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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.h>
28#include <linux/nsproxy.h>
29
30#include <asm/system.h>
31#include <asm/uaccess.h>
32
33#include <net/protocol.h>
34#include <linux/skbuff.h>
35#include <net/sock.h>
36#include <net/compat.h>
37#include <net/scm.h>
38
39
40
41
42
43
44
45static __inline__ int scm_check_creds(struct ucred *creds)
46{
47 const struct cred *cred = current_cred();
48
49 if ((creds->pid == task_tgid_vnr(current) || capable(CAP_SYS_ADMIN)) &&
50 ((creds->uid == cred->uid || creds->uid == cred->euid ||
51 creds->uid == cred->suid) || capable(CAP_SETUID)) &&
52 ((creds->gid == cred->gid || creds->gid == cred->egid ||
53 creds->gid == cred->sgid) || capable(CAP_SETGID))) {
54 return 0;
55 }
56 return -EPERM;
57}
58
59static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
60{
61 int *fdp = (int*)CMSG_DATA(cmsg);
62 struct scm_fp_list *fpl = *fplp;
63 struct file **fpp;
64 int i, num;
65
66 num = (cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr)))/sizeof(int);
67
68 if (num <= 0)
69 return 0;
70
71 if (num > SCM_MAX_FD)
72 return -EINVAL;
73
74 if (!fpl)
75 {
76 fpl = kmalloc(sizeof(struct scm_fp_list), GFP_KERNEL);
77 if (!fpl)
78 return -ENOMEM;
79 *fplp = fpl;
80 fpl->count = 0;
81 }
82 fpp = &fpl->fp[fpl->count];
83
84 if (fpl->count + num > SCM_MAX_FD)
85 return -EINVAL;
86
87
88
89
90
91 for (i=0; i< num; i++)
92 {
93 int fd = fdp[i];
94 struct file *file;
95
96 if (fd < 0 || !(file = fget(fd)))
97 return -EBADF;
98 *fpp++ = file;
99 fpl->count++;
100 }
101 return num;
102}
103
104void __scm_destroy(struct scm_cookie *scm)
105{
106 struct scm_fp_list *fpl = scm->fp;
107 int i;
108
109 if (fpl) {
110 scm->fp = NULL;
111 if (current->scm_work_list) {
112 list_add_tail(&fpl->list, current->scm_work_list);
113 } else {
114 LIST_HEAD(work_list);
115
116 current->scm_work_list = &work_list;
117
118 list_add(&fpl->list, &work_list);
119 while (!list_empty(&work_list)) {
120 fpl = list_first_entry(&work_list, struct scm_fp_list, list);
121
122 list_del(&fpl->list);
123 for (i=fpl->count-1; i>=0; i--)
124 fput(fpl->fp[i]);
125 kfree(fpl);
126 }
127
128 current->scm_work_list = NULL;
129 }
130 }
131}
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
143
144
145
146
147
148
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:
159 err=scm_fp_copy(cmsg, &p->fp);
160 if (err<0)
161 goto error;
162 break;
163 case SCM_CREDENTIALS:
164 if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
165 goto error;
166 memcpy(&p->creds, CMSG_DATA(cmsg), sizeof(struct ucred));
167 err = scm_check_creds(&p->creds);
168 if (err)
169 goto error;
170 break;
171 default:
172 goto error;
173 }
174 }
175
176 if (p->fp && !p->fp->count)
177 {
178 kfree(p->fp);
179 p->fp = NULL;
180 }
181 return 0;
182
183error:
184 scm_destroy(p);
185 return err;
186}
187
188int put_cmsg(struct msghdr * msg, int level, int type, int len, void *data)
189{
190 struct cmsghdr __user *cm
