linux-kernel - [PATCH v4 4/5] mm: hugetlb: fix missing cache flush in hugetlb_mcopy_atomic

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220208073617.70342-5-songmuchun@bytedance.com>
Date:   Tue,  8 Feb 2022 15:36:16 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     akpm@...ux-foundation.org, zi.yan@...rutgers.edu,
        kirill.shutemov@...ux.intel.com, rientjes@...gle.com,
        lars.persson@...s.com, mike.kravetz@...cle.com, ziy@...dia.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        duanxiongchun@...edance.com, fam.zheng@...edance.com,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH v4 4/5] mm: hugetlb: fix missing cache flush in hugetlb_mcopy_atomic_pte()

folio_copy() will copy the data from one page to the target page, then
the target page will be mapped to the user space address, which might
have an alias issue with the kernel address used to copy the data from
the page to.  There are 2 ways to fix this issue.

 1) insert flush_dcache_page() after folio_copy().
 2) replace folio_copy() with copy_user_huge_page() which already
    considers the cache maintenance.

We chose 2) way to fix the issue since architectures can optimize this
situation.

Fixes: 8cc5fcbb5be8 ("mm, hugetlb: fix racy resv_huge_pages underflow on UFFDIO_COPY")
Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 mm/hugetlb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a1baa198519a..eba7681d15d0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5818,7 +5818,8 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
 			*pagep = NULL;
 			goto out;
 		}
-		folio_copy(page_folio(page), page_folio(*pagep));
+		copy_user_huge_page(page, *pagep, dst_addr, dst_vma,
+				    pages_per_huge_page(h));
 		put_page(*pagep);
 		*pagep = NULL;
 	}
-- 
2.11.0