// 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_RESTORE struct 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; } #else struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) { return ERR_PTR(-ENOSYS); } #endif int 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; } }