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c35fe2a68f
Unfortunately, the name/value choice for the MTE ELF segment type
(PT_ARM_MEMTAG_MTE) was pretty poor: LOPROC+1 is already in use by
PT_AARCH64_UNWIND, as defined in the AArch64 ELF ABI
(https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst).
Update the ELF segment type value to LOPROC+2 and also change the define
to PT_AARCH64_MEMTAG_MTE to match the AArch64 ELF ABI namespace. The
AArch64 ELF ABI document is updating accordingly (segment type not
previously mentioned in the document).
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 761b9b366c
("elf: Introduce the ARM MTE ELF segment type")
Cc: Will Deacon <will@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Machado <luis.machado@arm.com>
Cc: Richard Earnshaw <Richard.Earnshaw@arm.com>
Link: https://lore.kernel.org/r/20220425151833.2603830-1-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
140 lines
2.9 KiB
C
140 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/coredump.h>
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#include <linux/elfcore.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <asm/cpufeature.h>
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#include <asm/mte.h>
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#define for_each_mte_vma(tsk, vma) \
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if (system_supports_mte()) \
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for (vma = tsk->mm->mmap; vma; vma = vma->vm_next) \
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if (vma->vm_flags & VM_MTE)
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static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma)
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{
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if (vma->vm_flags & VM_DONTDUMP)
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return 0;
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return vma_pages(vma) * MTE_PAGE_TAG_STORAGE;
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}
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/* Derived from dump_user_range(); start/end must be page-aligned */
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static int mte_dump_tag_range(struct coredump_params *cprm,
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unsigned long start, unsigned long end)
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{
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int ret = 1;
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unsigned long addr;
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void *tags = NULL;
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for (addr = start; addr < end; addr += PAGE_SIZE) {
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struct page *page = get_dump_page(addr);
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/*
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* get_dump_page() returns NULL when encountering an empty
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* page table entry that would otherwise have been filled with
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* the zero page. Skip the equivalent tag dump which would
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* have been all zeros.
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*/
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if (!page) {
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dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
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continue;
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}
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/*
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* Pages mapped in user space as !pte_access_permitted() (e.g.
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* PROT_EXEC only) may not have the PG_mte_tagged flag set.
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*/
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if (!test_bit(PG_mte_tagged, &page->flags)) {
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put_page(page);
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dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
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continue;
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}
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if (!tags) {
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tags = mte_allocate_tag_storage();
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if (!tags) {
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put_page(page);
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ret = 0;
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break;
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}
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}
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mte_save_page_tags(page_address(page), tags);
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put_page(page);
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if (!dump_emit(cprm, tags, MTE_PAGE_TAG_STORAGE)) {
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mte_free_tag_storage(tags);
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ret = 0;
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break;
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}
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}
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if (tags)
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mte_free_tag_storage(tags);
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return ret;
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}
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Elf_Half elf_core_extra_phdrs(void)
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{
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struct vm_area_struct *vma;
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int vma_count = 0;
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for_each_mte_vma(current, vma)
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vma_count++;
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return vma_count;
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}
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int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
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{
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struct vm_area_struct *vma;
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for_each_mte_vma(current, vma) {
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struct elf_phdr phdr;
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phdr.p_type = PT_AARCH64_MEMTAG_MTE;
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phdr.p_offset = offset;
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phdr.p_vaddr = vma->vm_start;
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phdr.p_paddr = 0;
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phdr.p_filesz = mte_vma_tag_dump_size(vma);
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phdr.p_memsz = vma->vm_end - vma->vm_start;
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offset += phdr.p_filesz;
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phdr.p_flags = 0;
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phdr.p_align = 0;
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if (!dump_emit(cprm, &phdr, sizeof(phdr)))
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return 0;
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}
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return 1;
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}
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size_t elf_core_extra_data_size(void)
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{
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struct vm_area_struct *vma;
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size_t data_size = 0;
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for_each_mte_vma(current, vma)
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data_size += mte_vma_tag_dump_size(vma);
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return data_size;
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}
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int elf_core_write_extra_data(struct coredump_params *cprm)
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{
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struct vm_area_struct *vma;
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for_each_mte_vma(current, vma) {
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if (vma->vm_flags & VM_DONTDUMP)
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continue;
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if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end))
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return 0;
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}
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return 1;
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}
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