1
2
3
4
5
6
7
8
9
10
11
12#include <linux/module.h>
13#include <linux/signal.h>
14#include <linux/capability.h>
15#include <linux/errno.h>
16#include <linux/sched.h>
17#include <linux/mm.h>
18#include <linux/kernel.h>
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>
27#include <linux/pid_namespace.h>
28#include <linux/pid.h>
29#include <linux/nsproxy.h>
30#include <linux/slab.h>
31
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>
39#include <net/cls_cgroup.h>
40
41
42
43
44
45
46
47static __inline__ int scm_check_creds(struct ucred *creds)
48{
49 const struct cred *cred = current_cred();
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;
55
56 if ((creds->pid == task_tgid_vnr(current) ||
57 ns_capable(task_active_pid_ns(current)->user_ns, CAP_SYS_ADMIN)) &&
58 ((uid_eq(uid, cred->uid) || uid_eq(uid, cred->euid) ||
59 uid_eq(uid, cred->suid)) || ns_capable(cred->user_ns, CAP_SETUID)) &&
60 ((gid_eq(gid, cred->gid) || gid_eq(gid, cred->egid) ||
61 gid_eq(gid, cred->sgid)) || ns_capable(cred->user_ns, CAP_SETGID))) {
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;
89 fpl->max = SCM_MAX_FD;
90 }
91 fpp = &fpl->fp[fpl->count];
92
93 if (fpl->count + num > fpl->max)
94 return -EINVAL;
95
96
97
98
99
100 for (i=0; i< num; i++)
101 {
102 int fd = fdp[i];
103 struct file *file;
104
105 if (fd < 0 || !(file = fget_raw(fd)))
106 return -EBADF;
107 *fpp++ = file;
108 fpl->count++;
109 }
110 return num;
111}
112
113void __scm_destroy(struct scm_cookie *scm)
114{
115 struct scm_fp_list *fpl = scm->fp;
116 int i;
117
118 if (fpl) {
119 scm->fp = NULL;
120 for (i=fpl->count-1; i>=0; i--)
121 fput(fpl->fp[i]);
122 kfree(fpl);
123 }
124}
125EXPORT_SYMBOL(__scm_destroy);
126
127int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
128{
129 struct cmsghdr *cmsg;
130 int err;
131
132 for_each_cmsghdr(cmsg, msg) {
133 err = -EINVAL;
134
135
136
137
138
139
140
141
142
143 if (!CMSG_OK(msg, cmsg))
144 goto error;
145
146 if (cmsg->cmsg_level != SOL_SOCKET)
147 continue;
148
149 switch (cmsg->cmsg_type)
150 {
151 case SCM_RIGHTS:
152 if (!sock->ops || sock->ops->family != PF_UNIX)
153 goto error;
154 err=scm_fp_copy(cmsg, &p->fp);
155 if (err<0)
156 goto error;
157 break;
158 case SCM_CREDENTIALS:
159 {
160 struct ucred creds;
161 kuid_t uid;
162 kgid_t gid;
163 if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
164 goto error;
165 memcpy(&creds, CMSG_DATA(cmsg), sizeof(struct ucred));
166 err = scm_check_creds(&creds);
167 if (err)
168 goto error;
169
170 p->creds.pid = creds.pid;
171 if (!p->pid || pid_vnr(p->pid) != creds.pid) {
172 struct pid *pid;
173 err = -ESRCH;
174 pid = find_get_pid(creds.pid);
175 if (!pid)
176 goto error;
177 put_pid(p->pid);
178 p->pid = pid;
179 }
180
181 err = -EINVAL;
182 uid = make_kuid(current_user_ns(), creds.uid);
183 gid = make_kgid(current_user_ns(), creds.gid);
184 if (!uid_valid(uid) || !gid_valid(gid))
185 goto error;
186
187 p->creds.uid = uid;
188 p->creds.gid = gid;
189 break;
190 }
191 default:
192 goto error;
193 }
194 }
195
196 if (p->fp && !p->fp->count)
197 {
198 kfree(p->fp);
199 p->fp = NULL;
200 }
201 return 0;
202
203error:
204 scm_destroy(p);
205 return err;
206}
207EXPORT_SYMBOL(__scm_send);
