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 #ifdef CONFIG_POSIX_MQUEUE 31 .mq_queues_max = DFLT_QUEUESMAX, 32 .mq_msg_max = DFLT_MSGMAX, 33 .mq_msgsize_max = DFLT_MSGSIZEMAX, 34 #endif 35 .user_ns = &init_user_ns, 36 }; 37 38 atomic_t nr_ipc_ns = ATOMIC_INIT(1); 39 40 struct msg_msgseg { 41 struct msg_msgseg* next; 42 /* the next part of the message follows immediately */ 43 }; 44 45 #define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg)) 46 #define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg)) 47 48 struct msg_msg *load_msg(const void __user *src, int len) 49 { 50 struct msg_msg *msg; 51 struct msg_msgseg **pseg; 52 int err; 53 int alen; 54 55 alen = len; 56 if (alen > DATALEN_MSG) 57 alen = DATALEN_MSG; 58 59 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); 60 if (msg == NULL) 61 return ERR_PTR(-ENOMEM); 62 63 msg->next = NULL; 64 msg->security = NULL; 65 66 if (copy_from_user(msg + 1, src, alen)) { 67 err = -EFAULT; 68 goto out_err; 69 } 70 71 len -= alen; 72 src = ((char __user *)src) + alen; 73 pseg = &msg->next; 74 while (len > 0) { 75 struct msg_msgseg *seg; 76 alen = len; 77 if (alen > DATALEN_SEG) 78 alen = DATALEN_SEG; 79 seg = kmalloc(sizeof(*seg) + alen, 80 GFP_KERNEL); 81 if (seg == NULL) { 82 err = -ENOMEM; 83 goto out_err; 84 } 85 *pseg = seg; 86 seg->next = NULL; 87 if (copy_from_user(seg + 1, src, alen)) { 88 err = -EFAULT; 89 goto out_err; 90 } 91 pseg = &seg->next; 92 len -= alen; 93 src = ((char __user *)src) + alen; 94 } 95 96 err = security_msg_msg_alloc(msg); 97 if (err) 98 goto out_err; 99 100 return msg; 101 102 out_err: 103 free_msg(msg); 104 return ERR_PTR(err); 105 } 106 107 int store_msg(void __user *dest, struct msg_msg *msg, int len) 108 { 109 int alen; 110 struct msg_msgseg *seg; 111 112 alen = len; 113 if (alen > DATALEN_MSG) 114 alen = DATALEN_MSG; 115 if (copy_to_user(dest, msg + 1, alen)) 116 return -1; 117 118 len -= alen; 119 dest = ((char __user *)dest) + alen; 120 seg = msg->next; 121 while (len > 0) { 122 alen = len; 123 if (alen > DATALEN_SEG) 124 alen = DATALEN_SEG; 125 if (copy_to_user(dest, seg + 1, alen)) 126 return -1; 127 len -= alen; 128 dest = ((char __user *)dest) + alen; 129 seg = seg->next; 130 } 131 return 0; 132 } 133 134 void free_msg(struct msg_msg *msg) 135 { 136 struct msg_msgseg *seg; 137 138 security_msg_msg_free(msg); 139 140 seg = msg->next; 141 kfree(msg); 142 while (seg != NULL) { 143 struct msg_msgseg *tmp = seg->next; 144 kfree(seg); 145 seg = tmp; 146 } 147 } 148