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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/ipc/msg.c | |
5a06a363 | 3 | * Copyright (C) 1992 Krishna Balasubramanian |
1da177e4 LT |
4 | * |
5 | * Removed all the remaining kerneld mess | |
6 | * Catch the -EFAULT stuff properly | |
7 | * Use GFP_KERNEL for messages as in 1.2 | |
8 | * Fixed up the unchecked user space derefs | |
9 | * Copyright (C) 1998 Alan Cox & Andi Kleen | |
10 | * | |
11 | * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <dragos@iname.com> | |
12 | * | |
13 | * mostly rewritten, threaded and wake-one semantics added | |
14 | * MSGMAX limit removed, sysctl's added | |
624dffcb | 15 | * (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
073115d6 SG |
16 | * |
17 | * support for audit of ipc object properties and permission changes | |
18 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
1e786937 KK |
19 | * |
20 | * namespaces support | |
21 | * OpenVZ, SWsoft Inc. | |
22 | * Pavel Emelianov <xemul@openvz.org> | |
1da177e4 LT |
23 | */ |
24 | ||
c59ede7b | 25 | #include <linux/capability.h> |
1da177e4 LT |
26 | #include <linux/slab.h> |
27 | #include <linux/msg.h> | |
28 | #include <linux/spinlock.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/proc_fs.h> | |
31 | #include <linux/list.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/sched.h> | |
34 | #include <linux/syscalls.h> | |
35 | #include <linux/audit.h> | |
19b4946c | 36 | #include <linux/seq_file.h> |
5f921ae9 | 37 | #include <linux/mutex.h> |
1e786937 | 38 | #include <linux/nsproxy.h> |
5f921ae9 | 39 | |
1da177e4 LT |
40 | #include <asm/current.h> |
41 | #include <asm/uaccess.h> | |
42 | #include "util.h" | |
43 | ||
5a06a363 IM |
44 | /* |
45 | * one msg_receiver structure for each sleeping receiver: | |
46 | */ | |
1da177e4 | 47 | struct msg_receiver { |
5a06a363 IM |
48 | struct list_head r_list; |
49 | struct task_struct *r_tsk; | |
1da177e4 | 50 | |
5a06a363 IM |
51 | int r_mode; |
52 | long r_msgtype; | |
53 | long r_maxsize; | |
1da177e4 | 54 | |
5a06a363 | 55 | volatile struct msg_msg *r_msg; |
1da177e4 LT |
56 | }; |
57 | ||
58 | /* one msg_sender for each sleeping sender */ | |
59 | struct msg_sender { | |
5a06a363 IM |
60 | struct list_head list; |
61 | struct task_struct *tsk; | |
1da177e4 LT |
62 | }; |
63 | ||
64 | #define SEARCH_ANY 1 | |
65 | #define SEARCH_EQUAL 2 | |
66 | #define SEARCH_NOTEQUAL 3 | |
67 | #define SEARCH_LESSEQUAL 4 | |
68 | ||
5a06a363 IM |
69 | static atomic_t msg_bytes = ATOMIC_INIT(0); |
70 | static atomic_t msg_hdrs = ATOMIC_INIT(0); | |
1da177e4 | 71 | |
1e786937 | 72 | static struct ipc_ids init_msg_ids; |
1da177e4 | 73 | |
1e786937 | 74 | #define msg_ids(ns) (*((ns)->ids[IPC_MSG_IDS])) |
1da177e4 | 75 | |
1e786937 KK |
76 | #define msg_lock(ns, id) ((struct msg_queue*)ipc_lock(&msg_ids(ns), id)) |
77 | #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) | |
78 | #define msg_rmid(ns, id) ((struct msg_queue*)ipc_rmid(&msg_ids(ns), id)) | |
79 | #define msg_checkid(ns, msq, msgid) \ | |
80 | ipc_checkid(&msg_ids(ns), &msq->q_perm, msgid) | |
81 | #define msg_buildid(ns, id, seq) \ | |
82 | ipc_buildid(&msg_ids(ns), id, seq) | |
83 | ||
84 | static void freeque (struct ipc_namespace *ns, struct msg_queue *msq, int id); | |
85 | static int newque (struct ipc_namespace *ns, key_t key, int msgflg); | |
1da177e4 | 86 | #ifdef CONFIG_PROC_FS |
19b4946c | 87 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it); |
1da177e4 LT |
88 | #endif |
89 | ||
1e786937 KK |
90 | static void __ipc_init __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) |
91 | { | |
92 | ns->ids[IPC_MSG_IDS] = ids; | |
93 | ns->msg_ctlmax = MSGMAX; | |
94 | ns->msg_ctlmnb = MSGMNB; | |
95 | ns->msg_ctlmni = MSGMNI; | |
96 | ipc_init_ids(ids, ns->msg_ctlmni); | |
97 | } | |
98 | ||
99 | #ifdef CONFIG_IPC_NS | |
100 | int msg_init_ns(struct ipc_namespace *ns) | |
101 | { | |
102 | struct ipc_ids *ids; | |
