From patchwork Mon Oct 31 11:25:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: cuigaosheng X-Patchwork-Id: 13025637 X-Patchwork-Delegate: paul@paul-moore.com 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 525B3C38A02 for ; Mon, 31 Oct 2022 11:25:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229628AbiJaLZp (ORCPT ); Mon, 31 Oct 2022 07:25:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33832 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbiJaLZp (ORCPT ); Mon, 31 Oct 2022 07:25:45 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95F441E4 for ; Mon, 31 Oct 2022 04:25:43 -0700 (PDT) Received: from kwepemi500012.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4N19mv6SRWzHv2d; Mon, 31 Oct 2022 19:25:19 +0800 (CST) Received: from cgs.huawei.com (10.244.148.83) by kwepemi500012.china.huawei.com (7.221.188.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 31 Oct 2022 19:25:36 +0800 From: Gaosheng Cui To: , , , , CC: Subject: [PATCH] capabilities: fix undefined behavior in bit shift for CAP_TO_MASK Date: Mon, 31 Oct 2022 19:25:36 +0800 Message-ID: <20221031112536.4177761-1-cuigaosheng1@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.244.148.83] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemi500012.china.huawei.com (7.221.188.12) X-CFilter-Loop: Reflected Precedence: bulk List-ID: Shifting signed 32-bit value by 31 bits is undefined, so changing significant bit to unsigned. The UBSAN warning calltrace like below: UBSAN: shift-out-of-bounds in security/commoncap.c:1252:2 left shift of 1 by 31 places cannot be represented in type 'int' Call Trace: dump_stack_lvl+0x7d/0xa5 dump_stack+0x15/0x1b ubsan_epilogue+0xe/0x4e __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c cap_task_prctl+0x561/0x6f0 security_task_prctl+0x5a/0xb0 __x64_sys_prctl+0x61/0x8f0 do_syscall_64+0x58/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: e338d263a76a ("Add 64-bit capability support to the kernel") Signed-off-by: Gaosheng Cui Acked-by: Andrew G. Morgan Reviewed-by: Serge Hallyn --- include/uapi/linux/capability.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h index 463d1ba2232a..3d61a0ae055d 100644 --- a/include/uapi/linux/capability.h +++ b/include/uapi/linux/capability.h @@ -426,7 +426,7 @@ struct vfs_ns_cap_data { */ #define CAP_TO_INDEX(x) ((x) >> 5) /* 1 << 5 == bits in __u32 */ -#define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */ +#define CAP_TO_MASK(x) (1U << ((x) & 31)) /* mask for indexed __u32 */ #endif /* _UAPI_LINUX_CAPABILITY_H */