From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B16C9C76196 for ; Mon, 3 Apr 2023 22:28:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 833A3900004; Mon, 3 Apr 2023 18:28:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7969B900002; Mon, 3 Apr 2023 18:28:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4D6FA900004; Mon, 3 Apr 2023 18:28:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 3CD53900002 for ; Mon, 3 Apr 2023 18:28:49 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 03EE4A0752 for ; Mon, 3 Apr 2023 22:28:48 +0000 (UTC) X-FDA: 80641520778.22.2DDA4C4 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) by imf14.hostedemail.com (Postfix) with ESMTP id 2B4D9100003 for ; Mon, 3 Apr 2023 22:28:46 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=ETUrq2dY; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf14.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.128.46 as permitted sender) smtp.mailfrom=lstoakes@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1680560927; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=D59V0g1YvYLKaUmx+LEoYjgFSrxRUczBZA1IoL7nlYU=; b=nmncRrtnI+aN7nzDySZHTZVU9eIzl811RVvvg48DJOnei8pb32vONTFikywPvIWAJwFQIK 4gS/km2nUy9cHHNCuPSwFrT9EP9ozrqwZOzoCXFr17/fidjw+GhNHnWd+kxXMZ+ztSJ5VR QY1/r667hojMLlYNEJxD/xFeS3USoPM= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=ETUrq2dY; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf14.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.128.46 as permitted sender) smtp.mailfrom=lstoakes@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1680560927; a=rsa-sha256; cv=none; b=ykMy0YHR3vdMjXg5hDsEhCpmwuutK0CB2MZey3wtW7GxiH/X1p/8dS00duMbQRG14maELx dzDzcc1XANmdVDvJufR1NsMxGarh6JxkZ2S1+SAj9rChJLG5ZKtpp0MMkcDoUsjADFLK+B 0WQpi0LFNleq68XFJ3rz4sIVZVtHYsc= Received: by mail-wm1-f46.google.com with SMTP id m6-20020a05600c3b0600b003ee6e324b19so18963989wms.1 for ; Mon, 03 Apr 2023 15:28:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680560925; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=D59V0g1YvYLKaUmx+LEoYjgFSrxRUczBZA1IoL7nlYU=; b=ETUrq2dY/Th4/JHEziKKqYHg+tGm411FZ0fvvHq7s2C38in0y6R3FaxLNn9Kj4sfr5 hMJgMJxsbvF+BQgibzC+VXG3bGSBAb1bW4IvDlePIroB7DzmvbD6AWL2l9Z+RxPcY2WH e3sRnk04MJf9JH+FTi70FLSupZ6xGpBWo6zhyM9EZJ3bUjmIhDmWb96l+t7TFGW18cS4 XhCagKRR19FhXNYIQfhhdh3fFJuSMOK5zHlYLX6Y/ZnRF/FdaP4FCYLzfxbyA7ummcqS lt4TjRqAoKPJLEu67p5KRYcTNockAGGP5JK2eJ2/xlawuQsKJgzPEOO4uoLNh7wk8jwv q2GQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680560925; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=D59V0g1YvYLKaUmx+LEoYjgFSrxRUczBZA1IoL7nlYU=; b=wv/oTINofbQJ0tXFyE39AQh5oS7iK4qwX/e0Ccqgu1dDyb9EMI0oNntT7DxvsE1Xfl sNlzgTiMUUNmtwK+eP005Zd71nwjv9HU4bWHJfR9+iv+bacYxlR+spkPmDZtz2hTUG+G 0Wkw0yrX6qQ4gRH2PM5za/DhW6owYzfIoyNm1lByQ5CVb2IKBbgFg1Vq3NgQcSmCx4fg 44/kn9WUMh1twwJDTLa13Jf1jsLv0n0FhniwhnHnCF0mYf6TYQgTe1QfP5qpv9XddXa0 VjeRtIEmdgziL9x5uhexxeXUY92ayoIgaHdP8a3FNXdG5p6JNAd18YkhZx9wru9qr+Bo 0UEA== X-Gm-Message-State: AAQBX9dFt3Y5glzsIH8T6cAQRf/z2Nq/45KPl14Rm5rrvWrPxdVo67ZJ rtF4i3YCuW62/pqmiUan8/Ld2+rweoA= X-Google-Smtp-Source: AKy350ZVfZY+bYiGepG6A9AZTHxDk2DIr9A7q/H3Bvhr9tEy2Ebxbza9JcTDslpZpvZNO6szjA4rCA== X-Received: by 2002:a1c:6a19:0:b0:3ed:2ae9:6c75 with SMTP id f25-20020a1c6a19000000b003ed2ae96c75mr593443wmc.37.1680560925406; Mon, 03 Apr 2023 15:28:45 -0700 (PDT) Received: from lucifer.home (host86-156-84-164.range86-156.btcentralplus.com. [86.156.84.164]) by smtp.googlemail.com with ESMTPSA id u17-20020a05600c19d100b003dd1bd0b915sm20731309wmq.22.2023.04.03.15.28.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Apr 2023 15:28:44 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton Cc: Matthew Wilcox , Mike Kravetz , Muchun Song , Alexander Viro , Christian Brauner , Andy Lutomirski , Lorenzo Stoakes Subject: [RFC PATCH 3/3] mm: perform the mapping_map_writable() check after call_mmap() Date: Mon, 3 Apr 2023 23:28:32 +0100 Message-Id: X-Mailer: git-send-email 2.40.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 2B4D9100003 X-Stat-Signature: doez31ucetkgc7grqxth8m7jt1wq6zg7 X-HE-Tag: 1680560926-335245 X-HE-Meta: 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 3SosD3G7 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 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: In order for a F_SEAL_WRITE sealed memfd mapping to have an opportunity to clear VM_MAYWRITE, we must be able to invoke the appropriate vm_ops->mmap() handler to do so. We would otherwise fail the mapping_map_writable() check before we had the opportunity to avoid it. This patch moves this check after the call_mmap() invocation. Only memfd actively denies write access causing a potential failure here (in memfd_add_seals()), so there should be no impact on non-memfd cases. This patch makes the userland-visible change that MAP_SHARED, PROT_READ mappings of an F_SEAL_WRITE sealed memfd mapping will now succeed. Signed-off-by: Lorenzo Stoakes --- mm/mmap.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index c96dcce90772..a166e9f3c474 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2596,17 +2596,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma->vm_pgoff = pgoff; if (file) { - if (is_shared_maywrite(vm_flags)) { - error = mapping_map_writable(file->f_mapping); - if (error) - goto free_vma; - } - vma->vm_file = get_file(file); error = call_mmap(file, vma); if (error) goto unmap_and_free_vma; + if (vma_is_shared_maywrite(vma)) { + error = mapping_map_writable(file->f_mapping); + if (error) + goto unmap_and_free_vma; + } + /* * Expansion is handled above, merging is handled below. * Drivers should not alter the address of the VMA. -- 2.40.0