1 /*
2 * linux/ipc/msgutil.c
3 * Copyright (C) 1999, 2004 Manfred Spraul
4 *
5 * This file is released under GNU General Public Licence version 2 or
6 * (at your option) any later version.
7 *
8 * See the file COPYING for more details.
9 */
10
11 #include <linux/spinlock.h>
12 #include <linux/init.h>
13 #include <linux/security.h>
14 #include <linux/slab.h>
15 #include <linux/ipc.h>
16 #include <linux/ipc_namespace.h>
17 #include <asm/uaccess.h>
18
19 #include "util.h"
20
21 DEFINE_SPINLOCK(mq_lock);
22
23 /*
24 * The next 2 defines are here bc this is the only file
25 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
26 * and not CONFIG_IPC_NS.
27 */
28 struct ipc_namespace init_ipc_ns = {
29 .count = ATOMIC_INIT(1),
30 #ifdef CONFIG_POSIX_MQUEUE
31 .mq_queues_max = DFLT_QUEUESMAX,
32 .mq_msg_max = DFLT_MSGMAX,
33 .mq_msgsize_max = DFLT_MSGSIZEMAX,
34 #endif
35 };
36
37 atomic_t nr_ipc_ns = ATOMIC_INIT(1);
38
39 struct msg_msgseg {
40 struct msg_msgseg* next;
41 /* the next part of the message follows immediately */
42 };
43
44 #define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
45 #define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
46
47 struct msg_msg *load_msg(const void __user *src, int len)
48 {
49 struct msg_msg *msg;
50 struct msg_msgseg **pseg;
51 int err;
52 int alen;
53
54 alen = len;
55 if (alen > DATALEN_MSG)
56 alen = DATALEN_MSG;
57
58 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
59 if (msg == NULL)
60 return ERR_PTR(-ENOMEM);
61
62 msg->next = NULL;
63 msg->security = NULL;
64
65 if (copy_from_user(msg + 1, src, alen)) {
66 err = -EFAULT;
67 goto out_err;
68 }
69
70 len -= alen;
71 src = ((char __user *)src) + alen;
72 pseg = &msg->next;
73 while (len > 0) {
74 struct msg_msgseg *seg;
75 alen = len;
76 if (alen > DATALEN_SEG)
77 alen = DATALEN_SEG;
78 seg = kmalloc(sizeof(*seg) + alen,
79 GFP_KERNEL);
80 if (seg == NULL) {
81 err = -ENOMEM;
82 goto out_err;
83 }
84 *pseg = seg;
85 seg->next = NULL;
86 if (copy_from_user(seg + 1, src, alen)) {
87 err = -EFAULT;
88 goto out_err;
89 }
90 pseg = &seg->next;
91 len -= alen;
92 src = ((char __user *)src) + alen;
93 }
94
95 err = security_msg_msg_alloc(msg);
96 if (err)
97 goto out_err;
98
99 return msg;
100
101 out_err:
102 free_msg(msg);
103 return ERR_PTR(err);
104 }
105
106 int store_msg(void __user *dest, struct msg_msg *msg, int len)
107 {
108 int alen;
109 struct msg_msgseg *seg;
110
111 alen = len;
112 if (alen > DATALEN_MSG)
113 alen = DATALEN_MSG;
114 if (copy_to_user(dest, msg + 1, alen))
115 return -1;
116
117 len -= alen;
118 dest = ((char __user *)dest) + alen;
119 seg = msg->next;
120 while (len > 0) {
121 alen = len;
122 if (alen > DATALEN_SEG)
123 alen = DATALEN_SEG;
124 if (copy_to_user(dest, seg + 1, alen))
125 return -1;
126 len -= alen;
127 dest = ((char __user *)dest) + alen;
128 seg = seg->next;
129 }
130 return 0;
131 }
132
133 void free_msg(struct msg_msg *msg)
134 {
135 struct msg_msgseg *seg;
136
137 security_msg_msg_free(msg);
138
139 seg = msg->next;
140 kfree(msg);
141 while (seg != NULL) {
142 struct msg_msgseg *tmp = seg->next;
143 kfree(seg);
144 seg = tmp;
145 }
146 }
147
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