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/msg.h>
17 #include <linux/ipc_namespace.h>
18 #include <linux/utsname.h>
19 #include <linux/proc_ns.h>
20 #include <linux/uaccess.h>
21 #include <linux/sched.h>
22
23 #include "util.h"
24
25 DEFINE_SPINLOCK(mq_lock);
26
27 /*
28 * The next 2 defines are here bc this is the only file
29 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
30 * and not CONFIG_IPC_NS.
31 */
32 struct ipc_namespace init_ipc_ns = {
33 .count = ATOMIC_INIT(1),
34 .user_ns = &init_user_ns,
35 .ns.inum = PROC_IPC_INIT_INO,
36 #ifdef CONFIG_IPC_NS
37 .ns.ops = &ipcns_operations,
38 #endif
39 };
40
41 atomic_t nr_ipc_ns = ATOMIC_INIT(1);
42
43 struct msg_msgseg {
44 struct msg_msgseg *next;
45 /* the next part of the message follows immediately */
46 };
47
48 #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg))
49 #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))
50
51
alloc_msg(size_t len)52 static struct msg_msg *alloc_msg(size_t len)
53 {
54 struct msg_msg *msg;
55 struct msg_msgseg **pseg;
56 size_t alen;
57
58 alen = min(len, DATALEN_MSG);
59 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
60 if (msg == NULL)
61 return NULL;
62
63 msg->next = NULL;
64 msg->security = NULL;
65
66 len -= alen;
67 pseg = &msg->next;
68 while (len > 0) {
69 struct msg_msgseg *seg;
70
71 cond_resched();
72
73 alen = min(len, DATALEN_SEG);
74 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL);
75 if (seg == NULL)
76 goto out_err;
77 *pseg = seg;
78 seg->next = NULL;
79 pseg = &seg->next;
80 len -= alen;
81 }
82
83 return msg;
84
85 out_err:
86 free_msg(msg);
87 return NULL;
88 }
89
load_msg(const void __user * src,size_t len)90 struct msg_msg *load_msg(const void __user *src, size_t len)
91 {
92 struct msg_msg *msg;
93 struct msg_msgseg *seg;
94 int err = -EFAULT;
95 size_t alen;
96
97 msg = alloc_msg(len);
98 if (msg == NULL)
99 return ERR_PTR(-ENOMEM);
100
101 alen = min(len, DATALEN_MSG);
102 if (copy_from_user(msg + 1, src, alen))
103 goto out_err;
104
105 for (seg = msg->next; seg != NULL; seg = seg->next) {
106 len -= alen;
107 src = (char __user *)src + alen;
108 alen = min(len, DATALEN_SEG);
109 if (copy_from_user(seg + 1, src, alen))
110 goto out_err;
111 }
112
113 err = security_msg_msg_alloc(msg);
114 if (err)
115 goto out_err;
116
117 return msg;
118
119 out_err:
120 free_msg(msg);
121 return ERR_PTR(err);
122 }
123 #ifdef CONFIG_CHECKPOINT_RESTORE
copy_msg(struct msg_msg * src,struct msg_msg * dst)124 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
125 {
126 struct msg_msgseg *dst_pseg, *src_pseg;
127 size_t len = src->m_ts;
128 size_t alen;
129
130 if (src->m_ts > dst->m_ts)
131 return ERR_PTR(-EINVAL);
132
133 alen = min(len, DATALEN_MSG);
134 memcpy(dst + 1, src + 1, alen);
135
136 for (dst_pseg = dst->next, src_pseg = src->next;
137 src_pseg != NULL;
138 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) {
139
140 len -= alen;
141 alen = min(len, DATALEN_SEG);
142 memcpy(dst_pseg + 1, src_pseg + 1, alen);
143 }
144
145 dst->m_type = src->m_type;
146 dst->m_ts = src->m_ts;
147
148 return dst;
149 }
150 #else
copy_msg(struct msg_msg * src,struct msg_msg * dst)151 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
152 {
153 return ERR_PTR(-ENOSYS);
154 }
155 #endif
store_msg(void __user * dest,struct msg_msg * msg,size_t len)156 int store_msg(void __user *dest, struct msg_msg *msg, size_t len)
157 {
158 size_t alen;
159 struct msg_msgseg *seg;
160
161 alen = min(len, DATALEN_MSG);
162 if (copy_to_user(dest, msg + 1, alen))
163 return -1;
164
165 for (seg = msg->next; seg != NULL; seg = seg->next) {
166 len -= alen;
167 dest = (char __user *)dest + alen;
168 alen = min(len, DATALEN_SEG);
169 if (copy_to_user(dest, seg + 1, alen))
170 return -1;
171 }
172 return 0;
173 }
174
free_msg(struct msg_msg * msg)175 void free_msg(struct msg_msg *msg)
176 {
177 struct msg_msgseg *seg;
178
179 security_msg_msg_free(msg);
180
181 seg = msg->next;
182 kfree(msg);
183 while (seg != NULL) {
184 struct msg_msgseg *tmp = seg->next;
185
186 cond_resched();
187 kfree(seg);
188 seg = tmp;
189 }
190 }
191