1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Wrapper functions for 16bit uid back compatibility. All nicely tied
4 * together in the faint hope we can take the out in five years time.
5 */
6
7#include <linux/mm.h>
8#include <linux/mman.h>
9#include <linux/notifier.h>
10#include <linux/reboot.h>
11#include <linux/prctl.h>
12#include <linux/capability.h>
13#include <linux/init.h>
14#include <linux/highuid.h>
15#include <linux/security.h>
16#include <linux/cred.h>
17#include <linux/syscalls.h>
18
19#include <linux/uaccess.h>
20
21#include "uid16.h"
22
23SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
24{
25 return ksys_chown(filename, low2highuid(user), low2highgid(group));
26}
27
28SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
29{
30 return ksys_lchown(filename, low2highuid(user), low2highgid(group));
31}
32
33SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
34{
35 return ksys_fchown(fd, low2highuid(user), low2highgid(group));
36}
37
38SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
39{
40 return __sys_setregid(low2highgid(rgid), low2highgid(egid));
41}
42
43SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
44{
45 return __sys_setgid(low2highgid(gid));
46}
47
48SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
49{
50 return __sys_setreuid(low2highuid(ruid), low2highuid(euid));
51}
52
53SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
54{
55 return __sys_setuid(low2highuid(uid));
56}
57
58SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
59{
60 return __sys_setresuid(low2highuid(ruid), low2highuid(euid),
61 low2highuid(suid));
62}
63
64SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
65{
66 const struct cred *cred = current_cred();
67 int retval;
68 old_uid_t ruid, euid, suid;
69
70 ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
71 euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
72 suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
73
74 if (!(retval = put_user(ruid, ruidp)) &&
75 !(retval = put_user(euid, euidp)))
76 retval = put_user(suid, suidp);
77
78 return retval;
79}
80
81SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
82{
83 return __sys_setresgid(low2highgid(rgid), low2highgid(egid),
84 low2highgid(sgid));
85}
86
87SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
88{
89 const struct cred *cred = current_cred();
90 int retval;
91 old_gid_t rgid, egid, sgid;
92
93 rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
94 egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
95 sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
96
97 if (!(retval = put_user(rgid, rgidp)) &&
98 !(retval = put_user(egid, egidp)))
99 retval = put_user(sgid, sgidp);
100
101 return retval;
102}
103
104SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
105{
106 return __sys_setfsuid(low2highuid(uid));
107}
108
109SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
110{
111 return __sys_setfsgid(low2highgid(gid));
112}
113
114static int groups16_to_user(old_gid_t __user *grouplist,
115 struct group_info *group_info)
116{
117 struct user_namespace *user_ns = current_user_ns();
118 int i;
119 old_gid_t group;
120 kgid_t kgid;
121
122 for (i = 0; i < group_info->ngroups; i++) {
123 kgid = group_info->gid[i];
124 group = high2lowgid(from_kgid_munged(user_ns, kgid));
125 if (put_user(group, grouplist+i))
126 return -EFAULT;
127 }
128
129 return 0;
130}
131
132static int groups16_from_user(struct group_info *group_info,
133 old_gid_t __user *grouplist)
134{
135 struct user_namespace *user_ns = current_user_ns();
136 int i;
137 old_gid_t group;
138 kgid_t kgid;
139
140 for (i = 0; i < group_info->ngroups; i++) {
141 if (get_user(group, grouplist+i))
142 return -EFAULT;
143
144 kgid = make_kgid(user_ns, low2highgid(group));
145 if (!gid_valid(kgid))
146 return -EINVAL;
147
148 group_info->gid[i] = kgid;
149 }
150
151 return 0;
152}
153
154SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
155{
156 const struct cred *cred = current_cred();
157 int i;
158
159 if (gidsetsize < 0)
160 return -EINVAL;
161
162 i = cred->group_info->ngroups;
163 if (gidsetsize) {
164 if (i > gidsetsize) {
165 i = -EINVAL;
166 goto out;
167 }
168 if (groups16_to_user(grouplist, cred->group_info)) {
169 i = -EFAULT;
170 goto out;
171 }
172 }
173out:
174 return i;
175}
176
177SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
178{
179 struct group_info *group_info;
180 int retval;
181
182 if (!may_setgroups())
183 return -EPERM;
184 if ((unsigned)gidsetsize > NGROUPS_MAX)
185 return -EINVAL;
186
187 group_info = groups_alloc(gidsetsize);
188 if (!group_info)
189 return -ENOMEM;
190 retval = groups16_from_user(group_info, grouplist);
191 if (retval) {
192 put_group_info(group_info);
193 return retval;
194 }
195
196 groups_sort(group_info);
197 retval = set_current_groups(group_info);
198 put_group_info(group_info);
199
200 return retval;
201}
202
203SYSCALL_DEFINE0(getuid16)
204{
205 return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
206}
207
208SYSCALL_DEFINE0(geteuid16)
209{
210 return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
211}
212
213SYSCALL_DEFINE0(getgid16)
214{
215 return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
216}
217
218SYSCALL_DEFINE0(getegid16)
219{
220 return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
221}
222