From patchwork Mon Aug 16 19:48:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12439145 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7E63FC4338F for ; Mon, 16 Aug 2021 19:49:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 10EBD60F58 for ; Mon, 16 Aug 2021 19:49:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 10EBD60F58 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 6EB2C8D0008; Mon, 16 Aug 2021 15:49:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 69B518D0001; Mon, 16 Aug 2021 15:49:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53BCD8D0008; Mon, 16 Aug 2021 15:49:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id 36C5C8D0001 for ; Mon, 16 Aug 2021 15:49:48 -0400 (EDT) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DB95C8249980 for ; Mon, 16 Aug 2021 19:49:47 +0000 (UTC) X-FDA: 78481984014.19.7CC6A17 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf17.hostedemail.com (Postfix) with ESMTP id 9A79BF00349E for ; Mon, 16 Aug 2021 19:49:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1629143387; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xeZs2Vbi3LPUYE5L2DmMtSeAlr7D2lLP2ZjOK1a2vac=; b=FqhFGGCFx6621JuYObxiXHXmR59J+pLvl2xLRdPVNy00SQ1wRmd7obh7BpqwlTLE0zZBCl IlKrbY8BW43036wKQwYX/Io1e83upZdrk94R1xXli3TEqbxRe15TTJiW+GMwWbZjPn0wOe iFye7rWvZA8p2KmtQ9j0EGJ2c9NuYRE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-468-CHcbLj9aNsi8F8QsqNZN7w-1; Mon, 16 Aug 2021 15:49:46 -0400 X-MC-Unique: CHcbLj9aNsi8F8QsqNZN7w-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AC5FA100A606; Mon, 16 Aug 2021 19:49:40 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.192.85]) by smtp.corp.redhat.com (Postfix) with ESMTP id 874FF18017; Mon, 16 Aug 2021 19:49:05 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Alexander Viro , Alexey Dobriyan , Steven Rostedt , Peter Zijlstra , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , "Eric W. Biederman" , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Catalin Marinas , "Matthew Wilcox (Oracle)" , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Michal Hocko , Miklos Szeredi , Chengguang Xu , =?utf-8?q?Christian_K=C3=B6nig?= , Florian Weimer , David Laight , linux-unionfs@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 1/7] binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib() Date: Mon, 16 Aug 2021 21:48:34 +0200 Message-Id: <20210816194840.42769-2-david@redhat.com> In-Reply-To: <20210816194840.42769-1-david@redhat.com> References: <20210816194840.42769-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=FqhFGGCF; spf=none (imf17.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9A79BF00349E X-Stat-Signature: 7dr74jdbp9ffhb8q13jibxn76odk14we X-HE-Tag: 1629143387-29519 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: uselib() is the legacy systemcall for loading shared libraries. Nowadays, applications use dlopen() to load shared libraries, completely implemented in user space via mmap(). For example, glibc uses MAP_COPY to mmap shared libraries. While this maps to MAP_PRIVATE | MAP_DENYWRITE on Linux, Linux ignores any MAP_DENYWRITE specification from user space in mmap. With this change, all remaining in-tree users of MAP_DENYWRITE use it to map an executable. We will be able to open shared libraries loaded via uselib() writable, just as we already can via dlopen() from user space. This is one step into the direction of removing MAP_DENYWRITE from the kernel. This can be considered a minor user space visible change. Acked-by: "Eric W. Biederman" Signed-off-by: David Hildenbrand --- arch/x86/ia32/ia32_aout.c | 2 +- fs/binfmt_aout.c | 2 +- fs/binfmt_elf.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c index 5e5b9fc2747f..321d7b22ad2d 100644 --- a/arch/x86/ia32/ia32_aout.c +++ b/arch/x86/ia32/ia32_aout.c @@ -293,7 +293,7 @@ static int load_aout_library(struct file *file) /* Now use mmap to map the library into memory. */ error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT, + MAP_FIXED | MAP_PRIVATE | MAP_32BIT, N_TXTOFF(ex)); retval = error; if (error != start_addr) diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c index 145917f734fe..d29de971d3f3 100644 --- a/fs/binfmt_aout.c +++ b/fs/binfmt_aout.c @@ -309,7 +309,7 @@ static int load_aout_library(struct file *file) /* Now use mmap to map the library into memory. */ error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE, + MAP_FIXED | MAP_PRIVATE; N_TXTOFF(ex)); retval = error; if (error != start_addr) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 439ed81e755a..6d2c79533631 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1384,7 +1384,7 @@ static int load_elf_library(struct file *file) (eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr)), PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED_NOREPLACE | MAP_PRIVATE | MAP_DENYWRITE, + MAP_FIXED_NOREPLACE | MAP_PRIVATE, (eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr))); if (error != ELF_PAGESTART(eppnt->p_vaddr))