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/ipc_namespace.h> 17 #include <asm/uaccess.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 .count = ATOMIC_INIT(1), 30 .user_ns = &init_user_ns, 31 }; 32 33 atomic_t nr_ipc_ns = ATOMIC_INIT(1); 34 35 struct msg_msgseg { 36 struct msg_msgseg* next; 37 /* the next part of the message follows immediately */ 38 }; 39 40 #define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg)) 41 #define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg)) 42 43 struct msg_msg *load_msg(const void __user *src, int len) 44 { 45 struct msg_msg *msg; 46 struct msg_msgseg **pseg; 47 int err; 48 int alen; 49 50 alen = len; 51 if (alen > DATALEN_MSG) 52 alen = DATALEN_MSG; 53 54 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 55 if (msg == NULL) 56 return ERR_PTR(-ENOMEM); 57 58 msg->next = NULL; 59 msg->security = NULL; 60 61 if (copy_from_user(msg + 1, src, alen)) { 62 err = -EFAULT; 63 goto out_err; 64 } 65 66 len -= alen; 67 src = ((char __user *)src) + alen; 68 pseg = &msg->next; 69 while (len > 0) { 70 struct msg_msgseg *seg; 71 alen = len; 72 if (alen > DATALEN_SEG) 73 alen = DATALEN_SEG; 74 seg = kmalloc(sizeof(*seg) + alen, 75 GFP_KERNEL); 76 if (seg == NULL) { 77 err = -ENOMEM; 78 goto out_err; 79 } 80 *pseg = seg; 81 seg->next = NULL; 82 if (copy_from_user(seg + 1, src, alen)) { 83 err = -EFAULT; 84 goto out_err; 85 } 86 pseg = &seg->next; 87 len -= alen; 88 src = ((char __user *)src) + alen; 89 } 90 91 err = security_msg_msg_alloc(msg); 92 if (err) 93 goto out_err; 94 95 return msg; 96 97 out_err: 98 free_msg(msg); 99 return ERR_PTR(err); 100 } 101 102 int store_msg(void __user *dest, struct msg_msg *msg, int len) 103 { 104 int alen; 105 struct msg_msgseg *seg; 106 107 alen = len; 108 if (alen > DATALEN_MSG) 109 alen = DATALEN_MSG; 110 if (copy_to_user(dest, msg + 1, alen)) 111 return -1; 112 113 len -= alen; 114 dest = ((char __user *)dest) + alen; 115 seg = msg->next; 116 while (len > 0) { 117 alen = len; 118 if (alen > DATALEN_SEG) 119 alen = DATALEN_SEG; 120 if (copy_to_user(dest, seg + 1, alen)) 121 return -1; 122 len -= alen; 123 dest = ((char __user *)dest) + alen; 124 seg = seg->next; 125 } 126 return 0; 127 } 128 129 void free_msg(struct msg_msg *msg) 130 { 131 struct msg_msgseg *seg; 132 133 security_msg_msg_free(msg); 134 135 seg = msg->next; 136 kfree(msg); 137 while (seg != NULL) { 138 struct msg_msgseg *tmp = seg->next; 139 kfree(seg); 140 seg = tmp; 141 } 142 } 143