From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f200.google.com (mail-ua0-f200.google.com [209.85.217.200]) by kanga.kvack.org (Postfix) with ESMTP id 0195B6B0027 for ; Fri, 30 Mar 2018 10:54:26 -0400 (EDT) Received: by mail-ua0-f200.google.com with SMTP id w9so5850768uae.8 for ; Fri, 30 Mar 2018 07:54:25 -0700 (PDT) Received: from userp2120.oracle.com (userp2120.oracle.com. [156.151.31.85]) by mx.google.com with ESMTPS id k29si2710055uai.27.2018.03.30.07.54.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 30 Mar 2018 07:54:24 -0700 (PDT) From: Mike Kravetz Subject: [PATCH v2] hugetlbfs: fix bug in pgoff overflow checking Date: Fri, 30 Mar 2018 07:54:02 -0700 Message-Id: <20180330145402.5053-1-mike.kravetz@oracle.com> In-Reply-To: <20180329041656.19691-1-mike.kravetz@oracle.com> References: <20180329041656.19691-1-mike.kravetz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Michal Hocko , Yisheng Xie , "Kirill A . Shutemov" , Nic Losby , Dan Rue , Andrew Morton , Mike Kravetz , stable@vger.kernel.org This is a fix for a regression in 32 bit kernels caused by an invalid check for pgoff overflow in hugetlbfs mmap setup. The check incorrectly specified that the size of a loff_t was the same as the size of a long. The regression prevents mapping hugetlbfs files at offsets greater than 4GB on 32 bit kernels. On 32 bit kernels conversion from a page based unsigned long can not overflow a loff_t byte offset. Therefore, skip this check if sizeof(unsigned long) != sizeof(loff_t). Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow") Cc: Reported-by: Dan Rue Signed-off-by: Mike Kravetz --- fs/hugetlbfs/inode.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index b9a254dcc0e7..d508c7844681 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -138,10 +138,14 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) /* * page based offset in vm_pgoff could be sufficiently large to - * overflow a (l)off_t when converted to byte offset. + * overflow a loff_t when converted to byte offset. This can + * only happen on architectures where sizeof(loff_t) == + * sizeof(unsigned long). So, only check in those instances. */ - if (vma->vm_pgoff & PGOFF_LOFFT_MAX) - return -EINVAL; + if (sizeof(unsigned long) == sizeof(loff_t)) { + if (vma->vm_pgoff & PGOFF_LOFFT_MAX) + return -EINVAL; + } /* must be huge page aligned */ if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT)) -- 2.13.6