utils/mountd/v4root.c

   1 /*
   2  * Copyright (C) 2009 Red Hat <nfs@redhat.com>
   3  *
   4  * support/export/v4root.c
   5  *
   6  * Routines used to support NFSv4 pseudo roots
   7  *
   8  */
   9
  10 #ifdef HAVE_CONFIG_H
  11 #include <config.h>
  12 #endif
  13
  14 #include <sys/types.h>
  15 #include <sys/stat.h>
  16 #include <sys/queue.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <ctype.h>
  20
  21 #include <unistd.h>
  22 #include <errno.h>
  23
  24 #include "xlog.h"
  25 #include "exportfs.h"
  26 #include "nfslib.h"
  27 #include "misc.h"
  28 #include "v4root.h"
  29
  30 int v4root_needed;
  31
  32 static nfs_export pseudo_root = {
  33         .m_next = NULL,
  34         .m_client = NULL,
  35         .m_export = {
  36                 .e_hostname = "*",
  37                 .e_path = "/",
  38                 .e_flags = NFSEXP_READONLY | NFSEXP_ROOTSQUASH
  39                                 | NFSEXP_NOSUBTREECHECK | NFSEXP_FSID
  40                                 | NFSEXP_V4ROOT,
  41                 .e_anonuid = 65534,
  42                 .e_anongid = 65534,
  43                 .e_squids = NULL,
  44                 .e_nsquids = 0,
  45                 .e_sqgids = NULL,
  46                 .e_nsqgids = 0,
  47                 .e_fsid = 0,
  48                 .e_mountpoint = NULL,
  49                 .e_ttl = DEFAULT_TTL,
  50         },
  51         .m_exported = 0,
  52         .m_xtabent = 1,
  53         .m_mayexport = 1,
  54         .m_changed = 0,
  55         .m_warned = 0,
  56 };
  57
  58 void set_pseudofs_security(struct exportent *pseudo, struct exportent *source)
  59 {
  60         struct sec_entry *se;
  61         int i;
  62
  63         if (source->e_flags & NFSEXP_INSECURE_PORT)
  64                 pseudo->e_flags |= NFSEXP_INSECURE_PORT;
  65         for (se = source->e_secinfo; se->flav; se++) {
  66                 struct sec_entry *new;
  67
  68                 i = secinfo_addflavor(se->flav, pseudo);
  69                 new = &pseudo->e_secinfo[i];
  70
  71                 if (se->flags & NFSEXP_INSECURE_PORT)
  72                         new->flags |= NFSEXP_INSECURE_PORT;
  73         }
  74 }
  75
  76 /*
  77  * Create a pseudo export
  78  */
  79 static struct exportent *
  80 v4root_create(char *path, nfs_export *export)
  81 {
  82         nfs_export *exp;
  83         struct exportent eep;
  84         struct exportent *curexp = &export->m_export;
  85
  86         dupexportent(&eep, &pseudo_root.m_export);
  87         eep.e_hostname = curexp->e_hostname;
  88         strncpy(eep.e_path, path, sizeof(eep.e_path));
  89         if (strcmp(path, "/") != 0)
  90                 eep.e_flags &= ~NFSEXP_FSID;
  91         set_pseudofs_security(&eep, curexp);
  92         exp = export_create(&eep, 0);
  93         if (exp == NULL)
  94                 return NULL;
  95         xlog(D_CALL, "v4root_create: path '%s'", exp->m_export.e_path);
  96         return &exp->m_export;
  97 }
  98
  99 /*
 100  * Make sure the kernel has pseudo root support.
 101  */
 102 static int
 103 v4root_support(void)
 104 {
 105         struct export_features *ef;
 106         static int warned = 0;
 107
 108         ef = get_export_features();
 109
 110         if (ef->flags & NFSEXP_V4ROOT)
 111                 return 1;
 112         if (!warned) {
 113                 xlog(L_WARNING, "Kernel does not have pseudo root support.");
 114                 xlog(L_WARNING, "NFS v4 mounts will be disabled unless fsid=0");
 115                 xlog(L_WARNING, "is specfied in /etc/exports file.");
 116                 warned++;
 117         }
 118         return 0;
 119 }
 120
 121 int pseudofs_update(char *hostname, char *path, nfs_export *source)
 122 {
 123         nfs_export *exp;
 124
 125         exp = export_lookup(hostname, path, 0);
 126         if (exp && !(exp->m_export.e_flags & NFSEXP_V4ROOT))
 127                 return 0;
 128         if (!exp) {
 129                 if (v4root_create(path, source) == NULL) {
 130                         xlog(L_WARNING, "v4root_set: Unable to create "
 131                                         "pseudo export for '%s'", path);
 132                         return -ENOMEM;
 133                 }
 134                 return 0;
 135         }
 136         /* Update an existing V4ROOT export: */
 137         set_pseudofs_security(&exp->m_export, &source->m_export);
 138         return 0;
 139 }
 140
 141 static int v4root_add_parents(nfs_export *exp)
 142 {
 143         char *hostname = exp->m_export.e_hostname;
 144         char *path;
 145         char *ptr;
 146
 147         path = strdup(exp->m_export.e_path);
 148         if (!path) {
 149                 xlog(L_WARNING, "v4root_add_parents: Unable to create "
 150                                 "pseudo export for '%s'", exp->m_export.e_path);
 151                 return -ENOMEM;
 152         }
 153         for (ptr = path + 1; ptr; ptr = strchr(ptr, '/')) {
 154                 int ret;
 155                 char saved;
 156
 157                 saved = *ptr;
 158                 *ptr = '\0';
 159                 ret = pseudofs_update(hostname, path, exp);
 160                 if (ret)
 161                         return ret;
 162                 *ptr = saved;
 163                 ptr++;
 164         }
 165         free(path);
 166         return 0;
 167 }
 168
 169 /*
 170  * Create pseudo exports by running through the real export
 171  * looking at the components of the path that make up the export.
 172  * Those path components, if not exported, will become pseudo
 173  * exports allowing them to be found when the kernel does an upcall
 174  * looking for components of the v4 mount.
 175  */
 176 void
 177 v4root_set()
 178 {
 179         nfs_export      *exp;
 180         int     i;
 181
 182         if (!v4root_needed)
 183                 return;
 184         if (!v4root_support())
 185                 return;
 186
 187         for (i = 0; i < MCL_MAXTYPES; i++) {
 188                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 189                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 190                                 /*
 191                                  * We just added this one, so its
 192                                  * parents are already dealt with!
 193                                  */
 194                                 continue;
 195
 196                         if (strcmp(exp->m_export.e_path, "/") == 0 &&
 197                             !(exp->m_export.e_flags & NFSEXP_FSID)) {
 198                                 /* Force '/' to be exported as fsid == 0*/
 199                                 exp->m_export.e_flags |= NFSEXP_FSID;
 200                                 exp->m_export.e_fsid = 0;
 201                         }
 202
 203                         v4root_add_parents(exp);
 204                         /* XXX: error handling! */
 205                 }
 206         }
 207 }