From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752033AbeBZP1E (ORCPT ); Mon, 26 Feb 2018 10:27:04 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47592 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751800AbeBZP0u (ORCPT ); Mon, 26 Feb 2018 10:26:50 -0500 From: Philipp Rudo To: kexec@lists.infradead.org, linux-s390@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Eric Biederman , Vivek Goyal , Michael Ellerman , Thiago Jung Bauermann , Martin Schwidefsky , Heiko Carstens , Andrew Morton , x86@kernel.org, Dave Young , AKASHI Takahiro Subject: [PATCH 03/11] kexec_file: Make purgatory_info->ehdr const Date: Mon, 26 Feb 2018 16:16:12 +0100 X-Mailer: git-send-email 2.13.5 In-Reply-To: <20180226151620.20970-1-prudo@linux.vnet.ibm.com> References: <20180226151620.20970-1-prudo@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18022615-0020-0000-0000-000003FC079D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022615-0021-0000-0000-000042902926 Message-Id: <20180226151620.20970-4-prudo@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-26_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802260205 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kexec_purgatory buffer is read-only. Thus all pointers into kexec_purgatory are read-only, too. Point this out by explicitly marking purgatory_info->ehdr as 'const' and update the comments in purgatory_info. Signed-off-by: Philipp Rudo --- include/linux/kexec.h | 17 +++++++++++------ kernel/kexec_file.c | 4 ++-- 2 files changed, 13 insertions(+), 8 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 7bae5e87bf0d..10842eece180 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -99,14 +99,19 @@ struct compat_kexec_segment { #ifdef CONFIG_KEXEC_FILE struct purgatory_info { - /* Pointer to elf header of read only purgatory */ - Elf_Ehdr *ehdr; - - /* Pointer to purgatory sechdrs which are modifiable */ + /* + * Pointer to elf header at the beginning of kexec_purgatory. + * Note: kexec_purgatory is read only + */ + const Elf_Ehdr *ehdr; + /* + * Temporary, modifiable buffer for sechdrs used for relocation. + * This memory can be freed post image load. + */ Elf_Shdr *sechdrs; /* - * Temporary buffer location where purgatory is loaded and relocated - * This memory can be freed post image load + * Temporary, modifiable buffer for stripped purgatory used for + * relocation. This memory can be freed post image load. */ void *purgatory_buf; diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 0f044457b40c..06fc9fdd2474 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -880,7 +880,7 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, if (kexec_purgatory_size <= 0) return -EINVAL; - pi->ehdr = (Elf_Ehdr *)kexec_purgatory; + pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; ret = __kexec_load_purgatory(image, min, max, top_down); if (ret) @@ -904,9 +904,9 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, const char *name) { + const Elf_Ehdr *ehdr; Elf_Sym *syms; Elf_Shdr *sechdrs; - Elf_Ehdr *ehdr; int i, k; const char *strtab; -- 2.13.5