From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751841AbeECQFv (ORCPT ); Thu, 3 May 2018 12:05:51 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:42125 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751763AbeECQFs (ORCPT ); Thu, 3 May 2018 12:05:48 -0400 X-Google-Smtp-Source: AB8JxZqrEBW3KXpUWcQFT8EQZhZYa3E1Qyd55vsasoA97DCT+T2A2T23pP8dLgOga9OFKYu/1z+cGA== Reply-To: alex.popov@linux.com Subject: Re: [PATCH 2/2] arm64: Clear the stack To: Laura Abbott , Kees Cook Cc: Mark Rutland , Ard Biesheuvel , Kernel Hardening , linux-arm-kernel , LKML References: <20180502203326.9491-1-labbott@redhat.com> <20180502203326.9491-3-labbott@redhat.com> <4b7e94c1-79c9-0380-25c6-762762ed595f@redhat.com> From: Alexander Popov Openpgp: preference=signencrypt Autocrypt: addr=alex.popov@linux.com; prefer-encrypt=mutual; keydata= xsFNBFX15q4BEADZartsIW3sQ9R+9TOuCFRIW+RDCoBWNHhqDLu+Tzf2mZevVSF0D5AMJW4f UB1QigxOuGIeSngfmgLspdYe2Kl8+P8qyfrnBcS4hLFyLGjaP7UVGtpUl7CUxz2Hct3yhsPz ID/rnCSd0Q+3thrJTq44b2kIKqM1swt/F2Er5Bl0B4o5WKx4J9k6Dz7bAMjKD8pHZJnScoP4 dzKPhrytN/iWM01eRZRc1TcIdVsRZC3hcVE6OtFoamaYmePDwWTRhmDtWYngbRDVGe3Tl8bT 7BYN7gv7Ikt7Nq2T2TOfXEQqr9CtidxBNsqFEaajbFvpLDpUPw692+4lUbQ7FL0B1WYLvWkG cVysClEyX3VBSMzIG5eTF0Dng9RqItUxpbD317ihKqYL95jk6eK6XyI8wVOCEa1V3MhtvzUo WGZVkwm9eMVZ05GbhzmT7KHBEBbCkihS+TpVxOgzvuV+heCEaaxIDWY/k8u4tgbrVVk+tIVG 99v1//kNLqd5KuwY1Y2/h2MhRrfxqGz+l/f/qghKh+1iptm6McN//1nNaIbzXQ2Ej34jeWDa xAN1C1OANOyV7mYuYPNDl5c9QrbcNGg3D6gOeGeGiMn11NjbjHae3ipH8MkX7/k8pH5q4Lhh Ra0vtJspeg77CS4b7+WC5jlK3UAKoUja3kGgkCrnfNkvKjrkEwARAQABzSZBbGV4YW5kZXIg UG9wb3YgPGFsZXgucG9wb3ZAbGludXguY29tPsLBgAQTAQoAKgIbIwIeAQIXgAULCQgHAwUV CgkICwUWAgMBAAUJB8+UXAUCWgsUegIZAQAKCRCODp3rvH6PqqpOEACX+tXHOgMJ6fGxaNJZ HkKRFR/9AGP1bxp5QS528Sd6w17bMMQ87V5NSFUsTMPMcbIoO73DganKQ3nN6tW0ZvDTKpRt pBUCUP8KPqNvoSs3kkskaQgNQ3FXv46YqPZ7DoYj9HevY9NUyGLwCTEWD2ER5zKuNbI2ek82 j4rwdqXn9kqqBf1ExAoEsszeNHzTKRl2d+bXuGDcOdpnOi7avoQfwi/O0oapR+goxz49Oeov YFf1EVaogHjDBREaqiqJ0MSKexfVBt8RD9ev9SGSIMcwfhgUHhMTX2JY/+6BXnUbzVcHD6HR EgqVGn/0RXfJIYmFsjH0Z6cHy34Vn+aqcGa8faztPnmkA/vNfhw8k5fEE7VlBqdEY8YeOiza hHdpaUi4GofNy/GoHIqpz16UulMjGB5SBzgsYKgCO+faNBrCcBrscWTl1aJfSNJvImuS1JhB EQnl/MIegxyBBRsH68x5BCffERo4FjaG0NDCmZLjXPOgMvl3vRywHLdDZThjAea3pwdGUq+W C77i7tnnUqgK7P9i+nEKwNWZfLpfjYgH5JE/jOgMf4tpHvO6fu4AnOffdz3kOxDyi+zFLVcz rTP5b46aVjI7D0dIDTIaCKUT+PfsLnJmP18x7dU/gR/XDcUaSEbWU3D9u61AvxP47g7tN5+a 5pFIJhJ44JLk6I5H/c7BTQRV9eauARAArcUVf6RdT14hkm0zT5TPc/3BJc6PyAghV/iCoPm8 kbzjKBIK80NvGodDeUV0MnQbX40jjFdSI0m96HNt86FtifQ3nwuW/BtS8dk8+lakRVwuTgMb hJWmXqKMFdVRCbjdyLbZWpdPip0WGND6p5i801xgPRmI8P6e5e4jBO4Cx1ToIFyJOzD/jvtb UhH9t5/naKUGa5BD9gSkguooXVOFvPdvKQKca19S7bb9hzjySh63H4qlbhUrG/7JGhX+Lr3g DwuAGrrFIV0FaVyIPGZ8U2fjLKpcBC7/lZJv0jRFpZ9CjHefILxt7NGxPB9hk2iDt2tE6jSl GNeloDYJUVItFmG+/giza2KrXmDEFKl+/mwfjRI/+PHR8PscWiB7S1zhsVus3DxhbM2mAK4x mmH4k0wNfgClh0Srw9zCU2CKJ6YcuRLi/RAAiyoxBb9wnSuQS5KkxoT32LRNwfyMdwlEtQGp WtC/vBI13XJVabx0Oalx7NtvRCcX1FX9rnKVjSFHX5YJ48heAd0dwRVmzOGL/EGywb1b9Q3O IWe9EFF8tmWV/JHs2thMz492qTHA5pm5JUsHQuZGBhBU+GqdOkdkFvujcNu4w7WyuEITBFAh 5qDiGkvY9FU1OH0fWQqVU/5LHNizzIYN2KjU6529b0VTVGb4e/M0HglwtlWpkpfQzHMAEQEA AcLBZQQYAQIADwUCVfXmrgIbDAUJCWYBgAAKCRCODp3rvH6PqrZtEACKsd/UUtpKmy4mrZwl 