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
nfsexp_flags(struct svc_rqst * rqstp,struct svc_export * exp)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
nfsd_setuser(struct svc_rqst * rqstp,struct svc_export * exp)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
29 validate_process_creds();
30
31 /* discard any old override before preparing the new set */
32 revert_creds(get_cred(current_real_cred()));
33 new = prepare_creds();
34 if (!new)
35 return -ENOMEM;
36
37 new->fsuid = rqstp->rq_cred.cr_uid;
38 new->fsgid = rqstp->rq_cred.cr_gid;
39
40 rqgi = rqstp->rq_cred.cr_group_info;
41
42 if (flags & NFSEXP_ALLSQUASH) {
43 new->fsuid = exp->ex_anon_uid;
44 new->fsgid = exp->ex_anon_gid;
45 gi = groups_alloc(0);
46 if (!gi)
47 goto oom;
48 } else if (flags & NFSEXP_ROOTSQUASH) {
49 if (uid_eq(new->fsuid, GLOBAL_ROOT_UID))
50 new->fsuid = exp->ex_anon_uid;
51 if (gid_eq(new->fsgid, GLOBAL_ROOT_GID))
52 new->fsgid = exp->ex_anon_gid;
53
54 gi = groups_alloc(rqgi->ngroups);
55 if (!gi)
56 goto oom;
57
58 for (i = 0; i < rqgi->ngroups; i++) {
59 if (gid_eq(GLOBAL_ROOT_GID, rqgi->gid[i]))
60 gi->gid[i] = exp->ex_anon_gid;
61 else
62 gi->gid[i] = rqgi->gid[i];
63 }
64
65 /* Each thread allocates its own gi, no race */
66 groups_sort(gi);
67 } else {
68 gi = get_group_info(rqgi);
69 }
70
71 if (uid_eq(new->fsuid, INVALID_UID))
72 new->fsuid = exp->ex_anon_uid;
73 if (gid_eq(new->fsgid, INVALID_GID))
74 new->fsgid = exp->ex_anon_gid;
75
76 set_groups(new, gi);
77 put_group_info(gi);
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 abort_creds(new);
92 return -ENOMEM;
93 }
94
95