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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/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/syscalls.h>
17 
18 #include <asm/uaccess.h>
19 
SYSCALL_DEFINE3(chown16,const char __user *,filename,old_uid_t,user,old_gid_t,group)20 SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
21 {
22 	long ret = sys_chown(filename, low2highuid(user), low2highgid(group));
23 	/* avoid REGPARM breakage on x86: */
24 	asmlinkage_protect(3, ret, filename, user, group);
25 	return ret;
26 }
27 
SYSCALL_DEFINE3(lchown16,const char __user *,filename,old_uid_t,user,old_gid_t,group)28 SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
29 {
30 	long ret = sys_lchown(filename, low2highuid(user), low2highgid(group));
31 	/* avoid REGPARM breakage on x86: */
32 	asmlinkage_protect(3, ret, filename, user, group);
33 	return ret;
34 }
35 
SYSCALL_DEFINE3(fchown16,unsigned int,fd,old_uid_t,user,old_gid_t,group)36 SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
37 {
38 	long ret = sys_fchown(fd, low2highuid(user), low2highgid(group));
39 	/* avoid REGPARM breakage on x86: */
40 	asmlinkage_protect(3, ret, fd, user, group);
41 	return ret;
42 }
43 
SYSCALL_DEFINE2(setregid16,old_gid_t,rgid,old_gid_t,egid)44 SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
45 {
46 	long ret = sys_setregid(low2highgid(rgid), low2highgid(egid));
47 	/* avoid REGPARM breakage on x86: */
48 	asmlinkage_protect(2, ret, rgid, egid);
49 	return ret;
50 }
51 
SYSCALL_DEFINE1(setgid16,old_gid_t,gid)52 SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
53 {
54 	long ret = sys_setgid(low2highgid(gid));
55 	/* avoid REGPARM breakage on x86: */
56 	asmlinkage_protect(1, ret, gid);
57 	return ret;
58 }
59 
SYSCALL_DEFINE2(setreuid16,old_uid_t,ruid,old_uid_t,euid)60 SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
61 {
62 	long ret = sys_setreuid(low2highuid(ruid), low2highuid(euid));
63 	/* avoid REGPARM breakage on x86: */
64 	asmlinkage_protect(2, ret, ruid, euid);
65 	return ret;
66 }
67 
SYSCALL_DEFINE1(setuid16,old_uid_t,uid)68 SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
69 {
70 	long ret = sys_setuid(low2highuid(uid));
71 	/* avoid REGPARM breakage on x86: */
72 	asmlinkage_protect(1, ret, uid);
73 	return ret;
74 }
75 
SYSCALL_DEFINE3(setresuid16,old_uid_t,ruid,old_uid_t,euid,old_uid_t,suid)76 SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
77 {
78 	long ret = sys_setresuid(low2highuid(ruid), low2highuid(euid),
79 				 low2highuid(suid));
80 	/* avoid REGPARM breakage on x86: */
81 	asmlinkage_protect(3, ret, ruid, euid, suid);
82 	return ret;
83 }
84 
SYSCALL_DEFINE3(getresuid16,old_uid_t __user *,ruid,old_uid_t __user *,euid,old_uid_t __user *,suid)85 SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruid, old_uid_t __user *, euid, old_uid_t __user *, suid)
86 {
87 	const struct cred *cred = current_cred();
88 	int retval;
89 
90 	if (!(retval   = put_user(high2lowuid(cred->uid),  ruid)) &&
91 	    !(retval   = put_user(high2lowuid(cred->euid), euid)))
92 		retval = put_user(high2lowuid(cred->suid), suid);
93 
94 	return retval;
95 }
96 
SYSCALL_DEFINE3(setresgid16,old_gid_t,rgid,old_gid_t,egid,old_gid_t,sgid)97 SYSCALL_DEFINE3(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 	asmlinkage_protect(3, ret, rgid, egid, sgid);
103 	return ret;
104 }
105 
106 
