Commit f5d09de9 authored by Kefeng Wang's avatar Kefeng Wang Committed by Andrew Morton
Browse files

mm: use aligned address in copy_user_gigantic_page() 

In current kernel, hugetlb_wp() calls copy_user_large_folio() with the
fault address.  Where the fault address may be not aligned with the huge
page size.  Then, copy_user_large_folio() may call
copy_user_gigantic_page() with the address, while
copy_user_gigantic_page() requires the address to be huge page size
aligned.  So, this may cause memory corruption or information leak,
addtional, use more obvious naming 'addr_hint' instead of 'addr' for
copy_user_gigantic_page().

Link: https://lkml.kernel.org/r/20241028145656.932941-2-wangkefeng.wang@huawei.com


Fixes: 530dd992 ("mm: memory: improve copy_user_large_folio()")
Signed-off-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8aca2bc9

mm/hugetlb.c

+2 −3
Original line number Diff line number Diff line
@@ -5340,7 +5340,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 
					break;

				}

				ret = copy_user_large_folio(new_folio, pte_folio,

						ALIGN_DOWN(addr, sz), dst_vma);

							    addr, dst_vma);

				folio_put(pte_folio);

				if (ret) {

					folio_put(new_folio);
@@ -6643,8 +6643,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte, 
			*foliop = NULL;

			goto out;

		}

		ret = copy_user_large_folio(folio, *foliop,

					    ALIGN_DOWN(dst_addr, size), dst_vma);

		ret = copy_user_large_folio(folio, *foliop, dst_addr, dst_vma);

		folio_put(*foliop);

		*foliop = NULL;

		if (ret) {

mm/memory.c

+3 −2
Original line number Diff line number Diff line
@@ -6852,13 +6852,14 @@ void folio_zero_user(struct folio *folio, unsigned long addr_hint) 
}



static int copy_user_gigantic_page(struct folio *dst, struct folio *src,

				   unsigned long addr,

				   unsigned long addr_hint,

				   struct vm_area_struct *vma,

				   unsigned int nr_pages)

{

	int i;

	unsigned long addr = ALIGN_DOWN(addr_hint, folio_size(dst));

	struct page *dst_page;

	struct page *src_page;

	int i;



	for (i = 0; i < nr_pages; i++) {

		dst_page = folio_page(dst, i);