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580218f967
The set_memory_*() bounds checks are buggy on several fronts: 1. They fail to round the region size up if the passed address is not page aligned. 2. The region check was incomplete, and didn't correspond with what was being asked of apply_to_page_range() So, rework change_memory_common() to fix these problems, adding an "in_region()" helper to determine whether the start & size fit within the provided region start and stop addresses. Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
98 lines
2.3 KiB
C
98 lines
2.3 KiB
C
/*
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* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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struct page_change_data {
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pgprot_t set_mask;
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pgprot_t clear_mask;
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};
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static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
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void *data)
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{
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struct page_change_data *cdata = data;
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pte_t pte = *ptep;
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pte = clear_pte_bit(pte, cdata->clear_mask);
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pte = set_pte_bit(pte, cdata->set_mask);
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set_pte_ext(ptep, pte, 0);
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return 0;
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}
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static bool in_range(unsigned long start, unsigned long size,
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unsigned long range_start, unsigned long range_end)
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{
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return start >= range_start && start < range_end &&
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size <= range_end - start;
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}
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static int change_memory_common(unsigned long addr, int numpages,
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pgprot_t set_mask, pgprot_t clear_mask)
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{
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unsigned long start = addr & PAGE_MASK;
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unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
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unsigned long size = end - start;
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int ret;
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struct page_change_data data;
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WARN_ON_ONCE(start != addr);
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if (!size)
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return 0;
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if (!in_range(start, size, MODULES_VADDR, MODULES_END))
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return -EINVAL;
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data.set_mask = set_mask;
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data.clear_mask = clear_mask;
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ret = apply_to_page_range(&init_mm, start, size, change_page_range,
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&data);
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flush_tlb_kernel_range(start, end);
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return ret;
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}
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int set_memory_ro(unsigned long addr, int numpages)
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{
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return change_memory_common(addr, numpages,
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__pgprot(L_PTE_RDONLY),
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__pgprot(0));
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}
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int set_memory_rw(unsigned long addr, int numpages)
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{
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return change_memory_common(addr, numpages,
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__pgprot(0),
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__pgprot(L_PTE_RDONLY));
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}
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int set_memory_nx(unsigned long addr, int numpages)
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{
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return change_memory_common(addr, numpages,
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__pgprot(L_PTE_XN),
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__pgprot(0));
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}
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int set_memory_x(unsigned long addr, int numpages)
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{
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return change_memory_common(addr, numpages,
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__pgprot(0),
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__pgprot(L_PTE_XN));
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}
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