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c26958cb5a
We need to take the mmap lock around find_vma() and subsequent use of the
VMA. Otherwise, we can race with concurrent operations like munmap(), which
can lead to use-after-free accesses to freed VMAs.
Fixes: 1000197d80 ("nios2: System calls handling")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/*
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* Copyright (C) 2013 Altera Corporation
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* Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
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* Copyright (C) 2004 Microtronix Datacom Ltd.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/export.h>
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/syscalls.h>
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#include <asm/cacheflush.h>
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#include <asm/traps.h>
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/* sys_cacheflush -- flush the processor cache. */
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asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len,
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unsigned int op)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = current->mm;
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if (len == 0)
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return 0;
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/* We only support op 0 now, return error if op is non-zero.*/
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if (op)
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return -EINVAL;
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/* Check for overflow */
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if (addr + len < addr)
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return -EFAULT;
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if (mmap_read_lock_killable(mm))
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return -EINTR;
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/*
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* Verify that the specified address region actually belongs
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* to this process.
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*/
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vma = find_vma(mm, addr);
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if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end) {
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mmap_read_unlock(mm);
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return -EFAULT;
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}
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flush_cache_range(vma, addr, addr + len);
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mmap_read_unlock(mm);
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return 0;
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}
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asmlinkage int sys_getpagesize(void)
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{
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return PAGE_SIZE;
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}
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