From: Aaron Tomlin <atomlin@redhat.com>
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
Subject: [RFC PATCH 06/12] module: Move strict rwx support to a separate file
Date: Tue, 28 Dec 2021 21:30:35 +0000 [thread overview]
Message-ID: <20211228213041.1356334-7-atomlin@redhat.com> (raw)
In-Reply-To: <20211228213041.1356334-1-atomlin@redhat.com>
No functional change.
This patch migrates code that makes module text
and rodata memory read-only and non-text memory
non-executable from core module code into
kernel/module/strict_rwx.c.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
---
include/linux/module.h | 18 ++++++++
kernel/module/Makefile | 1 +
kernel/module/main.c | 84 --------------------------------------
kernel/module/strict_rwx.c | 83 +++++++++++++++++++++++++++++++++++++
4 files changed, 102 insertions(+), 84 deletions(-)
create mode 100644 kernel/module/strict_rwx.c
diff --git a/include/linux/module.h b/include/linux/module.h
index caa7212cf754..218ac6768433 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -354,6 +354,24 @@ extern void module_enable_x(const struct module *mod);
static void module_enable_x(const struct module *mod) { }
#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
+#ifdef CONFIG_STRICT_MODULE_RWX
+extern void frob_rodata(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages));
+extern void frob_ro_after_init(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages));
+extern void frob_writable_data(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages));
+extern void module_enable_ro(const struct module *mod, bool after_init);
+extern void module_enable_nx(const struct module *mod);
+extern int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod);
+
+#else /* !CONFIG_STRICT_MODULE_RWX */
+static void module_enable_nx(const struct module *mod) { }
+static void module_enable_ro(const struct module *mod, bool after_init) {}
+static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ return 0;
+}
+#endif /* CONFIG_STRICT_MODULE_RWX */
+
#ifdef CONFIG_MODULES_TREE_LOOKUP
struct mod_tree_root {
struct latch_tree_root root;
diff --git a/kernel/module/Makefile b/kernel/module/Makefile
index 95fad95a0549..795fe10ac530 100644
--- a/kernel/module/Makefile
+++ b/kernel/module/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_MODULE_SIG_FORMAT) += signature.o
obj-$(CONFIG_LIVEPATCH) += livepatch.o
obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
obj-$(CONFIG_ARCH_HAS_STRICT_MODULE_RWX) += arch_strict_rwx.o
+obj-$(CONFIG_STRICT_MODULE_RWX) += strict_rwx.o
diff --git a/kernel/module/main.c b/kernel/module/main.c
index a0619256b343..c404d00f7958 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1774,90 +1774,6 @@ static void mod_sysfs_teardown(struct module *mod)
mod_sysfs_fini(mod);
}
-#ifdef CONFIG_STRICT_MODULE_RWX
-static void frob_rodata(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));
- BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
- set_memory((unsigned long)layout->base + layout->text_size,
- (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
-}
-
-static void frob_ro_after_init(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->ro_size & (PAGE_SIZE-1));
- BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
- set_memory((unsigned long)layout->base + layout->ro_size,
- (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
-}
-
-static void frob_writable_data(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->ro_after_init_size & (PAGE_SIZE-1));
- BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
- set_memory((unsigned long)layout->base + layout->ro_after_init_size,
- (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
-}
-
-static void module_enable_ro(const struct module *mod, bool after_init)
-{
- if (!rodata_enabled)
- return;
-
- set_vm_flush_reset_perms(mod->core_layout.base);
- set_vm_flush_reset_perms(mod->init_layout.base);
- frob_text(&mod->core_layout, set_memory_ro);
-
- frob_rodata(&mod->core_layout, set_memory_ro);
- frob_text(&mod->init_layout, set_memory_ro);
- frob_rodata(&mod->init_layout, set_memory_ro);
-
- if (after_init)
- frob_ro_after_init(&mod->core_layout, set_memory_ro);
-}
-
-static void module_enable_nx(const struct module *mod)
-{
- frob_rodata(&mod->core_layout, set_memory_nx);
- frob_ro_after_init(&mod->core_layout, set_memory_nx);
- frob_writable_data(&mod->core_layout, set_memory_nx);
- frob_rodata(&mod->init_layout, set_memory_nx);
- frob_writable_data(&mod->init_layout, set_memory_nx);
-}
-
-static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
- char *secstrings, struct module *mod)
-{
- const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
- int i;
-
- for (i = 0; i < hdr->e_shnum; i++) {
- if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
- pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
