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: 530dd9926dc1 ("mm: memory: improve copy_user_large_folio()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: David 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1caf29482da1c670e04ce2d8ce4dff01717c2831..d6f4d73b150d7f4e472323a1453e19e8526f37be 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5340,7 +5340,7 @@ again:
                                        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);
@@ -6639,8 +6639,7 @@ 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 cb2e19ff24fcba69d5977de91955cfa2e468fd59..229c6072f133dd71898c6ccab4ce4ae155d9bdba 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6840,13 +6840,14 @@ 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);