053nWp7+WCE+S9ke7CFytmXoMWf1CIrcQTk5cmdBmB4E0l3sr/DgKlJ8UrHTdRLcZZnbVqur +fnmVeQy9lqGkaIZvx/iXVYUqhT3+DNj9Zkjrynbe5pLsrGyxYWfsPRVL6J4mQatChadjuLw 7/WC6PBmWkRA2SxUVpxFEZlirpbboYWLSXk9I3JmS5/iJ+P5kHYiB0YqYkd1twFXXxixv1GB Zi/idvWTK7x6/bUh0AAGTKc5zFhyR4DJRGROGlFTAYM3WDoa9XbrHXsggJDLNoPZJTj9DMww u28SzHLvR3t2pY1dT61jzKNDLoE3pjvzgLKF/Olif0t7+m0IPKY+8umZvUEhJ9CAUcoFPCfG tEbL6t1xrcsT7dsUhZpkIX0Qc77op8GHlfNd/N6wZUt19Vn9G8B6xrH+dinc0ylUc4+4yxt6 6BsiEzma6Ah5jexChYIwaB5Oi21yjc6bBb4l6z01WWJQ052OGaOBzi+tS5iGmc5DWH4/pFqX OIkgJVVgjPv2y41qV66QJJEi2wT4WUKLY1zA9s6KXbt8dVSzJsNFvsrAoFdtzc8v6uqCo0/W f0Id8MBKoqN5FniTHWNxYX6b2dFwq8i5Rh6Oxc6q75Kg8279+co3/tLCkU6pGga28K7tUP2z h9AUWENlnWJX/YhP8MLBZQQYAQoADwIbDAUCWgsSOgUJB9eShwAKCRCODp3rvH6PqtoND/41 ozCKAS4WWBBCU6AYLm2SoJ0EGhg1kIf9VMiqy5PKlSrAnW5yl4WJQcv5wER/7EzvZ49Gj8aG uRWfz3lyQU8dH2KG6KLilDFCZF0mViEo2C7O4QUx5xmbpMUq41fWjY947Xvd3QDisc1T1/7G uNBAALEZdqzwnKsT9G27e9Cd3AW3KsLAD4MhsALFARg6OuuwDCbLl6k5fu++26PEqORGtpJQ rRBWan9ZWb/Y57P126IVIylWiH6vt6iEPlaEHBU8H9+Z0WF6wJ5rNz9gR6GhZhmo1qsyNedD 1HzOsXQhvCinsErpZs99VdZSF3d54dac8ypH4hvbjSmXZjY3Sblhyc6RLYlru5UXJFh7Hy+E TMuCg3hIVbdyFSDkvxVlvhHgUSf8+Uk3Ya4MO4a5l9ElUqxpSqYH7CvuwkG+mH5mN8tK3CCd +aKPCxUFfil62DfTa7YgLovr7sHQB+VMQkNDPXleC+amNqJb423L8M2sfCi9gw/lA1ha6q80 ydgbcFEkNjqz4OtbrSwEHMy/ADsUWksYuzVbw7/pQTc6OAskESBr5igP7B/rIACUgiIjdOVB ktD1IQcezrDcuzVCIpuq8zC6LwLm7V1Tr6zfU9FWwnqzoQeQZH4QlP7MBuOeswCpxIl07mz9 jXz/74kjFsyRgZA+d6a1pGtOwITEBxtxxg== Message-ID: Date: Thu, 3 May 2018 19:05:41 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <4b7e94c1-79c9-0380-25c6-762762ed595f@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Laura and Kees, On 03.05.2018 02:07, Laura Abbott wrote: > On 05/02/2018 02:31 PM, Kees Cook wrote: >> On Wed, May 2, 2018 at 1:33 PM, Laura Abbott wrote: >>> >>> Implementation of stackleak based heavily on the x86 version >> >> Awesome! Notes below for both you and Alexander, since I think we can >> create a common code base instead of having near-duplicates in the >> arch/ trees... Yes, sure. I will extract the common part and send v12 for x86. Then Laura will be able to add arm64 support in a separate patch series. Is it fine? >>> Signed-off-by: Laura Abbott >>> --- >>> Now written in C instead of a bunch of assembly. >>> --- >>> arch/arm64/Kconfig | 1 + >>> arch/arm64/include/asm/processor.h | 6 ++++ >>> arch/arm64/kernel/Makefile | 3 ++ >>> arch/arm64/kernel/entry.S | 6 ++++ >>> arch/arm64/kernel/erase.c | 55 +++++++++++++++++++++++++++++++++++ >>> arch/arm64/kernel/process.c | 16 ++++++++++ >>> drivers/firmware/efi/libstub/Makefile | 3 +- >>> scripts/Makefile.gcc-plugins | 5 +++- >>> 8 files changed, 93 insertions(+), 2 deletions(-) >>> create mode 100644 arch/arm64/kernel/erase.c >>> >>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >>> index eb2cf4938f6d..b0221db95dc9 100644 >>> --- a/arch/arm64/Kconfig >>> +++ b/arch/arm64/Kconfig >>> @@ -92,6 +92,7 @@ config ARM64 >>> select HAVE_ARCH_MMAP_RND_BITS >>> select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT >>> select HAVE_ARCH_SECCOMP_FILTER >>> + select HAVE_ARCH_STACKLEAK >>> select HAVE_ARCH_THREAD_STRUCT_WHITELIST >>> select HAVE_ARCH_TRACEHOOK >>> select HAVE_ARCH_TRANSPARENT_HUGEPAGE >>> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h >>> index 767598932549..d31ab80ff647 100644 >>> --- a/arch/arm64/include/asm/processor.h >>> +++ b/arch/arm64/include/asm/processor.h >>> @@ -124,6 +124,12 @@ struct thread_struct { >>> unsigned long fault_address; /* fault info */ >>> unsigned long fault_code; /* ESR_EL1 value */ >>> struct debug_info debug; /* debugging */ >>> +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK >>> + unsigned long lowest_stack; >>> +#ifdef CONFIG_STACKLEAK_METRICS >>> + unsigned long prev_lowest_stack; >>> +#endif >>> +#endif >> >> I wonder if x86 and arm64 could include a common struct here that was >> empty when the plugin is disabled... it would keep the ifdefs in one >> place. Maybe include/linux/stackleak.h could be: >> >> ---start--- >> /* Poison value points to the unused hole in the virtual memory map */ >> #define STACKLEAK_POISON -0xBEEF >> #define STACKLEAK_POISON_CHECK_DEPTH 128 >> >> struct stackleak { >> #ifdef CONFIG_GCC_PLUGIN_STACKLEAK >> unsigned long lowest; >> #ifdef CONFIG_STACKLEAK_METRICS >> unsigned long prev_lowest; >> #endif >> #endif >> }; >> > > Is this well defined across all compilers if the plugin is off? > This seems to compile with gcc at least but 0 sized structs > make me a little uneasy. Empty struct is not defined by C standard but is permitted by gcc https://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty-Structures Fast example: #include int main(void) { struct a {}; printf("size %zu\n", sizeof(struct a)); return 0; } # gcc -pedantic t.c -o t t.c: In function ‘main’: t.c:5:9: warning: struct has no members [-Wpedantic] struct a {}; ^ # clang -Weverything t.c -o tc t.c:5:2: warning: empty struct has size 0 in C, size 1 in C++ [-Wc++-compat] struct a {}; ^ t.c:5:2: warning: empty struct is a GNU extension [-Wgnu-empty-struct] 2 warnings generated. But both programs print "size 0". There are a lot of empty structs around the kernel, so I'll create another one. >> asmlinkage void erase_kstack(void); >> ---eof--- >> >> and arch/*/include/asm/processor.h could do: >> >> @@ -124,6 +124,12 @@ struct thread_struct { >> unsigned long fault_address; /* fault info */ >> unsigned long fault_code; /* ESR_EL1 value */ >> struct debug_info debug; /* debugging */ >> + struct stackleak stackleak; >> >> and arch/x86/entry/erase.c could move to maybe kernel/stackleak.c? >> (Oh, I notice this needs an SPDX line too.) Thanks, I'll add it. >>> static inline void arch_thread_struct_whitelist(unsigned long *offset, >>> diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile >>> index bf825f38d206..0ceea613c65b 100644 >>> --- a/arch/arm64/kernel/Makefile >>> +++ b/arch/arm64/kernel/Makefile >>> @@ -55,6 +55,9 @@ arm64-reloc-test-y := reloc_test_core.o reloc_test_syms.o >>> arm64-obj-$(CONFIG_CRASH_DUMP) += crash_dump.o >>> arm64-obj-$(CONFIG_ARM_SDE_INTERFACE) += sdei.o >>> >>> +arm64-obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += erase.o >>> +KASAN_SANITIZE_erase.o := n >>> + >>> obj-y += $(arm64-obj-y) vdso/ probes/ >>> obj-m += $(arm64-obj-m) >>> head-y := head.o >>> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S >>> index ec2ee720e33e..3144f1ebdc18 