Despite the word 'debug' in CONFIG_DEBUG_RODATA, this kernel option
provides key security features that are to be expected on a modern
system. Change the name to CONFIG_HARDENED_PAGE_MAPPINGS which more
accurately describes what this option is intended to do.
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
Documentation/DocBook/kgdb.tmpl | 8 ++++----
Documentation/security/self-protection.txt | 2 +-
arch/arm/Kconfig | 1 +
arch/arm/configs/aspeed_g4_defconfig | 2 +-
arch/arm/configs/aspeed_g5_defconfig | 2 +-
arch/arm/include/asm/cacheflush.h | 2 +-
arch/arm/kernel/patch.c | 2 +-
arch/arm/kernel/vmlinux.lds.S | 8 ++++----
arch/arm/mm/Kconfig | 14 +-------------
arch/arm/mm/init.c | 4 ++--
arch/arm64/Kconfig | 4 +---
arch/arm64/Kconfig.debug | 2 +-
arch/parisc/Kconfig | 1 +
arch/parisc/Kconfig.debug | 11 -----------
arch/parisc/configs/712_defconfig | 2 +-
arch/parisc/configs/c3000_defconfig | 2 +-
arch/parisc/mm/init.c | 2 +-
arch/s390/Kconfig | 4 +---
arch/x86/Kconfig | 4 +---
include/linux/init.h | 4 ++--
init/main.c | 4 ++--
kernel/configs/android-recommended.config | 2 +-
kernel/power/hibernate.c | 2 +-
kernel/power/power.h | 4 ++--
kernel/power/snapshot.c | 4 ++--
security/Kconfig | 16 ++++++++++++++++
26 files changed, 51 insertions(+), 62 deletions(-)
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl
index f3abca7..a79b638 100644
--- a/Documentation/DocBook/kgdb.tmpl
+++ b/Documentation/DocBook/kgdb.tmpl
@@ -115,12 +115,12 @@
</para>
<para>
If the architecture that you are using supports the kernel option
- CONFIG_DEBUG_RODATA, you should consider turning it off. This
+ CONFIG_HARDENED_PAGE_MAPPINGS, you should consider turning it off. This
option will prevent the use of software breakpoints because it
marks certain regions of the kernel's memory space as read-only.
If kgdb supports it for the architecture you are using, you can
use hardware breakpoints if you desire to run with the
- CONFIG_DEBUG_RODATA option turned on, else you need to turn off
+ CONFIG_HARDENED_PAGE_MAPPINGS option turned on, else you need to turn off
this option.
</para>
<para>
@@ -135,7 +135,7 @@
<para>Here is an example set of .config symbols to enable or
disable for kgdb:
<itemizedlist>
- <listitem><para># CONFIG_DEBUG_RODATA is not set</para></listitem>
+ <listitem><para># CONFIG_HARDENED_PAGE_MAPPINGS is not set</para></listitem>
<listitem><para>CONFIG_FRAME_POINTER=y</para></listitem>
<listitem><para>CONFIG_KGDB=y</para></listitem>
<listitem><para>CONFIG_KGDB_SERIAL_CONSOLE=y</para></listitem>
@@ -166,7 +166,7 @@
</para>
<para>Here is an example set of .config symbols to enable/disable kdb:
<itemizedlist>
- <listitem><para># CONFIG_DEBUG_RODATA is not set</para></listitem>
+ <listitem><para># CONFIG_HARDENED_PAGE_MAPPINGS is not set</para></listitem>
<listitem><para>CONFIG_FRAME_POINTER=y</para></listitem>
<listitem><para>CONFIG_KGDB=y</para></listitem>
<listitem><para>CONFIG_KGDB_SERIAL_CONSOLE=y</para></listitem>
diff --git a/Documentation/security/self-protection.txt b/Documentation/security/self-protection.txt
index 3010576..da8cb36 100644
--- a/Documentation/security/self-protection.txt
+++ b/Documentation/security/self-protection.txt
@@ -51,7 +51,7 @@ kernel, they are implemented in a way where the memory is temporarily
made writable during the update, and then returned to the original
permissions.)
-In support of this are (the poorly named) CONFIG_DEBUG_RODATA and
+In support of this are CONFIG_HARDENED_PAGE_MAPPINGS and
CONFIG_DEBUG_SET_MODULE_RONX, which seek to make sure that code is not
writable, data is not executable, and read-only data is neither writable
nor executable.
