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_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 | |
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(left: 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 | |