100644 >>> --- a/arch/arm64/kernel/entry.S >>> +++ b/arch/arm64/kernel/entry.S >>> @@ -401,6 +401,11 @@ tsk .req x28 // current thread_info >>> >>> .text >>> >>> + .macro ERASE_KSTACK >>> +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK >>> + bl erase_kstack >>> +#endif >>> + .endm >>> /* >>> * Exception vectors. >>> */ >>> @@ -906,6 +911,7 @@ ret_to_user: >>> cbnz x2, work_pending >>> finish_ret_to_user: >>> enable_step_tsk x1, x2 >>> + ERASE_KSTACK >>> kernel_exit 0 >>> ENDPROC(ret_to_user) >> >> Nice. All of the return paths end up here (I went looking for >> ret_from_fork's path). :) >> >>> >>> diff --git a/arch/arm64/kernel/erase.c b/arch/arm64/kernel/erase.c >>> new file mode 100644 >>> index 000000000000..b8b5648d893b >>> --- /dev/null >>> +++ b/arch/arm64/kernel/erase.c >>> @@ -0,0 +1,55 @@ >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +asmlinkage void erase_kstack(void) >>> +{ >>> + unsigned long p = current->thread.lowest_stack; >>> + unsigned long boundary = p & ~(THREAD_SIZE - 1); >>> + unsigned long poison = 0; >>> + const unsigned long check_depth = STACKLEAK_POISON_CHECK_DEPTH / >>> + sizeof(unsigned long); >>> + >>> + /* >>> + * Let's search for the poison value in the stack. >>> + * Start from the lowest_stack and go to the bottom. >>> + */ >>> + while (p > boundary && poison <= check_depth) { >>> + if (*(unsigned long *)p == STACKLEAK_POISON) >>> + poison++; >>> + else >>> + poison = 0; >>> + >>> + p -= sizeof(unsigned long); >>> + } >>> + >>> + /* >>> + * One long int at the bottom of the thread stack is reserved and >>> + * should not be poisoned (see CONFIG_SCHED_STACK_END_CHECK). >>> + */ >>> + if (p == boundary) >>> + p += sizeof(unsigned long); >>> + >>> +#ifdef CONFIG_STACKLEAK_METRICS >>> + current->thread.prev_lowest_stack = p; >>> +#endif >>> + >>> + /* >>> + * So let's write the poison value to the kernel stack. >>> + * Start from the address in p and move up till the new boundary. >>> + */ >>> + boundary = current_stack_pointer; >> >> This is the only difference between x86 and arm64 in this code. What >> do you think about implementing on_thread_stack() to match x86: >> >> if (on_thread_stack()) >> boundary = current_stack_pointer; >> else >> boundary = current_top_of_stack(); >> >> then we could make this common code too instead of having two copies in arch/? >> > > The issue isn't on_thread_stack, it's current_top_of_stack which isn't > defined on arm64. I agree it would be good if the code would be common > but I'm not sure how much we want to start trying to force APIs. > >>> + BUG_ON(boundary - p >= THREAD_SIZE); >>> + >>> + while (p < boundary) { >>> + *(unsigned long *)p = STACKLEAK_POISON; >>> + p += sizeof(unsigned long); >>> + } >>> + >>> + /* Reset the lowest_stack value for the next syscall */ >>> + current->thread.lowest_stack = current_stack_pointer; >>> +} >>> + >>> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c >>> index f08a2ed9db0d..156fa0a0da19 100644 >>> --- a/arch/arm64/kernel/process.c >>> +++ b/arch/arm64/kernel/process.c >>> @@ -364,6 +364,9 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, >>> p->thread.cpu_context.pc = (unsigned