fs/nfsd/auth.c

   1 /* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */
   2
   3 #include <linux/sched.h>
   4 #include <linux/user_namespace.h>
   5 #include "nfsd.h"
   6 #include "auth.h"
   7
   8 int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
   9 {
  10         struct exp_flavor_info *f;
  11         struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
  12
  13         for (f = exp->ex_flavors; f < end; f++) {
  14                 if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
  15                         return f->flags;
  16         }
  17         return exp->ex_flags;
  18
  19 }
  20
  21 int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
  22 {
  23         struct group_info *rqgi;
  24         struct group_info *gi;
  25         struct cred *new;
  26         int i;
  27         int flags = nfsexp_flags(rqstp, exp);
  28         int ret;
  29
  30         validate_process_creds();
  31
  32         /* discard any old override before preparing the new set */
  33         revert_creds(get_cred(current->real_cred));
  34         new = prepare_creds();
  35         if (!new)
  36                 return -ENOMEM;
  37
  38         new->fsuid = rqstp->rq_cred.cr_uid;
  39         new->fsgid = rqstp->rq_cred.cr_gid;
  40
  41         rqgi = rqstp->rq_cred.cr_group_info;
  42
  43         if (flags & NFSEXP_ALLSQUASH) {
  44                 new->fsuid = exp->ex_anon_uid;
  45                 new->fsgid = exp->ex_anon_gid;
  46                 gi = groups_alloc(0);
  47                 if (!gi)
  48                         goto oom;
  49         } else if (flags & NFSEXP_ROOTSQUASH) {
  50                 if (!new->fsuid)
  51                         new->fsuid = exp->ex_anon_uid;
  52                 if (!new->fsgid)
  53                         new->fsgid = exp->ex_anon_gid;
  54
  55                 gi = groups_alloc(rqgi->ngroups);
  56                 if (!gi)
  57                         goto oom;
  58
  59                 for (i = 0; i < rqgi->ngroups; i++) {
  60                         if (gid_eq(GLOBAL_ROOT_GID, GROUP_AT(rqgi, i)))
  61                                 GROUP_AT(gi, i) = make_kgid(&init_user_ns, exp->ex_anon_gid);
  62                         else
  63                                 GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
  64                 }
  65         } else {
  66                 gi = get_group_info(rqgi);
  67         }
  68
  69         if (new->fsuid == (uid_t) -1)
  70                 new->fsuid = exp->ex_anon_uid;
  71         if (new->fsgid == (gid_t) -1)
  72                 new->fsgid = exp->ex_anon_gid;
  73
  74         ret = set_groups(new, gi);
  75         put_group_info(gi);
  76         if (ret < 0)
  77                 goto error;
  78
  79         if (new->fsuid)
  80                 new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
  81         else
  82                 new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
  83                                                         new->cap_permitted);
  84         validate_process_creds();
  85         put_cred(override_creds(new));
  86         put_cred(new);
  87         validate_process_creds();
  88         return 0;
  89
  90 oom:
  91         ret = -ENOMEM;
  92 error:
  93         abort_creds(new);
  94         return ret;
  95 }
  96