103 | ||
104 | ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL); | |
105 | if (ids == NULL) | |
106 | return -ENOMEM; | |
107 | ||
108 | __msg_init_ns(ns, ids); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | void msg_exit_ns(struct ipc_namespace *ns) | |
113 | { | |
114 | int i; | |
115 | struct msg_queue *msq; | |
116 | ||
117 | mutex_lock(&msg_ids(ns).mutex); | |
118 | for (i = 0; i <= msg_ids(ns).max_id; i++) { | |
119 | msq = msg_lock(ns, i); | |
120 | if (msq == NULL) | |
121 | continue; | |
122 | ||
123 | freeque(ns, msq, i); | |
124 | } | |
125 | mutex_unlock(&msg_ids(ns).mutex); | |
126 | ||
c7e12b83 | 127 | ipc_fini_ids(ns->ids[IPC_MSG_IDS]); |
1e786937 KK |
128 | kfree(ns->ids[IPC_MSG_IDS]); |
129 | ns->ids[IPC_MSG_IDS] = NULL; | |
130 | } | |
131 | #endif | |
132 | ||
5a06a363 | 133 | void __init msg_init(void) |
1da177e4 | 134 | { |
1e786937 | 135 | __msg_init_ns(&init_ipc_ns, &init_msg_ids); |
19b4946c MW |
136 | ipc_init_proc_interface("sysvipc/msg", |
137 | " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n", | |
1e786937 | 138 | IPC_MSG_IDS, sysvipc_msg_proc_show); |
1da177e4 LT |
139 | } |
140 | ||
1e786937 | 141 | static int newque (struct ipc_namespace *ns, key_t key, int msgflg) |
1da177e4 | 142 | { |
1da177e4 | 143 | struct msg_queue *msq; |
5a06a363 | 144 | int id, retval; |
1da177e4 | 145 | |
5a06a363 IM |
146 | msq = ipc_rcu_alloc(sizeof(*msq)); |
147 | if (!msq) | |
1da177e4 LT |
148 | return -ENOMEM; |
149 | ||
5a06a363 | 150 | msq->q_perm.mode = msgflg & S_IRWXUGO; |
1da177e4 LT |
151 | msq->q_perm.key = key; |
152 | ||
153 | msq->q_perm.security = NULL; | |
154 | retval = security_msg_queue_alloc(msq); | |
155 | if (retval) { | |
156 | ipc_rcu_putref(msq); | |
157 | return retval; | |
158 | } | |
159 | ||
1e786937 | 160 | id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); |
5a06a363 | 161 | if (id == -1) { |
1da177e4 LT |
162 | security_msg_queue_free(msq); |
163 | ipc_rcu_putref(msq); | |
164 | return -ENOSPC; | |
165 | } | |
166 | ||
1e786937 | 167 | msq->q_id = msg_buildid(ns, id, msq->q_perm.seq); |
1da177e4 LT |
168 | msq->q_stime = msq->q_rtime = 0; |
169 | msq->q_ctime = get_seconds(); | |
170 | msq->q_cbytes = msq->q_qnum = 0; | |
1e786937 | 171 | msq->q_qbytes = ns->msg_ctlmnb; |
1da177e4 LT |
172 | msq->q_lspid = msq->q_lrpid = 0; |
173 | INIT_LIST_HEAD(&msq->q_messages); | |
174 | INIT_LIST_HEAD(&msq->q_receivers); | |
175 | INIT_LIST_HEAD(&msq->q_senders); | |
176 | msg_unlock(msq); | |
177 | ||
19b4946c | 178 | return msq->q_id; |
1da177e4 LT |
179 | } |
180 | ||
5a06a363 | 181 | static inline void ss_add(struct msg_queue *msq, struct msg_sender *mss) |
1da177e4 | 182 | { |
5a06a363 IM |
183 | mss->tsk = current; |
184 | current->state = TASK_INTERRUPTIBLE; | |
185 | list_add_tail(&mss->list, &msq->q_senders); | |
1da177e4 LT |
186 | } |
187 | ||
5a06a363 | 188 | static inline void ss_del(struct msg_sender *mss) |
1da177e4 | 189 | { |
5a06a363 | 190 | if (mss->list.next != NULL) |
1da177e4 LT |
191 | list_del(&mss->list); |
192 | } | |
193 | ||
5a06a363 | 194 | static void ss_wakeup(struct list_head *h, int kill) |
1da177e4 LT |
195 | { |
196 | struct list_head *tmp; | |
197 | ||
198 | tmp = h->next; | |
199 | while (tmp != h) { | |
5a06a363 IM |
200 | struct msg_sender *mss; |
201 | ||
202 | mss = list_entry(tmp, struct msg_sender, list); | |
1da177e4 | 203 | tmp = tmp->next; |
5a06a363 IM |
204 | if (kill) |
205 | mss->list.next = NULL; | |
1da177e4 LT |
206 | wake_up_process(mss->tsk); |
207 | } | |
208 | } | |
209 | ||
5a06a363 | 210 | static void expunge_all(struct msg_queue *msq, int res) |
1da177e4 LT |
211 | { |
212 | struct list_head *tmp; | |
213 | ||
214 | tmp = msq->q_receivers.next; | |
215 | while (tmp != &msq->q_receivers) { | |
5a06a363 IM |
216 | struct msg_receiver *msr; |
217 | ||
218 | msr = list_entry(tmp, struct msg_receiver, r_list); | |
1da177e4 LT |
219 | tmp = tmp->next; |
