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e6a2e1b6c2
This effectively unexports set_memory_ro and set_memory_rw functions from
commit 11d91a770f ("arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support").
No module user of those is in mainline kernel and we explicitly do not want
modules to use these functions, as they i.e. RO-protect eBPF (interpreted and
JIT'ed) images from malicious modifications/bugs.
Outside of eBPF scope, I believe also other set_memory_* functions should
be unexported on arm64 due to non-existant mainline module user. Laura
mentioned that they have some uses for modules doing set_memory_*, but
none that are in mainline and it's unclear if they would ever get there.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
99 lines
2.3 KiB
C
99 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/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/sched.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(ptep, pte);
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return 0;
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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;
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unsigned long size = PAGE_SIZE*numpages;
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unsigned long end = start + size;
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int ret;
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struct page_change_data data;
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if (!IS_ALIGNED(addr, PAGE_SIZE)) {
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start &= PAGE_MASK;
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end = start + size;
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WARN_ON_ONCE(1);
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}
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if (start < MODULES_VADDR || start >= MODULES_END)
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return -EINVAL;
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if (end < MODULES_VADDR || end >= 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(PTE_RDONLY),
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__pgprot(PTE_WRITE));
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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(PTE_WRITE),
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__pgprot(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(PTE_PXN),
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__pgprot(0));
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}
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EXPORT_SYMBOL_GPL(set_memory_nx);
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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(PTE_PXN));
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}
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EXPORT_SYMBOL_GPL(set_memory_x);
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