xref: /openbmc/linux/fs/nfsd/auth.c (revision fd589a8f)
1 /*
2  * linux/fs/nfsd/auth.c
3  *
4  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
5  */
6 
7 #include <linux/types.h>
8 #include <linux/sched.h>
9 #include <linux/sunrpc/svc.h>
10 #include <linux/sunrpc/svcauth.h>
11 #include <linux/nfsd/nfsd.h>
12 #include <linux/nfsd/export.h>
13 #include "auth.h"
14 
15 int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
16 {
17 	struct exp_flavor_info *f;
18 	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
19 
20 	for (f = exp->ex_flavors; f < end; f++) {
21 		if (f->pseudoflavor == rqstp->rq_flavor)
22 			return f->flags;
23 	}
24 	return exp->ex_flags;
25 
26 }
27 
28 int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
29 {
30 	struct group_info *rqgi;
31 	struct group_info *gi;
32 	struct cred *new;
33 	int i;
34 	int flags = nfsexp_flags(rqstp, exp);
35 	int ret;
36 
37 	validate_process_creds();
38 
39 	/* discard any old override before preparing the new set */
40 	revert_creds(get_cred(current->real_cred));
41 	new = prepare_creds();
42 	if (!new)
43 		return -ENOMEM;
44 
45 	new->fsuid = rqstp->rq_cred.cr_uid;
46 	new->fsgid = rqstp->rq_cred.cr_gid;
47 
48 	rqgi = rqstp->rq_cred.cr_group_info;
49 
50 	if (flags & NFSEXP_ALLSQUASH) {
51 		new->fsuid = exp->ex_anon_uid;
52 		new->fsgid = exp->ex_anon_gid;
53 		gi = groups_alloc(0);
54 		if (!gi)
55 			goto oom;
56 	} else if (flags & NFSEXP_ROOTSQUASH) {
57 		if (!new->fsuid)
58 			new->fsuid = exp->ex_anon_uid;
59 		if (!new->fsgid)
60 			new->fsgid = exp->ex_anon_gid;
61 
62 		gi = groups_alloc(rqgi->ngroups);
63 		if (!gi)
64 			goto oom;
65 
66 		for (i = 0; i < rqgi->ngroups; i++) {
67 			if (!GROUP_AT(rqgi, i))
68 				GROUP_AT(gi, i) = exp->ex_anon_gid;
69 			else
70 				GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
71 		}
72 	} else {
73 		gi = get_group_info(rqgi);
74 	}
75 
76 	if (new->fsuid == (uid_t) -1)
77 		new->fsuid = exp->ex_anon_uid;
78 	if (new->fsgid == (gid_t) -1)
79 		new->fsgid = exp->ex_anon_gid;
80 
81 	ret = set_groups(new, gi);
82 	put_group_info(gi);
83 	if (ret < 0)
84 		goto error;
85 
86 	if (new->fsuid)
87 		new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
88 	else
89 		new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
90 							new->cap_permitted);
91 	validate_process_creds();
92 	put_cred(override_creds(new));
93 	put_cred(new);
94 	validate_process_creds();
95 	return 0;
96 
97 oom:
98 	ret = -ENOMEM;
99 error:
100 	abort_creds(new);
101 	return ret;
102 }
103 
104