220 | msr->r_msg = NULL; | |
221 | wake_up_process(msr->r_tsk); | |
222 | smp_mb(); | |
223 | msr->r_msg = ERR_PTR(res); | |
224 | } | |
225 | } | |
5a06a363 IM |
226 | |
227 | /* | |
228 | * freeque() wakes up waiters on the sender and receiver waiting queue, | |
229 | * removes the message queue from message queue ID | |
1da177e4 LT |
230 | * array, and cleans up all the messages associated with this queue. |
231 | * | |
5f921ae9 IM |
232 | * msg_ids.mutex and the spinlock for this message queue is hold |
233 | * before freeque() is called. msg_ids.mutex remains locked on exit. | |
1da177e4 | 234 | */ |
1e786937 | 235 | static void freeque(struct ipc_namespace *ns, struct msg_queue *msq, int id) |
1da177e4 LT |
236 | { |
237 | struct list_head *tmp; | |
238 | ||
5a06a363 IM |
239 | expunge_all(msq, -EIDRM); |
240 | ss_wakeup(&msq->q_senders, 1); | |
1e786937 | 241 | msq = msg_rmid(ns, id); |
1da177e4 | 242 | msg_unlock(msq); |
5a06a363 | 243 | |
1da177e4 | 244 | tmp = msq->q_messages.next; |
5a06a363 IM |
245 | while (tmp != &msq->q_messages) { |
246 | struct msg_msg *msg = list_entry(tmp, struct msg_msg, m_list); | |
247 | ||
1da177e4 LT |
248 | tmp = tmp->next; |
249 | atomic_dec(&msg_hdrs); | |
250 | free_msg(msg); | |
251 | } | |
252 | atomic_sub(msq->q_cbytes, &msg_bytes); | |
253 | security_msg_queue_free(msq); | |
254 | ipc_rcu_putref(msq); | |
255 | } | |
256 | ||
5a06a363 | 257 | asmlinkage long sys_msgget(key_t key, int msgflg) |
1da177e4 | 258 | { |
1da177e4 | 259 | struct msg_queue *msq; |
5a06a363 | 260 | int id, ret = -EPERM; |
1e786937 KK |
261 | struct ipc_namespace *ns; |
262 | ||
263 | ns = current->nsproxy->ipc_ns; | |
1da177e4 | 264 | |
1e786937 | 265 | mutex_lock(&msg_ids(ns).mutex); |
1da177e4 | 266 | if (key == IPC_PRIVATE) |
1e786937 KK |
267 | ret = newque(ns, key, msgflg); |
268 | else if ((id = ipc_findkey(&msg_ids(ns), key)) == -1) { /* key not used */ | |
1da177e4 LT |
269 | if (!(msgflg & IPC_CREAT)) |
270 | ret = -ENOENT; | |
271 | else | |
1e786937 | 272 | ret = newque(ns, key, msgflg); |
1da177e4 LT |
273 | } else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) { |
274 | ret = -EEXIST; | |
275 | } else { | |
1e786937 | 276 | msq = msg_lock(ns, id); |
5a06a363 | 277 | BUG_ON(msq == NULL); |
1da177e4 LT |
278 | if (ipcperms(&msq->q_perm, msgflg)) |
279 | ret = -EACCES; | |
280 | else { | |
1e786937 | 281 | int qid = msg_buildid(ns, id, msq->q_perm.seq); |
5a06a363 IM |
282 | |
283 | ret = security_msg_queue_associate(msq, msgflg); | |
1da177e4 LT |
284 | if (!ret) |
285 | ret = qid; | |
286 | } | |
287 | msg_unlock(msq); | |
288 | } | |
1e786937 | 289 | mutex_unlock(&msg_ids(ns).mutex); |
5a06a363 | 290 | |
1da177e4 LT |
291 | return ret; |
292 | } | |
293 | ||
5a06a363 IM |
294 | static inline unsigned long |
295 | copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version) | |
1da177e4 LT |
296 | { |
297 | switch(version) { | |
298 | case IPC_64: | |
5a06a363 | 299 | return copy_to_user(buf, in, sizeof(*in)); |
1da177e4 | 300 | case IPC_OLD: |
5a06a363 | 301 | { |
1da177e4 LT |
302 | struct msqid_ds out; |
303 | ||
5a06a363 | 304 | memset(&out, 0, sizeof(out)); |
1da177e4 LT |
305 | |
306 | ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm); | |
307 | ||
308 | out.msg_stime = in->msg_stime; | |
309 | out.msg_rtime = in->msg_rtime; | |
310 | out.msg_ctime = in->msg_ctime; | |
311 | ||
5a06a363 | 312 | if (in->msg_cbytes > USHRT_MAX) |
1da177e4 LT |
313 | out.msg_cbytes = USHRT_MAX; |
314 | else | |
315 | out.msg_cbytes = in->msg_cbytes; | |
316 | out.msg_lcbytes = in->msg_cbytes; | |
317 | ||
5a06a363 | 318 | if (in->msg_qnum > USHRT_MAX) |
1da177e4 LT |
319 | out.msg_qnum = USHRT_MAX; |
320 | else | |
321 | out.msg_qnum = in->msg_qnum; | |
322 | ||
5a06a363 | 323 | if (in->msg_qbytes > USHRT_MAX) |
1da177e4 LT |
324 | out.msg_qbytes = USHRT_MAX; |
325 | else | |
326 | out.msg_qbytes = in->msg_qbytes; | |
