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 (uid_eq(new->fsuid, GLOBAL_ROOT_UID)) 51 new->fsuid = exp->ex_anon_uid; 52 if (gid_eq(new->fsgid, GLOBAL_ROOT_GID)) 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) = 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 (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 ret = set_groups(new, gi); 75 put_group_info(gi); 76 if (ret < 0) 77 goto error; 78 79 if (!uid_eq(new->fsuid, GLOBAL_ROOT_UID)) 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 97