msgutil.c (3647B)
1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * linux/ipc/msgutil.c 4 * Copyright (C) 1999, 2004 Manfred Spraul 5 */ 6 7#include <linux/spinlock.h> 8#include <linux/init.h> 9#include <linux/security.h> 10#include <linux/slab.h> 11#include <linux/ipc.h> 12#include <linux/msg.h> 13#include <linux/ipc_namespace.h> 14#include <linux/utsname.h> 15#include <linux/proc_ns.h> 16#include <linux/uaccess.h> 17#include <linux/sched.h> 18 19#include "util.h" 20 21DEFINE_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 */ 28struct ipc_namespace init_ipc_ns = { 29 .ns.count = REFCOUNT_INIT(1), 30 .user_ns = &init_user_ns, 31 .ns.inum = PROC_IPC_INIT_INO, 32#ifdef CONFIG_IPC_NS 33 .ns.ops = &ipcns_operations, 34#endif 35}; 36 37struct msg_msgseg { 38 struct msg_msgseg *next; 39 /* the next part of the message follows immediately */ 40}; 41 42#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) 43#define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) 44 45 46static struct msg_msg *alloc_msg(size_t len) 47{ 48 struct msg_msg *msg; 49 struct msg_msgseg **pseg; 50 size_t alen; 51 52 alen = min(len, DATALEN_MSG); 53 msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT); 54 if (msg == NULL) 55 return NULL; 56 57 msg->next = NULL; 58 msg->security = NULL; 59 60 len -= alen; 61 pseg = &msg->next; 62 while (len > 0) { 63 struct msg_msgseg *seg; 64 65 cond_resched(); 66 67 alen = min(len, DATALEN_SEG); 68 seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT); 69 if (seg == NULL) 70 goto out_err; 71 *pseg = seg; 72 seg->next = NULL; 73 pseg = &seg->next; 74 len -= alen; 75 } 76 77 return msg; 78 79out_err: 80 free_msg(msg); 81 return NULL; 82} 83 84struct msg_msg *load_msg(const void __user *src, size_t len) 85{ 86 struct msg_msg *msg; 87 struct msg_msgseg *seg; 88 int err = -EFAULT; 89 size_t alen; 90 91 msg = alloc_msg(len); 92 if (msg == NULL) 93 return ERR_PTR(-ENOMEM); 94 95 alen = min(len, DATALEN_MSG); 96 if (copy_from_user(msg + 1, src, alen)) 97 goto out_err; 98 99 for (seg = msg->next; seg != NULL; seg = seg->next) { 100 len -= alen; 101 src = (char __user *)src + alen; 102 alen = min(len, DATALEN_SEG); 103 if (copy_from_user(seg + 1, src, alen)) 104 goto out_err; 105 } 106 107 err = security_msg_msg_alloc(msg); 108 if (err) 109 goto out_err; 110 111 return msg; 112 113out_err: 114 free_msg(msg); 115 return ERR_PTR(err); 116} 117#ifdef CONFIG_CHECKPOINT_RESTORE 118struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 119{ 120 struct msg_msgseg *dst_pseg, *src_pseg; 121 size_t len = src->m_ts; 122 size_t alen; 123 124 if (src->m_ts > dst->m_ts) 125 return ERR_PTR(-EINVAL); 126 127 alen = min(len, DATALEN_MSG); 128 memcpy(dst + 1, src + 1, alen); 129 130 for (dst_pseg = dst->next, src_pseg = src->next; 131 src_pseg != NULL; 132 dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { 133 134 len -= alen; 135 alen = min(len, DATALEN_SEG); 136 memcpy(dst_pseg + 1, src_pseg + 1, alen); 137 } 138 139 dst->m_type = src->m_type; 140 dst->m_ts = src->m_ts; 141 142 return dst; 143} 144#else 145struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) 146{ 147 return ERR_PTR(-ENOSYS); 148} 149#endif 150int store_msg(void __user *dest, struct msg_msg *msg, size_t len) 151{ 152 size_t alen; 153 struct msg_msgseg *seg; 154 155 alen = min(len, DATALEN_MSG); 156 if (copy_to_user(dest, msg + 1, alen)) 157 return -1; 158 159 for (seg = msg->next; seg != NULL; seg = seg->next) { 160 len -= alen; 161 dest = (char __user *)dest + alen; 162 alen = min(len, DATALEN_SEG); 163 if (copy_to_user(dest, seg + 1, alen)) 164 return -1; 165 } 166 return 0; 167} 168 169void free_msg(struct msg_msg *msg) 170{ 171 struct msg_msgseg *seg; 172 173 security_msg_msg_free(msg); 174 175 seg = msg->next; 176 kfree(msg); 177 while (seg != NULL) { 178 struct msg_msgseg *tmp = seg->next; 179 180 cond_resched(); 181 kfree(seg); 182 seg = tmp; 183 } 184}