// SPDX-License-Identifier: GPL-2.0-or-later/* * linux/ipc/msgutil.c * Copyright (C) 1999, 2004 Manfred Spraul */ #include <linux/spinlock.h>#include <linux/init.h>#include <linux/security.h>#include <linux/slab.h>#include <linux/ipc.h>#include <linux/msg.h>#include <linux/ipc_namespace.h>#include <linux/utsname.h>#include <linux/proc_ns.h>#include <linux/uaccess.h>#include <linux/sched.h> #include "util.h" DEFINE_SPINLOCK(mq_lock); /* * The next 2 defines are here bc this is the only file * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE * and not CONFIG_IPC_NS. */struct ipc_namespace init_ipc_ns = {	.count		= REFCOUNT_INIT(1),	.user_ns = &init_user_ns,	.ns.inum = PROC_IPC_INIT_INO,#ifdef CONFIG_IPC_NS	.ns.ops = &ipcns_operations,#endif}; struct msg_msgseg {	struct msg_msgseg *next;	/* the next part of the message follows immediately */}; #define DATALEN_MSG	((size_t)PAGE_SIZE-sizeof(struct msg_msg))#define DATALEN_SEG	((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))  static struct msg_msg *alloc_msg(size_t len){	struct msg_msg *msg;	struct msg_msgseg **pseg;	size_t alen; 	alen = min(len, DATALEN_MSG);	msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT);	if (msg == NULL)		return NULL; 	msg->next = NULL;	msg->security = NULL; 	len -= alen;	pseg = &msg->next;	while (len > 0) {		struct msg_msgseg *seg; 		cond_resched(); 		alen = min(len, DATALEN_SEG);		seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT);		if (seg == NULL)			goto out_err;		*pseg = seg;		seg->next = NULL;		pseg = &seg->next;		len -= alen;	} 	return msg; out_err:	free_msg(msg);	return NULL;} struct msg_msg *load_msg(const void __user *src, size_t len){	struct msg_msg *msg;	struct msg_msgseg *seg;	int err = -EFAULT;	size_t alen; 	msg = alloc_msg(len);	if (msg == NULL)		return ERR_PTR(-ENOMEM); 	alen = min(len, DATALEN_MSG);	if (copy_from_user(msg + 1, src, alen))		goto out_err; 	for (seg = msg->next; seg != NULL; seg = seg->next) {		len -= alen;		src = (char __user *)src + alen;		alen = min(len, DATALEN_SEG);		if (copy_from_user(seg + 1, src, alen))			goto out_err;	} 	err = security_msg_msg_alloc(msg);	if (err)		goto out_err; 	return msg; out_err:	free_msg(msg);	return ERR_PTR(err);}#ifdef CONFIG_CHECKPOINT_RESTOREstruct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst){	struct msg_msgseg *dst_pseg, *src_pseg;	size_t len = src->m_ts;	size_t alen; 	if (src->m_ts > dst->m_ts)		return ERR_PTR(-EINVAL); 	alen = min(len, DATALEN_MSG);	memcpy(dst + 1, src + 1, alen); 	for (dst_pseg = dst->next, src_pseg = src->next;	     src_pseg != NULL;	     dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { 		len -= alen;		alen = min(len, DATALEN_SEG);		memcpy(dst_pseg + 1, src_pseg + 1, alen);	} 	dst->m_type = src->m_type;	dst->m_ts = src->m_ts; 	return dst;}#elsestruct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst){	return ERR_PTR(-ENOSYS);}#endifint store_msg(void __user *dest, struct msg_msg *msg, size_t len){	size_t alen;	struct msg_msgseg *seg; 	alen = min(len, DATALEN_MSG);	if (copy_to_user(dest, msg + 1, alen))		return -1; 	for (seg = msg->next; seg != NULL; seg = seg->next) {		len -= alen;		dest = (char __user *)dest + alen;		alen = min(len, DATALEN_SEG);		if (copy_to_user(dest, seg + 1, alen))			return -1;	}	return 0;} void free_msg(struct msg_msg *msg){	struct msg_msgseg *seg; 	security_msg_msg_free(msg); 	seg = msg->next;	kfree(msg);	while (seg != NULL) {		struct msg_msgseg *tmp = seg->next; 		cond_resched();		kfree(seg);		seg = tmp;	}}