long)ret_from_fork; >>> p->thread.cpu_context.sp = (unsigned long)childregs; >>> >>> +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK >>> + p->thread.lowest_stack = (unsigned long)task_stack_page(p); >>> +#endif I think it should be (unsigned long)task_stack_page(p) + sizeof(unsigned long). >>> ptrace_hw_copy_thread(p); >>> >>> return 0; >>> @@ -493,3 +496,16 @@ void arch_setup_new_exec(void) >>> { >>> current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; >>> } >>> + >>> +#ifdef CONFIG_GCC_PLUGIN_STACKLEAK >>> +void __used check_alloca(unsigned long size) >>> +{ >>> + unsigned long sp, stack_left; >>> + >>> + sp = current_stack_pointer; >>> + >>> + stack_left = sp & (THREAD_SIZE - 1); >>> + BUG_ON(stack_left < 256 || size >= stack_left - 256); >>> +} >>> +EXPORT_SYMBOL(check_alloca); >> >> This is pretty different from x86. Is this just an artifact of ORC, or >> something else? >> > > This was based on the earlier version of x86. I'll confess to > not seeing how the current x86 version ended up with get_stack_info > but I suspect it's either related to ORC unwinding or it's best > practice. I've changed that in v4. Quote from the changelog: - Fixed the surplus and erroneous code for calculating stack_left in check_alloca() on x86_64. That code repeats the work which is already done in get_stack_info() and it misses the fact that different exception stacks on x86_64 have different size. http://www.openwall.com/lists/kernel-hardening/2017/10/04/68 We can see that in arch/x86/kernel/dumpstack_64.c. Is it fine if check_alloca() would be arch-specific? >>> +#endif >>> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile >>> index a34e9290a699..25dd2a14560d 100644 >>> --- a/drivers/firmware/efi/libstub/Makefile >>> +++ b/drivers/firmware/efi/libstub/Makefile >>> @@ -20,7 +20,8 @@ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt >>> KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ >>> -D__NO_FORTIFY \ >>> $(call cc-option,-ffreestanding) \ >>> - $(call cc-option,-fno-stack-protector) >>> + $(call cc-option,-fno-stack-protector) \ >>> + $(DISABLE_STACKLEAK_PLUGIN) >>> >>> GCOV_PROFILE := n >>> KASAN_SANITIZE := n >>> diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins >>> index 8d6070fc538f..6cc0e35d3324 100644 >>> --- a/scripts/Makefile.gcc-plugins >>> +++ b/scripts/Makefile.gcc-plugins >>> @@ -37,11 +37,14 @@ ifdef CONFIG_GCC_PLUGINS >>> >>> gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so >>> gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) += -DSTACKLEAK_PLUGIN -fplugin-arg-stackleak_plugin-track-min-size=$(CONFIG_STACKLEAK_TRACK_MIN_SIZE) >>> + ifdef CONFIG_GCC_PLUGIN_STACKLEAK >>> + DISABLE_STACKLEAK_PLUGIN += -fplugin-arg-stackleak_plugin-disable >>> + endif >>> >>> GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y)) >>> >>> export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR >>> - export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN >>> + export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN DISABLE_STACKLEAK_PLUGIN >>> >>> ifneq ($(PLUGINCC),) >>> # SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication. >>> -- >>> 2.14.3 >>> Best regards, Alexander