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 <asm/uaccess.h> 20 21 #include "util.h" 22 23 DEFINE_SPINLOCK(mq_lock); 24 25 /* 26 * The next 2 defines are here bc this is the only file 27 * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE 28 * and not CONFIG_IPC_NS. 29 */ 30 struct ipc_namespace init_ipc_ns = { 31 .count = ATOMIC_INIT(1), 32 .user_ns = &init_user_ns, 33 }; 34 35 atomic_t nr_ipc_ns = ATOMIC_INIT(1); 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 (PAGE_SIZE-sizeof(struct msg_msg)) 43 #define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg)) 44 45 struct msg_msg *load_msg(const void __user *src, int len) 46 { 47 struct msg_msg *msg; 48 struct msg_msgseg **pseg; 49 int err; 50 int alen; 51 52 alen = len; 53 if (alen > DATALEN_MSG) 54 alen = DATALEN_MSG; 55 56 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 57 if (msg == NULL) 58 return ERR_PTR(-ENOMEM); 59 60 msg->next = NULL; 61 msg->security = NULL; 62 63 if (copy_from_user(msg + 1, src, alen)) { 64 err = -EFAULT; 65 goto out_err; 66 } 67 68 len -= alen; 69 src = ((char __user *)src) + alen; 70 pseg = &msg->next; 71 while (len > 0) { 72 struct msg_msgseg *seg; 73 alen = len; 74 if (alen > DATALEN_SEG) 75 alen = DATALEN_SEG; 76 seg = kmalloc(sizeof(*seg) + alen, 77 GFP_KERNEL); 78 if (seg == NULL) { 79 err = -ENOMEM; 80 goto out_err; 81 } 82 *pseg = seg; 83 seg->next = NULL; 84 if (copy_from_user(seg + 1, src, alen)) { 85 err = -EFAULT; 86 goto out_err; 87 } 88 pseg = &seg->next; 89 len -= alen; 90 src = ((char __user *)src) + alen; 91 } 92 93 err = security_msg_msg_alloc(msg); 94 if (err) 95 goto out_err; 96 97 return msg; 98 99 out_err: 100 free_msg(msg); 101 return ERR_PTR(err); 102 } 103 104 int store_msg(void __user *dest, struct msg_msg *msg, int len) 105 { 106 int alen; 107 struct msg_msgseg *seg; 108 109 alen = len; 110 if (alen > DATALEN_MSG) 111 alen = DATALEN_MSG; 112 if (copy_to_user(dest, msg + 1, alen)) 113 return -1; 114 115 len -= alen; 116 dest = ((char __user *)dest) + alen; 117 seg = msg->next; 118 while (len > 0) { 119 alen = len; 120 if (alen > DATALEN_SEG) 121 alen = DATALEN_SEG; 122 if (copy_to_user(dest, seg + 1, alen)) 123 return -1; 124 len -= alen; 125 dest = ((char __user *)dest) + alen; 126 seg = seg->next; 127 } 128 return 0; 129 } 130 131 void free_msg(struct msg_msg *msg) 132 { 133 struct msg_msgseg *seg; 134 135 security_msg_msg_free(msg); 136 137 seg = msg->next; 138 kfree(msg); 139 while (seg != NULL) { 140 struct msg_msgseg *tmp = seg->next; 141 kfree(seg); 142 seg = tmp; 143 } 144 } 145