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The vDSO address is added to the userspace auxiliary vectors even if the vDSO was not allocated. When accessing the page, userspace processes will crash. Enforce that the allocation works. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-3-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
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*/
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/page.h>
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#include <asm/elf.h>
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#include <linux/init.h>
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unsigned long um_vdso_addr;
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static struct page *um_vdso;
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extern unsigned long task_size;
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extern char vdso_start[], vdso_end[];
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static int __init init_vdso(void)
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{
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BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
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um_vdso_addr = task_size - PAGE_SIZE;
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um_vdso = alloc_page(GFP_KERNEL);
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if (!um_vdso)
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panic("Cannot allocate vdso\n");
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copy_page(page_address(um_vdso), vdso_start);
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return 0;
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}
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subsys_initcall(init_vdso);
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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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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static struct vm_special_mapping vdso_mapping = {
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.name = "[vdso]",
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.pages = &um_vdso,
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};
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if (mmap_write_lock_killable(mm))
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return -EINTR;
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vma = _install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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&vdso_mapping);
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mmap_write_unlock(mm);
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return IS_ERR(vma) ? PTR_ERR(vma) : 0;
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}
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