diff mbox series

[v8,06/13] module: Move strict rwx support to a separate file

Message ID 20220222141303.1392190-7-atomlin@redhat.com (mailing list archive)
State Superseded
Headers show
Series module: core code clean up | expand

Commit Message

Aaron Tomlin Feb. 22, 2022, 2:12 p.m. UTC
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>
---
 kernel/module/Makefile     |  1 +
 kernel/module/internal.h   | 32 ++++++++++++
 kernel/module/main.c       | 99 +-------------------------------------
 kernel/module/strict_rwx.c | 85 ++++++++++++++++++++++++++++++++
 4 files changed, 120 insertions(+), 97 deletions(-)
 create mode 100644 kernel/module/strict_rwx.c

Comments

Christophe Leroy Feb. 22, 2022, 5:59 p.m. UTC | #1
Le 22/02/2022 à 15:12, Aaron Tomlin a écrit :
> 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>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   kernel/module/Makefile     |  1 +
>   kernel/module/internal.h   | 32 ++++++++++++
>   kernel/module/main.c       | 99 +-------------------------------------
>   kernel/module/strict_rwx.c | 85 ++++++++++++++++++++++++++++++++
>   4 files changed, 120 insertions(+), 97 deletions(-)
>   create mode 100644 kernel/module/strict_rwx.c
> 
> diff --git a/kernel/module/Makefile b/kernel/module/Makefile
> index 88774e386276..d313c8472cb3 100644
> --- a/kernel/module/Makefile
> +++ b/kernel/module/Makefile
> @@ -12,3 +12,4 @@ obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
>   obj-$(CONFIG_MODULE_SIG) += signing.o
>   obj-$(CONFIG_LIVEPATCH) += livepatch.o
>   obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
> +obj-$(CONFIG_STRICT_MODULE_RWX) += strict_rwx.o
> diff --git a/kernel/module/internal.h b/kernel/module/internal.h
> index f1682e3677be..a6895bb5598a 100644
> --- a/kernel/module/internal.h
> +++ b/kernel/module/internal.h
> @@ -20,6 +20,17 @@
>   /* Maximum number of characters written by module_flags() */
>   #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
>   
> +/*
> + * 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) PAGE_ALIGN(X)
> +#else
> +# define debug_align(X) (X)
> +#endif
> +
>   extern struct mutex module_mutex;
>   extern struct list_head modules;
>   
> @@ -126,3 +137,24 @@ static inline struct module *mod_find(unsigned long addr)
>   	return NULL;
>   }
>   #endif /* CONFIG_MODULES_TREE_LOOKUP */
> +
> +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
> +void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start,
> +								     int num_pages));
> +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
> +
> +#ifdef CONFIG_STRICT_MODULE_RWX
> +void module_enable_ro(const struct module *mod, bool after_init);
> +void module_enable_nx(const struct module *mod);
> +int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
> +				char *secstrings, struct module *mod);
> +
> +#else /* !CONFIG_STRICT_MODULE_RWX */
> +static inline void module_enable_nx(const struct module *mod) { }
> +static inline void module_enable_ro(const struct module *mod, bool after_init) {}
> +static inline int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
> +				       char *secstrings, struct module *mod)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_STRICT_MODULE_RWX */
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index 76b53880ad91..5cd63f14b1ef 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -63,17 +63,6 @@
>   #define CREATE_TRACE_POINTS
>   #include <trace/events/module.h>
>   
> -/*
> - * 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),
> @@ -1819,8 +1808,8 @@ static void mod_sysfs_teardown(struct module *mod)
>    * 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))
> +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));
> @@ -1837,90 +1826,6 @@ static 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
> -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..7949dfd449c2
> --- /dev/null
> +++ b/kernel/module/strict_rwx.c
> @@ -0,0 +1,85 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Module strict rwx
> + *
> + * Copyright (C) 2015 Rusty Russell
> + */
> +
> +#include <linux/module.h>
> +#include <linux/mm.h>
> +#include <linux/vmalloc.h>
> +#include <linux/set_memory.h>
> +#include "internal.h"
> +
> +static void frob_rodata(const struct module_layout *layout,
> +		 int (*set_memory)(unsigned long start, int num_pages))
> +{
> +	BUG_ON(!PAGE_ALIGNED(layout->base));
> +	BUG_ON(!PAGE_ALIGNED(layout->text_size));
> +	BUG_ON(!PAGE_ALIGNED(layout->ro_size));
> +	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(!PAGE_ALIGNED(layout->base));
> +	BUG_ON(!PAGE_ALIGNED(layout->ro_size));
> +	BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size));
> +	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(!PAGE_ALIGNED(layout->base));
> +	BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size));
> +	BUG_ON(!PAGE_ALIGNED(layout->size));
> +	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;
> +}
diff mbox series

