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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 41EC3C47259 for ; Tue, 5 May 2020 10:13:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20A3B206B9 for ; Tue, 5 May 2020 10:13:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mplopeTS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728737AbgEEKNb (ORCPT ); Tue, 5 May 2020 06:13:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728727AbgEEKN1 (ORCPT ); Tue, 5 May 2020 06:13:27 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11D9EC061A0F; Tue, 5 May 2020 03:13:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=0bHppblaPmDxTAjn3jOg5XHlDLubZOOc/MJ2gG3CZzc=; b=mplopeTSiFGW6qyoJEY67/74uJ B4c0b6qCTqcztRxwKqid7gyrWJ/1xrJuFYoYH6BkxSg4qxCkEBwPlbyDX4D4H9vQ1XKnEMrMeQuQd sRE4dVtLTSxs4CsQibco9O6uyr2agdhZomhHmwhoTwXEu2VRYKJba7+WfxFUyenCkTqldLFAGc0bW SAjxUzWvs9Dxmi4SlCIrFx0aAd/yWFTxfy95XTfOgx/tpibtmlLsSUnHjYB9dAU7vfy3tbrugr1QJ 1vfhONYSuTiDGGrd4kV4+WPOTiUei9+b9UVljXpESqX//frFBxaJnVMIzE6xEMuN04E7peMK6Qx5h 1S6/Dcaw==; Received: from [2001:4bb8:191:66b6:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jVuZf-0006wC-RN; Tue, 05 May 2020 10:13:16 +0000 From: Christoph Hellwig To: Andrew Morton , Alexander Viro Cc: Linus Torvalds , Jeremy Kerr , Arnd Bergmann , Oleg Nesterov , "Eric W . Biederman" , x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/7] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Date: Tue, 5 May 2020 12:12:55 +0200 Message-Id: <20200505101256.3121270-7-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200505101256.3121270-1-hch@lst.de> References: <20200505101256.3121270-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org There is no logic in elf_core_dump itself or in the various arch helpers called from it which use uaccess routines on kernel pointers except for the file writes thate are nicely encapsulated by using __kernel_write in dump_emit. Signed-off-by: Christoph Hellwig --- fs/binfmt_elf.c | 16 +--------------- 1 file changed, 1 insertion(+), 15 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a1f57e20c3cf2..ba6f87ba029a7 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1355,7 +1355,6 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { u32 __user *header = (u32 __user *) vma->vm_start; u32 word; - mm_segment_t fs = get_fs(); /* * Doing it this way gets the constant folded by GCC. */ @@ -1368,14 +1367,8 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, magic.elfmag[EI_MAG1] = ELFMAG1; magic.elfmag[EI_MAG2] = ELFMAG2; magic.elfmag[EI_MAG3] = ELFMAG3; - /* - * Switch to the user "segment" for get_user(), - * then put back what elf_core_dump() had in place. - */ - set_fs(USER_DS); if (unlikely(get_user(word, header))) word = 0; - set_fs(fs); if (word == magic.cmp) return PAGE_SIZE; } @@ -2183,7 +2176,6 @@ static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum, static int elf_core_dump(struct coredump_params *cprm) { int has_dumped = 0; - mm_segment_t fs; int segs, i; size_t vma_data_size = 0; struct vm_area_struct *vma, *gate_vma; @@ -2232,13 +2224,10 @@ static int elf_core_dump(struct coredump_params *cprm) * notes. This also sets up the file header. */ if (!fill_note_info(&elf, e_phnum, &info, cprm->siginfo, cprm->regs)) - goto cleanup; + goto end_coredump; has_dumped = 1; - fs = get_fs(); - set_fs(KERNEL_DS); - offset += sizeof(elf); /* Elf header */ offset += segs * sizeof(struct elf_phdr); /* Program headers */ @@ -2366,9 +2355,6 @@ static int elf_core_dump(struct coredump_params *cprm) } end_coredump: - set_fs(fs); - -cleanup: free_note_info(&info); kfree(shdr4extnum); kvfree(vma_filesz); -- 2.26.2