From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1167918AbdDYG6S (ORCPT ); Tue, 25 Apr 2017 02:58:18 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:5796 "EHLO dggrg01-dlp.huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S941212AbdDYG6L (ORCPT ); Tue, 25 Apr 2017 02:58:11 -0400 Subject: [PATCH REPOST] fs: Preventing READ_IMPLIES_EXEC Propagation References: <2414e3b3-03f6-bd6c-5aa4-ad58c66b5aa5@huawei.com> To: CC: , Al Viro , "linux-kernel@vger.kernel.org" , , , arm-mail-list , Mark Rutland From: "dongbo (E)" X-Forwarded-Message-Id: <2414e3b3-03f6-bd6c-5aa4-ad58c66b5aa5@huawei.com> Message-ID: <481124c6-07ba-4cb8-ca56-fb228b05f796@huawei.com> Date: Tue, 25 Apr 2017 14:58:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <2414e3b3-03f6-bd6c-5aa4-ad58c66b5aa5@huawei.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.63.194.120] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A090205.58FEF37F.00D3,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: e51ce522744e42986321ab63ed020c60 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dong Bo In load_elf_binary(), once the READ_IMPLIES_EXEC flag is set, the flag is propagated to its child processes, even the elf files are marked as not requiring executable stack. It may cause superfluous operations on some arch, e.g. __sync_icache_dcache on aarch64 due to a PROT_READ mmap is also marked as PROT_EXEC. This patch was originally posted and discussed here: https://patchwork.kernel.org/patch/9685891/ Signed-off-by: Dong Bo --- fs/binfmt_elf.c | 2 ++ fs/binfmt_elf_fdpic.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 5075fd5..c52e670 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -863,6 +863,8 @@ static int load_elf_binary(struct linux_binprm *bprm) SET_PERSONALITY2(loc->elf_ex, &arch_state); if (elf_read_implies_exec(loc->elf_ex, executable_stack)) current->personality |= READ_IMPLIES_EXEC; + else + current->personality &= ~READ_IMPLIES_EXEC; if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) current->flags |= PF_RANDOMIZE; diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index cf93a4f..c4bc4d0 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -354,6 +354,8 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) set_personality(PER_LINUX); if (elf_read_implies_exec(&exec_params.hdr, executable_stack)) current->personality |= READ_IMPLIES_EXEC; + else + current->personality &= ~READ_IMPLIES_EXEC; setup_new_exec(bprm); -- 1.9.1 .