From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter =?utf-8?q?M=C3=BCller?= To: development@lists.ipfire.org Subject: Re: [PATCH] linux: Randomize layout of sensitive kernel structures Date: Tue, 02 Aug 2022 15:13:35 +0000 Message-ID: In-Reply-To: <77D7E523-2F62-4FDD-87C6-73420073B946@ipfire.org> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8551246240159555026==" List-Id: --===============8551246240159555026== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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 h= ave experienced before. Thanks, and best regards, Peter M=C3=BCller > Do we finally know how much the impact is at compile time? >=20 > -Michael >=20 >> On 1 Aug 2022, at 18:18, Peter M=C3=BCller wr= ote: >> >> 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 M=C3=BCller >> --- >> 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/ker= nel.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=3Dy >> CONFIG_GCC_PLUGINS=3Dy >> # CONFIG_GCC_PLUGIN_CYC_COMPLEXITY is not set >> CONFIG_GCC_PLUGIN_LATENT_ENTROPY=3Dy >> -# CONFIG_GCC_PLUGIN_RANDSTRUCT is not set >> +CONFIG_GCC_PLUGIN_RANDSTRUCT=3Dy >> +CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE=3Dy >> # end of General architecture-dependent options >> >> CONFIG_RT_MUTEXES=3Dy >> diff --git a/config/rootfiles/common/aarch64/linux b/config/rootfiles/comm= on/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_PERFO= RMANCE >> #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_plugi= n.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/commo= n/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_PERFO= RMANCE >> #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_plugi= n.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/commo= n/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_PERFO= RMANCE >> #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_plugi= n.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 >> --=20 >> 2.35.3 >=20 --===============8551246240159555026==--