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 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 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 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 145 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 146 { 147 return ERR_PTR(-ENOSYS); 148 } 149 #endif 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 } 168 169 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