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 (int)(PAGE_SIZE-sizeof(struct msg_msg)) 45 #define DATALEN_SEG (int)(PAGE_SIZE-sizeof(struct msg_msgseg)) 46 47 48 static struct msg_msg *alloc_msg(int len) 49 { 50 struct msg_msg *msg; 51 struct msg_msgseg **pseg; 52 int 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 83 struct msg_msg *load_msg(const void __user *src, int len) 84 { 85 struct msg_msg *msg; 86 struct msg_msgseg *seg; 87 int err = -EFAULT; 88 int 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 117 struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 118 { 119 struct msg_msgseg *dst_pseg, *src_pseg; 120 int len = src->m_ts; 121 int 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 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, int len) 151 { 152 int 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 kfree(seg); 180 seg = tmp; 181 } 182 } 183