327 | out.msg_lqbytes = in->msg_qbytes; | |
328 | ||
329 | out.msg_lspid = in->msg_lspid; | |
330 | out.msg_lrpid = in->msg_lrpid; | |
331 | ||
5a06a363 IM |
332 | return copy_to_user(buf, &out, sizeof(out)); |
333 | } | |
1da177e4 LT |
334 | default: |
335 | return -EINVAL; | |
336 | } | |
337 | } | |
338 | ||
339 | struct msq_setbuf { | |
340 | unsigned long qbytes; | |
341 | uid_t uid; | |
342 | gid_t gid; | |
343 | mode_t mode; | |
344 | }; | |
345 | ||
5a06a363 IM |
346 | static inline unsigned long |
347 | copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) | |
1da177e4 LT |
348 | { |
349 | switch(version) { | |
350 | case IPC_64: | |
5a06a363 | 351 | { |
1da177e4 LT |
352 | struct msqid64_ds tbuf; |
353 | ||
5a06a363 | 354 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) |
1da177e4 LT |
355 | return -EFAULT; |
356 | ||
357 | out->qbytes = tbuf.msg_qbytes; | |
358 | out->uid = tbuf.msg_perm.uid; | |
359 | out->gid = tbuf.msg_perm.gid; | |
360 | out->mode = tbuf.msg_perm.mode; | |
361 | ||
362 | return 0; | |
5a06a363 | 363 | } |
1da177e4 | 364 | case IPC_OLD: |
5a06a363 | 365 | { |
1da177e4 LT |
366 | struct msqid_ds tbuf_old; |
367 | ||
5a06a363 | 368 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
1da177e4 LT |
369 | return -EFAULT; |
370 | ||
371 | out->uid = tbuf_old.msg_perm.uid; | |
372 | out->gid = tbuf_old.msg_perm.gid; | |
373 | out->mode = tbuf_old.msg_perm.mode; | |
374 | ||
5a06a363 | 375 | if (tbuf_old.msg_qbytes == 0) |
1da177e4 LT |
376 | out->qbytes = tbuf_old.msg_lqbytes; |
377 | else | |
378 | out->qbytes = tbuf_old.msg_qbytes; | |
379 | ||
380 | return 0; | |
5a06a363 | 381 | } |
1da177e4 LT |
382 | default: |
383 | return -EINVAL; | |
384 | } | |
385 | } | |
386 | ||
5a06a363 | 387 | asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) |
1da177e4 | 388 | { |
1da177e4 | 389 | struct kern_ipc_perm *ipcp; |
5a06a363 IM |
390 | struct msq_setbuf setbuf; |
391 | struct msg_queue *msq; | |
392 | int err, version; | |
1e786937 | 393 | struct ipc_namespace *ns; |
5a06a363 | 394 | |
1da177e4 LT |
395 | if (msqid < 0 || cmd < 0) |
396 | return -EINVAL; | |
397 | ||
398 | version = ipc_parse_version(&cmd); | |
1e786937 | 399 | ns = current->nsproxy->ipc_ns; |
1da177e4 LT |
400 | |
401 | switch (cmd) { | |
5a06a363 IM |
402 | case IPC_INFO: |
403 | case MSG_INFO: | |
404 | { | |
1da177e4 LT |
405 | struct msginfo msginfo; |
406 | int max_id; | |
5a06a363 | 407 | |
1da177e4 LT |
408 | if (!buf) |
409 | return -EFAULT; | |
5a06a363 IM |
410 | /* |
411 | * We must not return kernel stack data. | |
1da177e4 LT |
412 | * due to padding, it's not enough |
413 | * to set all member fields. | |
414 | */ | |
1da177e4 LT |
415 | err = security_msg_queue_msgctl(NULL, cmd); |
416 | if (err) | |
417 | return err; | |
418 | ||
5a06a363 | 419 | memset(&msginfo, 0, sizeof(msginfo)); |
1e786937 KK |
420 | msginfo.msgmni = ns->msg_ctlmni; |
421 | msginfo.msgmax = ns->msg_ctlmax; | |
422 | msginfo.msgmnb = ns->msg_ctlmnb; | |
1da177e4 LT |
423 | msginfo.msgssz = MSGSSZ; |
424 | msginfo.msgseg = MSGSEG; | |
1e786937 | 425 | mutex_lock(&msg_ids(ns).mutex); |
1da177e4 | 426 | if (cmd == MSG_INFO) { |
1e786937 | 427 | msginfo.msgpool = msg_ids(ns).in_use; |
1da177e4 LT |
428 | msginfo.msgmap = atomic_read(&msg_hdrs); |
429 | msginfo.msgtql = atomic_read(&msg_bytes); | |
430 | } else { | |
431 | msginfo.msgmap = MSGMAP; | |
432 | msginfo.msgpool = MSGPOOL; | |
433 | msginfo.msgtql = MSGTQL; | |
434 | } | |
1e786937 KK |
435 | max_id = msg_ids(ns).max_id; |
436 | mutex_unlock(&msg_ids(ns).mutex); | |
5a06a363 | 437 | if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) |
1da177e4 | 438 | return -EFAULT; |
5a06a363 | 439 | return (max_id < 0) ? 0 : max_id; |
1da177e4 LT |
440 | } |
441 | case MSG_STAT: | |
442 | case IPC_STAT: | |
443 | { | |
444 | struct msqid64_ds tbuf; | |
445 | int success_return; | |
5a06a363 | 446 | |
1da177e4 LT |
447 | if (!buf) |
448 | return -EFAULT; | |
