xref: /linux/kernel/uid16.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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/utsname.h>
8 #include <linux/mman.h>
9 #include <linux/smp_lock.h>
10 #include <linux/notifier.h>
11 #include <linux/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/capability.h>
14 #include <linux/init.h>
15 #include <linux/highuid.h>
16 #include <linux/security.h>
17 #include <linux/syscalls.h>
18 
19 #include <asm/uaccess.h>
20 
21 asmlinkage long sys_chown16(const char __user * filename, old_uid_t user, old_gid_t group)
22 {
23 	long ret = sys_chown(filename, low2highuid(user), low2highgid(group));
24 	/* avoid REGPARM breakage on x86: */
25 	prevent_tail_call(ret);
26 	return ret;
27 }
28 
29 asmlinkage long sys_lchown16(const char __user * filename, old_uid_t user, old_gid_t group)
30 {
31 	long ret = sys_lchown(filename, low2highuid(user), low2highgid(group));
32 	/* avoid REGPARM breakage on x86: */
33 	prevent_tail_call(ret);
34 	return ret;
35 }
36 
37 asmlinkage long sys_fchown16(unsigned int fd, old_uid_t user, old_gid_t group)
38 {
39 	long ret = sys_fchown(fd, low2highuid(user), low2highgid(group));
40 	/* avoid REGPARM breakage on x86: */
41 	prevent_tail_call(ret);
42 	return ret;
43 }
44 
45 asmlinkage long sys_setregid16(old_gid_t rgid, old_gid_t egid)
46 {
47 	long ret = sys_setregid(low2highgid(rgid), low2highgid(egid));
48 	/* avoid REGPARM breakage on x86: */
49 	prevent_tail_call(ret);
50 	return ret;
51 }
52 
53 asmlinkage long sys_setgid16(old_gid_t gid)
54 {
55 	long ret = sys_setgid(low2highgid(gid));
56 	/* avoid REGPARM breakage on x86: */
57 	prevent_tail_call(ret);
58 	return ret;
59 }
60 
61 asmlinkage long sys_setreuid16(old_uid_t ruid, old_uid_t euid)
62 {
63 	long ret = sys_setreuid(low2highuid(ruid), low2highuid(euid));
64 	/* avoid REGPARM breakage on x86: */
65 	prevent_tail_call(ret);
66 	return ret;
67 }
68 
69 asmlinkage long sys_setuid16(old_uid_t uid)
70 {
71 	long ret = sys_setuid(low2highuid(uid));
72 	/* avoid REGPARM breakage on x86: */
73 	prevent_tail_call(ret);
74 	return ret;
75 }
76 
77 asmlinkage long sys_setresuid16(old_uid_t ruid, old_uid_t euid, old_uid_t suid)
78 {
79 	long ret = sys_setresuid(low2highuid(ruid), low2highuid(euid),
80 				 low2highuid(suid));
81 	/* avoid REGPARM breakage on x86: */
82 	prevent_tail_call(ret);
83 	return ret;
84 }
85 
86 asmlinkage long sys_getresuid16(old_uid_t __user *ruid, old_uid_t __user *euid, old_uid_t __user *suid)
87 {
88 	int retval;
89 
90 	if (!(retval = put_user(high2lowuid(current->uid), ruid)) &&
91 	    !(retval = put_user(high2lowuid(current->euid), euid)))
92 		retval = put_user(high2lowuid(current->suid), suid);
93 
94 	return retval;
95 }
96 
97 asmlinkage long sys_setresgid16(old_gid_t rgid, old_gid_t egid, old_gid_t sgid)
98 {
99 	long ret = sys_setresgid(low2highgid(rgid), low2highgid(egid),
100 				 low2highgid(sgid));
101 	/* avoid REGPARM breakage on x86: */
102 	prevent_tail_call(ret);
103 	return ret;
104 }
105 
106 asmlinkage long sys_getresgid16(old_gid_t __user *rgid, old_gid_t __user *egid, old_gid_t __user *sgid)
107 {
108 	int retval;
109 
110 	if (!(retval = put_user(high2lowgid(current->gid), rgid)) &&
111 	    !(retval = put_user(high2lowgid(current->egid), egid)))
112 		retval = put_user(high2lowgid(current->sgid), sgid);
113 
114 	return retval;
115 }
116 
117 asmlinkage long sys_setfsuid16(old_uid_t uid)
118 {
119 	long ret = sys_setfsuid(low2highuid(uid));
120 	/* avoid REGPARM breakage on x86: */
121 	prevent_tail_call(ret);
122 	return ret;
123 }
124 
125 asmlinkage long sys_setfsgid16(old_gid_t gid)
126 {
127 	long ret = sys_setfsgid(low2highgid(gid));
128 	/* avoid REGPARM breakage on x86: */
129 	prevent_tail_call(ret);
130 	return ret;
131 }
132 
133 static int groups16_to_user(old_gid_t __user *grouplist,
134     struct group_info *group_info)
135 {
136 	int i;
137 	old_gid_t group;
138 
139 	for (i = 0; i < group_info->ngroups; i++) {
140 		group = high2lowgid(GROUP_AT(group_info, i));
141 		if (put_user(group, grouplist+i))
142 			return -EFAULT;
143 	}
144 
145 	return 0;
146 }
147 
148 static int groups16_from_user(struct group_info *group_info,
149     old_gid_t __user *grouplist)
150 {
151 	int i;
152 	old_gid_t group;
153 
154 	for (i = 0; i < group_info->ngroups; i++) {
155 		if (get_user(group, grouplist+i))
156 			return  -EFAULT;
157 		GROUP_AT(group_info, i) = low2highgid(group);
158 	}
159 
160 	return 0;
161 }
162 
163 asmlinkage long sys_getgroups16(int gidsetsize, old_gid_t __user *grouplist)
164 {
165 	int i = 0;
166 
167 	if (gidsetsize < 0)
168 		return -EINVAL;
169 
170 	get_group_info(current->group_info);
171 	i = current->group_info->ngroups;
172 	if (gidsetsize) {
173 		if (i > gidsetsize) {
174 			i = -EINVAL;
175 			goto out;
176 		}
177 		if (groups16_to_user(grouplist, current->group_info)) {
178 			i = -EFAULT;
179 			goto out;
180 		}
181 	}
182 out:
183 	put_group_info(current->group_info);
184 	return i;
185 }
186 
187 asmlinkage long sys_setgroups16(int gidsetsize, old_gid_t __user *grouplist)
188 {
189 	struct group_info *group_info;
190 	int retval;
191 
192 	if (!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 
212 asmlinkage long sys_getuid16(void)
213 {
214 	return high2lowuid(current->uid);
215 }
216 
217 asmlinkage long sys_geteuid16(void)
218 {
219 	return high2lowuid(current->euid);
220 }
221 
222 asmlinkage long sys_getgid16(void)
223 {
224 	return high2lowgid(current->gid);
225 }
226 
227 asmlinkage long sys_getegid16(void)
228 {
229 	return high2lowgid(current->egid);
230 }
231