Merge tag 'v3.10.99' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / core / scm.c
CommitLineData
1da177e4
LT
1/* scm.c - Socket level control messages processing.
2 *
3 * Author: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
4 * Alignment and value checking mods by Craig Metz
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/signal.h>
4fc268d2 14#include <linux/capability.h>
1da177e4
LT
15#include <linux/errno.h>
16#include <linux/sched.h>
17#include <linux/mm.h>
18#include <linux/kernel.h>
1da177e4
LT
19#include <linux/stat.h>
20#include <linux/socket.h>
21#include <linux/file.h>
22#include <linux/fcntl.h>
23#include <linux/net.h>
24#include <linux/interrupt.h>
25#include <linux/netdevice.h>
26#include <linux/security.h>
92f28d97 27#include <linux/pid_namespace.h>
b488893a
PE
28#include <linux/pid.h>
29#include <linux/nsproxy.h>
5a0e3ad6 30#include <linux/slab.h>
1da177e4 31
1da177e4
LT
32#include <asm/uaccess.h>
33
34#include <net/protocol.h>
35#include <linux/skbuff.h>
36#include <net/sock.h>
37#include <net/compat.h>
38#include <net/scm.h>
d8429506 39#include <net/cls_cgroup.h>
1da177e4
LT
40
41
42/*
4ec93edb 43 * Only allow a user to send credentials, that they could set with
1da177e4
LT
44 * setu(g)id.
45 */
46
47static __inline__ int scm_check_creds(struct ucred *creds)
48{
86a264ab 49 const struct cred *cred = current_cred();
b2e4f544
EB
50 kuid_t uid = make_kuid(cred->user_ns, creds->uid);
51 kgid_t gid = make_kgid(cred->user_ns, creds->gid);
52
53 if (!uid_valid(uid) || !gid_valid(gid))
54 return -EINVAL;
b6dff3ec 55
92f28d97 56 if ((creds->pid == task_tgid_vnr(current) ||
979ad974 57 ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
b2e4f544 58 ((uid_eq(uid, cred->uid) || uid_eq(uid, cred->euid) ||
00f70de0 59 uid_eq(uid, cred->suid)) || nsown_capable(CAP_SETUID)) &&
b2e4f544 60 ((gid_eq(gid, cred->gid) || gid_eq(gid, cred->egid) ||
00f70de0 61 gid_eq(gid, cred->sgid)) || nsown_capable(CAP_SETGID))) {
1da177e4
LT
62 return 0;
63 }
64 return -EPERM;
65}
66
67static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
68{
69 int *fdp = (int*)CMSG_DATA(cmsg);
70 struct scm_fp_list *fpl = *fplp;
71 struct file **fpp;
72 int i, num;
73
74 num = (cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr)))/sizeof(int);
75
76 if (num <= 0)
77 return 0;
78
79 if (num > SCM_MAX_FD)
80 return -EINVAL;
81
82 if (!fpl)
83 {
84 fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL);
85 if (!fpl)
86 return -ENOMEM;
87 *fplp = fpl;
88 fpl->count = 0;
bba14de9 89 fpl->max = SCM_MAX_FD;
341f09c0 90 fpl->user = NULL;
1da177e4
LT
91 }
92 fpp = &fpl->fp[fpl->count];
93
bba14de9 94 if (fpl->count + num > fpl->max)
1da177e4 95 return -EINVAL;
4ec93edb 96
1da177e4
LT
97 /*
98 * Verify the descriptors and increment the usage count.
99 */
4ec93edb 100
1da177e4
LT
101 for (i=0; i< num; i++)
102 {
103 int fd = fdp[i];
104 struct file *file;
105
326be7b4 106 if (fd < 0 || !(file = fget_raw(fd)))
1da177e4
LT
107 return -EBADF;
108 *fpp++ = file;
109 fpl->count++;
110 }
341f09c0
HFS
111
112 if (!fpl->user)
113 fpl->user = get_uid(current_user());
114
1da177e4
LT
115 return num;
116}
117
118void __scm_destroy(struct scm_cookie *scm)
119{
120 struct scm_fp_list *fpl = scm->fp;
121 int i;
122
123 if (fpl) {
124 scm->fp = NULL;
6120d3db
AV
125 for (i=fpl->count-1; i>=0; i--)
126 fput(fpl->fp[i]);
341f09c0 127 free_uid(fpl->user);
6120d3db 128 kfree(fpl);
1da177e4
LT
129 }
130}
9e34a5b5 131EXPORT_SYMBOL(__scm_destroy);
1da177e4
LT
132
133int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
134{
135 struct cmsghdr *cmsg;
136 int err;
137
138 for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg))
139 {
140 err = -EINVAL;
141
142 /* Verify that cmsg_len is at least sizeof(struct cmsghdr) */
143 /* The first check was omitted in <= 2.2.5. The reasoning was
144 that parser checks cmsg_len in any case, so that
145 additional check would be work duplication.