191 = (__force struct cmsghdr __user *)msg->msg_control;
192 struct cmsghdr cmhdr;
193 int cmlen = CMSG_LEN(len);
194 int err;
195
196 if (MSG_CMSG_COMPAT & msg->msg_flags)
197 return put_cmsg_compat(msg, level, type, len, data);
198
199 if (cm==NULL || msg->msg_controllen < sizeof(*cm)) {
200 msg->msg_flags |= MSG_CTRUNC;
201 return 0;
202 }
203 if (msg->msg_controllen < cmlen) {
204 msg->msg_flags |= MSG_CTRUNC;
205 cmlen = msg->msg_controllen;
206 }
207 cmhdr.cmsg_level = level;
208 cmhdr.cmsg_type = type;
209 cmhdr.cmsg_len = cmlen;
210
211 err = -EFAULT;
212 if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
213 goto out;
214 if (copy_to_user(CMSG_DATA(cm), data, cmlen - sizeof(struct cmsghdr)))
215 goto out;
216 cmlen = CMSG_SPACE(len);
217 if (msg->msg_controllen < cmlen)
218 cmlen = msg->msg_controllen;
219 msg->msg_control += cmlen;
220 msg->msg_controllen -= cmlen;
221 err = 0;
222out:
223 return err;
224}
225
226void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
227{
228 struct cmsghdr __user *cm
229 = (__force struct cmsghdr __user*)msg->msg_control;
230
231 int fdmax = 0;
232 int fdnum = scm->fp->count;
233 struct file **fp = scm->fp->fp;
234 int __user *cmfptr;
235 int err = 0, i;
236
237 if (MSG_CMSG_COMPAT & msg->msg_flags) {
238 scm_detach_fds_compat(msg, scm);
239 return;
240 }
241
242 if (msg->msg_controllen > sizeof(struct cmsghdr))
243 fdmax = ((msg->msg_controllen - sizeof(struct cmsghdr))
244 / sizeof(int));
245
246 if (fdnum < fdmax)
247 fdmax = fdnum;
248
249 for (i=0, cmfptr=(__force int __user *)CMSG_DATA(cm); i<fdmax;
250 i++, cmfptr++)
251 {
252 int new_fd;
253 err = security_file_receive(fp[i]);
254 if (err)
255 break;
256 err = get_unused_fd_flags(MSG_CMSG_CLOEXEC & msg->msg_flags
257 ? O_CLOEXEC : 0);
258 if (err < 0)
259 break;
260 new_fd = err;
261 err = put_user(new_fd, cmfptr);
262 if (err) {
263 put_unused_fd(new_fd);
264 break;
265 }
266
267 get_file(fp[i]);
268 fd_install(new_fd, fp[i]);
269 }
270
271 if (i > 0)
272 {
273 int cmlen = CMSG_LEN(i*sizeof(int));
274 err = put_user(SOL_SOCKET, &cm->cmsg_level);
275 if (!err)
276 err = put_user(SCM_RIGHTS, &cm->cmsg_type);
277 if (!err)
278 err = put_user(cmlen, &cm->cmsg_len);
279 if (!err) {
280 cmlen = CMSG_SPACE(i*sizeof(int));
281 msg->msg_control += cmlen;
282 msg->msg_controllen -= cmlen;
283 }
284 }
285 if (i < fdnum || (fdnum && fdmax <= 0))
286 msg->msg_flags |= MSG_CTRUNC;
287
288
289
290
291
292 __scm_destroy(scm);
293}
294
295struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
296{
297 struct scm_fp_list *new_fpl;
298 int i;
299
300 if (!fpl)
301 return NULL;
302
303 new_fpl = kmalloc(sizeof(*fpl), GFP_KERNEL);
304 if (new_fpl) {
305 for (i=fpl->count-1; i>=0; i--)
306 get_file(fpl->fp[i]);
307 memcpy(new_fpl, fpl, sizeof(*fpl));
308 }
309 return new_fpl;
310}
311
312EXPORT_SYMBOL(__scm_destroy);
313EXPORT_SYMBOL(__scm_send);
314EXPORT_SYMBOL(put_cmsg);
315EXPORT_SYMBOL(scm_detach_fds);
316EXPORT_SYMBOL(scm_fp_dup);
317
