| Message ID | 20240110164847.3304707-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | x86-64/cet: Make CET feature check specific to Linux/x86 | expand |
On Wed, Jan 10, 2024 at 8:49 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > CET feature bits in TCB, which are Linux specific, are used to check if > CET features are active. Move CET feature check to Linux/x86 directory. > --- > .../sysv/linux/x86/bits/platform/features.h | 48 +++++++++++++++++++ > sysdeps/unix/sysv/linux/x86_64/dl-cet.h | 8 ++++ > .../linux/x86_64/get-cpuid-feature-leaf.c | 24 ++++++++++ > sysdeps/x86/Makefile | 6 ++- > sysdeps/x86/bits/platform/features.h | 27 +++++++++++ > sysdeps/x86/bits/platform/x86.h | 8 ---- > sysdeps/x86/get-cpuid-feature-leaf.c | 8 ---- > sysdeps/x86/sys/platform/x86.h | 19 ++------ > sysdeps/x86_64/dl-machine.h | 9 ++-- > 9 files changed, 120 insertions(+), 37 deletions(-) > create mode 100644 sysdeps/unix/sysv/linux/x86/bits/platform/features.h > create mode 100644 sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c > create mode 100644 sysdeps/x86/bits/platform/features.h > > diff --git a/sysdeps/unix/sysv/linux/x86/bits/platform/features.h b/sysdeps/unix/sysv/linux/x86/bits/platform/features.h > new file mode 100644 > index 0000000000..7704febe92 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/x86/bits/platform/features.h > @@ -0,0 +1,48 @@ > +/* Inline functions for x86 CPU features. > + This file is part of the GNU C Library. > + Copyright (C) 2024 Free Software Foundation, Inc. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <https://www.gnu.org/licenses/>. */ > + > +#ifndef _SYS_PLATFORM_X86_H > +# error "Never include <bits/platform/features.h> directly; use <sys/platform/x86.h> instead." > +#endif > + > +/* Bits in the feature_1 field in TCB. */ > + > +enum > +{ > + x86_feature_1_ibt = 1U << 0, > + x86_feature_1_shstk = 1U << 1 > +}; > + > +static __inline__ _Bool > +x86_cpu_cet_active (unsigned int __index) > +{ > +#ifdef __x86_64__ > + unsigned int __feature_1; > +# ifdef __LP64__ > + __asm__ ("mov %%fs:72, %0" : "=r" (__feature_1)); > +# else > + __asm__ ("mov %%fs:40, %0" : "=r" (__feature_1)); > +# endif > + if (__index == x86_cpu_IBT) > + return __feature_1 & x86_feature_1_ibt; > + else > + return __feature_1 & x86_feature_1_shstk; > +#else > + return false; > +#endif > +} > diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h > index a00c7ee662..1fe3133406 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h > +++ b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h > @@ -54,6 +54,14 @@ dl_cet_get_cet_status (void) > return status; > } > > +static __always_inline bool > +dl_cet_ibt_enabled (void) > +{ > + unsigned int feature_1 = THREAD_GETMEM (THREAD_SELF, > + header.feature_1); > + return (feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; > +} > + > /* Enable shadow stack with a macro to avoid shadow stack underflow. */ > #define ENABLE_X86_CET(cet_feature) \ > if ((cet_feature & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) \ > diff --git a/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c b/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c > new file mode 100644 > index 0000000000..39b342463c > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c > @@ -0,0 +1,24 @@ > +/* Get CPUID feature leaf. Linux/x86-64 version. > + Copyright (C) 2024 Free Software Foundation, Inc. