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[82.17.115.212]) by smtp.gmail.com with ESMTPSA id h2sm1892114wrr.96.2022.01.06.15.43.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jan 2022 15:43:23 -0800 (PST) From: Aaron Tomlin To: mcgrof@kernel.org Cc: cl@linux.com, pmladek@suse.com, mbenes@suse.cz, akpm@linux-foundation.org, jeyu@kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, atomlin@atomlin.com, ghalat@redhat.com, allen.lkml@gmail.com Subject: [RFC PATCH v2 03/13] module: Move livepatch support to a separate file Date: Thu, 6 Jan 2022 23:43:09 +0000 Message-Id: <20220106234319.2067842-4-atomlin@redhat.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220106234319.2067842-1-atomlin@redhat.com> References: <20220106234319.2067842-1-atomlin@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org No functional change. This patch migrates livepatch support (i.e. used during module add/or load and remove/or deletion) from core module code into kernel/module/livepatch.c. At the moment it contains code to persist Elf information about a given livepatch module, only. Signed-off-by: Aaron Tomlin --- kernel/module/Makefile | 1 + kernel/module/internal.h | 12 ++++++ kernel/module/livepatch.c | 75 +++++++++++++++++++++++++++++++++ kernel/module/main.c | 89 +-------------------------------------- 4 files changed, 89 insertions(+), 88 deletions(-) create mode 100644 kernel/module/livepatch.c diff --git a/kernel/module/Makefile b/kernel/module/Makefile index a9cf6e822075..47d70bb18da3 100644 --- a/kernel/module/Makefile +++ b/kernel/module/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_MODULES) += main.o obj-$(CONFIG_MODULE_SIG) += signing.o obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o +obj-$(CONFIG_LIVEPATCH) += livepatch.o diff --git a/kernel/module/internal.h b/kernel/module/internal.h index ffc50df010a7..91ef152aeffb 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -51,3 +51,15 @@ struct load_info { }; extern int mod_verify_sig(const void *mod, struct load_info *info); + +#ifdef CONFIG_LIVEPATCH +extern int copy_module_elf(struct module *mod, struct load_info *info); +extern void free_module_elf(struct module *mod); +extern int check_modinfo_livepatch(struct module *mod, struct load_info *info); +#else /* !CONFIG_LIVEPATCH */ +static inline int copy_module_elf(struct module *mod, struct load_info *info) +{ + return 0; +} +static inline void free_module_elf(struct module *mod) { } +#endif /* CONFIG_LIVEPATCH */ diff --git a/kernel/module/livepatch.c b/kernel/module/livepatch.c new file mode 100644 index 000000000000..e147f5418327 --- /dev/null +++ b/kernel/module/livepatch.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * kernel/module/livepatch.c - module livepatch support + * + * Copyright (C) 2016 Jessica Yu + */ + +#include +#include +#include +#include "internal.h" + +/* + * Persist Elf information about a module. Copy the Elf header, + * section header table, section string table, and symtab section + * index from info to mod->klp_info. + */ +int copy_module_elf(struct module *mod, struct load_info *info) +{ + unsigned int size, symndx; + int ret; + + size = sizeof(*mod->klp_info); + mod->klp_info = kmalloc(size, GFP_KERNEL); + if (mod->klp_info == NULL) + return -ENOMEM; + + /* Elf header */ + size = sizeof(mod->klp_info->hdr); + memcpy(&mod->klp_info->hdr, info->hdr, size); + + /* Elf section header table */ + size = sizeof(*info->sechdrs) * info->hdr->e_shnum; + mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL); + if (mod->klp_info->sechdrs == NULL) { + ret = -ENOMEM; + goto free_info; + } + + /* Elf section name string table */ + size = info->sechdrs[info->hdr->e_shstrndx].sh_size; + mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL); + if (mod->klp_info->secstrings == NULL) { + ret = -ENOMEM; + goto free_sechdrs; + } + + /* Elf symbol section index */ + symndx = info->index.sym; + mod->klp_info->symndx = symndx; + + /* + * For livepatch modules, core_kallsyms.symtab is a complete + * copy of the original symbol table. Adjust sh_addr to point + * to core_kallsyms.symtab since the copy of the symtab in module + * init memory is freed at the end of do_init_module(). + */ + mod->klp_info->sechdrs[symndx].sh_addr = \ + (unsigned long) mod->core_kallsyms.symtab; + + return 0; + +free_sechdrs: + kfree(mod->klp_info->sechdrs); +free_info: + kfree(mod->klp_info); + return ret; +} + +void free_module_elf(struct module *mod) +{ + kfree(mod->klp_info->sechdrs); + kfree(mod->klp_info->secstrings); + kfree(mod->klp_info); +} diff --git a/kernel/module/main.c b/kernel/module/main.c index 2a6b859716c0..9bcaf251e109 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -2043,81 +2043,6 @@ static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, } #endif /* CONFIG_STRICT_MODULE_RWX */ -#ifdef CONFIG_LIVEPATCH -/* - * Persist Elf information about a module. Copy the Elf header, - * section header table, section string table, and symtab section - * index from info to mod->klp_info. - */ -static int copy_module_elf(struct module *mod, struct load_info *info) -{ - unsigned int size, symndx; - int ret; - - size = sizeof(*mod->klp_info); - mod->klp_info = kmalloc(size, GFP_KERNEL); - if (mod->klp_info == NULL) - return -ENOMEM; - - /* Elf header */ - size = sizeof(mod->klp_info->hdr); - memcpy(&mod->klp_info->hdr, info->hdr, size); - - /* Elf section header table */ - size = sizeof(*info->sechdrs) * info->hdr->e_shnum; - mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL); - if (mod->klp_info->sechdrs == NULL) { - ret = -ENOMEM; - goto free_info; - } - - /* Elf section name string table */ - size = info->sechdrs[info->hdr->e_shstrndx].sh_size; - mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL); - if (mod->klp_info->secstrings == NULL) { - ret = -ENOMEM; - goto free_sechdrs; - } - - /* Elf symbol section index */ - symndx = info->index.sym; - mod->klp_info->symndx = symndx; - - /* - * For livepatch modules, core_kallsyms.symtab is a complete - * copy of the original symbol table. Adjust sh_addr to point - * to core_kallsyms.symtab since the copy of the symtab in module - * init memory is freed at the end of do_init_module(). - */ - mod->klp_info->sechdrs[symndx].sh_addr = \ - (unsigned long) mod->core_kallsyms.symtab; - - return 0; - -free_sechdrs: - kfree(mod->klp_info->sechdrs); -free_info: - kfree(mod->klp_info); - return ret; -} - -static void free_module_elf(struct module *mod) -{ - kfree(mod->klp_info->sechdrs); - kfree(mod->klp_info->secstrings); - kfree(mod->klp_info); -} -#else /* !CONFIG_LIVEPATCH */ -static int copy_module_elf(struct module *mod, struct load_info *info) -{ - return 0; -} - -static void free_module_elf(struct module *mod) -{ -} -#endif /* CONFIG_LIVEPATCH */ - void __weak module_memfree(void *module_region) { /* @@ -3052,19 +2977,7 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l return 0; } -#ifdef CONFIG_LIVEPATCH -static int check_modinfo_livepatch(struct module *mod, struct load_info *info) -{ - if (get_modinfo(info, "livepatch")) { - mod->klp = true; - add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK); - pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n", - mod->name); - } - - return 0; -} -#else /* !CONFIG_LIVEPATCH */ +#ifndef CONFIG_LIVEPATCH static int check_modinfo_livepatch(struct module *mod, struct load_info *info) { if (get_modinfo(info, "livepatch")) { -- 2.31.1