- mod->name, secstrings + sechdrs[i].sh_name, i);
- return -ENOEXEC;
- }
- }
-
- return 0;
-}
-
-#else /* !CONFIG_STRICT_MODULE_RWX */
-static void module_enable_nx(const struct module *mod) { }
-static void module_enable_ro(const struct module *mod, bool after_init) {}
-static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
- char *secstrings, struct module *mod)
-{
- return 0;
-}
-#endif /* CONFIG_STRICT_MODULE_RWX */
-
void __weak module_memfree(void *module_region)
{
/*
diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c
new file mode 100644
index 000000000000..8a513ced02c6
--- /dev/null
+++ b/kernel/module/strict_rwx.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * kernel/module/strict_rwx.c - module strict rwx
+ *
+ * Copyright (C) 2015 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+
+void frob_rodata(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));
+ BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
+ set_memory((unsigned long)layout->base + layout->text_size,
+ (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
+}
+
+void frob_ro_after_init(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->ro_size & (PAGE_SIZE-1));
+ BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
+ set_memory((unsigned long)layout->base + layout->ro_size,
+ (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
+}
+
+void frob_writable_data(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->ro_after_init_size & (PAGE_SIZE-1));
+ BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
+ set_memory((unsigned long)layout->base + layout->ro_after_init_size,
+ (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
+}
+
+void module_enable_ro(const struct module *mod, bool after_init)
+{
+ if (!rodata_enabled)
+ return;
+
+ set_vm_flush_reset_perms(mod->core_layout.base);
+ set_vm_flush_reset_perms(mod->init_layout.base);
+ frob_text(&mod->core_layout, set_memory_ro);
+
+ frob_rodata(&mod->core_layout, set_memory_ro);
+ frob_text(&mod->init_layout, set_memory_ro);
+ frob_rodata(&mod->init_layout, set_memory_ro);
+
+ if (after_init)
+ frob_ro_after_init(&mod->core_layout, set_memory_ro);
+}
+
+void module_enable_nx(const struct module *mod)
+{
+ frob_rodata(&mod->core_layout, set_memory_nx);
+ frob_ro_after_init(&mod->core_layout, set_memory_nx);
+ frob_writable_data(&mod->core_layout, set_memory_nx);
+ frob_rodata(&mod->init_layout, set_memory_nx);
+ frob_writable_data(&mod->init_layout, set_memory_nx);
+}
+
+int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
+ int i;
+
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
+ pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
+ mod->name, secstrings + sechdrs[i].sh_name, i);
+ return -ENOEXEC;
+ }
+ }
+
+ return 0;
+}
--
2.31.1
next prev parent reply other threads:[~2021-12-28 21:30 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 17:33 [RFC PATCH] module: Introduce module unload taint tracking Aaron Tomlin
2021-12-08 20:47 ` Luis Chamberlain
2021-12-09 16:49 ` Aaron Tomlin
2021-12-09 23:42 ` Luis Chamberlain
2021-12-10 10:00 ` Petr Mladek
2021-12-10 16:09 ` Aaron Tomlin
2021-12-10 17:09 ` Luis Chamberlain
2021-12-13 15:16 ` Petr Mladek
2021-12-21 11:58 ` Aaron Tomlin
2021-12-10 17:03 ` Luis Chamberlain
2021-12-10 15:48 ` Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 00/12] module: core code clean up Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 01/12] module: Move all into module/ Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 02/12] module: Simple refactor in preparation for split Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 03/12] module: Move livepatch support to a separate file Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 04/12] module: Move latched RB-tree " Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 05/12] module: Move arch strict rwx " Aaron Tomlin
2022-01-12 16:13 ` Luis Chamberlain
2021-12-28 21:30 ` Aaron Tomlin [this message]
2021-12-28 21:30 ` [RFC PATCH 07/12] module: Move extra signature support out of core code Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 08/12] module: Move kmemleak support to a separate file Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 09/12] module: Move kallsyms support into " Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 10/12] module: Move procfs " Aaron Tomlin
2021-12-28 21:30 ` [RFC PATCH 11/12] module: Move sysfs " Aaron Tomlin
2022-01-12 16:20 ` Luis Chamberlain
2021-12-28 21:30 ` [RFC PATCH 12/12] module: Move kdb_modules list out of core code Aaron Tomlin
2021-12-29 8:58 ` [RFC PATCH 00/12] module: core code clean up Aaron Tomlin
2022-01-12 16:21 ` Luis Chamberlain
2021-12-13 13:00 ` [RFC PATCH] module: Introduce module unload taint tracking Allen
2021-12-20 19:23 ` Luis Chamberlain
2021-12-21 11:44 ` Aaron Tomlin
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