SYSCALL_DEFINE3(getresgid16,old_gid_t __user *,rgid,old_gid_t __user *,egid,old_gid_t __user *,sgid)107 SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgid, old_gid_t __user *, egid, old_gid_t __user *, sgid)
108 {
109 	const struct cred *cred = current_cred();
110 	int retval;
111 
112 	if (!(retval   = put_user(high2lowgid(cred->gid),  rgid)) &&
113 	    !(retval   = put_user(high2lowgid(cred->egid), egid)))
114 		retval = put_user(high2lowgid(cred->sgid), sgid);
115 
116 	return retval;
117 }
118 
SYSCALL_DEFINE1(setfsuid16,old_uid_t,uid)119 SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
120 {
121 	long ret = sys_setfsuid(low2highuid(uid));
122 	/* avoid REGPARM breakage on x86: */
123 	asmlinkage_protect(1, ret, uid);
124 	return ret;
125 }
126 
SYSCALL_DEFINE1(setfsgid16,old_gid_t,gid)127 SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
128 {
129 	long ret = sys_setfsgid(low2highgid(gid));
130 	/* avoid REGPARM breakage on x86: */
131 	asmlinkage_protect(1, ret, gid);
132 	return ret;
133 }
134 
groups16_to_user(old_gid_t __user * grouplist,struct group_info * group_info)135 static int groups16_to_user(old_gid_t __user *grouplist,
136     struct group_info *group_info)
137 {
138 	int i;
139 	old_gid_t group;
140 
141 	for (i = 0; i < group_info->ngroups; i++) {
142 		group = high2lowgid(GROUP_AT(group_info, i));
143 		if (put_user(group, grouplist+i))
144 			return -EFAULT;
145 	}
146 
147 	return 0;
148 }
149 
groups16_from_user(struct group_info * group_info,old_gid_t __user * grouplist)150 static int groups16_from_user(struct group_info *group_info,
151     old_gid_t __user *grouplist)
152 {
153 	int i;
154 	old_gid_t group;
155 
156 	for (i = 0; i < group_info->ngroups; i++) {
157 		if (get_user(group, grouplist+i))
158 			return  -EFAULT;
159 		GROUP_AT(group_info, i) = low2highgid(group);
160 	}
161 
162 	return 0;
163 }
164 
SYSCALL_DEFINE2(getgroups16,int,gidsetsize,old_gid_t __user *,grouplist)165 SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
166 {
167 	const struct cred *cred = current_cred();
168 	int i;
169 
170 	if (gidsetsize < 0)
171 		return -EINVAL;
172 
173 	i = cred->group_info->ngroups;
174 	if (gidsetsize) {
175 		if (i > gidsetsize) {
176 			i = -EINVAL;
177 			goto out;
178 		}
179 		if (groups16_to_user(grouplist, cred->group_info)) {
180 			i = -EFAULT;
181 			goto out;
182 		}
183 	}
184 out:
185 	return i;
186 }
187 
SYSCALL_DEFINE2(setgroups16,int,gidsetsize,old_gid_t __user *,grouplist)188 SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
189 {
190 	struct group_info *group_info;
191 	int retval;
192 
193 	if (!capable(CAP_SETGID))
194 		return -EPERM;
195 	if ((unsigned)gidsetsize > NGROUPS_MAX)
196 		return -EINVAL;
197 
198 	group_info = groups_alloc(gidsetsize);
199 	if (!group_info)
200 		return -ENOMEM;
201 	retval = groups16_from_user(group_info, grouplist);
202 	if (retval) {
203 		put_group_info(group_info);
204 		return retval;
205 	}
206 
207 	retval = set_current_groups(group_info);
208 	put_group_info(group_info);
209 
210 	return retval;
211 }
212 
SYSCALL_DEFINE0(getuid16)213 SYSCALL_DEFINE0(getuid16)
214 {
215 	return high2lowuid(current_uid());
216 }
217 
SYSCALL_DEFINE0(geteuid16)218 SYSCALL_DEFINE0(geteuid16)
219 {
220 	return high2lowuid(current_euid());
221 }
222 
SYSCALL_DEFINE0(getgid16)223 SYSCALL_DEFINE0(getgid16)
224 {
225 	return high2lowgid(current_gid());
226 }
227 
SYSCALL_DEFINE0(getegid16)228 SYSCALL_DEFINE0(getegid16)
229 {
230 	return high2lowgid(current_egid());
231 }
232