1e786937 | 449 | if (cmd == MSG_STAT && msqid >= msg_ids(ns).entries->size) |
1da177e4 LT |
450 | return -EINVAL; |
451 | ||
5a06a363 | 452 | memset(&tbuf, 0, sizeof(tbuf)); |
1da177e4 | 453 | |
1e786937 | 454 | msq = msg_lock(ns, msqid); |
1da177e4 LT |
455 | if (msq == NULL) |
456 | return -EINVAL; | |
457 | ||
5a06a363 | 458 | if (cmd == MSG_STAT) { |
1e786937 | 459 | success_return = msg_buildid(ns, msqid, msq->q_perm.seq); |
1da177e4 LT |
460 | } else { |
461 | err = -EIDRM; | |
1e786937 | 462 | if (msg_checkid(ns, msq, msqid)) |
1da177e4 LT |
463 | goto out_unlock; |
464 | success_return = 0; | |
465 | } | |
466 | err = -EACCES; | |
5a06a363 | 467 | if (ipcperms(&msq->q_perm, S_IRUGO)) |
1da177e4 LT |
468 | goto out_unlock; |
469 | ||
470 | err = security_msg_queue_msgctl(msq, cmd); | |
471 | if (err) | |
472 | goto out_unlock; | |
473 | ||
474 | kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm); | |
475 | tbuf.msg_stime = msq->q_stime; | |
476 | tbuf.msg_rtime = msq->q_rtime; | |
477 | tbuf.msg_ctime = msq->q_ctime; | |
478 | tbuf.msg_cbytes = msq->q_cbytes; | |
479 | tbuf.msg_qnum = msq->q_qnum; | |
480 | tbuf.msg_qbytes = msq->q_qbytes; | |
481 | tbuf.msg_lspid = msq->q_lspid; | |
482 | tbuf.msg_lrpid = msq->q_lrpid; | |
483 | msg_unlock(msq); | |
484 | if (copy_msqid_to_user(buf, &tbuf, version)) | |
485 | return -EFAULT; | |
486 | return success_return; | |
487 | } | |
488 | case IPC_SET: | |
489 | if (!buf) | |
490 | return -EFAULT; | |
5a06a363 | 491 | if (copy_msqid_from_user(&setbuf, buf, version)) |
1da177e4 | 492 | return -EFAULT; |
1da177e4 LT |
493 | break; |
494 | case IPC_RMID: | |
495 | break; | |
496 | default: | |
497 | return -EINVAL; | |
498 | } | |
499 | ||
1e786937 KK |
500 | mutex_lock(&msg_ids(ns).mutex); |
501 | msq = msg_lock(ns, msqid); | |
5a06a363 | 502 | err = -EINVAL; |
1da177e4 LT |
503 | if (msq == NULL) |
504 | goto out_up; | |
505 | ||
506 | err = -EIDRM; | |
1e786937 | 507 | if (msg_checkid(ns, msq, msqid)) |
1da177e4 LT |
508 | goto out_unlock_up; |
509 | ipcp = &msq->q_perm; | |
073115d6 SG |
510 | |
511 | err = audit_ipc_obj(ipcp); | |
512 | if (err) | |
513 | goto out_unlock_up; | |
ac03221a | 514 | if (cmd==IPC_SET) { |
5a06a363 IM |
515 | err = audit_ipc_set_perm(setbuf.qbytes, setbuf.uid, setbuf.gid, |
516 | setbuf.mode); | |
ac03221a LK |
517 | if (err) |
518 | goto out_unlock_up; | |
519 | } | |
073115d6 | 520 | |
1da177e4 | 521 | err = -EPERM; |
5a06a363 | 522 | if (current->euid != ipcp->cuid && |
1da177e4 | 523 | current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN)) |
5a06a363 | 524 | /* We _could_ check for CAP_CHOWN above, but we don't */ |
1da177e4 LT |
525 | goto out_unlock_up; |
526 | ||
527 | err = security_msg_queue_msgctl(msq, cmd); | |
528 | if (err) | |
529 | goto out_unlock_up; | |
530 | ||
531 | switch (cmd) { | |
532 | case IPC_SET: | |
533 | { | |
534 | err = -EPERM; | |
1e786937 | 535 | if (setbuf.qbytes > ns->msg_ctlmnb && !capable(CAP_SYS_RESOURCE)) |
1da177e4 LT |
536 | goto out_unlock_up; |
537 | ||
538 | msq->q_qbytes = setbuf.qbytes; | |
539 | ||
540 | ipcp->uid = setbuf.uid; | |
541 | ipcp->gid = setbuf.gid; | |
5a06a363 IM |
542 | ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | |
543 | (S_IRWXUGO & setbuf.mode); | |
1da177e4 LT |
544 | msq->q_ctime = get_seconds(); |
545 | /* sleeping receivers might be excluded by | |
546 | * stricter permissions. | |
547 | */ | |
5a06a363 | 548 | expunge_all(msq, -EAGAIN); |
1da177e4 LT |
549 | /* sleeping senders might be able to send |
550 | * due to a larger queue size. | |
551 | */ | |
5a06a363 | 552 | ss_wakeup(&msq->q_senders, 0); |
1da177e4 LT |
553 | msg_unlock(msq); |
554 | break; | |
555 | } | |
556 | case IPC_RMID: | |
1e786937 | 557 | freeque(ns, msq, msqid); |
1da177e4 LT |
558 | break; |
559 | } | |
560 | err = 0; | |
561 | out_up: | |
1e786937 | 562 | mutex_unlock(&msg_ids(ns).mutex); |
1da177e4 LT |
563 | return err; |
