linux-stable/arch/arm64/kernel/elfcore.c
Catalin Marinas c35fe2a68f elf: Fix the arm64 MTE ELF segment name and value
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>
2022-04-28 11:37:06 +01:00

139 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/coredump.h>
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/cpufeature.h>
#include <asm/mte.h>
#define for_each_mte_vma(tsk, vma) \
if (system_supports_mte()) \
for (vma = tsk->mm->mmap; vma; vma = vma->vm_next) \
if (vma->vm_flags & VM_MTE)
static unsigned long mte_vma_tag_dump_size(struct vm_area_struct *vma)
{
if (vma->vm_flags & VM_DONTDUMP)
return 0;
return vma_pages(vma) * MTE_PAGE_TAG_STORAGE;
}
/* Derived from dump_user_range(); start/end must be page-aligned */
static int mte_dump_tag_range(struct coredump_params *cprm,
unsigned long start, unsigned long end)
{
int ret = 1;
unsigned long addr;
void *tags = NULL;
for (addr = start; addr < end; addr += PAGE_SIZE) {
struct page *page = get_dump_page(addr);
/*
* get_dump_page() returns NULL when encountering an empty
* page table entry that would otherwise have been filled with
* the zero page. Skip the equivalent tag dump which would
* have been all zeros.
*/
if (!page) {
dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
continue;
}
/*
* Pages mapped in user space as !pte_access_permitted() (e.g.
* PROT_EXEC only) may not have the PG_mte_tagged flag set.
*/
if (!test_bit(PG_mte_tagged, &page->flags)) {
put_page(page);
dump_skip(cprm, MTE_PAGE_TAG_STORAGE);
continue;
}
if (!tags) {
tags = mte_allocate_tag_storage();
if (!tags) {
put_page(page);
ret = 0;
break;
}
}
mte_save_page_tags(page_address(page), tags);
put_page(page);
if (!dump_emit(cprm, tags, MTE_PAGE_TAG_STORAGE)) {
mte_free_tag_storage(tags);
ret = 0;
break;
}
}
if (tags)
mte_free_tag_storage(tags);
return ret;
}
Elf_Half elf_core_extra_phdrs(void)
{
struct vm_area_struct *vma;
int vma_count = 0;
for_each_mte_vma(current, vma)
vma_count++;
return vma_count;
}
int elf_core_write_extra_phdrs(struct coredump_params *cprm, loff_t offset)
{
struct vm_area_struct *vma;
for_each_mte_vma(current, vma) {
struct elf_phdr phdr;
phdr.p_type = PT_AARCH64_MEMTAG_MTE;
phdr.p_offset = offset;
phdr.p_vaddr = vma->vm_start;
phdr.p_paddr = 0;
phdr.p_filesz = mte_vma_tag_dump_size(vma);
phdr.p_memsz = vma->vm_end - vma->vm_start;
offset += phdr.p_filesz;
phdr.p_flags = 0;
phdr.p_align = 0;
if (!dump_emit(cprm, &phdr, sizeof(phdr)))
return 0;
}
return 1;
}
size_t elf_core_extra_data_size(void)
{
struct vm_area_struct *vma;
size_t data_size = 0;
for_each_mte_vma(current, vma)
data_size += mte_vma_tag_dump_size(vma);
return data_size;
}
int elf_core_write_extra_data(struct coredump_params *cprm)
{
struct vm_area_struct *vma;
for_each_mte_vma(current, vma) {
if (vma->vm_flags & VM_DONTDUMP)
continue;
if (!mte_dump_tag_range(cprm, vma->vm_start, vma->vm_end))
return 0;
}
return 1;
}