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[82.17.115.212]) by smtp.gmail.com with ESMTPSA id p190sm7246166wmp.16.2022.01.30.13.32.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Jan 2022 13:32:23 -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, live-patching@vger.kernel.org, atomlin@atomlin.com, ghalat@redhat.com, allen.lkml@gmail.com, void@manifault.com, joe@perches.com Subject: [RFC PATCH v4 05/13] module: Move arch strict rwx support to a separate file Date: Sun, 30 Jan 2022 21:32:06 +0000 Message-Id: <20220130213214.1042497-6-atomlin@redhat.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220130213214.1042497-1-atomlin@redhat.com> References: <20220130213214.1042497-1-atomlin@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org No functional change. This patch migrates applicable architecture code that support strict module rwx from core module code into kernel/module/arch_strict_rwx.c Signed-off-by: Aaron Tomlin --- include/linux/module.h | 17 +++++++++++ kernel/module/Makefile | 1 + kernel/module/arch_strict_rwx.c | 44 ++++++++++++++++++++++++++++ kernel/module/main.c | 51 --------------------------------- 4 files changed, 62 insertions(+), 51 deletions(-) create mode 100644 kernel/module/arch_strict_rwx.c diff --git a/include/linux/module.h b/include/linux/module.h index faeb7ae49b89..8b75380bc340 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -339,6 +339,23 @@ struct module_layout { #endif }; +/* + * Modules' sections will be aligned on page boundaries + * to ensure complete separation of code and data, but + * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y + */ +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX +# define debug_align(X) ALIGN(X, PAGE_SIZE) + +extern void frob_text(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)); +extern void module_enable_x(const struct module *mod); +#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ +# define debug_align(X) (X) + +static void module_enable_x(const struct module *mod) { } +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ + #ifdef CONFIG_MODULES_TREE_LOOKUP /* Only touch one cacheline for common rbtree-for-core-layout case. */ #define __module_layout_align ____cacheline_aligned diff --git a/kernel/module/Makefile b/kernel/module/Makefile index fc6d7a053a62..146509978708 100644 --- a/kernel/module/Makefile +++ b/kernel/module/Makefile @@ -10,4 +10,5 @@ obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o ifdef CONFIG_MODULES obj-$(CONFIG_LIVEPATCH) += livepatch.o obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o +obj-$(CONFIG_ARCH_HAS_STRICT_MODULE_RWX) += arch_strict_rwx.o endif diff --git a/kernel/module/arch_strict_rwx.c b/kernel/module/arch_strict_rwx.c new file mode 100644 index 000000000000..9801cb4fef36 --- /dev/null +++ b/kernel/module/arch_strict_rwx.c @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Module arch strict rwx + * + * Copyright (C) 2015 Rusty Russell + */ + +#include +#include + +/* + * LKM RO/NX protection: protect module's text/ro-data + * from modification and any data from execution. + * + * General layout of module is: + * [text] [read-only-data] [ro-after-init] [writable data] + * text_size -----^ ^ ^ ^ + * ro_size ------------------------| | | + * ro_after_init_size -----------------------------| | + * size -----------------------------------------------------------| + * + * These values are always page-aligned (as is base) + */ + +/* + * Since some arches are moving towards PAGE_KERNEL module allocations instead + * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the + * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of + * whether we are strict. + */ +void frob_text(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)) +{ + BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); + BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); + set_memory((unsigned long)layout->base, + layout->text_size >> PAGE_SHIFT); +} + +void module_enable_x(const struct module *mod) +{ + frob_text(&mod->core_layout, set_memory_x); + frob_text(&mod->init_layout, set_memory_x); +} diff --git a/kernel/module/main.c b/kernel/module/main.c index 941be7788626..7e98ea12b146 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -13,7 +13,6 @@ #include #include #include -#include #include #include #include @@ -63,17 +62,6 @@ #define CREATE_TRACE_POINTS #include -/* - * Modules' sections will be aligned on page boundaries - * to ensure complete separation of code and data, but - * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y - */ -#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX -# define debug_align(X) ALIGN(X, PAGE_SIZE) -#else -# define debug_align(X) (X) -#endif - /* * Mutex protects: * 1) List of modules (also safely readable with preempt_disable), @@ -1794,45 +1782,6 @@ static void mod_sysfs_teardown(struct module *mod) mod_sysfs_fini(mod); } -/* - * LKM RO/NX protection: protect module's text/ro-data - * from modification and any data from execution. - * - * General layout of module is: - * [text] [read-only-data] [ro-after-init] [writable data] - * text_size -----^ ^ ^ ^ - * ro_size ------------------------| | | - * ro_after_init_size -----------------------------| | - * size -----------------------------------------------------------| - * - * These values are always page-aligned (as is base) - */ - -/* - * Since some arches are moving towards PAGE_KERNEL module allocations instead - * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the - * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of - * whether we are strict. - */ -#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX -static void frob_text(const struct module_layout *layout, - int (*set_memory)(unsigned long start, int num_pages)) -{ - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); - set_memory((unsigned long)layout->base, - layout->text_size >> PAGE_SHIFT); -} - -static void module_enable_x(const struct module *mod) -{ - frob_text(&mod->core_layout, set_memory_x); - frob_text(&mod->init_layout, set_memory_x); -} -#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ -static void module_enable_x(const struct module *mod) { } -#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ - #ifdef CONFIG_STRICT_MODULE_RWX static void frob_rodata(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) -- 2.34.1