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         },
  50         .m_exported = 0,
  51         .m_xtabent = 1,
  52         .m_mayexport = 1,
  53         .m_changed = 0,
  54         .m_warned = 0,
  55 };
  56
  57 void set_pseudofs_security(struct exportent *pseudo, struct exportent *source)
  58 {
  59         struct sec_entry *se;
  60         int i;
  61
  62         if (source->e_flags & NFSEXP_INSECURE_PORT)
  63                 pseudo->e_flags |= NFSEXP_INSECURE_PORT;
  64         for (se = source->e_secinfo; se->flav; se++) {
  65                 struct sec_entry *new;
  66
  67                 i = secinfo_addflavor(se->flav, pseudo);
  68                 new = &pseudo->e_secinfo[i];
  69
  70                 if (se->flags & NFSEXP_INSECURE_PORT)
  71                         new->flags |= NFSEXP_INSECURE_PORT;
  72         }
  73 }
  74
  75 /*
  76  * Create a pseudo export
  77  */
  78 static struct exportent *
  79 v4root_create(char *path, nfs_export *export)
  80 {
  81         nfs_export *exp;
  82         struct exportent eep;
  83         struct exportent *curexp = &export->m_export;
  84
  85         dupexportent(&eep, &pseudo_root.m_export);
  86         eep.e_hostname = curexp->e_hostname;
  87         strncpy(eep.e_path, path, sizeof(eep.e_path));
  88         if (strcmp(path, "/") != 0)
  89                 eep.e_flags &= ~NFSEXP_FSID;
  90         set_pseudofs_security(&eep, curexp);
  91         exp = export_create(&eep, 0);
  92         if (exp == NULL)
  93                 return NULL;
  94         xlog(D_CALL, "v4root_create: path '%s'", exp->m_export.e_path);
  95         return &exp->m_export;
  96 }
  97
  98 /*
  99  * Make sure the kernel has pseudo root support.
 100  */
 101 static int
 102 v4root_support(void)
 103 {
 104         struct export_features *ef;
 105         static int warned = 0;
 106
 107         ef = get_export_features();
 108
 109         if (ef->flags & NFSEXP_V4ROOT)
 110                 return 1;
 111         if (!warned) {
 112                 xlog(L_WARNING, "Kernel does not have pseudo root support.");
 113                 xlog(L_WARNING, "NFS v4 mounts will be disabled unless fsid=0");
 114                 xlog(L_WARNING, "is specfied in /etc/exports file.");
 115                 warned++;
 116         }
 117         return 0;
 118 }
 119
 120 int pseudofs_update(char *hostname, char *path, nfs_export *source)
 121 {
 122         nfs_export *exp;
 123
 124         exp = export_lookup(hostname, path, 0);
 125         if (exp && !(exp->m_export.e_flags & NFSEXP_V4ROOT))
 126                 return 0;
 127         if (!exp) {
 128                 if (v4root_create(path, source) == NULL) {
 129                         xlog(L_WARNING, "v4root_set: Unable to create "
 130                                         "pseudo export for '%s'", path);
 131                         return -ENOMEM;
 132                 }
 133                 return 0;
 134         }
 135         /* Update an existing V4ROOT export: */
 136         set_pseudofs_security(&exp->m_export, &source->m_export);
 137         return 0;
 138 }
 139
 140 static int v4root_add_parents(nfs_export *exp)
 141 {
 142         char *hostname = exp->m_export.e_hostname;
 143         char *path;
 144         char *ptr;
 145
 146         path = strdup(exp->m_export.e_path);
 147         if (!path) {
 148                 xlog(L_WARNING, "v4root_add_parents: Unable to create "
 149                                 "pseudo export for '%s'", exp->m_export.e_path);
 150                 return -ENOMEM;
 151         }
 152         for (ptr = path + 1; ptr; ptr = strchr(ptr, '/')) {
 153                 int ret;
 154                 char saved;
 155
 156                 saved = *ptr;
 157                 *ptr = '\0';
 158                 ret = pseudofs_update(hostname, path, exp);
 159                 if (ret)
 160                         return ret;
 161                 *ptr = saved;
 162                 ptr++;
 163         }
 164         free(path);
 165         return 0;
 166 }
 167
 168 /*
 169  * Create pseudo exports by running through the real export
 170  * looking at the components of the path that make up the export.
 171  * Those path components, if not exported, will become pseudo
 172  * exports allowing them to be found when the kernel does an upcall
 173  * looking for components of the v4 mount.
 174  */
 175 void
 176 v4root_set()
 177 {
 178         nfs_export      *exp;
 179         int     i;
 180
 181         if (!v4root_needed)
 182                 return;
 183         if (!v4root_support())
 184                 return;
 185
 186         for (i = 0; i < MCL_MAXTYPES; i++) {
 187                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 188                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 189                                 /*
 190                                  * We just added this one, so its
 191                                  * parents are already dealt with!
 192                                  */
 193                                 continue;
 194
 195                         if (strcmp(exp->m_export.e_path, "/") == 0 &&
 196                             !(exp->m_export.e_flags & NFSEXP_FSID)) {
 197                                 /* Force '/' to be exported as fsid == 0*/
 198                                 exp->m_export.e_flags |= NFSEXP_FSID;
 199                                 exp->m_export.e_fsid = 0;
 200                         }
 201
 202                         v4root_add_parents(exp);
 203                         /* XXX: error handling! */
 204                 }
 205         }
 206 }