4ec93edb 146 But if cmsg_level is not SOL_SOCKET, we do not check
1da177e4
LT
147 for too short ancillary data object at all! Oops.
148 OK, let's add it...
149 */
150 if (!CMSG_OK(msg, cmsg))
151 goto error;
152
153 if (cmsg->cmsg_level != SOL_SOCKET)
154 continue;
155
156 switch (cmsg->cmsg_type)
157 {
158 case SCM_RIGHTS:
76dadd76
EB
159 if (!sock->ops || sock->ops->family != PF_UNIX)
160 goto error;
1da177e4
LT
161 err=scm_fp_copy(cmsg, &p->fp);
162 if (err<0)
163 goto error;
164 break;
165 case SCM_CREDENTIALS:
b2e4f544 166 {
dbe9a417 167 struct ucred creds;
b2e4f544
EB
168 kuid_t uid;
169 kgid_t gid;
1da177e4
LT
170 if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
171 goto error;
dbe9a417
EB
172 memcpy(&creds, CMSG_DATA(cmsg), sizeof(struct ucred));
173 err = scm_check_creds(&creds);
1da177e4
LT
174 if (err)
175 goto error;
257b5358 176
dbe9a417
EB
177 p->creds.pid = creds.pid;
178 if (!p->pid || pid_vnr(p->pid) != creds.pid) {
257b5358
EB
179 struct pid *pid;
180 err = -ESRCH;
dbe9a417 181 pid = find_get_pid(creds.pid);
257b5358
EB
182 if (!pid)
183 goto error;
184 put_pid(p->pid);
185 p->pid = pid;
186 }
187
b2e4f544 188 err = -EINVAL;
dbe9a417
EB
189 uid = make_kuid(current_user_ns(), creds.uid);
190 gid = make_kgid(current_user_ns(), creds.gid);
b2e4f544
EB
191 if (!uid_valid(uid) || !gid_valid(gid))
192 goto error;
193
dbe9a417
EB
194 p->creds.uid = uid;
195 p->creds.gid = gid;
1da177e4 196 break;
b2e4f544 197 }
1da177e4
LT
198 default:
199 goto error;
200 }
201 }
202
203 if (p->fp && !p->fp->count)
204 {
205 kfree(p->fp);
206 p->fp = NULL;
207 }
208 return 0;
4ec93edb 209
1da177e4
LT
210error:
211 scm_destroy(p);
212 return err;
213}
9e34a5b5 214EXPORT_SYMBOL(__scm_send);
1da177e4
LT
215
216int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
217{
cfcabdcc
SH
218 struct cmsghdr __user *cm
219 = (__force struct cmsghdr __user *)msg->msg_control;
1da177e4
LT
220 struct cmsghdr cmhdr;
221 int cmlen = CMSG_LEN(len);
222 int err;
223
224 if (MSG_CMSG_COMPAT & msg->msg_flags)
225 return put_cmsg_compat(msg, level, type, len, data);
226
227 if (cm==NULL || msg->msg_controllen < sizeof(*cm)) {
228 msg->msg_flags |= MSG_CTRUNC;
229 return 0; /* XXX: return error? check spec. */
230 }
231 if (msg->msg_controllen < cmlen) {
232 msg->msg_flags |= MSG_CTRUNC;
233 cmlen = msg->msg_controllen;
234 }
235 cmhdr.cmsg_level = level;
236 cmhdr.cmsg_type = type;
237 cmhdr.cmsg_len = cmlen;
238
239 err = -EFAULT;
240 if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
4ec93edb 241 goto out;
1da177e4
LT
242 if (copy_to_user(CMSG_DATA(cm), data, cmlen - sizeof(struct cmsghdr)))
243 goto out;
244 cmlen = CMSG_SPACE(len);
1ac70e7a
WY
245 if (msg->msg_controllen < cmlen)
246 cmlen = msg->msg_controllen;
1da177e4
LT
247 msg->msg_control += cmlen;
