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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AB41C433FE for ; Tue, 28 Sep 2021 12:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23E3061262 for ; Tue, 28 Sep 2021 12:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240730AbhI1M64 (ORCPT ); Tue, 28 Sep 2021 08:58:56 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:12770 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240488AbhI1M6z (ORCPT ); Tue, 28 Sep 2021 08:58:55 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HJfd81S3QzVpvy; Tue, 28 Sep 2021 20:55:56 +0800 (CST) Received: from dggpeml500017.china.huawei.com (7.185.36.243) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 28 Sep 2021 20:57:14 +0800 Received: from linux-suspe12sp5.huawei.com (10.67.133.83) by dggpeml500017.china.huawei.com (7.185.36.243) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 28 Sep 2021 20:57:07 +0800 From: Chen Jingwen To: Chen Jingwen , , CC: Alexander Viro , Michal Hocko , Andrei Vagin , Khalid Aziz , Michael Ellerman , Andrew Morton Subject: [PATCH] elf: don't use MAP_FIXED_NOREPLACE for elf interpreter mappings Date: Tue, 28 Sep 2021 20:56:57 +0800 Message-ID: <20210928125657.153293-1-chenjingwen6@huawei.com> X-Mailer: git-send-email 2.12.3 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.67.133.83] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500017.china.huawei.com (7.185.36.243) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In commit b212921b13bd ("elf: don't use MAP_FIXED_NOREPLACE for elf executable mappings") we still leave MAP_FIXED_NOREPLACE in place for load_elf_interp. Unfortunately, this will cause kernel to fail to start with [ 2.384321] 1 (init): Uhuuh, elf segment at 00003ffff7ffd000 requested but the memory is mapped already [ 2.386240] Failed to execute /init (error -17) The reason is that the elf interpreter (ld.so) has overlapping segments. readelf -l ld-2.31.so Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x000000000002c94c 0x000000000002c94c R E 0x10000 LOAD 0x000000000002dae0 0x000000000003dae0 0x000000000003dae0 0x00000000000021e8 0x0000000000002320 RW 0x10000 LOAD 0x000000000002fe00 0x000000000003fe00 0x000000000003fe00 0x00000000000011ac 0x0000000000001328 RW 0x10000 The reason for this problem is the same as described in commit ad55eac74f20 ("elf: enforce MAP_FIXED on overlaying elf segments"). Not only executable binaries, elf interpreters (e.g. ld.so) can have overlapping elf segments, so we better drop MAP_FIXED_NOREPLACE and go back to MAP_FIXED in load_elf_interp. Fixes: 4ed28639519c ("fs, elf: drop MAP_FIXED usage from elf_map") Cc: # v4.19 Signed-off-by: Chen Jingwen --- fs/binfmt_elf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 69d900a8473d..a813b70f594e 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -630,7 +630,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, vaddr = eppnt->p_vaddr; if (interp_elf_ex->e_type == ET_EXEC || load_addr_set) - elf_type |= MAP_FIXED_NOREPLACE; + elf_type |= MAP_FIXED; else if (no_base && interp_elf_ex->e_type == ET_DYN) load_addr = -vaddr; -- 2.12.3