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 186c4c2..09aff28 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -7,6 +7,7 @@ config ARM
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_HARDENED_MAPPINGS if MMU && !XIP_KERNEL
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_USE_BUILTIN_BSWAP
diff --git a/arch/arm/configs/aspeed_g4_defconfig b/arch/arm/configs/aspeed_g4_defconfig
index ca39c04..8ccc216 100644
--- a/arch/arm/configs/aspeed_g4_defconfig
+++ b/arch/arm/configs/aspeed_g4_defconfig
@@ -25,7 +25,7 @@ CONFIG_MODULE_UNLOAD=y
# CONFIG_ARCH_MULTI_V7 is not set
CONFIG_ARCH_ASPEED=y
CONFIG_MACH_ASPEED_G4=y
-CONFIG_DEBUG_RODATA=y
+CONFIG_HARDENED_PAGE_MAPPINGS=y
CONFIG_AEABI=y
CONFIG_UACCESS_WITH_MEMCPY=y
CONFIG_SECCOMP=y
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index 4f366b0..90c5ce4 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -26,7 +26,7 @@ CONFIG_ARCH_MULTI_V6=y
# CONFIG_ARCH_MULTI_V7 is not set
CONFIG_ARCH_ASPEED=y
CONFIG_MACH_ASPEED_G5=y
-CONFIG_DEBUG_RODATA=y
+CONFIG_HARDENED_PAGE_MAPPINGS=y
CONFIG_AEABI=y
CONFIG_UACCESS_WITH_MEMCPY=y
CONFIG_SECCOMP=y
diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index bdd283b..c3a7a72 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -490,7 +490,7 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
#endif
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
void set_kernel_text_rw(void);
void set_kernel_text_ro(void);
#else
diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c
index 69bda1a..9da1bf5 100644
--- a/arch/arm/kernel/patch.c
+++ b/arch/arm/kernel/patch.c
@@ -26,7 +26,7 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
page = vmalloc_to_page(addr);
- else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
+ else if (!module && IS_ENABLED(CONFIG_HARDENED_PAGE_MAPPINGS))
page = virt_to_page(addr);
else
return addr;
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index f7f55df..5c6a2e8 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -97,7 +97,7 @@ SECTIONS
HEAD_TEXT
}
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
. = ALIGN(1<<SECTION_SHIFT);
#endif
@@ -158,7 +158,7 @@ SECTIONS
NOTES
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(PAGE_SIZE);
@@ -230,7 +230,7 @@ SECTIONS
PERCPU_SECTION(L1_CACHE_BYTES)
#endif
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(THREAD_SIZE);
@@ -325,7 +325,7 @@ SECTIONS
STABS_DEBUG
}
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
/*
* Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will
* be the first section-aligned location after __start_rodata. Otherwise,
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index f68e8ec..e770dc9 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -1051,21 +1051,9 @@ config ARCH_SUPPORTS_BIG_ENDIAN
This option specifies the architecture can support big endian
operation.
-config DEBUG_RODATA
- bool "Make kernel text and rodata read-only"
- depends on MMU && !XIP_KERNEL
- default y if CPU_V7
- help
- If this is set, kernel text and rodata memory will be made
- read-only, and non-text kernel memory will be made non-executable.
- The tradeoff is that each region is padded to section-size (1MiB)
- boundaries (because their permissions are different and splitting
- the 1M pages into 4K ones causes TLB performance problems), which
- can waste memory.
-
config DEBUG_ALIGN_RODATA
bool "Make rodata strictly non-executable"
- depends on DEBUG_RODATA
+ depends on HARDENED_PAGE_MAPPINGS
default y
help
If this is set, rodata will be made explicitly non-executable. This
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 370581a..303bee4 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -572,7 +572,7 @@ void __init mem_init(void)
}
}
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
struct section_perm {
const char *name;
unsigned long start;
@@ -741,7 +741,7 @@ void set_kernel_text_ro(void)
#else
static inline void fix_kernmem_perms(void) { }
-#endif /* CONFIG_DEBUG_RODATA */
+#endif /* CONFIG_HARDENED_PAGE_MAPPINGS */
void free_tcmmem(void)
{
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1117421..06fed56 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -11,6 +11,7 @@ config ARM64
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
+ select ARCH_HAS_HARDENED_MAPPINGS
select ARCH_HAS_KCOV
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
@@ -123,9 +124,6 @@ config ARCH_PHYS_ADDR_T_64BIT
config MMU
def_bool y
-config DEBUG_RODATA
- def_bool y
-
config ARM64_PAGE_SHIFT
int
default 16 if ARM64_64K_PAGES
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index d1ebd46..a26d27f 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -83,7 +83,7 @@ config DEBUG_SET_MODULE_RONX
If in doubt, say Y.
