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 .ns.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 static kmem_buckets *msg_buckets __ro_after_init;
46
47 static int __init init_msg_buckets(void)
48 {
49 msg_buckets = kmem_buckets_create("msg_msg", SLAB_ACCOUNT,
50 sizeof(struct msg_msg),
51 DATALEN_MSG, NULL);
52
53 return 0;
54 }
55 subsys_initcall(init_msg_buckets);
56
57 static struct msg_msg *alloc_msg(size_t len)
58 {
59 struct msg_msg *msg;
60 struct msg_msgseg **pseg;
61 size_t alen;
62
63 alen = min(len, DATALEN_MSG);
64 msg = kmem_buckets_alloc(msg_buckets, sizeof(*msg) + alen, GFP_KERNEL);
65 if (msg == NULL)
66 return NULL;
67
68 msg->next = NULL;
69 msg->security = NULL;
70
71 len -= alen;
72 pseg = &msg->next;
73 while (len > 0) {
74 struct msg_msgseg *seg;
75
76 cond_resched();
77
78 alen = min(len, DATALEN_SEG);
79 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT);
80 if (seg == NULL)
81 goto out_err;
82 *pseg = seg;
83 seg->next = NULL;
84 pseg = &seg->next;
85 len -= alen;
86 }
87
88 return msg;
89
90 out_err:
91 free_msg(msg);
92 return NULL;
93 }
94
95 struct msg_msg *load_msg(const void __user *src, size_t len)
96 {
97 struct msg_msg *msg;
98 struct msg_msgseg *seg;
99 int err = -EFAULT;
100 size_t alen;
101
102 msg = alloc_msg(len);
103 if (msg == NULL)
104 return ERR_PTR(-ENOMEM);
105
106 alen = min(len, DATALEN_MSG);
107 if (copy_from_user(msg + 1, src, alen))
108 goto out_err;
109
110 for (seg = msg->next; seg != NULL; seg = seg->next) {
111 len -= alen;
112 src = (char __user *)src + alen;
113 alen = min(len, DATALEN_SEG);
114 if (copy_from_user(seg + 1, src, alen))
115 goto out_err;
116 }
117
118 err = security_msg_msg_alloc(msg);
119 if (err)
120 goto out_err;
121
122 return msg;
123
124 out_err:
125 free_msg(msg);
126 return ERR_PTR(err);
127 }
128 #ifdef CONFIG_CHECKPOINT_RESTORE
129 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
130 {
131 struct msg_msgseg *dst_pseg, *src_pseg;
132 size_t len = src->m_ts;
133 size_t alen;
134
135 if (src->m_ts > dst->m_ts)
136 return ERR_PTR(-EINVAL);
137
138 alen = min(len, DATALEN_MSG);
139 memcpy(dst + 1, src + 1, alen);
140
141 for (dst_pseg = dst->next, src_pseg = src->next;
142 src_pseg != NULL;
143 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) {
144
145 len -= alen;
146 alen = min(len, DATALEN_SEG);
147 memcpy(dst_pseg + 1, src_pseg + 1, alen);
148 }
149
150 dst->m_type = src->m_type;
151 dst->m_ts = src->m_ts;
152
153 return dst;
154 }
155 #else
156 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst)
157 {
158 return ERR_PTR(-ENOSYS);
159 }
160 #endif
161 int store_msg(void __user *dest, struct msg_msg *msg, size_t len)
162 {
163 size_t alen;
164 struct msg_msgseg *seg;
165
166 alen = min(len, DATALEN_MSG);
167 if (copy_to_user(dest, msg + 1, alen))
168 return -1;
169
170 for (seg = msg->next; seg != NULL; seg = seg->next) {
171 len -= alen;
172 dest = (char __user *)dest + alen;
173 alen = min(len, DATALEN_SEG);
174 if (copy_to_user(dest, seg + 1, alen))
175 return -1;
176 }
177 return 0;
178 }
179
180 void free_msg(struct msg_msg *msg)
181 {
182 struct msg_msgseg *seg;
183
184 security_msg_msg_free(msg);
185
186 seg = msg->next;
187 kfree(msg);
188 while (seg != NULL) {
189 struct msg_msgseg *tmp = seg->next;
190
191 cond_resched();
192 kfree(seg);
193 seg = tmp;
194 }
195 }
196
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