jump_label: Fix NULL dereference bug in __jump_label_mod_update()
[linux-2.6-block.git] / kernel / groups.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
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2/*
3 * Supplementary group IDs
4 */
5#include <linux/cred.h>
9984de1a 6#include <linux/export.h>
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7#include <linux/slab.h>
8#include <linux/security.h>
b7b2562f 9#include <linux/sort.h>
30639b6a 10#include <linux/syscalls.h>
273d2c67 11#include <linux/user_namespace.h>
81243eac 12#include <linux/vmalloc.h>
7c0f6ba6 13#include <linux/uaccess.h>
30639b6a 14
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15struct group_info *groups_alloc(int gidsetsize)
16{
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17 struct group_info *gi;
18 unsigned int len;
19
20 len = sizeof(struct group_info) + sizeof(kgid_t) * gidsetsize;
21 gi = kmalloc(len, GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_NORETRY);
22 if (!gi)
19809c2d 23 gi = __vmalloc(len, GFP_KERNEL_ACCOUNT, PAGE_KERNEL);
81243eac 24 if (!gi)
30639b6a 25 return NULL;
30639b6a 26
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27 atomic_set(&gi->usage, 1);
28 gi->ngroups = gidsetsize;
29 return gi;
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30}
31
32EXPORT_SYMBOL(groups_alloc);
33
34void groups_free(struct group_info *group_info)
35{
81243eac 36 kvfree(group_info);
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37}
38
39EXPORT_SYMBOL(groups_free);
40
41/* export the group_info to a user-space array */
42static int groups_to_user(gid_t __user *grouplist,
43 const struct group_info *group_info)
44{
ae2975bc 45 struct user_namespace *user_ns = current_user_ns();
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46 int i;
47 unsigned int count = group_info->ngroups;
48
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49 for (i = 0; i < count; i++) {
50 gid_t gid;
81243eac 51 gid = from_kgid_munged(user_ns, group_info->gid[i]);
ae2975bc 52 if (put_user(gid, grouplist+i))
30639b6a 53 return -EFAULT;
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54 }
55 return 0;
56}
57
58/* fill a group_info from a user-space array - it must be allocated already */
59static int groups_from_user(struct group_info *group_info,
60 gid_t __user *grouplist)
61{
ae2975bc 62 struct user_namespace *user_ns = current_user_ns();
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63 int i;
64 unsigned int count = group_info->ngroups;
65
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66 for (i = 0; i < count; i++) {
67 gid_t gid;
68 kgid_t kgid;
69 if (get_user(gid, grouplist+i))
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70 return -EFAULT;
71
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72 kgid = make_kgid(user_ns, gid);
73 if (!gid_valid(kgid))
74 return -EINVAL;
75
81243eac 76 group_info->gid[i] = kgid;
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77 }
78 return 0;
79}
80
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81static int gid_cmp(const void *_a, const void *_b)
82{
83 kgid_t a = *(kgid_t *)_a;
84 kgid_t b = *(kgid_t *)_b;
85
86 return gid_gt(a, b) - gid_lt(a, b);
87}
88
bdcf0a42 89void groups_sort(struct group_info *group_info)
30639b6a 90{
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91 sort(group_info->gid, group_info->ngroups, sizeof(*group_info->gid),
92 gid_cmp, NULL);
30639b6a 93}
bdcf0a42 94EXPORT_SYMBOL(groups_sort);
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95
96/* a simple bsearch */
ae2975bc 97int groups_search(const struct group_info *group_info, kgid_t grp)
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98{
99 unsigned int left, right;
100
101 if (!group_info)
102 return 0;
103
104 left = 0;
105 right = group_info->ngroups;
106 while (left < right) {
107 unsigned int mid = (left+right)/2;
81243eac 108 if (gid_gt(grp, group_info->gid[mid]))
30639b6a 109 left = mid + 1;
81243eac 110 else if (gid_lt(grp, group_info->gid[mid]))
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111 right = mid;
112 else
113 return 1;
114 }
115 return 0;
116}
117
118/**
119 * set_groups - Change a group subscription in a set of credentials
120 * @new: The newly prepared set of credentials to alter
121 * @group_info: The group list to install
30639b6a 122 */
8f6c5ffc 123void set_groups(struct cred *new, struct group_info *group_info)
30639b6a 124{
30639b6a 125 put_group_info(new->group_info);
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126 get_group_info(group_info);
127 new->group_info = group_info;
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128}
129
130EXPORT_SYMBOL(set_groups);
131
132/**
133 * set_current_groups - Change current's group subscription
134 * @group_info: The group list to impose
135 *
136 * Validate a group subscription and, if valid, impose it upon current's task
137 * security record.
138 */
139int set_current_groups(struct group_info *group_info)
140{
141 struct cred *new;
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142
143 new = prepare_creds();
144 if (!new)
145 return -ENOMEM;
146
8f6c5ffc 147 set_groups(new, group_info);
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148 return commit_creds(new);
149}
150
151EXPORT_SYMBOL(set_current_groups);
152
153SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
154{
155 const struct cred *cred = current_cred();
156 int i;
157
158 if (gidsetsize < 0)
159 return -EINVAL;
160
161 /* no need to grab task_lock here; it cannot change */
162 i = cred->group_info->ngroups;
163 if (gidsetsize) {
164 if (i > gidsetsize) {
165 i = -EINVAL;
166 goto out;
167 }
168 if (groups_to_user(grouplist, cred->group_info)) {
169 i = -EFAULT;
170 goto out;
171 }
172 }
173out:
174 return i;
175}
176
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177bool may_setgroups(void)
178{
179 struct user_namespace *user_ns = current_user_ns();
180
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181 return ns_capable(user_ns, CAP_SETGID) &&
182 userns_may_setgroups(user_ns);
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183}
184
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185/*
186 * SMP: Our groups are copy-on-write. We can set them safely
187 * without another task interfering.
188 */
189
190SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
191{
192 struct group_info *group_info;
193 int retval;
194
7ff4d90b 195 if (!may_setgroups())
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196 return -EPERM;
197 if ((unsigned)gidsetsize > NGROUPS_MAX)
198 return -EINVAL;
199
200 group_info = groups_alloc(gidsetsize);
201 if (!group_info)
202 return -ENOMEM;
203 retval = groups_from_user(group_info, grouplist);
204 if (retval) {
205 put_group_info(group_info);
206 return retval;
207 }
208
bdcf0a42 209 groups_sort(group_info);
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210 retval = set_current_groups(group_info);
211 put_group_info(group_info);
212
213 return retval;
214}
215
216/*
217 * Check whether we're fsgid/egid or in the supplemental group..
218 */
72cda3d1 219int in_group_p(kgid_t grp)
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220{
221 const struct cred *cred = current_cred();
222 int retval = 1;
223
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224 if (!gid_eq(grp, cred->fsgid))
225 retval = groups_search(cred->group_info, grp);
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226 return retval;
227}
228
229EXPORT_SYMBOL(in_group_p);
230
72cda3d1 231int in_egroup_p(kgid_t grp)
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232{
233 const struct cred *cred = current_cred();
234 int retval = 1;
235
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236 if (!gid_eq(grp, cred->egid))
237 retval = groups_search(cred->group_info, grp);
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238 return retval;
239}
240
241EXPORT_SYMBOL(in_egroup_p);