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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 26EB2C43217 for ; Wed, 23 Dec 2020 02:31:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07ADA22273 for ; Wed, 23 Dec 2020 02:31:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730539AbgLWCap (ORCPT ); Tue, 22 Dec 2020 21:30:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:55404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730537AbgLWCZe (ORCPT ); Tue, 22 Dec 2020 21:25:34 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 08C1B22202; Wed, 23 Dec 2020 02:25:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608690318; bh=zHAXgintszTEn94mqTcrle1JwyCDLOMBGU4/rP5FDzw=; h=From:To:Cc:Subject:Date:From; b=hZhX3HpWWdm1IF+y9NKcXiGTd6/DbrYLOGwjqTXxD4y4yeyLwjEZ+X7mL0oJ8JKEG txEdw7NMoI64zT/yftQ2fOY11BdkHCBW+7lWf2fND7VrssoelAhqL6ySlw53mt/Blq 2ckQ5lPzhPd2CpMwwXe8VvCNAfX6LRgVQQsgWkgzZL1cp2xoamNbHs0hGKssTcEQ8N fh9ITFsfApMsWrSwE/KJUMETMKDQ9ZQUHjWrUjLxCRnXUfecZ2etyEqAoaaJfEjaap 1fBpuTgFMkHoNUOEjZqLweURdAYU14vyfYEI+i/k/QHfFF0j2nLWaQ3ZkBJkf06HLV is64S5Okxb3Dw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Luo Meng , Jeff Layton , Sasha Levin , linux-fsdevel@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 01/38] locks: Fix UBSAN undefined behaviour in flock64_to_posix_lock Date: Tue, 22 Dec 2020 21:24:39 -0500 Message-Id: <20201223022516.2794471-1-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Luo Meng [ Upstream commit 16238415eb9886328a89fe7a3cb0b88c7335fe16 ] When the sum of fl->fl_start and l->l_len overflows, UBSAN shows the following warning: UBSAN: Undefined behaviour in fs/locks.c:482:29 signed integer overflow: 2 + 9223372036854775806 cannot be represented in type 'long long int' Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xe4/0x14e lib/dump_stack.c:118 ubsan_epilogue+0xe/0x81 lib/ubsan.c:161 handle_overflow+0x193/0x1e2 lib/ubsan.c:192 flock64_to_posix_lock fs/locks.c:482 [inline] flock_to_posix_lock+0x595/0x690 fs/locks.c:515 fcntl_setlk+0xf3/0xa90 fs/locks.c:2262 do_fcntl+0x456/0xf60 fs/fcntl.c:387 __do_sys_fcntl fs/fcntl.c:483 [inline] __se_sys_fcntl fs/fcntl.c:468 [inline] __x64_sys_fcntl+0x12d/0x180 fs/fcntl.c:468 do_syscall_64+0xc8/0x5a0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix it by parenthesizing 'l->l_len - 1'. Signed-off-by: Luo Meng Signed-off-by: Jeff Layton Signed-off-by: Sasha Levin --- fs/locks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/locks.c b/fs/locks.c index 2c8e1e429cf7e..5cb012e4a2fc4 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -434,7 +434,7 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, if (l->l_len > 0) { if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) return -EOVERFLOW; - fl->fl_end = fl->fl_start + l->l_len - 1; + fl->fl_end = fl->fl_start + (l->l_len - 1); } else if (l->l_len < 0) { if (fl->fl_start + l->l_len < 0) -- 2.27.0