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 #include <linux/nstree.h> 19 20 #include "util.h" 21 22 DEFINE_SPINLOCK(mq_lock); 23 24 /* 25 * The next 2 defines are here bc this is the only file 26 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE 27 * and not CONFIG_IPC_NS. 28 */ 29 struct ipc_namespace init_ipc_ns = { 30 .ns = NS_COMMON_INIT(init_ipc_ns), 31 .user_ns = &init_user_ns, 32 }; 33 34 struct msg_msgseg { 35 struct msg_msgseg *next; 36 /* the next part of the message follows immediately */ 37 }; 38 39 #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) 40 #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) 41 42 static kmem_buckets *msg_buckets __ro_after_init; 43 44 static int __init init_msg_buckets(void) 45 { 46 msg_buckets = kmem_buckets_create("msg_msg", SLAB_ACCOUNT, 47 sizeof(struct msg_msg), 48 DATALEN_MSG, NULL); 49 50 return 0; 51 } 52 subsys_initcall(init_msg_buckets); 53 54 static struct msg_msg *alloc_msg(size_t len) 55 { 56 struct msg_msg *msg; 57 struct msg_msgseg **pseg; 58 size_t alen; 59 60 alen = min(len, DATALEN_MSG); 61 msg = kmem_buckets_alloc(msg_buckets, sizeof(*msg) + alen, GFP_KERNEL); 62 if (msg == NULL) 63 return NULL; 64 65 msg->next = NULL; 66 msg->security = NULL; 67 68 len -= alen; 69 pseg = &msg->next; 70 while (len > 0) { 71 struct msg_msgseg *seg; 72 73 cond_resched(); 74 75 alen = min(len, DATALEN_SEG); 76 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT); 77 if (seg == NULL) 78 goto out_err; 79 *pseg = seg; 80 seg->next = NULL; 81 pseg = &seg->next; 82 len -= alen; 83 } 84 85 return msg; 86 87 out_err: 88 free_msg(msg); 89 return NULL; 90 } 91 92 struct msg_msg *load_msg(const void __user *src, size_t len) 93 { 94 struct msg_msg *msg; 95 struct msg_msgseg *seg; 96 int err = -EFAULT; 97 size_t alen; 98 99 msg = alloc_msg(len); 100 if (msg == NULL) 101 return ERR_PTR(-ENOMEM); 102 103 alen = min(len, DATALEN_MSG); 104 if (copy_from_user(msg + 1, src, alen)) 105 goto out_err; 106 107 for (seg = msg->next; seg != NULL; seg = seg->next) { 108 len -= alen; 109 src = (char __user *)src + alen; 110 alen = min(len, DATALEN_SEG); 111 if (copy_from_user(seg + 1, src, alen)) 112 goto out_err; 113 } 114 115 err = security_msg_msg_alloc(msg); 116 if (err) 117 goto out_err; 118 119 return msg; 120 121 out_err: 122 free_msg(msg); 123 return ERR_PTR(err); 124 } 125 #ifdef CONFIG_CHECKPOINT_RESTORE 126 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 127 { 128 struct msg_msgseg *dst_pseg, *src_pseg; 129 size_t len = src->m_ts; 130 size_t alen; 131 132 if (src->m_ts > dst->m_ts) 133 return ERR_PTR(-EINVAL); 134 135 alen = min(len, DATALEN_MSG); 136 memcpy(dst + 1, src + 1, alen); 137 138 for (dst_pseg = dst->next, src_pseg = src->next; 139 src_pseg != NULL; 140 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { 141 142 len -= alen; 143 alen = min(len, DATALEN_SEG); 144 memcpy(dst_pseg + 1, src_pseg + 1, alen); 145 } 146 147 dst->m_type = src->m_type; 148 dst->m_ts = src->m_ts; 149 150 return dst; 151 } 152 #else 153 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 154 { 155 return ERR_PTR(-ENOSYS); 156 } 157 #endif 158 int store_msg(void __user *dest, struct msg_msg *msg, size_t len) 159 { 160 size_t alen; 161 struct msg_msgseg *seg; 162 163 alen = min(len, DATALEN_MSG); 164 if (copy_to_user(dest, msg + 1, alen)) 165 return -1; 166 167 for (seg = msg->next; seg != NULL; seg = seg->next) { 168 len -= alen; 169 dest = (char __user *)dest + alen; 170 alen = min(len, DATALEN_SEG); 171 if (copy_to_user(dest, seg + 1, alen)) 172 return -1; 173 } 174 return 0; 175 } 176 177 void free_msg(struct msg_msg *msg) 178 { 179 struct msg_msgseg *seg; 180 181 security_msg_msg_free(msg); 182 183 seg = msg->next; 184 kfree(msg); 185 while (seg != NULL) { 186 struct msg_msgseg *tmp = seg->next; 187 188 cond_resched(); 189 kfree(seg); 190 seg = tmp; 191 } 192 } 193