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Message-Id: <1484789346-21012-2-git-send-email-labbott@redhat.com> Date: Wed, 18 Jan 2017 17:29:05 -0800 From: Laura Abbott <labbott@...hat.com> To: Kees Cook <keescook@...omium.org> Cc: Laura Abbott <labbott@...hat.com>, Jason Wessel <jason.wessel@...driver.com>, Jonathan Corbet <corbet@....net>, Russell King <linux@...linux.org.uk>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will.deacon@....com>, "James E.J. Bottomley" <jejb@...isc-linux.org>, Helge Deller <deller@....de>, Martin Schwidefsky <schwidefsky@...ibm.com>, Heiko Carstens <heiko.carstens@...ibm.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org, Rob Herring <robh@...nel.org>, "Rafael J. Wysocki" <rjw@...ysocki.net>, Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>, Mark Rutland <mark.rutland@....com>, Jessica Yu <jeyu@...hat.com>, linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-parisc@...r.kernel.org, linux-s390@...r.kernel.org, linux-pm@...r.kernel.org, kernel-hardening@...ts.openwall.com Subject: [PATCH 1/2] security: Change name of CONFIG_DEBUG_RODATA 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@...hat.com> --- 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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