564 | out_unlock_up: | |
565 | msg_unlock(msq); | |
566 | goto out_up; | |
567 | out_unlock: | |
568 | msg_unlock(msq); | |
569 | return err; | |
570 | } | |
571 | ||
5a06a363 | 572 | static int testmsg(struct msg_msg *msg, long type, int mode) |
1da177e4 LT |
573 | { |
574 | switch(mode) | |
575 | { | |
576 | case SEARCH_ANY: | |
577 | return 1; | |
578 | case SEARCH_LESSEQUAL: | |
5a06a363 | 579 | if (msg->m_type <=type) |
1da177e4 LT |
580 | return 1; |
581 | break; | |
582 | case SEARCH_EQUAL: | |
5a06a363 | 583 | if (msg->m_type == type) |
1da177e4 LT |
584 | return 1; |
585 | break; | |
586 | case SEARCH_NOTEQUAL: | |
5a06a363 | 587 | if (msg->m_type != type) |
1da177e4 LT |
588 | return 1; |
589 | break; | |
590 | } | |
591 | return 0; | |
592 | } | |
593 | ||
5a06a363 | 594 | static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg) |
1da177e4 | 595 | { |
5a06a363 | 596 | struct list_head *tmp; |
1da177e4 LT |
597 | |
598 | tmp = msq->q_receivers.next; | |
599 | while (tmp != &msq->q_receivers) { | |
5a06a363 IM |
600 | struct msg_receiver *msr; |
601 | ||
602 | msr = list_entry(tmp, struct msg_receiver, r_list); | |
1da177e4 | 603 | tmp = tmp->next; |
5a06a363 IM |
604 | if (testmsg(msg, msr->r_msgtype, msr->r_mode) && |
605 | !security_msg_queue_msgrcv(msq, msg, msr->r_tsk, | |
606 | msr->r_msgtype, msr->r_mode)) { | |
607 | ||
1da177e4 | 608 | list_del(&msr->r_list); |
5a06a363 | 609 | if (msr->r_maxsize < msg->m_ts) { |
1da177e4 LT |
610 | msr->r_msg = NULL; |
611 | wake_up_process(msr->r_tsk); | |
612 | smp_mb(); | |
613 | msr->r_msg = ERR_PTR(-E2BIG); | |
614 | } else { | |
615 | msr->r_msg = NULL; | |
616 | msq->q_lrpid = msr->r_tsk->pid; | |
617 | msq->q_rtime = get_seconds(); | |
618 | wake_up_process(msr->r_tsk); | |
619 | smp_mb(); | |
620 | msr->r_msg = msg; | |
5a06a363 | 621 | |
1da177e4 LT |
622 | return 1; |
623 | } | |
624 | } | |
625 | } | |
626 | return 0; | |
627 | } | |
628 | ||
5a06a363 IM |
629 | asmlinkage long |
630 | sys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz, int msgflg) | |
1da177e4 LT |
631 | { |
632 | struct msg_queue *msq; | |
633 | struct msg_msg *msg; | |
634 | long mtype; | |
635 | int err; | |
1e786937 KK |
636 | struct ipc_namespace *ns; |
637 | ||
638 | ns = current->nsproxy->ipc_ns; | |
5a06a363 | 639 | |
1e786937 | 640 | if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0) |
1da177e4 LT |
641 | return -EINVAL; |
642 | if (get_user(mtype, &msgp->mtype)) | |
5a06a363 | 643 | return -EFAULT; |
1da177e4 LT |
644 | if (mtype < 1) |
645 | return -EINVAL; | |
646 | ||
647 | msg = load_msg(msgp->mtext, msgsz); | |
5a06a363 | 648 | if (IS_ERR(msg)) |
1da177e4 LT |
649 | return PTR_ERR(msg); |
650 | ||
651 | msg->m_type = mtype; | |
652 | msg->m_ts = msgsz; | |
653 | ||
1e786937 | 654 | msq = msg_lock(ns, msqid); |
5a06a363 IM |
655 | err = -EINVAL; |
656 | if (msq == NULL) | |
1da177e4 LT |
657 | goto out_free; |
658 | ||
659 | err= -EIDRM; | |
1e786937 | 660 | if (msg_checkid(ns, msq, msqid)) |
1da177e4 LT |
661 | goto out_unlock_free; |
662 | ||
663 | for (;;) { | |
664 | struct msg_sender s; | |
665 | ||
5a06a363 | 666 | err = -EACCES; |
1da177e4 LT |
667 | if (ipcperms(&msq->q_perm, S_IWUGO)) |
668 | goto out_unlock_free; | |
669 | ||
670 | err = security_msg_queue_msgsnd(msq, msg, msgflg); | |
671 | if (err) | |
672 | goto out_unlock_free; | |
673 | ||
5a06a363 | 674 | if (msgsz + msq->q_cbytes <= msq->q_qbytes && |
1da177e4 LT |
675 | 1 + msq->q_qnum <= msq->q_qbytes) { |
676 | break; | |
677 | } | |
678 | ||
679 | /* queue full, wait: */ | |
5a06a363 IM |
680 | if (msgflg & IPC_NOWAIT) { |
681 | err = -EAGAIN; | |
1da177e4 LT |
682 | goto out_unlock_free; |
683 | } | |
684 | ss_add(msq, &s); | |
685 | ipc_rcu_getref(msq); | |
686 | msg_unlock(msq); | |
687 | schedule(); | |
688 | ||
689 | ipc_lock_by_ptr(&msq->q_perm); | |
690 | ipc_rcu_putref(msq); | |
691 | if (msq->q_perm.deleted) { | |
692 | err = -EIDRM; | |
