 1,
  495                                     (int)strlen(gp->name) - 1,
  496                                     gp->name,
  497                                     slice + 5);
  498                                 g_topology_unlock();
  499                                 ms->type[slice] = dp[0].dp_typ;
  500                                 slice++;
  501                         }
  502                         if (dp[1].dp_flag != 0)
  503                                 break;
  504                         if (dp[1].dp_typ != DOSPTYP_EXT &&
  505                             dp[1].dp_typ != DOSPTYP_EXTLBA)
  506                                 break;
  507                         if (dp[1].dp_size == 0)
  508                                 break;
  509                         off = ((off_t)dp[1].dp_start) << 9ULL;
  510                 }
  511                 break;
  512         } while (0);
  513         g_topology_lock();
  514         g_access(cp, -1, 0, 0);
  515         if (LIST_EMPTY(&gp->provider)) {
  516                 g_slice_spoiled(cp);
  517                 return (NULL);
  518         }
  519         return (gp);
  520 }
  521 
  522 
  523 static struct g_class g_mbrext_class    = {
  524         .name = MBREXT_CLASS_NAME,
  525         .version = G_VERSION,
  526         .taste = g_mbrext_taste,
  527         .dumpconf = g_mbrext_dumpconf,
  528 };
  529 
  530 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
  531 MODULE_VERSION(geom_mbr, 0);
Cache object: 91c3ab15ef5b2efd154dad073dfe583f
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FreeBSD/Linux Kernel Cross Reference sys/geom/geom_mbr.c

FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_mbr.c
