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x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664130512; a=rsa-sha256; cv=none; b=kMRrJFm4nwmWmJCo6Ql3yrsanC5guNQui5UNeA/hQKHO6HuYbl1Mxu9lHpVLzw+WUR3KbA 2XzA9BZZGLjE70cdG4HfAQ1BIdp7ht17WTqPT+PW61MFn3L/tDz/pnYrAcTReNn9sCtZ8L DM+xNseFJUtuTDkW9OMhI8hqhrD0fQs= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=ppeR53xd; dmarc=none; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664130512; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=BLEZYnPJvJWaZte5frRplYEwxYxAvU3h6r/GMgPChMM=; b=BZ3gOp3IYM5hj82RQMN3si0BQqbDkKipUMtuAQOGXhE+AnEhB08BB6OZUGovVL8uZpuzM9 vBfLKRbwu2GjVntZxalxL5ICzwZhNZBHvW6cV8kOmnhzFiFimMimvsAQ/0lNofaZTSoQcO pYtLtbvH860vsWISPipzK/BzXLvkH3E= X-Rspamd-Server: rspam11 X-Rspam-User: X-Rspamd-Queue-Id: 2653640004 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=ppeR53xd; dmarc=none; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Stat-Signature: uupzx6zeucz75itw18m15y98f8hk5bmo X-HE-Tag: 1664130511-848711 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, 24 Sep 2022 11:49:05 +0800 Liu Shixin wrote: > The vma_lock and hugetlb_fault_mutex are dropped before handling > userfault and reacquire them again after handle_userfault(), but > reacquire the vma_lock could lead to UAF[1,2] due to the following > race, > > hugetlb_fault > hugetlb_no_page > /*unlock vma_lock */ > hugetlb_handle_userfault > handle_userfault > /* unlock mm->mmap_lock*/ > vm_mmap_pgoff > do_mmap > mmap_region > munmap_vma_range > /* clean old vma */ > /* lock vma_lock again <--- UAF */ > /* unlock vma_lock */ > > Since the vma_lock will unlock immediately after hugetlb_handle_userfault(), > let's drop the unneeded lock and unlock in hugetlb_handle_userfault() to fix > the issue. > Thanks. Turns out that porting all the pending material on top of this change was not a confidence-inspiring activity. So I ended up merging your v3. Please work with Greg on the backporting when he gets on to it? Hopefully that will merely involve sending him this v4.