| 1 | |
| 2 | * linux/ipc/msgutil.c
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| 3 | * Copyright (C) 1999, 2004 Manfred Spraul
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| 4 | *
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| 5 | * This file is released under GNU General Public Licence version 2 or
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| 6 | * (at your option) any later version.
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| 7 | *
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| 8 | * See the file COPYING for more details.
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| 9 |
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| 10 |
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| 11 | #include <linux/spinlock.h>
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| 12 | #include <linux/init.h>
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| 13 | #include <linux/security.h>
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| 14 | #include <linux/slab.h>
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| 15 | #include <linux/ipc.h>
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| 16 | #include <linux/msg.h>
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| 17 | #include <linux/ipc_namespace.h>
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| 18 | #include <linux/utsname.h>
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| 19 | #include <asm/uaccess.h>
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| 20 |
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| 21 | #include "util.h"
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| 22 |
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| 23 | DEFINE_SPINLOCK(mq_lock);
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| 24 |
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| 25 | |
| 26 | * The next 2 defines are here bc this is the only file
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| 27 | * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
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| 28 | * and not CONFIG_IPC_NS.
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| 29 |
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| 30 | struct ipc_namespace init_ipc_ns = {
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| 31 | .count = ATOMIC_INIT(1),
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| 32 | .user_ns = &init_user_ns,
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| 33 | };
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| 34 |
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| 35 | atomic_t nr_ipc_ns = ATOMIC_INIT(1);
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| 36 |
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| 37 | struct msg_msgseg {
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| 38 | struct msg_msgseg* next;
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| 39 |
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| 40 | };
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| 41 |
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| 42 | #define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
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| 43 | #define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
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| 44 |
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| 45 | struct msg_msg *load_msg(const void __user *src, int len)
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| 46 | {
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| 47 | struct msg_msg *msg;
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| 48 | struct msg_msgseg **pseg;
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| 49 | int err;
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| 50 | int alen;
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| 51 |
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| 52 | alen = len;
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| 53 | if (alen > DATALEN_MSG)
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| 54 | alen = DATALEN_MSG;
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| 55 |
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| 56 | msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
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| 57 | if (msg == NULL)
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| 58 | return ERR_PTR(-ENOMEM);
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| 59 |
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| 60 | msg->next = NULL;
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| 61 | msg->security = NULL;
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| 62 |
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| 63 | if (copy_from_user(msg + 1, src, alen)) {
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| 64 | err = -EFAULT;
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| 65 | goto out_err;
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| 66 | }
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| 67 |
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| 68 | len -= alen;
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| 69 | src = ((char __user *)src) + alen;
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| 70 | pseg = &msg->next;
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| 71 | while (len > 0) {
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| 72 | struct msg_msgseg *seg;
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| 73 | alen = len;
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| 74 | if (alen > DATALEN_SEG)
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| 75 | alen = DATALEN_SEG;
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| 76 | seg = kmalloc(sizeof(*seg) + alen,
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| 77 | GFP_KERNEL);
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| 78 | if (seg == NULL) {
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| 79 | err = -ENOMEM;
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| 80 | goto out_err;
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| 81 | }
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| 82 | *pseg = seg;
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| 83 | seg->next = NULL;
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| 84 | if (copy_from_user(seg + 1, src, alen)) {
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| 85 | err = -EFAULT;
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| 86 | goto out_err;
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| 87 | }
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| 88 | pseg = &seg->next;
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| 89 | len -= alen;
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| 90 | src = ((char __user *)src) + alen;
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| 91 | }
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| 92 |
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| 93 | err = security_msg_msg_alloc(msg);
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| 94 | if (err)
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| 95 | goto out_err;
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| 96 |
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| 97 | return msg;
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| 98 |
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| 99 | out_err:
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| 100 | free_msg(msg);
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| 101 | return ERR_PTR(err);
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| 102 | }
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| 103 |
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| 104 | int store_msg(void __user *dest, struct msg_msg *msg, int len)
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| 105 | {
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| 106 | int alen;
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| 107 | struct msg_msgseg *seg;
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| 108 |
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| 109 | alen = len;
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| 110 | if (alen > DATALEN_MSG)
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| 111 | alen = DATALEN_MSG;
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| 112 | if (copy_to_user(dest, msg + 1, alen))
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| 113 | return -1;
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| 114 |
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| 115 | len -= alen;
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| 116 | dest = ((char __user *)dest) + alen;
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| 117 | seg = msg->next;
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| 118 | while (len > 0) {
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| 119 | alen = len;
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| 120 | if (alen > DATALEN_SEG)
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| 121 | alen = DATALEN_SEG;
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| 122 | if (copy_to_user(dest, seg + 1, alen))
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| 123 | return -1;
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| 124 | len -= alen;
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| 125 | dest = ((char __user *)dest) + alen;
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| 126 | seg = seg->next;
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| 127 | }
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| 128 | return 0;
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| 129 | }
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| 130 |
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| 131 | void free_msg(struct msg_msg *msg)
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| 132 | {
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| 133 | struct msg_msgseg *seg;
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| 134 |
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| 135 | security_msg_msg_free(msg);
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| 136 |
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| 137 | seg = msg->next;
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| 138 | kfree(msg);
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| 139 | while (seg != NULL) {
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| 140 | struct msg_msgseg *tmp = seg->next;
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| 141 | kfree(seg);
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| 142 | seg = tmp;
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| 143 | }
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| 144 | }
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