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ipc/msgutil.c
3.56 KB
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// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* linux/ipc/msgutil.c |
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* Copyright (C) 1999, 2004 Manfred Spraul |
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*/ #include <linux/spinlock.h> #include <linux/init.h> #include <linux/security.h> #include <linux/slab.h> #include <linux/ipc.h> |
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#include <linux/msg.h> |
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#include <linux/ipc_namespace.h> |
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#include <linux/utsname.h> |
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#include <linux/proc_ns.h> |
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#include <linux/uaccess.h> |
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#include <linux/sched.h> |
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#include "util.h" |
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DEFINE_SPINLOCK(mq_lock); |
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/* * 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 = { |
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.ns.count = REFCOUNT_INIT(1), |
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.user_ns = &init_user_ns, |
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.ns.inum = PROC_IPC_INIT_INO, |
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#ifdef CONFIG_IPC_NS .ns.ops = &ipcns_operations, #endif |
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}; |
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struct msg_msgseg { |
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struct msg_msgseg *next; |
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/* the next part of the message follows immediately */ }; |
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#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) |
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static struct msg_msg *alloc_msg(size_t len) |
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{ struct msg_msg *msg; struct msg_msgseg **pseg; |
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size_t alen; |
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alen = min(len, DATALEN_MSG); |
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msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT); |
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if (msg == NULL) |
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return NULL; |
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msg->next = NULL; msg->security = NULL; |
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len -= alen; pseg = &msg->next; while (len > 0) { struct msg_msgseg *seg; |
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cond_resched(); |
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alen = min(len, DATALEN_SEG); |
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seg = kmalloc(sizeof(*seg) + alen, GFP_KERNEL_ACCOUNT); |
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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; } |
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struct msg_msg *load_msg(const void __user *src, size_t len) |
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{ struct msg_msg *msg; struct msg_msgseg *seg; |
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int err = -EFAULT; |
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size_t alen; |
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msg = alloc_msg(len); if (msg == NULL) return ERR_PTR(-ENOMEM); alen = min(len, DATALEN_MSG); |
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if (copy_from_user(msg + 1, src, alen)) |
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goto out_err; |
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for (seg = msg->next; seg != NULL; seg = seg->next) { len -= alen; src = (char __user *)src + alen; |
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alen = min(len, DATALEN_SEG); |
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if (copy_from_user(seg + 1, src, alen)) |
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goto out_err; |
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} err = security_msg_msg_alloc(msg); if (err) goto out_err; return msg; out_err: free_msg(msg); return ERR_PTR(err); } |
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#ifdef CONFIG_CHECKPOINT_RESTORE struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) { struct msg_msgseg *dst_pseg, *src_pseg; |
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size_t len = src->m_ts; size_t alen; |
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if (src->m_ts > dst->m_ts) return ERR_PTR(-EINVAL); |
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alen = min(len, DATALEN_MSG); |
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memcpy(dst + 1, src + 1, alen); |
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for (dst_pseg = dst->next, src_pseg = src->next; src_pseg != NULL; dst_pseg = dst_pseg->next, src_pseg = src_pseg->next) { len -= alen; |
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alen = min(len, DATALEN_SEG); |
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memcpy(dst_pseg + 1, src_pseg + 1, alen); |
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} dst->m_type = src->m_type; dst->m_ts = src->m_ts; return dst; } |
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#else struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst) { return ERR_PTR(-ENOSYS); } |
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#endif |
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int store_msg(void __user *dest, struct msg_msg *msg, size_t len) |
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{ |
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size_t alen; |
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struct msg_msgseg *seg; |
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alen = min(len, DATALEN_MSG); |
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if (copy_to_user(dest, msg + 1, alen)) return -1; |
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for (seg = msg->next; seg != NULL; seg = seg->next) { len -= alen; dest = (char __user *)dest + alen; |
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alen = min(len, DATALEN_SEG); |
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if (copy_to_user(dest, seg + 1, alen)) return -1; |
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} 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; |
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cond_resched(); |
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kfree(seg); seg = tmp; } } |