693 | goto out_unlock_free; | |
694 | } | |
695 | ss_del(&s); | |
5a06a363 | 696 | |
1da177e4 | 697 | if (signal_pending(current)) { |
5a06a363 | 698 | err = -ERESTARTNOHAND; |
1da177e4 LT |
699 | goto out_unlock_free; |
700 | } | |
701 | } | |
702 | ||
703 | msq->q_lspid = current->tgid; | |
704 | msq->q_stime = get_seconds(); | |
705 | ||
5a06a363 | 706 | if (!pipelined_send(msq, msg)) { |
1da177e4 | 707 | /* noone is waiting for this message, enqueue it */ |
5a06a363 | 708 | list_add_tail(&msg->m_list, &msq->q_messages); |
1da177e4 LT |
709 | msq->q_cbytes += msgsz; |
710 | msq->q_qnum++; | |
5a06a363 | 711 | atomic_add(msgsz, &msg_bytes); |
1da177e4 LT |
712 | atomic_inc(&msg_hdrs); |
713 | } | |
5a06a363 | 714 | |
1da177e4 LT |
715 | err = 0; |
716 | msg = NULL; | |
717 | ||
718 | out_unlock_free: | |
719 | msg_unlock(msq); | |
720 | out_free: | |
5a06a363 | 721 | if (msg != NULL) |
1da177e4 LT |
722 | free_msg(msg); |
723 | return err; | |
724 | } | |
725 | ||
5a06a363 | 726 | static inline int convert_mode(long *msgtyp, int msgflg) |
1da177e4 | 727 | { |
5a06a363 | 728 | /* |
1da177e4 LT |
729 | * find message of correct type. |
730 | * msgtyp = 0 => get first. | |
731 | * msgtyp > 0 => get first message of matching type. | |
5a06a363 | 732 | * msgtyp < 0 => get message with least type must be < abs(msgtype). |
1da177e4 | 733 | */ |
5a06a363 | 734 | if (*msgtyp == 0) |
1da177e4 | 735 | return SEARCH_ANY; |
5a06a363 IM |
736 | if (*msgtyp < 0) { |
737 | *msgtyp = -*msgtyp; | |
1da177e4 LT |
738 | return SEARCH_LESSEQUAL; |
739 | } | |
5a06a363 | 740 | if (msgflg & MSG_EXCEPT) |
1da177e4 LT |
741 | return SEARCH_NOTEQUAL; |
742 | return SEARCH_EQUAL; | |
743 | } | |
744 | ||
5a06a363 IM |
745 | asmlinkage long sys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz, |
746 | long msgtyp, int msgflg) | |
1da177e4 LT |
747 | { |
748 | struct msg_queue *msq; | |
749 | struct msg_msg *msg; | |
750 | int mode; | |
1e786937 | 751 | struct ipc_namespace *ns; |
1da177e4 LT |
752 | |
753 | if (msqid < 0 || (long) msgsz < 0) | |
754 | return -EINVAL; | |
5a06a363 | 755 | mode = convert_mode(&msgtyp, msgflg); |
1e786937 | 756 | ns = current->nsproxy->ipc_ns; |
1da177e4 | 757 | |
1e786937 | 758 | msq = msg_lock(ns, msqid); |
5a06a363 | 759 | if (msq == NULL) |
1da177e4 LT |
760 | return -EINVAL; |
761 | ||
762 | msg = ERR_PTR(-EIDRM); | |
1e786937 | 763 | if (msg_checkid(ns, msq, msqid)) |
1da177e4 LT |
764 | goto out_unlock; |
765 | ||
766 | for (;;) { | |
767 | struct msg_receiver msr_d; | |
5a06a363 | 768 | struct list_head *tmp; |
1da177e4 LT |
769 | |
770 | msg = ERR_PTR(-EACCES); | |
5a06a363 | 771 | if (ipcperms(&msq->q_perm, S_IRUGO)) |
1da177e4 LT |
772 | goto out_unlock; |
773 | ||
774 | msg = ERR_PTR(-EAGAIN); | |
775 | tmp = msq->q_messages.next; | |
776 | while (tmp != &msq->q_messages) { | |
777 | struct msg_msg *walk_msg; | |
5a06a363 IM |
778 | |
779 | walk_msg = list_entry(tmp, struct msg_msg, m_list); | |
780 | if (testmsg(walk_msg, msgtyp, mode) && | |
781 | !security_msg_queue_msgrcv(msq, walk_msg, current, | |
782 | msgtyp, mode)) { | |
783 | ||
1da177e4 | 784 | msg = walk_msg; |
5a06a363 IM |
785 | if (mode == SEARCH_LESSEQUAL && |
786 | walk_msg->m_type != 1) { | |
787 | msg = walk_msg; | |
788 | msgtyp = walk_msg->m_type - 1; | |
1da177e4 | 789 | } else { |
5a06a363 | 790 | msg = walk_msg; |
1da177e4 LT |
791 | break; |
792 | } | |
793 | } | |
794 | tmp = tmp->next; | |
795 | } | |
5a06a363 IM |
796 | if (!IS_ERR(msg)) { |
797 | /* | |
798 | * Found a suitable message. | |
799 | * Unlink it from the queue. | |
800 | */ | |
1da177e4 LT |
801 | if ((msgsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) { |
802 | msg = ERR_PTR(-E2BIG); | |
803 | goto out_unlock; | |
804 | } | |
805 | list_del(&msg->m_list); | |
806 | msq->q_qnum--; | |
807 | msq->q_rtime = get_seconds(); | |
808 | msq->q_lrpid = current->tgid; | |
809 | msq->q_cbytes -= msg->m_ts; | |
