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 *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
85{
86    const struct cred *cred = current_cred();
87    int retval;
88    old_uid_t ruid, euid, suid;
89
90    ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
91    euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
92    suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
93
94    if (!(retval = put_user(ruid, ruidp)) &&
95        !(retval = put_user(euid, euidp)))
96        retval = put_user(suid, suidp);
97
98    return retval;
99}
100
101SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
102{
103    long ret = sys_setresgid(low2highgid(rgid), low2highgid(egid),
104                 low2highgid(sgid));
105    /* avoid REGPARM breakage on x86: */
106    asmlinkage_protect(3, ret, rgid, egid, sgid);
107    return ret;
108}
109
110
111SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
112{
113    const struct cred *cred = current_cred();
114    int retval;
115    old_gid_t rgid, egid, sgid;
116
117    rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
118    egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
119    sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
120
121    if (!(retval = put_user(rgid, rgidp)) &&
122        !(retval = put_user(egid, egidp)))
123        retval = put_user(sgid, sgidp);
124
125    return retval;
126}
127
128SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
129{
130    long ret = sys_setfsuid(low2highuid(uid));
131    /* avoid REGPARM breakage on x86: */
132    asmlinkage_protect(1, ret, uid);
133    return ret;
134}
135
136SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
137{
138    long ret = sys_setfsgid(low2highgid(gid));
139    /* avoid REGPARM breakage on x86: */
140    asmlinkage_protect(1, ret, gid);
141    return ret;
142}
143
144static int groups16_to_user(old_gid_t __user *grouplist,
145    struct group_info *group_info)
146{
147    struct user_namespace *user_ns = current_user_ns();
148    int i;
149    old_gid_t group;
150    kgid_t kgid;
151
152    for (i = 0; i < group_info->ngroups; i++) {
153        kgid = GROUP_AT(group_info, i);
154        group = high2lowgid(from_kgid_munged(user_ns, kgid));
155        if (put_user(group, grouplist+i))
156            return -EFAULT;
157    }
158
159    return 0;
160}
161
162static int groups16_from_user(struct group_info *group_info,
163    old_gid_t __user *grouplist)
164{
165    struct user_namespace *user_ns = current_user_ns();
166    int i;
167    old_gid_t group;
168    kgid_t kgid;
169
170    for (i = 0; i < group_info->ngroups; i++) {
171        if (get_user(group, grouplist+i))
172            return -EFAULT;
173
174        kgid = make_kgid(user_ns, low2highgid(group));
175        if (!gid_valid(kgid))
176            return -EINVAL;
177
178        GROUP_AT(group_info, i) = kgid;
179    }
180
181    return 0;
182}
183
184SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
185{
186    const struct cred *cred = current_cred();
187    int i;
188
189    if (gidsetsize < 0)
190        return -EINVAL;
191
192    i = cred->group_info->ngroups;
193    if (gidsetsize) {
194        if (i > gidsetsize) {
195            i = -EINVAL;
196            goto out;
197        }
198        if (groups16_to_user(grouplist, cred->group_info)) {
199            i = -EFAULT;
200            goto out;
201        }
202    }
203out:
204    return i;
205}
206
207SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
208{
209    struct group_info *group_info;
210    int retval;
211
212    if (!nsown_capable(CAP_SETGID))
213        return -EPERM;
214    if ((unsigned)gidsetsize > NGROUPS_MAX)
215        return -EINVAL;
216
217    group_info = groups_alloc(gidsetsize);
218    if (!group_info)
219        return -ENOMEM;
220    retval = groups16_from_user(group_info, grouplist);
221    if (retval) {
222        put_group_info(group_info);
223        return retval;
224    }
225
226    retval = set_current_groups(group_info);
227    put_group_info(group_info);
228
229    return retval;
230}
231
232SYSCALL_DEFINE0(getuid16)
233{
234    return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
235}
236
237SYSCALL_DEFINE0(geteuid16)
238{
239    return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
240}
241
242SYSCALL_DEFINE0(getgid16)
243{
244    return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
245}
246
247SYSCALL_DEFINE0(getegid16)
248{
249    return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
250}
251

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