| Message ID | 20241028145656.932941-2-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3,1/2] mm: use aligned address in clear_gigantic_page() | expand |
On 28.10.24 15:56, Kefeng Wang wrote: > 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(). > > Fixes: 530dd9926dc1 ("mm: memory: improve copy_user_large_folio()") > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 2c8c5da0f5d3..15b5d46d49d2 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5338,7 +5338,7 @@ 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); @@ -6641,8 +6641,7 @@ 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) { diff --git a/mm/memory.c b/mm/memory.c index 84864387f965..209885a4134f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -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);
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(). Fixes: 530dd9926dc1 ("mm: memory: improve copy_user_large_folio()") Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- v3: - revise patch description, suggested by Huang Ying - use addr_hint for copy_user_gigantic_page(), suggested by David v2: - update changelog to clarify the impact, per Andrew mm/hugetlb.c | 5 ++--- mm/memory.c | 5 +++-- 2 files changed, 5 insertions(+), 5 deletions(-)