208
209int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
210{
211 struct cmsghdr __user *cm
212 = (__force struct cmsghdr __user *)msg->msg_control;
213 struct cmsghdr cmhdr;
214 int cmlen = CMSG_LEN(len);
215 int err;
216
217 if (MSG_CMSG_COMPAT & msg->msg_flags)
218 return put_cmsg_compat(msg, level, type, len, data);
219
220 if (cm==NULL || msg->msg_controllen < sizeof(*cm)) {
221 msg->msg_flags |= MSG_CTRUNC;
222 return 0;
223 }
224 if (msg->msg_controllen < cmlen) {
225 msg->msg_flags |= MSG_CTRUNC;
226 cmlen = msg->msg_controllen;
227 }
228 cmhdr.cmsg_level = level;
229 cmhdr.cmsg_type = type;
230 cmhdr.cmsg_len = cmlen;
231
232 err = -EFAULT;
233 if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
234 goto out;
235 if (copy_to_user(CMSG_DATA(cm), data, cmlen - sizeof(struct cmsghdr)))
236 goto out;
237 cmlen = CMSG_SPACE(len);
238 if (msg->msg_controllen < cmlen)
239 cmlen = msg->msg_controllen;
240 msg->msg_control += cmlen;
241 msg->msg_controllen -= cmlen;
242 err = 0;
243out:
244 return err;
245}
246EXPORT_SYMBOL(put_cmsg);
247
248void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
249{
250 struct cmsghdr __user *cm
251 = (__force struct cmsghdr __user*)msg->msg_control;
252
253 int fdmax = 0;
254 int fdnum = scm->fp->count;
255 struct file **fp = scm->fp->fp;
256 int __user *cmfptr;
257 int err = 0, i;
258
259 if (MSG_CMSG_COMPAT & msg->msg_flags) {
260 scm_detach_fds_compat(msg, scm);
261 return;
262 }
263
264 if (msg->msg_controllen > sizeof(struct cmsghdr))
265 fdmax = ((msg->msg_controllen - sizeof(struct cmsghdr))
266 / sizeof(int));
267
268 if (fdnum < fdmax)
269 fdmax = fdnum;
270
271 for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
272 i++, cmfptr++)
273 {
274 struct socket *sock;
275 int new_fd;
276 err = security_file_receive(fp[i]);
277 if (err)
278 break;
279 err = get_unused_fd_flags(MSG_CMSG_CLOEXEC & msg->msg_flags
280 ? O_CLOEXEC : 0);
281 if (err < 0)
282 break;
283 new_fd = err;
284 err = put_user(new_fd, cmfptr);
285 if (err) {
286 put_unused_fd(new_fd);
287 break;
288 }
289
290 sock = sock_from_file(fp[i], &err);
291 if (sock) {
292 sock_update_netprioidx(sock->sk);
293 sock_update_classid(sock->sk);
294 }
295 fd_install(new_fd, get_file(fp[i]));
296 }
297
298 if (i > 0)
299 {
300 int cmlen = CMSG_LEN(i*sizeof(int));
301 err = put_user(SOL_SOCKET, &cm->cmsg_level);
302 if (!err)
303 err = put_user(SCM_RIGHTS, &cm->cmsg_type);
304 if (!err)
305 err = put_user(cmlen, &cm->cmsg_len);
306 if (!err) {
307 cmlen = CMSG_SPACE(i*sizeof(int));
308 msg->msg_control += cmlen;
309 msg->msg_controllen -= cmlen;
310 }
311 }
312 if (i < fdnum || (fdnum && fdmax <= 0))
313 msg->msg_flags |= MSG_CTRUNC;
314
315
316
317
318
319 __scm_destroy(scm);
320}
321EXPORT_SYMBOL(scm_detach_fds);
322
323struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
324{
325 struct scm_fp_list *new_fpl;
326 int i;
327
328 if (!fpl)
329 return NULL;
330
331 new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
332 GFP_KERNEL);
333 if (new_fpl) {
334 for (i = 0; i < fpl->count; i++)
335 get_file(fpl->fp[i]);
336 new_fpl->max = new_fpl->count;
337 }
338 return new_fpl;
339}
340EXPORT_SYMBOL(scm_fp_dup);
341
