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         if ((source->e_flags & NFSEXP_ROOTSQUASH) == 0)
  66                 pseudo->e_flags &= ~NFSEXP_ROOTSQUASH;
  67         for (se = source->e_secinfo; se->flav; se++) {
  68                 struct sec_entry *new;
  69
  70                 i = secinfo_addflavor(se->flav, pseudo);
  71                 new = &pseudo->e_secinfo[i];
  72
  73                 if (se->flags & NFSEXP_INSECURE_PORT)
  74                         new->flags |= NFSEXP_INSECURE_PORT;
  75         }
  76 }
  77
  78 /*
  79  * Create a pseudo export
  80  */
  81 static struct exportent *
  82 v4root_create(char *path, nfs_export *export)
  83 {
  84         nfs_export *exp;
  85         struct exportent eep;
  86         struct exportent *curexp = &export->m_export;
  87
  88         dupexportent(&eep, &pseudo_root.m_export);
  89         eep.e_hostname = curexp->e_hostname;
  90         strncpy(eep.e_path, path, sizeof(eep.e_path));
  91         if (strcmp(path, "/") != 0)
  92                 eep.e_flags &= ~NFSEXP_FSID;
  93         set_pseudofs_security(&eep, curexp);
  94         exp = export_create(&eep, 0);
  95         if (exp == NULL)
  96                 return NULL;
  97         xlog(D_CALL, "v4root_create: path '%s' flags 0x%x",
  98                 exp->m_export.e_path, exp->m_export.e_flags);
  99         return &exp->m_export;
 100 }
 101
 102 /*
 103  * Make sure the kernel has pseudo root support.
 104  */
 105 static int
 106 v4root_support(void)
 107 {
 108         struct export_features *ef;
 109         static int warned = 0;
 110
 111         ef = get_export_features();
 112
 113         if (ef->flags & NFSEXP_V4ROOT)
 114                 return 1;
 115         if (!warned) {
 116                 xlog(L_WARNING, "Kernel does not have pseudo root support.");
 117                 xlog(L_WARNING, "NFS v4 mounts will be disabled unless fsid=0");
 118                 xlog(L_WARNING, "is specfied in /etc/exports file.");
 119                 warned++;
 120         }
 121         return 0;
 122 }
 123
 124 int pseudofs_update(char *hostname, char *path, nfs_export *source)
 125 {
 126         nfs_export *exp;
 127
 128         exp = export_lookup(hostname, path, 0);
 129         if (exp && !(exp->m_export.e_flags & NFSEXP_V4ROOT))
 130                 return 0;
 131         if (!exp) {
 132                 if (v4root_create(path, source) == NULL) {
 133                         xlog(L_WARNING, "v4root_set: Unable to create "
 134                                         "pseudo export for '%s'", path);
 135                         return -ENOMEM;
 136                 }
 137                 return 0;
 138         }
 139         /* Update an existing V4ROOT export: */
 140         set_pseudofs_security(&exp->m_export, &source->m_export);
 141         return 0;
 142 }
 143
 144 static int v4root_add_parents(nfs_export *exp)
 145 {
 146         char *hostname = exp->m_export.e_hostname;
 147         char *path;
 148         char *ptr;
 149
 150         path = strdup(exp->m_export.e_path);
 151         if (!path) {
 152                 xlog(L_WARNING, "v4root_add_parents: Unable to create "
 153                                 "pseudo export for '%s'", exp->m_export.e_path);
 154                 return -ENOMEM;
 155         }
 156         for (ptr = path; ptr; ptr = strchr(ptr, '/')) {
 157                 int ret;
 158                 char saved;
 159
 160                 saved = *ptr;
 161                 *ptr = '\0';
 162                 ret = pseudofs_update(hostname, *path ? path : "/", exp);
 163                 if (ret)
 164                         return ret;
 165                 *ptr = saved;
 166                 ptr++;
 167         }
 168         free(path);
 169         return 0;
 170 }
 171
 172 /*
 173  * Create pseudo exports by running through the real export
 174  * looking at the components of the path that make up the export.
 175  * Those path components, if not exported, will become pseudo
 176  * exports allowing them to be found when the kernel does an upcall
 177  * looking for components of the v4 mount.
 178  */
 179 void
 180 v4root_set()
 181 {
 182         nfs_export      *exp;
 183         int     i;
 184
 185         if (!v4root_needed)
 186                 return;
 187         if (!v4root_support())
 188                 return;
 189
 190         for (i = 0; i < MCL_MAXTYPES; i++) {
 191                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 192                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
 193                                 /*
 194                                  * We just added this one, so its
 195                                  * parents are already dealt with!
 196                                  */
 197                                 continue;
 198
 199                         if (strcmp(exp->m_export.e_path, "/") == 0 &&
 200                             !(exp->m_export.e_flags & NFSEXP_FSID)) {
 201                                 /* Force '/' to be exported as fsid == 0*/
 202                                 exp->m_export.e_flags |= NFSEXP_FSID;
 203                                 exp->m_export.e_fsid = 0;
 204                         }
 205
 206                         v4root_add_parents(exp);
 207                         /* XXX: error handling! */
 208                 }
 209         }
 210 }