5a06a363 | 810 | atomic_sub(msg->m_ts, &msg_bytes); |
1da177e4 | 811 | atomic_dec(&msg_hdrs); |
5a06a363 | 812 | ss_wakeup(&msq->q_senders, 0); |
1da177e4 LT |
813 | msg_unlock(msq); |
814 | break; | |
815 | } | |
816 | /* No message waiting. Wait for a message */ | |
817 | if (msgflg & IPC_NOWAIT) { | |
818 | msg = ERR_PTR(-ENOMSG); | |
819 | goto out_unlock; | |
820 | } | |
5a06a363 | 821 | list_add_tail(&msr_d.r_list, &msq->q_receivers); |
1da177e4 LT |
822 | msr_d.r_tsk = current; |
823 | msr_d.r_msgtype = msgtyp; | |
824 | msr_d.r_mode = mode; | |
5a06a363 | 825 | if (msgflg & MSG_NOERROR) |
1da177e4 | 826 | msr_d.r_maxsize = INT_MAX; |
5a06a363 | 827 | else |
1da177e4 LT |
828 | msr_d.r_maxsize = msgsz; |
829 | msr_d.r_msg = ERR_PTR(-EAGAIN); | |
830 | current->state = TASK_INTERRUPTIBLE; | |
831 | msg_unlock(msq); | |
832 | ||
833 | schedule(); | |
834 | ||
835 | /* Lockless receive, part 1: | |
836 | * Disable preemption. We don't hold a reference to the queue | |
837 | * and getting a reference would defeat the idea of a lockless | |
838 | * operation, thus the code relies on rcu to guarantee the | |
839 | * existance of msq: | |
840 | * Prior to destruction, expunge_all(-EIRDM) changes r_msg. | |
841 | * Thus if r_msg is -EAGAIN, then the queue not yet destroyed. | |
842 | * rcu_read_lock() prevents preemption between reading r_msg | |
843 | * and the spin_lock() inside ipc_lock_by_ptr(). | |
844 | */ | |
845 | rcu_read_lock(); | |
846 | ||
847 | /* Lockless receive, part 2: | |
848 | * Wait until pipelined_send or expunge_all are outside of | |
849 | * wake_up_process(). There is a race with exit(), see | |
850 | * ipc/mqueue.c for the details. | |
851 | */ | |
5a06a363 | 852 | msg = (struct msg_msg*)msr_d.r_msg; |
1da177e4 LT |
853 | while (msg == NULL) { |
854 | cpu_relax(); | |
5a06a363 | 855 | msg = (struct msg_msg *)msr_d.r_msg; |
1da177e4 LT |
856 | } |
857 | ||
858 | /* Lockless receive, part 3: | |
859 | * If there is a message or an error then accept it without | |
860 | * locking. | |
861 | */ | |
5a06a363 | 862 | if (msg != ERR_PTR(-EAGAIN)) { |
1da177e4 LT |
863 | rcu_read_unlock(); |
864 | break; | |
865 | } | |
866 | ||
867 | /* Lockless receive, part 3: | |
868 | * Acquire the queue spinlock. | |
869 | */ | |
870 | ipc_lock_by_ptr(&msq->q_perm); | |
871 | rcu_read_unlock(); | |
872 | ||
873 | /* Lockless receive, part 4: | |
874 | * Repeat test after acquiring the spinlock. | |
875 | */ | |
876 | msg = (struct msg_msg*)msr_d.r_msg; | |
5a06a363 | 877 | if (msg != ERR_PTR(-EAGAIN)) |
1da177e4 LT |
878 | goto out_unlock; |
879 | ||
880 | list_del(&msr_d.r_list); | |
881 | if (signal_pending(current)) { | |
882 | msg = ERR_PTR(-ERESTARTNOHAND); | |
883 | out_unlock: | |
884 | msg_unlock(msq); | |
885 | break; | |
886 | } | |
887 | } | |
888 | if (IS_ERR(msg)) | |
5a06a363 | 889 | return PTR_ERR(msg); |
1da177e4 LT |
890 | |
891 | msgsz = (msgsz > msg->m_ts) ? msg->m_ts : msgsz; | |
892 | if (put_user (msg->m_type, &msgp->mtype) || | |
893 | store_msg(msgp->mtext, msg, msgsz)) { | |
5a06a363 | 894 | msgsz = -EFAULT; |
1da177e4 LT |
895 | } |
896 | free_msg(msg); | |
5a06a363 | 897 | |
1da177e4 LT |
898 | return msgsz; |
899 | } | |
900 | ||
901 | #ifdef CONFIG_PROC_FS | |
19b4946c | 902 | static int sysvipc_msg_proc_show(struct seq_file *s, void *it) |
1da177e4 | 903 | { |
19b4946c MW |
904 | struct msg_queue *msq = it; |
905 | ||
906 | return seq_printf(s, | |
5a06a363 IM |
907 | "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10lu %10lu %10lu\n", |
908 | msq->q_perm.key, | |
909 | msq->q_id, | |
910 | msq->q_perm.mode, | |
911 | msq->q_cbytes, | |
912 | msq->q_qnum, | |
913 | msq->q_lspid, | |
914 | msq->q_lrpid, | |
915 | msq->q_perm.uid, | |
916 | msq->q_perm.gid, | |
917 | msq->q_perm.cuid, | |
918 | msq->q_perm.cgid, | |
919 | msq->q_stime, | |
920 | msq->q_rtime, | |
921 | msq->q_ctime); | |
1da177e4 LT |
922 | } |
923 | #endif |