1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * linux/ipc/msgutil.c
4 * Copyright (C) 1999, 2004 Manfred Spraul
5 */
6
7 #include <linux/spinlock.h>
8 #include <linux/init.h>
9 #include <linux/security.h>
10 #include <linux/slab.h>
11 #include <linux/ipc.h>
12 #include <linux/msg.h>
13 #include <linux/ipc_namespace.h>
14 #include <linux/utsname.h>
15 #include <linux/proc_ns.h>
16 #include <linux/uaccess.h>
17 #include <linux/sched.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 = REFCOUNT_INIT(1),
30 .user_ns = &init_user_ns,
31 .ns.inum = PROC_IPC_INIT_INO,
32 #ifdef CONFIG_IPC_NS
33 .ns.ops = &ipcns_operations,
34 #endif
35 };
36
37 struct msg_msgseg {
38 struct msg_msgseg *next;
39 /* the next part of the message follows immediately */
40 };
41
42 #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg))
43 #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))
44
45
alloc_msg(size_t len)46 static struct msg_msg *alloc_msg(size_t len)
47 {
48 struct msg_msg *msg;
49 struct msg_msgseg **pseg;
50 size_t alen;
51
52 alen = min(len, DATALEN_MSG);
53 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT);
54 if (msg == NULL)
55 return NULL;
56
57 msg->next = NULL;
58 msg->security = NULL;
59
60 len -= alen;
61 pseg = &msg->next;
62 while (len > 0) {
63 struct msg_msgseg *seg;
64
65 cond_resched();
66
67 alen = min(len, DATALEN_SEG);
68 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT);
69 if (seg == NULL)
70 goto out_err;
71 *pseg = seg;
72 seg->next = NULL;
73 pseg = &seg->next;
74 len -= alen;
75 }
76
77 return msg;
78
79 out_err:
80 free_msg(msg);
81 return NULL;
82 }
83
load_msg(const void __user * src,size_t len)84 struct msg_msg *load_msg(const void __user *src, size_t len)
85 {
86 struct msg_msg *msg;
87 struct msg_msgseg *seg;
88 int err = -EFAULT;
89 size_t alen;
90
91 msg = alloc_msg(len);
92 if (msg == NULL)
93 return ERR_PTR(-ENOMEM);
94
95 alen = min(len, DATALEN_MSG);
96 if (copy_from_user(msg + 1, src, alen))
97 goto out_err;
98
99 for (seg = msg->next; seg != NULL; seg = seg->next) {
100 len -= alen;
101 src = (char __user *)src + alen;
102 alen = min(len, DATALEN_SEG);
103 if (copy_from_user(seg + 1, src, alen))
104 goto out_err;
105 }
106
107 err = security_msg_msg_alloc(msg);
108 if (err)
109 goto out_err;
110
111 return msg;
112
113 out_err:
114 free_msg(msg);
115 return ERR_PTR(err);
116 }
117 #ifdef CONFIG_CHECKPOINT_RESTORE
copy_msg(struct msg_msg * src,struct msg_msg * dst)118 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
119 {
120 struct msg_msgseg *dst_pseg, *src_pseg;
121 size_t len = src->m_ts;
122 size_t alen;
123
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
180 cond_resched();
181 kfree(seg);
182 seg = tmp;
183 }
184 }
185