Patch

diff --git a/kernel/module/Makefile b/kernel/module/Makefile
index 88774e386276..d313c8472cb3 100644
--- a/kernel/module/Makefile
+++ b/kernel/module/Makefile
@@ -12,3 +12,4 @@  obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o
 obj-$(CONFIG_MODULE_SIG) += signing.o
 obj-$(CONFIG_LIVEPATCH) += livepatch.o
 obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o
+obj-$(CONFIG_STRICT_MODULE_RWX) += strict_rwx.o
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index f1682e3677be..a6895bb5598a 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -20,6 +20,17 @@ 
 /* Maximum number of characters written by module_flags() */
 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
 
+/*
+ * 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) PAGE_ALIGN(X)
+#else
+# define debug_align(X) (X)
+#endif
+
 extern struct mutex module_mutex;
 extern struct list_head modules;
 
@@ -126,3 +137,24 @@  static inline struct module *mod_find(unsigned long addr)
 	return NULL;
 }
 #endif /* CONFIG_MODULES_TREE_LOOKUP */
+
+#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
+void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start,
+								     int num_pages));
+#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
+
+#ifdef CONFIG_STRICT_MODULE_RWX
+void module_enable_ro(const struct module *mod, bool after_init);
+void module_enable_nx(const struct module *mod);
+int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+				char *secstrings, struct module *mod);
+
+#else /* !CONFIG_STRICT_MODULE_RWX */
+static inline void module_enable_nx(const struct module *mod) { }
+static inline void module_enable_ro(const struct module *mod, bool after_init) {}
+static inline int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+				       char *secstrings, struct module *mod)
+{
+	return 0;
+}
+#endif /* CONFIG_STRICT_MODULE_RWX */
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 76b53880ad91..5cd63f14b1ef 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -63,17 +63,6 @@ 
 #define CREATE_TRACE_POINTS
 #include <trace/events/module.h>
 
-/*
- * 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),
@@ -1819,8 +1808,8 @@  static void mod_sysfs_teardown(struct module *mod)
  * 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))
+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));
@@ -1837,90 +1826,6 @@  static 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
-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..7949dfd449c2
--- /dev/null
+++ b/kernel/module/strict_rwx.c
@@ -0,0 +1,85 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Module strict rwx
+ *
+ * Copyright (C) 2015 Rusty Russell
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+#include "internal.h"
+
+static void frob_rodata(const struct module_layout *layout,
+		 int (*set_memory)(unsigned long start, int num_pages))
+{
+	BUG_ON(!PAGE_ALIGNED(layout->base));
+	BUG_ON(!PAGE_ALIGNED(layout->text_size));
+	BUG_ON(!PAGE_ALIGNED(layout->ro_size));
+	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(!PAGE_ALIGNED(layout->base));
+	BUG_ON(!PAGE_ALIGNED(layout->ro_size));
+	BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size));
+	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(!PAGE_ALIGNED(layout->base));
+	BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size));
+	BUG_ON(!PAGE_ALIGNED(layout->size));
+	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;
+}