Root/fs/nfsd/auth.c

1/* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */
2
3#include <linux/sched.h>
4#include "nfsd.h"
5#include "auth.h"
6
7int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
8{
9    struct exp_flavor_info *f;
10    struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
11
12    for (f = exp->ex_flavors; f < end; f++) {
13        if (f->pseudoflavor == rqstp->rq_flavor)
14            return f->flags;
15    }
16    return exp->ex_flags;
17
18}
19
20int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
21{
22    struct group_info *rqgi;
23    struct group_info *gi;
24    struct cred *new;
25    int i;
26    int flags = nfsexp_flags(rqstp, exp);
27    int ret;
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 (!new->fsuid)
50            new->fsuid = exp->ex_anon_uid;
51        if (!new->fsgid)
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 (!GROUP_AT(rqgi, i))
60                GROUP_AT(gi, i) = exp->ex_anon_gid;
61            else
62                GROUP_AT(gi, i) = GROUP_AT(rqgi, i);
63        }
64    } else {
65        gi = get_group_info(rqgi);
66    }
67
68    if (new->fsuid == (uid_t) -1)
69        new->fsuid = exp->ex_anon_uid;
70    if (new->fsgid == (gid_t) -1)
71        new->fsgid = exp->ex_anon_gid;
72
73    ret = set_groups(new, gi);
74    put_group_info(gi);
75    if (ret < 0)
76        goto error;
77
78    if (new->fsuid)
79        new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
80    else
81        new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
82                            new->cap_permitted);
83    validate_process_creds();
84    put_cred(override_creds(new));
85    put_cred(new);
86    validate_process_creds();
87    return 0;
88
89oom:
90    ret = -ENOMEM;
91error:
92    abort_creds(new);
93    return ret;
94}
95
96

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