config DEBUG_ALIGN_RODATA
- depends on DEBUG_RODATA
+ depends on ARCH_HAS_HARDENED_MAPPINGS
bool "Align linker sections up to SECTION_SIZE"
help
If this option is enabled, sections that may potentially be marked as
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 3a71f38..7c73eaa 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -8,6 +8,7 @@ config PARISC
select HAVE_SYSCALL_TRACEPOINTS
select ARCH_WANT_FRAME_POINTERS
select ARCH_HAS_ELF_RANDOMIZE
+ select ARCH_HAS_HARDENED_MAPPINGS
select RTC_CLASS
select RTC_DRV_GENERIC
select INIT_ALL_POSSIBLE
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index 68b7cbd..0d856b9 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -5,15 +5,4 @@ source "lib/Kconfig.debug"
config TRACE_IRQFLAGS_SUPPORT
def_bool y
-config DEBUG_RODATA
- bool "Write protect kernel read-only data structures"
- depends on DEBUG_KERNEL
- default y
- help
- Mark the kernel read-only data as write-protected in the pagetables,
- in order to catch accidental (and incorrect) writes to such const
- data. This option may have a slight performance impact because a
- portion of the kernel code won't be covered by a TLB anymore.
- If in doubt, say "N".
-
endmenu
diff --git a/arch/parisc/configs/712_defconfig b/arch/parisc/configs/712_defconfig
index db8f56b..f1a4732 100644
--- a/arch/parisc/configs/712_defconfig
+++ b/arch/parisc/configs/712_defconfig
@@ -182,7 +182,7 @@ CONFIG_DEBUG_FS=y
CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_MUTEXES=y
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
-CONFIG_DEBUG_RODATA=y
+CONFIG_HARDENED_PAGE_MAPPINGS=y
CONFIG_CRYPTO_NULL=m
CONFIG_CRYPTO_TEST=m
CONFIG_CRYPTO_HMAC=y
diff --git a/arch/parisc/configs/c3000_defconfig b/arch/parisc/configs/c3000_defconfig
index fb92b89..03e88e2 100644
--- a/arch/parisc/configs/c3000_defconfig
+++ b/arch/parisc/configs/c3000_defconfig
@@ -166,7 +166,7 @@ CONFIG_DEBUG_KERNEL=y
CONFIG_DEBUG_MUTEXES=y
# CONFIG_DEBUG_BUGVERBOSE is not set
# CONFIG_RCU_CPU_STALL_DETECTOR is not set
-CONFIG_DEBUG_RODATA=y
+CONFIG_HARDENED_PAGE_MAPPINGS=y
CONFIG_CRYPTO_NULL=m
CONFIG_CRYPTO_TEST=m
CONFIG_CRYPTO_MD5=m
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index e02ada3..f76f8ad 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -545,7 +545,7 @@ void free_initmem(void)
}
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
void mark_rodata_ro(void)
{
/* rodata memory was already mapped with KERNEL_RO access rights by
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index c6722112..8e70ae5 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -62,15 +62,13 @@ config PCI_QUIRKS
config ARCH_SUPPORTS_UPROBES
def_bool y
-config DEBUG_RODATA
- def_bool y
-
config S390
def_bool y
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
+ select ARCH_HAS_HARDENED_MAPPINGS
select ARCH_HAS_KCOV
select ARCH_HAS_SG_CHAIN
select ARCH_HAS_UBSAN_SANITIZE_ALL
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e487493..9d80cd8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -50,6 +50,7 @@ config X86
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FAST_MULTIPLIER
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_HARDENED_MAPPINGS
select ARCH_HAS_KCOV if X86_64
select ARCH_HAS_MMIO_FLUSH
select ARCH_HAS_PMEM_API if X86_64
@@ -309,9 +310,6 @@ config ARCH_SUPPORTS_UPROBES
config FIX_EARLYCON_MEM
def_bool y
-config DEBUG_RODATA
- def_bool y
-
config PGTABLE_LEVELS
int
default 4 if X86_64
diff --git a/include/linux/init.h b/include/linux/init.h
index 885c3e6..9967bc9 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -126,10 +126,10 @@ void prepare_namespace(void);
void __init load_default_modules(void);
int __init init_rootfs(void);
-#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX)
+#if defined(CONFIG_HARDENED_PAGE_MAPPINGS) || defined(CONFIG_DEBUG_SET_MODULE_RONX)
extern bool rodata_enabled;
#endif
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
void mark_rodata_ro(void);