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <https://www.gnu.org/licenses/>. */ > + > +#include <sysdeps/x86/get-cpuid-feature-leaf.c> > + > +#ifdef __LP64__ > +_Static_assert (FEATURE_1_OFFSET == 72, "FEATURE_1_OFFSET != 72"); > +#else > +_Static_assert (FEATURE_1_OFFSET == 40, "FEATURE_1_OFFSET != 40"); > +#endif > diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile > index bf913594c1..4d50b327b5 100644 > --- a/sysdeps/x86/Makefile > +++ b/sysdeps/x86/Makefile > @@ -5,7 +5,11 @@ endif > ifeq ($(subdir),elf) > sysdep_routines += get-cpuid-feature-leaf > sysdep-dl-routines += dl-get-cpu-features > -sysdep_headers += sys/platform/x86.h bits/platform/x86.h > +sysdep_headers += \ > + bits/platform/features.h \ > + bits/platform/x86.h \ > + sys/platform/x86.h \ > +# sysdep_headers > > CFLAGS-dl-get-cpu-features.os += $(rtld-early-cflags) > CFLAGS-get-cpuid-feature-leaf.o += $(no-stack-protector) > diff --git a/sysdeps/x86/bits/platform/features.h b/sysdeps/x86/bits/platform/features.h > new file mode 100644 > index 0000000000..f02489266e > --- /dev/null > +++ b/sysdeps/x86/bits/platform/features.h > @@ -0,0 +1,27 @@ > +/* Inline functions for x86 CPU features. > + This file is part of the GNU C Library. > + Copyright (C) 2024 Free Software Foundation, Inc. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <https://www.gnu.org/licenses/>. */ > + > +#ifndef _SYS_PLATFORM_X86_H > +# error "Never include <bits/platform/features.h> directly; use <sys/platform/x86.h> instead." > +#endif > + > +static __inline__ _Bool > +x86_cpu_cet_active (unsigned int __index) > +{ > + return false; > +} > diff --git a/sysdeps/x86/bits/platform/x86.h b/sysdeps/x86/bits/platform/x86.h > index c31d086194..8b157d99b3 100644 > --- a/sysdeps/x86/bits/platform/x86.h > +++ b/sysdeps/x86/bits/platform/x86.h > @@ -337,11 +337,3 @@ enum > x86_cpu_AVX10_YMM = x86_cpu_index_24_ecx_0_ebx + 17, > x86_cpu_AVX10_ZMM = x86_cpu_index_24_ecx_0_ebx + 18, > }; > - > -/* Bits in the feature_1 field in TCB. */ > - > -enum > -{ > - x86_feature_1_ibt = 1U << 0, > - x86_feature_1_shstk = 1U << 1 > -}; > diff --git a/sysdeps/x86/get-cpuid-feature-leaf.c b/sysdeps/x86/get-cpuid-feature-leaf.c > index e6a41cc79c..6f67346081 100644 > --- a/sysdeps/x86/get-cpuid-feature-leaf.c > +++ b/sysdeps/x86/get-cpuid-feature-leaf.c > @@ -19,14 +19,6 @@ > #include <tcb-offsets.h> > #include <ldsodefs.h> > > -#ifdef __x86_64__ > -# ifdef __LP64__ > -_Static_assert (FEATURE_1_OFFSET == 72, "FEATURE_1_OFFSET != 72"); > -# else > -_Static_assert (FEATURE_1_OFFSET == 40, "FEATURE_1_OFFSET != 40"); > -# endif > -#endif > - > const struct cpuid_feature * > __x86_get_cpuid_feature_leaf (unsigned int leaf) > { > diff --git a/sysdeps/x86/sys/platform/x86.h b/sysdeps/x86/sys/platform/x86.h > index 4d77c0991d..b8066ccc9f 100644 > --- a/sysdeps/x86/sys/platform/x86.h > +++ b/sysdeps/x86/sys/platform/x86.h > @@ -22,6 +22,7 @@ > #include <features.h> > #include <stdbool.h> > #include <bits/platform/x86.h> > +#include <bits/platform/features.h> > > __BEGIN_DECLS > > @@ -46,22 +47,8 @@ static __inline__ _Bool > x86_cpu_active (unsigned int __index) > { > if (__index == x86_cpu_IBT || __index == x86_cpu_SHSTK) > - { > -#ifdef __x86_64__ > - unsigned int __feature_1; > -# ifdef __LP64__ > - __asm__ ("mov %%fs:72, %0" : "=r" (__feature_1)); > -# else > - __asm__ ("mov %%fs:40, %0" : "=r" (__feature_1)); > -# endif > - if (__index == x86_cpu_IBT) > - return __feature_1 & x86_feature_1_ibt; > - else > - return __feature_1 & x86_feature_1_shstk; > -#else > - return false; > -#endif > - } > + return x86_cpu_cet_active (__index); > + > const struct cpuid_feature *__ptr = __x86_get_cpuid_feature_leaf > (__index / (8 * sizeof (unsigned int) * 4)); > unsigned int __reg > diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h > index 2d2ce503a5..6d605d0d32 100644 > --- a/sysdeps/x86_64/dl-machine.h > +++ b/sysdeps/x86_64/dl-machine.h > @@ -587,10 +587,11 @@ x86_64_rewrite_plt (struct link_map *map, ElfW(Addr) plt_rewrite) > const ElfW(Rela) *reloc = (const void *) start; > const ElfW(Rela) *reloc_end = (const void *) (start + size); > > - unsigned int feature_1 = THREAD_GETMEM (THREAD_SELF, > - header.feature_1); > - bool ibt_enabled_p > - = (feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; > +# ifdef __CET__ > + bool ibt_enabled_p = dl_cet_ibt_enabled (); > +# else > + bool ibt_enabled_p = false; > +# endif > > if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) > _dl_debug_printf ("\nchanging PLT in '%s' to direct branch\n", > -- > 2.43.0 > LGTM. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
diff --git a/sysdeps/unix/sysv/linux/x86/bits/platform/features.h b/sysdeps/unix/sysv/linux/x86/bits/platform/features.h new file mode 100644 index 0000000000..7704febe92 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86/bits/platform/features.h @@ -0,0 +1,48 @@ +/* Inline functions for x86 CPU features. + This file is part of the GNU C Library. + Copyright (C) 2024 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _SYS_PLATFORM_X86_H +# error "Never include <bits/platform/features.h> directly; use <sys/platform/x86.h> instead." +#endif + +/* Bits in the feature_1 field in TCB. */ + +enum +{ + x86_feature_1_ibt = 1U << 0, + x86_feature_1_shstk = 1U << 1 +}; + +static __inline__ _Bool +x86_cpu_cet_active (unsigned int __index) +{ +#ifdef __x86_64__ + unsigned int __feature_1; +# ifdef __LP64__ + __asm__ ("mov %%fs:72, %0" : "=r" (__feature_1)); +# else + __asm__ ("mov %%fs:40, %0" : "=r" (__feature_1)); +# endif + if (__index == x86_cpu_IBT) + return __feature_1 & x86_feature_1_ibt; + else + return __feature_1 & x86_feature_1_shstk; +#else + return false; +#endif +} diff --git a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h index a00c7ee662..1fe3133406 100644 --- a/sysdeps/unix/sysv/linux/x86_64/dl-cet.h +++ b/sysdeps/unix/sysv/linux/x86_64/dl-cet.h @@ -54,6 +54,14 @@ dl_cet_get_cet_status (void) return status; } +static __always_inline bool +dl_cet_ibt_enabled (void) +{ + unsigned int feature_1 = THREAD_GETMEM (THREAD_SELF, + header.feature_1); + return (feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; +} + /* Enable shadow stack with a macro to avoid shadow stack underflow. */ #define ENABLE_X86_CET(cet_feature) \ if ((cet_feature & GNU_PROPERTY_X86_FEATURE_1_SHSTK)) \ diff --git a/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c b/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c new file mode 100644 index 0000000000..39b342463c --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/get-cpuid-feature-leaf.c @@ -0,0 +1,24 @@ +/* Get CPUID feature leaf. Linux/x86-64 version. + Copyright (C) 2024 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <sysdeps/x86/get-cpuid-feature-leaf.c> + +#ifdef __LP64__ +_Static_assert (FEATURE_1_OFFSET == 72, "FEATURE_1_OFFSET != 72"); +#else +_Static_assert (FEATURE_1_OFFSET == 40, "FEATURE_1_OFFSET != 40"); +#endif diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile index bf913594c1..4d50b327b5 100644 --- a/sysdeps/x86/Makefile +++ b/sysdeps/x86/Makefile @@ -5,7 +5,11 @@ endif ifeq ($(subdir),elf) sysdep_routines += get-cpuid-feature-leaf sysdep-dl-routines += dl-get-cpu-features -sysdep_headers += sys/platform/x86.h bits/platform/x86.h +sysdep_headers += \ + bits/platform/features.h \ + bits/platform/x86.h \ + sys/platform/x86.h \ +# sysdep_headers CFLAGS-dl-get-cpu-features.os += $(rtld-early-cflags) CFLAGS-get-cpuid-feature-leaf.o += $(no-stack-protector) diff --git a/sysdeps/x86/bits/platform/features.h b/sysdeps/x86/bits/platform/features.h new file mode 100644 index 0000000000..f02489266e --- /dev/null +++ b/sysdeps/x86/bits/platform/features.h @@ -0,0 +1,27 @@ +/* Inline functions for x86 CPU features. + This file is part of the GNU C Library. + Copyright (C) 2024 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _SYS_PLATFORM_X86_H +# error "Never include <bits/platform/features.h> directly; use <sys/platform/x86.h> instead." +#endif + +static __inline__ _Bool +x86_cpu_cet_active (unsigned int __index) +{ + return false; +} diff --git a/sysdeps/x86/bits/platform/x86.h b/sysdeps/x86/bits/platform/x86.h index c31d086194..8b157d99b3 100644 --- a/sysdeps/x86/bits/platform/x86.h +++ b/sysdeps/x86/bits/platform/x86.h @@ -337,11 +337,3 @@ enum x86_cpu_AVX10_YMM = x86_cpu_index_24_ecx_0_ebx + 17, x86_cpu_AVX10_ZMM = x86_cpu_index_24_ecx_0_ebx + 18, }; - -/* Bits in the feature_1 field in TCB. */ - -enum -{ - x86_feature_1_ibt = 1U << 0, - x86_feature_1_shstk = 1U << 1 -}; diff --git a/sysdeps/x86/get-cpuid-feature-leaf.c b/sysdeps/x86/get-cpuid-feature-leaf.c index e6a41cc79c..6f67346081 100644 --- a/sysdeps/x86/get-cpuid-feature-leaf.c +++ b/sysdeps/x86/get-cpuid-feature-leaf.c @@ -19,14 +19,6 @@ #include <tcb-offsets.h> #include <ldsodefs.h> -#ifdef __x86_64__ -# ifdef __LP64__ -_Static_assert (FEATURE_1_OFFSET == 72, "FEATURE_1_OFFSET != 72"); -# else -_Static_assert (FEATURE_1_OFFSET == 40, "FEATURE_1_OFFSET != 40"); -# endif -#endif - const struct cpuid_feature * __x86_get_cpuid_feature_leaf (unsigned int leaf) { diff --git a/sysdeps/x86/sys/platform/x86.h b/sysdeps/x86/sys/platform/x86.h index 4d77c0991d..b8066ccc9f 100644 --- a/sysdeps/x86/sys/platform/x86.h +++ b/sysdeps/x86/sys/platform/x86.h @@ -22,6 +22,7 @@ #include <features.h> #include <stdbool.h> #include <bits/platform/x86.h> +#include <bits/platform/features.h> __BEGIN_DECLS @@ -46,22 +47,8 @@ static __inline__ _Bool x86_cpu_active (unsigned int __index) { if (__index == x86_cpu_IBT || __index == x86_cpu_SHSTK) - { -#ifdef __x86_64__ - unsigned int __feature_1; -# ifdef __LP64__ - __asm__ ("mov %%fs:72, %0" : "=r" (__feature_1)); -# else - __asm__ ("mov %%fs:40, %0" : "=r" (__feature_1)); -# endif - if (__index == x86_cpu_IBT) - return __feature_1 & x86_feature_1_ibt; - else - return __feature_1 & x86_feature_1_shstk; -#else - return false; -#endif - } + return x86_cpu_cet_active (__index); + const struct cpuid_feature *__ptr = __x86_get_cpuid_feature_leaf (__index / (8 * sizeof (unsigned int) * 4)); unsigned int __reg diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h index 2d2ce503a5..6d605d0d32 100644 --- a/sysdeps/x86_64/dl-machine.h +++ b/sysdeps/x86_64/dl-machine.h @@ -587,10 +587,11 @@ x86_64_rewrite_plt (struct link_map *map, ElfW(Addr) plt_rewrite) const ElfW(Rela) *reloc = (const void *) start; const ElfW(Rela) *reloc_end = (const void *) (start + size); - unsigned int feature_1 = THREAD_GETMEM (THREAD_SELF, - header.feature_1); - bool ibt_enabled_p - = (feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0; +# ifdef __CET__ + bool ibt_enabled_p = dl_cet_ibt_enabled (); +# else + bool ibt_enabled_p = false; +# endif if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) _dl_debug_printf ("\nchanging PLT in '%s' to direct branch\n",