From patchwork Sat Aug 13 03:18:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thiago Jung Bauermann X-Patchwork-Id: 9278309 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5D90660CF5 for ; Sat, 13 Aug 2016 03:19:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5040228AD6 for ; Sat, 13 Aug 2016 03:19:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B98028B44; Sat, 13 Aug 2016 03:19:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BE68828AD6 for ; Sat, 13 Aug 2016 03:19:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753162AbcHMDT2 (ORCPT ); Fri, 12 Aug 2016 23:19:28 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:55192 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753160AbcHMDTZ (ORCPT ); Fri, 12 Aug 2016 23:19:25 -0400 Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u7D3IshF038350 for ; Fri, 12 Aug 2016 23:19:20 -0400 Received: from e24smtp03.br.ibm.com (e24smtp03.br.ibm.com [32.104.18.24]) by mx0b-001b2d01.pphosted.com with ESMTP id 24ru321pc4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 12 Aug 2016 23:19:20 -0400 Received: from localhost by e24smtp03.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Sat, 13 Aug 2016 00:19:15 -0300 X-IBM-Helo: d24dlp01.br.ibm.com X-IBM-MailFrom: bauerman@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org; linux-security-module@vger.kernel.org Received: from d24relay01.br.ibm.com (d24relay01.br.ibm.com [9.8.31.16]) by d24dlp01.br.ibm.com (Postfix) with ESMTP id AC1C3352006E; Fri, 12 Aug 2016 23:18:54 -0400 (EDT) Received: from d24av05.br.ibm.com (d24av05.br.ibm.com [9.18.232.44]) by d24relay01.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u7D3JFvE4931824; Sat, 13 Aug 2016 00:19:15 -0300 Received: from d24av05.br.ibm.com (localhost [127.0.0.1]) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u7D3JCx5014187; Sat, 13 Aug 2016 00:19:15 -0300 Received: from hactar.ibm.com ([9.78.148.164]) by d24av05.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u7D3ImfX013761; Sat, 13 Aug 2016 00:19:01 -0300 From: Thiago Jung Bauermann To: kexec@lists.infradead.org Cc: linux-security-module@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, x86@kernel.org, Eric Biederman , Dave Young , Vivek Goyal , Baoquan He , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Stewart Smith , Samuel Mendoza-Jonas , Mimi Zohar , Eric Richter , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , Petko Manolov , David Laight , Balbir Singh , Thiago Jung Bauermann Subject: [PATCH v2 4/6] kexec_file: Add mechanism to update kexec segments. Date: Sat, 13 Aug 2016 00:18:23 -0300 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1471058305-30198-1-git-send-email-bauerman@linux.vnet.ibm.com> References: <1471058305-30198-1-git-send-email-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16081303-0024-0000-0000-000000F19775 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16081303-0025-0000-0000-0000157C9E6A Message-Id: <1471058305-30198-5-git-send-email-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-08-12_10:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=13 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608130039 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP kexec_update_segment allows a given segment in kexec_image to have its contents updated. This is useful if the current kernel wants to send information to the next kernel that is up-to-date at the time of reboot. Signed-off-by: Thiago Jung Bauermann --- include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 101 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 37eea32fdff1..14dda81e3e01 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -259,6 +259,8 @@ extern int kexec_purgatory_get_set_symbol(struct kimage *image, unsigned int size, bool get_value); extern void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name); +int kexec_update_segment(const char *buffer, unsigned long bufsz, + unsigned long load_addr, unsigned long memsz); extern void __crash_kexec(struct pt_regs *); extern void crash_kexec(struct pt_regs *); int kexec_should_crash(struct task_struct *); diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 561675589511..806735201de6 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -721,6 +721,105 @@ static struct page *kimage_alloc_page(struct kimage *image, return page; } +/** + * kexec_update_segment - update the contents of a kimage segment + * @buffer: New contents of the segment. + * @bufsz: @buffer size. + * @load_addr: Segment's physical address in the next kernel. + * @memsz: Segment size. + * + * This function assumes kexec_mutex is held. + * + * Return: 0 on success, negative errno on error. + */ +int kexec_update_segment(const char *buffer, unsigned long bufsz, + unsigned long load_addr, unsigned long memsz) +{ + int i; + unsigned long entry; + unsigned long *ptr = NULL; + void *dest = NULL; + + if (kexec_image == NULL) { + pr_err("Can't update segment: no kexec image loaded.\n"); + return -EINVAL; + } + + /* + * kexec_add_buffer rounds up segment sizes to PAGE_SIZE, so + * we have to do it here as well. + */ + memsz = ALIGN(memsz, PAGE_SIZE); + + for (i = 0; i < kexec_image->nr_segments; i++) + /* We only support updating whole segments. */ + if (load_addr == kexec_image->segment[i].mem && + memsz == kexec_image->segment[i].memsz) { + if (kexec_image->segment[i].do_checksum) { + pr_err("Trying to update non-modifiable segment.\n"); + return -EINVAL; + } + + break; + } + if (i == kexec_image->nr_segments) { + pr_err("Couldn't find segment to update: 0x%lx, size 0x%lx\n", + load_addr, memsz); + return -EINVAL; + } + + for (entry = kexec_image->head; !(entry & IND_DONE) && memsz; + entry = *ptr++) { + void *addr = (void *) (entry & PAGE_MASK); + + switch (entry & IND_FLAGS) { + case IND_DESTINATION: + dest = addr; + break; + case IND_INDIRECTION: + ptr = __va(addr); + break; + case IND_SOURCE: + /* Shouldn't happen, but verify just to be safe. */ + if (dest == NULL) { + pr_err("Invalid kexec entries list."); + return -EINVAL; + } + + if (dest == (void *) load_addr) { + struct page *page; + char *ptr; + size_t uchunk, mchunk; + + page = kmap_to_page(addr); + + ptr = kmap(page); + ptr += load_addr & ~PAGE_MASK; + mchunk = min_t(size_t, memsz, + PAGE_SIZE - (load_addr & ~PAGE_MASK)); + uchunk = min(bufsz, mchunk); + memcpy(ptr, buffer, uchunk); + + kunmap(page); + + bufsz -= uchunk; + load_addr += mchunk; + buffer += mchunk; + memsz -= mchunk; + } + dest += PAGE_SIZE; + } + + /* Shouldn't happen, but verify just to be safe. */ + if (ptr == NULL) { + pr_err("Invalid kexec entries list."); + return -EINVAL; + } + } + + return 0; +} + static int kimage_load_normal_segment(struct kimage *image, struct kexec_segment *segment) {