248 msg->msg_controllen -= cmlen;
249 err = 0;
250out:
251 return err;
252}
9e34a5b5 253EXPORT_SYMBOL(put_cmsg);
1da177e4
LT
254
255void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
256{
cfcabdcc
SH
257 struct cmsghdr __user *cm
258 = (__force struct cmsghdr __user*)msg->msg_control;
1da177e4
LT
259
260 int fdmax = 0;
261 int fdnum = scm->fp->count;
262 struct file **fp = scm->fp->fp;
263 int __user *cmfptr;
264 int err = 0, i;
265
266 if (MSG_CMSG_COMPAT & msg->msg_flags) {
267 scm_detach_fds_compat(msg, scm);
268 return;
269 }
270
271 if (msg->msg_controllen > sizeof(struct cmsghdr))
272 fdmax = ((msg->msg_controllen - sizeof(struct cmsghdr))
273 / sizeof(int));
274
275 if (fdnum < fdmax)
276 fdmax = fdnum;
277
cfcabdcc
SH
278 for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
279 i++, cmfptr++)
1da177e4 280 {
48a87cc2 281 struct socket *sock;
1da177e4
LT
282 int new_fd;
283 err = security_file_receive(fp[i]);
284 if (err)
285 break;
4a19542e
UD
286 err = get_unused_fd_flags(MSG_CMSG_CLOEXEC & msg->msg_flags
287 ? O_CLOEXEC : 0);
1da177e4
LT
288 if (err < 0)
289 break;
290 new_fd = err;
291 err = put_user(new_fd, cmfptr);
292 if (err) {
293 put_unused_fd(new_fd);
294 break;
295 }
296 /* Bump the usage count and install the file. */
48a87cc2 297 sock = sock_from_file(fp[i], &err);
d8429506 298 if (sock) {
6ffd4641 299 sock_update_netprioidx(sock->sk);
211d2f97 300 sock_update_classid(sock->sk);
d8429506 301 }
cb0942b8 302 fd_install(new_fd, get_file(fp[i]));
1da177e4
LT
303 }
304
305 if (i > 0)
306 {
307 int cmlen = CMSG_LEN(i*sizeof(int));
effee6a0 308 err = put_user(SOL_SOCKET, &cm->cmsg_level);
1da177e4
LT
309 if (!err)
310 err = put_user(SCM_RIGHTS, &cm->cmsg_type);
311 if (!err)
312 err = put_user(cmlen, &cm->cmsg_len);
313 if (!err) {
314 cmlen = CMSG_SPACE(i*sizeof(int));
40e1d408
DB
315 if (msg->msg_controllen < cmlen)
316 cmlen = msg->msg_controllen;
1da177e4
LT
317 msg->msg_control += cmlen;
318 msg->msg_controllen -= cmlen;
319 }
320 }
321 if (i < fdnum || (fdnum && fdmax <= 0))
322 msg->msg_flags |= MSG_CTRUNC;
323
324 /*
325 * All of the files that fit in the message have had their
326 * usage counts incremented, so we just free the list.
327 */
328 __scm_destroy(scm);
329}
9e34a5b5 330EXPORT_SYMBOL(scm_detach_fds);
1da177e4
LT
331
332struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
333{
334 struct scm_fp_list *new_fpl;
335 int i;
336
337 if (!fpl)
338 return NULL;
339
bba14de9
ED
340 new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
341 GFP_KERNEL);
1da177e4 342 if (new_fpl) {
bba14de9 343 for (i = 0; i < fpl->count; i++)
1da177e4 344 get_file(fpl->fp[i]);
bba14de9 345 new_fpl->max = new_fpl->count;
341f09c0 346 new_fpl->user = get_uid(fpl->user);
1da177e4
LT
347 }
348 return new_fpl;
349}
1da177e4 350EXPORT_SYMBOL(scm_fp_dup);