#endif
diff --git a/init/main.c b/init/main.c
index b0c9d6f..4b3bcc4 100644
--- a/init/main.c
+++ b/init/main.c
@@ -925,7 +925,7 @@ static int try_to_run_init_process(const char *init_filename)
static noinline void __init kernel_init_freeable(void);
-#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX)
+#if defined(CONFIG_HARDENED_PAGE_MAPPINGS) || defined(CONFIG_DEBUG_SET_MODULE_RONX)
bool rodata_enabled __ro_after_init = true;
static int __init set_debug_rodata(char *str)
{
@@ -934,7 +934,7 @@ static int __init set_debug_rodata(char *str)
__setup("rodata=", set_debug_rodata);
#endif
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
static void mark_readonly(void)
{
if (rodata_enabled)
diff --git a/kernel/configs/android-recommended.config b/kernel/configs/android-recommended.config
index 297756b..b796bc8 100644
--- a/kernel/configs/android-recommended.config
+++ b/kernel/configs/android-recommended.config
@@ -11,7 +11,7 @@ CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_SIZE=8192
CONFIG_COMPACTION=y
-CONFIG_DEBUG_RODATA=y
+CONFIG_HARDENED_PAGE_MAPPINGS=y
CONFIG_DM_CRYPT=y
CONFIG_DM_UEVENT=y
CONFIG_DM_VERITY=y
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index b26dbc4..f7a3ea3 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1156,7 +1156,7 @@ static int __init hibernate_setup(char *str)
} else if (!strncmp(str, "no", 2)) {
noresume = 1;
nohibernate = 1;
- } else if (IS_ENABLED(CONFIG_DEBUG_RODATA)
+ } else if (IS_ENABLED(CONFIG_HARDENED_PAGE_MAPPINGS)
&& !strncmp(str, "protect_image", 13)) {
enable_restore_image_protection();
}
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 1dfa0da..dc2c7b8 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -61,12 +61,12 @@ extern int hibernation_snapshot(int platform_mode);
extern int hibernation_restore(int platform_mode);
extern int hibernation_platform_enter(void);
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
/* kernel/power/snapshot.c */
extern void enable_restore_image_protection(void);
#else
static inline void enable_restore_image_protection(void) {}
-#endif /* CONFIG_DEBUG_RODATA */
+#endif /* CONFIG_HARDENED_PAGE_MAPPINGS */
#else /* !CONFIG_HIBERNATION */
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 2d8e2b2..a7c793e 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -38,7 +38,7 @@
#include "power.h"
-#ifdef CONFIG_DEBUG_RODATA
+#ifdef CONFIG_HARDENED_PAGE_MAPPINGS
static bool hibernate_restore_protection;
static bool hibernate_restore_protection_active;
@@ -73,7 +73,7 @@ static inline void hibernate_restore_protection_begin(void) {}
static inline void hibernate_restore_protection_end(void) {}
static inline void hibernate_restore_protect_page(void *page_address) {}
static inline void hibernate_restore_unprotect_page(void *page_address) {}
-#endif /* CONFIG_DEBUG_RODATA */
+#endif /* CONFIG_HARDENED_PAGE_MAPPINGS */
static int swsusp_page_is_free(struct page *);
static void swsusp_set_page_forbidden(struct page *);
diff --git a/security/Kconfig b/security/Kconfig
index 118f454..ad6ce82 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -158,6 +158,22 @@ config HARDENED_USERCOPY_PAGESPAN
been removed. This config is intended to be used only while
trying to find such users.
+config ARCH_HAS_HARDENED_MAPPINGS
+ def_bool n
+
+config HARDENED_PAGE_MAPPINGS
+ bool "Mark kernel mappings with stricter permissions (RO/W^X)"
+ default y
+ depends on ARCH_HAS_HARDENED_MAPPINGS
+ help
+ If this is set, kernel text and rodata memory will be made read-only,
+ and non-text memory will be made non-executable. This provides
+ protection against certain security attacks (e.g. executing the heap
+ or modifying text).
+
+ Unless your system has known restrictions or performance issues, it
+ is recommended to say Y here.
+
source security/selinux/Kconfig
source security/smack/Kconfig
source security/tomoyo/Kconfig
--
2.7.4
--
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