From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tremer To: development@lists.ipfire.org Subject: Re: [PATCH] linux: Randomize layout of sensitive kernel structures Date: Mon, 01 Aug 2022 21:18:47 +0100 Message-ID: <77D7E523-2F62-4FDD-87C6-73420073B946@ipfire.org> In-Reply-To: <6f293556-db9a-086e-1b2d-5e7d10eee48b@ipfire.org> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============6453367944729711019==" List-Id: --===============6453367944729711019== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Do we finally know how much the impact is at compile time? -Michael > On 1 Aug 2022, at 18:18, Peter M=C3=BCller wro= te: >=20 > To quote from the kernel documentation: >=20 >> 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. >>=20 >> 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). >>=20 >> 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. >>=20 >> Note that the implementation requires gcc 4.7 or newer. >=20 > 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(-) >=20 > diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kern= el.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 >=20 > CONFIG_RT_MUTEXES=3Dy > diff --git a/config/rootfiles/common/aarch64/linux b/config/rootfiles/commo= n/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_PERFOR= MANCE > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_A= LL > #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_PERFOR= MANCE > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_A= LL > #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_PERFOR= MANCE > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK > #lib/modules/KVER-ipfire/build/include/config/GCC_PLUGIN_STRUCTLEAK_BYREF_A= LL > #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 > --=20 > 2.35.3 --===============6453367944729711019==--