Root/kernel/uid16.c

1/*
2 * Wrapper functions for 16bit uid back compatibility. All nicely tied
3 * together in the faint hope we can take the out in five years time.
4 */
5
6#include <linux/mm.h>
7#include <linux/mman.h>
8#include <linux/notifier.h>
9#include <linux/reboot.h>
10#include <linux/prctl.h>
11#include <linux/capability.h>
12#include <linux/init.h>
13#include <linux/highuid.h>
14#include <linux/security.h>
15#include <linux/syscalls.h>
16
17#include <asm/uaccess.h>
18
19SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
20{
21    long ret = sys_chown(filename, low2highuid(user), low2highgid(group));
22    /* avoid REGPARM breakage on x86: */
23    asmlinkage_protect(3, ret, filename, user, group);
24    return ret;
25}
26
27SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
28{
29    long ret = sys_lchown(filename, low2highuid(user), low2highgid(group));
30    /* avoid REGPARM breakage on x86: */
31    asmlinkage_protect(3, ret, filename, user, group);
32    return ret;
33}
34
35SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
36{
37    long ret = sys_fchown(fd, low2highuid(user), low2highgid(group));
38    /* avoid REGPARM breakage on x86: */
39    asmlinkage_protect(3, ret, fd, user, group);
40    return ret;
41}
42
43SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
44{
45    long ret = sys_setregid(low2highgid(rgid), low2highgid(egid));
46    /* avoid REGPARM breakage on x86: */
47    asmlinkage_protect(2, ret, rgid, egid);
48    return ret;
49}
50
51SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
52{
53    long ret = sys_setgid(low2highgid(gid));
54    /* avoid REGPARM breakage on x86: */
55    asmlinkage_protect(1, ret, gid);
56    return ret;
57}
58
59SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
60{
61    long ret = sys_setreuid(low2highuid(ruid), low2highuid(euid));
62    /* avoid REGPARM breakage on x86: */
63    asmlinkage_protect(2, ret, ruid, euid);
64    return ret;
65}
66
67SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
68{
69    long ret = sys_setuid(low2highuid(uid));
70    /* avoid REGPARM breakage on x86: */
71    asmlinkage_protect(1, ret, uid);
72    return ret;
73}
74
75SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
76{
77    long ret = sys_setresuid(low2highuid(ruid), low2highuid(euid),
78                 low2highuid(suid));
79    /* avoid REGPARM breakage on x86: */
80    asmlinkage_protect(3, ret, ruid, euid, suid);
81    return ret;
82}
83
84SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruid, old_uid_t __user *, euid, old_uid_t __user *, suid)
85{
86    const struct cred *cred = current_cred();
87    int retval;
88
89    if (!(retval = put_user(high2lowuid(cred->uid), ruid)) &&
90        !(retval = put_user(high2lowuid(cred->euid), euid)))
91        retval = put_user(high2lowuid(cred->suid), suid);
92
93    return retval;
94}
95
96SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
97{
98    long ret = sys_setresgid(low2highgid(rgid), low2highgid(egid),
99                 low2highgid(sgid));
100    /* avoid REGPARM breakage on x86: */
101    asmlinkage_protect(3, ret, rgid, egid, sgid);
102    return ret;
103}
104
105
106SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgid, old_gid_t __user *, egid, old_gid_t __user *, sgid)
107{
108    const struct cred *cred = current_cred();
109    int retval;
110
111    if (!(retval = put_user(high2lowgid(cred->gid), rgid)) &&
112        !(retval = put_user(high2lowgid(cred->egid), egid)))
113        retval = put_user(high2lowgid(cred->sgid), sgid);
114
115    return retval;
116}
117
118SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
119{
120    long ret = sys_setfsuid(low2highuid(uid));
121    /* avoid REGPARM breakage on x86: */
122    asmlinkage_protect(1, ret, uid);
123    return ret;
124}
125
126SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
127{
128    long ret = sys_setfsgid(low2highgid(gid));
129    /* avoid REGPARM breakage on x86: */
130    asmlinkage_protect(1, ret, gid);
131    return ret;
132}
133
134static int groups16_to_user(old_gid_t __user *grouplist,
135    struct group_info *group_info)
136{
137    int i;
138    old_gid_t group;
139
140    for (i = 0; i < group_info->ngroups; i++) {
141        group = high2lowgid(GROUP_AT(group_info, i));
142        if (put_user(group, grouplist+i))
143            return -EFAULT;
144    }
145
146    return 0;
147}
148
149static int groups16_from_user(struct group_info *group_info,
150    old_gid_t __user *grouplist)
151{
152    int i;
153    old_gid_t group;
154
155    for (i = 0; i < group_info->ngroups; i++) {
156        if (get_user(group, grouplist+i))
157            return -EFAULT;
158        GROUP_AT(group_info, i) = low2highgid(group);
159    }
160
161    return 0;
162}
163
164SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
165{
166    const struct cred *cred = current_cred();
167    int i;
168
169    if (gidsetsize < 0)
170        return -EINVAL;
171
172    i = cred->group_info->ngroups;
173    if (gidsetsize) {
174        if (i > gidsetsize) {
175            i = -EINVAL;
176            goto out;
177        }
178        if (groups16_to_user(grouplist, cred->group_info)) {
179            i = -EFAULT;
180            goto out;
181        }
182    }
183out:
184    return i;
185}
186
187SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
188{
189    struct group_info *group_info;
190    int retval;
191
192    if (!nsown_capable(CAP_SETGID))
193        return -EPERM;
194    if ((unsigned)gidsetsize > NGROUPS_MAX)
195        return -EINVAL;
196
197    group_info = groups_alloc(gidsetsize);
198    if (!group_info)
199        return -ENOMEM;
200    retval = groups16_from_user(group_info, grouplist);
201    if (retval) {
202        put_group_info(group_info);
203        return retval;
204    }
205
206    retval = set_current_groups(group_info);
207    put_group_info(group_info);
208
209    return retval;
210}
211
212SYSCALL_DEFINE0(getuid16)
213{
214    return high2lowuid(current_uid());
215}
216
217SYSCALL_DEFINE0(geteuid16)
218{
219    return high2lowuid(current_euid());
220}
221
222SYSCALL_DEFINE0(getgid16)
223{
224    return high2lowgid(current_gid());
225}
226
227SYSCALL_DEFINE0(getegid16)
228{
229    return high2lowgid(current_egid());
230}
231

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