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,URIBL_BLOCKED,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 C8ADDC2BB85 for ; Tue, 14 Apr 2020 07:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6AE220735 for ; Tue, 14 Apr 2020 07:02:57 +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="MgaL3NTX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406258AbgDNHCz (ORCPT ); Tue, 14 Apr 2020 03:02:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406222AbgDNHCN (ORCPT ); Tue, 14 Apr 2020 03:02:13 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC1CDC008748 for ; Tue, 14 Apr 2020 00:02:05 -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=0ScYERNgAM3OzcxIvuau2j6vPKv0bwWymt+S2nWzjZI=; b=MgaL3NTXsro9AncjawcJu0iXUQ pqh2e6SP+0uxTWpWvhGMexBUeT6lo6qpT17vpuOPTlFOQm+0ZL8ycKC6b8KmA/dLQ8157PFHza+Dd kR4EDwgiUn83TbpsNmfJmd/bnLNAtuErQQNHNVD/F0giPzDEzyAXIQN8igsQuO8AWGDgUwW44szjS ARGArQnoCnlB0erWNrjpNu9tHzG9GReb5XWt7qGBCalV8fCCDStAukm8ER5VPUPFVORFzKTvszz/t +KJOxwPMJS4Rt0lnjGNzXLAWQR1D6cqouAJxf1f2ygwXHTzxMgxrp/Tlb1nU4/clVbq3OliH+W0zB goJpFwzg==; Received: from [2001:4bb8:180:384b:4c21:af7:dd95:e552] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOFa3-0005Z5-5U; Tue, 14 Apr 2020 07:01:59 +0000 From: Christoph Hellwig To: Andrew Morton , Alexander Viro Cc: Jeremy Kerr , Arnd Bergmann , "Eric W . Biederman" , linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5/8] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Date: Tue, 14 Apr 2020 09:01:39 +0200 Message-Id: <20200414070142.288696-6-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200414070142.288696-1-hch@lst.de> References: <20200414070142.288696-1-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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 actual file writes that nicely encapsulated in __kernel_write used by dump_emit. Signed-off-by: Christoph Hellwig --- fs/binfmt_elf.c | 40 +++++++++++++--------------------------- 1 file changed, 13 insertions(+), 27 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 607c5a5f855e..a53a6faa34b1 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; } @@ -2187,7 +2180,6 @@ 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; @@ -2240,9 +2232,6 @@ static int elf_core_dump(struct coredump_params *cprm) has_dumped = 1; - fs = get_fs(); - set_fs(KERNEL_DS); - offset += sizeof(elf); /* Elf header */ offset += segs * sizeof(struct elf_phdr); /* Program headers */ @@ -2254,7 +2243,7 @@ static int elf_core_dump(struct coredump_params *cprm) phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); if (!phdr4note) - goto end_coredump; + goto cleanup; fill_elf_note_phdr(phdr4note, sz, offset); offset += sz; @@ -2269,7 +2258,7 @@ static int elf_core_dump(struct coredump_params *cprm) vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)), GFP_KERNEL); if (!vma_filesz) - goto end_coredump; + goto cleanup; for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { @@ -2287,17 +2276,17 @@ static int elf_core_dump(struct coredump_params *cprm) if (e_phnum == PN_XNUM) { shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL); if (!shdr4extnum) - goto end_coredump; + goto cleanup; fill_extnum_info(&elf, shdr4extnum, e_shoff, segs); } offset = dataoff; if (!dump_emit(cprm, &elf, sizeof(elf))) - goto end_coredump; + goto cleanup; if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) - goto end_coredump; + goto cleanup; /* Write program headers for segments dump */ for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; @@ -2319,22 +2308,22 @@ static int elf_core_dump(struct coredump_params *cprm) phdr.p_align = ELF_EXEC_PAGESIZE; if (!dump_emit(cprm, &phdr, sizeof(phdr))) - goto end_coredump; + goto cleanup; } if (!elf_core_write_extra_phdrs(cprm, offset)) - goto end_coredump; + goto cleanup; /* write out the notes section */ if (!write_note_info(&info, cprm)) - goto end_coredump; + goto cleanup; if (elf_coredump_extra_notes_write(cprm)) - goto end_coredump; + goto cleanup; /* Align to page */ if (!dump_skip(cprm, dataoff - cprm->pos)) - goto end_coredump; + goto cleanup; for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { @@ -2356,22 +2345,19 @@ static int elf_core_dump(struct coredump_params *cprm) } else stop = !dump_skip(cprm, PAGE_SIZE); if (stop) - goto end_coredump; + goto cleanup; } } dump_truncate(cprm); if (!elf_core_write_extra_data(cprm)) - goto end_coredump; + goto cleanup; if (e_phnum == PN_XNUM) { if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum))) - goto end_coredump; + goto cleanup; } -end_coredump: - set_fs(fs); - cleanup: free_note_info(&info); kfree(shdr4extnum); -- 2.25.1