| 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 | .ns.inum = PROC_IPC_INIT_INO, |
| 35 | #ifdef CONFIG_IPC_NS |
| 36 | .ns.ops = &ipcns_operations, |
| 37 | #endif |
| 38 | }; |
| 39 | |
| 40 | atomic_t nr_ipc_ns = ATOMIC_INIT(1); |
| 41 | |
| 42 | struct msg_msgseg { |
| 43 | struct msg_msgseg *next; |
| 44 | /* the next part of the message follows immediately */ |
| 45 | }; |
| 46 | |
| 47 | #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) |
| 48 | #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) |
| 49 | |
| 50 | |
| 51 | static struct msg_msg *alloc_msg(size_t len) |
| 52 | { |
| 53 | struct msg_msg *msg; |
| 54 | struct msg_msgseg **pseg; |
| 55 | size_t alen; |
| 56 | |
| 57 | alen = min(len, DATALEN_MSG); |
| 58 | msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL); |
| 59 | if (msg == NULL) |
| 60 | return NULL; |
| 61 | |
| 62 | msg->next = NULL; |
| 63 | msg->security = NULL; |
| 64 | |
| 65 | len -= alen; |
| 66 | pseg = &msg->next; |
| 67 | while (len > 0) { |
| 68 | struct msg_msgseg *seg; |
| 69 | alen = min(len, DATALEN_SEG); |
| 70 | seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL); |
| 71 | if (seg == NULL) |
| 72 | goto out_err; |
| 73 | *pseg = seg; |
| 74 | seg->next = NULL; |
| 75 | pseg = &seg->next; |
| 76 | len -= alen; |
| 77 | } |
| 78 | |
| 79 | return msg; |
| 80 | |
| 81 | out_err: |
| 82 | free_msg(msg); |
| 83 | return NULL; |
| 84 | } |
| 85 | |
| 86 | struct msg_msg *load_msg(const void __user *src, size_t len) |
| 87 | { |
| 88 | struct msg_msg *msg; |
| 89 | struct msg_msgseg *seg; |
| 90 | int err = -EFAULT; |
| 91 | size_t alen; |
| 92 | |
| 93 | msg = alloc_msg(len); |
| 94 | if (msg == NULL) |
| 95 | return ERR_PTR(-ENOMEM); |
| 96 | |
| 97 | alen = min(len, DATALEN_MSG); |
| 98 | if (copy_from_user(msg + 1, src, alen)) |
| 99 | goto out_err; |
| 100 | |
| 101 | for (seg = msg->next; seg != NULL; seg = seg->next) { |
| 102 | len -= alen; |
| 103 | src = (char __user *)src + alen; |
| 104 | alen = min(len, DATALEN_SEG); |
| 105 | if (copy_from_user(seg + 1, src, alen)) |
| 106 | goto out_err; |
| 107 | } |
| 108 | |
| 109 | err = security_msg_msg_alloc(msg); |
| 110 | if (err) |
| 111 | goto out_err; |
| 112 | |
| 113 | return msg; |
| 114 | |
| 115 | out_err: |
| 116 | free_msg(msg); |
| 117 | return ERR_PTR(err); |
| 118 | } |
| 119 | #ifdef CONFIG_CHECKPOINT_RESTORE |
| 120 | struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) |
| 121 | { |
| 122 | struct msg_msgseg *dst_pseg, *src_pseg; |
| 123 | size_t len = src->m_ts; |
| 124 | size_t alen; |
| 125 | |
| 126 | BUG_ON(dst == NULL); |
| 127 | if (src->m_ts > dst->m_ts) |
| 128 | return ERR_PTR(-EINVAL); |
| 129 | |
| 130 | alen = min(len, DATALEN_MSG); |
| 131 | memcpy(dst + 1, src + 1, alen); |
| 132 | |
| 133 | for (dst_pseg = dst->next, src_pseg = src->next; |
| 134 | src_pseg != NULL; |
| 135 | dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { |
| 136 | |
| 137 | len -= alen; |
| 138 | alen = min(len, DATALEN_SEG); |
| 139 | memcpy(dst_pseg + 1, src_pseg + 1, alen); |
| 140 | } |
| 141 | |
| 142 | dst->m_type = src->m_type; |
| 143 | dst->m_ts = src->m_ts; |
| 144 | |
| 145 | return dst; |
| 146 | } |
| 147 | #else |
| 148 | struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) |
| 149 | { |
| 150 | return ERR_PTR(-ENOSYS); |
| 151 | } |
| 152 | #endif |
| 153 | int store_msg(void __user *dest, struct msg_msg *msg, size_t len) |
| 154 | { |
| 155 | size_t alen; |
| 156 | struct msg_msgseg *seg; |
| 157 | |
| 158 | alen = min(len, DATALEN_MSG); |
| 159 | if (copy_to_user(dest, msg + 1, alen)) |
| 160 | return -1; |
| 161 | |
| 162 | for (seg = msg->next; seg != NULL; seg = seg->next) { |
| 163 | len -= alen; |
| 164 | dest = (char __user *)dest + alen; |
| 165 | alen = min(len, DATALEN_SEG); |
| 166 | if (copy_to_user(dest, seg + 1, alen)) |
| 167 | return -1; |
| 168 | } |
| 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | void free_msg(struct msg_msg *msg) |
| 173 | { |
| 174 | struct msg_msgseg *seg; |
| 175 | |
| 176 | security_msg_msg_free(msg); |
| 177 | |
| 178 | seg = msg->next; |
| 179 | kfree(msg); |
| 180 | while (seg != NULL) { |
| 181 | struct msg_msgseg *tmp = seg->next; |
| 182 | kfree(seg); |
| 183 | seg = tmp; |
| 184 | } |
| 185 | } |