1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */ 3 4 #include <linux/sched.h> 5 #include "nfsd.h" 6 #include "auth.h" 7 8 int nfsexp_flags(struct svc_cred *cred, 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 == cred->cr_flavor) 15 return f->flags; 16 } 17 return exp->ex_flags; 18 19 } 20 21 int nfsd_setuser(struct svc_cred *cred, 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(cred, exp); 28 29 /* discard any old override before preparing the new set */ 30 revert_creds(get_cred(current_real_cred())); 31 new = prepare_creds(); 32 if (!new) 33 return -ENOMEM; 34 35 new->fsuid = cred->cr_uid; 36 new->fsgid = cred->cr_gid; 37 38 rqgi = cred->cr_group_info; 39 40 if (flags & NFSEXP_ALLSQUASH) { 41 new->fsuid = exp->ex_anon_uid; 42 new->fsgid = exp->ex_anon_gid; 43 gi = groups_alloc(0); 44 if (!gi) 45 goto oom; 46 } else if (flags & NFSEXP_ROOTSQUASH) { 47 if (uid_eq(new->fsuid, GLOBAL_ROOT_UID)) 48 new->fsuid = exp->ex_anon_uid; 49 if (gid_eq(new->fsgid, GLOBAL_ROOT_GID)) 50 new->fsgid = exp->ex_anon_gid; 51 52 gi = groups_alloc(rqgi->ngroups); 53 if (!gi) 54 goto oom; 55 56 for (i = 0; i < rqgi->ngroups; i++) { 57 if (gid_eq(GLOBAL_ROOT_GID, rqgi->gid[i])) 58 gi->gid[i] = exp->ex_anon_gid; 59 else 60 gi->gid[i] = rqgi->gid[i]; 61 } 62 63 /* Each thread allocates its own gi, no race */ 64 groups_sort(gi); 65 } else { 66 gi = get_group_info(rqgi); 67 } 68 69 if (uid_eq(new->fsuid, INVALID_UID)) 70 new->fsuid = exp->ex_anon_uid; 71 if (gid_eq(new->fsgid, INVALID_GID)) 72 new->fsgid = exp->ex_anon_gid; 73 74 set_groups(new, gi); 75 put_group_info(gi); 76 77 if (!uid_eq(new->fsuid, GLOBAL_ROOT_UID)) 78 new->cap_effective = cap_drop_nfsd_set(new->cap_effective); 79 else 80 new->cap_effective = cap_raise_nfsd_set(new->cap_effective, 81 new->cap_permitted); 82 put_cred(override_creds(new)); 83 put_cred(new); 84 return 0; 85 86 oom: 87 abort_creds(new); 88 return -ENOMEM; 89 } 90 91