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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLACK,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D0C2C433DF for ; Mon, 8 Jun 2020 23:16:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F00972083E for ; Mon, 8 Jun 2020 23:16:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pnSKcxu0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F00972083E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9DFDC6B005A; Mon, 8 Jun 2020 19:16:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 96A0F6B005D; Mon, 8 Jun 2020 19:16:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 857876B0062; Mon, 8 Jun 2020 19:16:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0077.hostedemail.com [216.40.44.77]) by kanga.kvack.org (Postfix) with ESMTP id 676A36B005A for ; Mon, 8 Jun 2020 19:16:05 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 333428044FD2 for ; Mon, 8 Jun 2020 23:16:05 +0000 (UTC) X-FDA: 76907604690.09.twist09_4115d4326dbd Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin09.hostedemail.com (Postfix) with ESMTP id 0713D1801D3EF for ; Mon, 8 Jun 2020 23:16:05 +0000 (UTC) X-HE-Tag: twist09_4115d4326dbd X-Filterd-Recvd-Size: 4641 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Mon, 8 Jun 2020 23:16:04 +0000 (UTC) Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 914762076C; Mon, 8 Jun 2020 23:16:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658163; bh=DeTCi+evNa25ktxq1NUlS81kxYThJ6DbPYwt78qnKrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pnSKcxu0oHzosChxZachnqvWDKSeL3Oufd18X6/oMM034JwiLhHy+JJn4+eto5GbP Xeowak7D8p12Q6qA5YLfE7u2Pc28VgNU35yjPSMQIqrESnYIqsi2Y4Bd1yA9OvYp0u uOjk2lpmVwhriM3zADYIwi5almyPw18o1hSqHejs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Uladzislau Rezki , Vitaly Wool , Andrew Morton , Qian Cai , Raymond Jennings , Linus Torvalds , Greg Kroah-Hartman , linux-mm@kvack.org Subject: [PATCH AUTOSEL 5.6 192/606] z3fold: fix use-after-free when freeing handles Date: Mon, 8 Jun 2020 19:05:17 -0400 Message-Id: <20200608231211.3363633-192-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-Rspamd-Queue-Id: 0713D1801D3EF X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable 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: From: Uladzislau Rezki commit d8f117abb380ba968b5e3ef2042d901c02872a4c upstream. free_handle() for a foreign handle may race with inter-page compaction, what can lead to memory corruption. To avoid that, take write lock not read lock in free_handle to be synchronized with __release_z3fold_page(). For example KASAN can detect it: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: use-after-free in LZ4_decompress_safe+0x2c4/0x3b8 Read of size 1 at addr ffffffc976695ca3 by task GoogleApiHandle/4121 CPU: 0 PID: 4121 Comm: GoogleApiHandle Tainted: P S OE 4.19= .81-perf+ #162 Hardware name: Sony Mobile Communications. PDX-203(KONA) (DT) Call trace: LZ4_decompress_safe+0x2c4/0x3b8 lz4_decompress_crypto+0x3c/0x70 crypto_decompress+0x58/0x70 zcomp_decompress+0xd4/0x120 ... Apart from that, initialize zhdr->mapped_count in init_z3fold_page() and remove "newpage" variable because it is not used anywhere. Signed-off-by: Uladzislau Rezki Signed-off-by: Vitaly Wool Signed-off-by: Andrew Morton Cc: Qian Cai Cc: Raymond Jennings Cc: Link: http://lkml.kernel.org/r/20200520082100.28876-1-vitaly.wool@konsulk= o.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/z3fold.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index 42f31c4b53ad..8c3bb5e508b8 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -318,16 +318,16 @@ static inline void free_handle(unsigned long handle= ) slots =3D handle_to_slots(handle); write_lock(&slots->lock); *(unsigned long *)handle =3D 0; - write_unlock(&slots->lock); - if (zhdr->slots =3D=3D slots) + if (zhdr->slots =3D=3D slots) { + write_unlock(&slots->lock); return; /* simple case, nothing else to do */ + } =20 /* we are freeing a foreign handle if we are here */ zhdr->foreign_handles--; is_free =3D true; - read_lock(&slots->lock); if (!test_bit(HANDLES_ORPHANED, &slots->pool)) { - read_unlock(&slots->lock); + write_unlock(&slots->lock); return; } for (i =3D 0; i <=3D BUDDY_MASK; i++) { @@ -336,7 +336,7 @@ static inline void free_handle(unsigned long handle) break; } } - read_unlock(&slots->lock); + write_unlock(&slots->lock); =20 if (is_free) { struct z3fold_pool *pool =3D slots_to_pool(slots); @@ -422,6 +422,7 @@ static struct z3fold_header *init_z3fold_page(struct = page *page, bool headless, zhdr->start_middle =3D 0; zhdr->cpu =3D -1; zhdr->foreign_handles =3D 0; + zhdr->mapped_count =3D 0; zhdr->slots =3D slots; zhdr->pool =3D pool; INIT_LIST_HEAD(&zhdr->buddy); --=20 2.25.1