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