Blame view

fs/nfsd/auth.c 2.13 KB
81f7e3824   Eric Lee   Initial Release, ...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
  // SPDX-License-Identifier: GPL-2.0
  /* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */
  
  #include <linux/sched.h>
  #include "nfsd.h"
  #include "auth.h"
  
  int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
  {
  	struct exp_flavor_info *f;
  	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
  
  	for (f = exp->ex_flavors; f < end; f++) {
  		if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
  			return f->flags;
  	}
  	return exp->ex_flags;
  
  }
  
  int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
  {
  	struct group_info *rqgi;
  	struct group_info *gi;
  	struct cred *new;
  	int i;
  	int flags = nfsexp_flags(rqstp, exp);
  
  	validate_process_creds();
  
  	/* discard any old override before preparing the new set */
  	revert_creds(get_cred(current_real_cred()));
  	new = prepare_creds();
  	if (!new)
  		return -ENOMEM;
  
  	new->fsuid = rqstp->rq_cred.cr_uid;
  	new->fsgid = rqstp->rq_cred.cr_gid;
  
  	rqgi = rqstp->rq_cred.cr_group_info;
  
  	if (flags & NFSEXP_ALLSQUASH) {
  		new->fsuid = exp->ex_anon_uid;
  		new->fsgid = exp->ex_anon_gid;
  		gi = groups_alloc(0);
  		if (!gi)
  			goto oom;
  	} else if (flags & NFSEXP_ROOTSQUASH) {
  		if (uid_eq(new->fsuid, GLOBAL_ROOT_UID))
  			new->fsuid = exp->ex_anon_uid;
  		if (gid_eq(new->fsgid, GLOBAL_ROOT_GID))
  			new->fsgid = exp->ex_anon_gid;
  
  		gi = groups_alloc(rqgi->ngroups);
  		if (!gi)
  			goto oom;
  
  		for (i = 0; i < rqgi->ngroups; i++) {
  			if (gid_eq(GLOBAL_ROOT_GID, rqgi->gid[i]))
  				gi->gid[i] = exp->ex_anon_gid;
  			else
  				gi->gid[i] = rqgi->gid[i];
  		}
  
  		/* Each thread allocates its own gi, no race */
  		groups_sort(gi);
  	} else {
  		gi = get_group_info(rqgi);
  	}
  
  	if (uid_eq(new->fsuid, INVALID_UID))
  		new->fsuid = exp->ex_anon_uid;
  	if (gid_eq(new->fsgid, INVALID_GID))
  		new->fsgid = exp->ex_anon_gid;
  
  	set_groups(new, gi);
  	put_group_info(gi);
  
  	if (!uid_eq(new->fsuid, GLOBAL_ROOT_UID))
  		new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
  	else
  		new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
  							new->cap_permitted);
  	validate_process_creds();
  	put_cred(override_creds(new));
  	put_cred(new);
  	validate_process_creds();
  	return 0;
  
  oom:
  	abort_creds(new);
  	return -ENOMEM;
  }