From: "Peter Müller" <peter.mueller@ipfire.org>
To: development@lists.ipfire.org
Subject: Re: [PATCH] linux: Randomize layout of sensitive kernel structures
Date: Tue, 02 Aug 2022 15:13:35 +0000 [thread overview]
Message-ID: <e122bb16-b627-29b9-482b-e29059cefca5@ipfire.org> (raw)
In-Reply-To: <77D7E523-2F62-4FDD-87C6-73420073B946@ipfire.org>
[-- Attachment #1: Type: text/plain, Size: 8589 bytes --]
Hello Michael,
on my local workstation (featuring an Intel i5-6500), the kernel takes ~ 48
minutes to compile with randstruct enabled, which is around the same time I have
experienced before.
Thanks, and best regards,
Peter Müller
> Do we finally know how much the impact is at compile time?
>
> -Michael
>
>> On 1 Aug 2022, at 18:18, Peter Müller <peter.mueller(a)ipfire.org> wrote:
>>
>> To quote from the kernel documentation:
>>
>>> If you say Y here, the layouts of structures that are entirely
>>> function pointers (and have not been manually annotated with
>>> __no_randomize_layout), or structures that have been explicitly
>>> marked with __randomize_layout, will be randomized at compile-time.
>>> This can introduce the requirement of an additional information
>>> exposure vulnerability for exploits targeting these structure
>>> types.
>>>
>>> Enabling this feature will introduce some performance impact,
>>> slightly increase memory usage, and prevent the use of forensic
>>> tools like Volatility against the system (unless the kernel
>>> source tree isn't cleaned after kernel installation).
>>>
>>> The seed used for compilation is located at
>>> scripts/gcc-plgins/randomize_layout_seed.h. It remains after
>>> a make clean to allow for external modules to be compiled with
>>> the existing seed and will be removed by a make mrproper or
>>> make distclean.
>>>
>>> Note that the implementation requires gcc 4.7 or newer.
>>
>> Signed-off-by: Peter Müller <peter.mueller(a)ipfire.org>
>> ---
>> config/kernel/kernel.config.x86_64-ipfire | 3 ++-
>> config/rootfiles/common/aarch64/linux | 5 +++++
>> config/rootfiles/common/armv6l/linux | 5 +++++
>> config/rootfiles/common/x86_64/linux | 5 +++++
>> 4 files changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel.config.x86_64-ipfire
>> index 40975b5fc..c8e7ada01 100644
>> --- a/config/kernel/kernel.config.x86_64-ipfire
>> +++ b/config/kernel/kernel.config.x86_64-ipfire
>> @@ -793,7 +793,8 @@ CONFIG_HAVE_GCC_PLUGINS=y
>> CONFIG_GCC_PLUGINS=y
>> # CONFIG_GCC_PLUGIN_CYC_COMPLEXITY is not set
>> CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
>> -# CONFIG_GCC_PLUGIN_RANDSTRUCT is not set
>> +CONFIG_GCC_PLUGIN_RANDSTRUCT=y
>> +CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE=y
>> # end of General architecture-dependent options
>>
>> CONFIG_RT_MUTEXES=y
>> diff --git a/config/rootfiles/common/aarch64/linux b/config/rootfiles/common/aarch64/linux
>> index dbd6e8f2f..b3a642e56 100644
>> --- a/config/rootfiles/common/aarch64/linux
>> +++ b/config/rootfiles/common/aarch64/linux
>> @@ -7646,6 +7646,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/config/GARP
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGINS
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_LATENT_ENTROPY
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
>> #lib/modules/KVER-ipfire/build/include/config/GCC_VERSION
>> @@ -11684,6 +11686,7 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/generated/autoconf.h
>> #lib/modules/KVER-ipfire/build/include/generated/bounds.h
>> #lib/modules/KVER-ipfire/build/include/generated/compile.h
>> +#lib/modules/KVER-ipfire/build/include/generated/randomize_layout_hash.h
>> #lib/modules/KVER-ipfire/build/include/generated/timeconst.h
>> #lib/modules/KVER-ipfire/build/include/generated/uapi
>> #lib/modules/KVER-ipfire/build/include/generated/uapi/linux
>> @@ -17129,6 +17132,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.so
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.c
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.so
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_seed.h
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/sancov_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/stackleak_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/structleak_plugin.c
>> diff --git a/config/rootfiles/common/armv6l/linux b/config/rootfiles/common/armv6l/linux
>> index 79e4facfe..c3411fe8d 100644
>> --- a/config/rootfiles/common/armv6l/linux
>> +++ b/config/rootfiles/common/armv6l/linux
>> @@ -8071,6 +8071,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGINS
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_ARM_SSP_PER_TASK
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_LATENT_ENTROPY
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
>> #lib/modules/KVER-ipfire/build/include/config/GCC_VERSION
>> @@ -12134,6 +12136,7 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/generated/autoconf.h
>> #lib/modules/KVER-ipfire/build/include/generated/bounds.h
>> #lib/modules/KVER-ipfire/build/include/generated/compile.h
>> +#lib/modules/KVER-ipfire/build/include/generated/randomize_layout_hash.h
>> #lib/modules/KVER-ipfire/build/include/generated/timeconst.h
>> #lib/modules/KVER-ipfire/build/include/generated/uapi
>> #lib/modules/KVER-ipfire/build/include/generated/uapi/linux
>> @@ -17579,6 +17582,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.so
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.c
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.so
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_seed.h
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/sancov_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/stackleak_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/structleak_plugin.c
>> diff --git a/config/rootfiles/common/x86_64/linux b/config/rootfiles/common/x86_64/linux
>> index b25f85a3a..1b78fe8c5 100644
>> --- a/config/rootfiles/common/x86_64/linux
>> +++ b/config/rootfiles/common/x86_64/linux
>> @@ -7624,6 +7624,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/config/GARP
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGINS
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_LATENT_ENTROPY
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT
>> +#lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK
>> #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
>> #lib/modules/KVER-ipfire/build/include/config/GCC_VERSION
>> @@ -12128,6 +12130,7 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/include/generated/autoconf.h
>> #lib/modules/KVER-ipfire/build/include/generated/bounds.h
>> #lib/modules/KVER-ipfire/build/include/generated/compile.h
>> +#lib/modules/KVER-ipfire/build/include/generated/randomize_layout_hash.h
>> #lib/modules/KVER-ipfire/build/include/generated/timeconst.h
>> #lib/modules/KVER-ipfire/build/include/generated/uapi
>> #lib/modules/KVER-ipfire/build/include/generated/uapi/linux
>> @@ -17567,6 +17570,8 @@ etc/modprobe.d/ipv6.conf
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/latent_entropy_plugin.so
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.c
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_plugin.so
>> +#lib/modules/KVER-ipfire/build/scripts/gcc-plugins/randomize_layout_seed.h
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/sancov_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/stackleak_plugin.c
>> #lib/modules/KVER-ipfire/build/scripts/gcc-plugins/structleak_plugin.c
>> --
>> 2.35.3
>
next prev parent reply other threads:[~2022-08-02 15:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-01 17:18 Peter Müller
2022-08-01 20:18 ` Michael Tremer
2022-08-02 15:13 ` Peter Müller [this message]
2022-08-03 8:30 ` Michael Tremer
2022-08-03 9:59 ` Peter Müller
2022-08-03 10:28 ` Michael Tremer
2022-08-03 10:51 ` Michael Tremer
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