Check an ELF file's .note.gnu.property, and setup shadow stack if the application supports it.
Signed-off-by: Yu-cheng Yu <[email protected]> --- v9: - Change cpu_feature_enabled() to static_cpu_has(). arch/x86/Kconfig | 2 ++ arch/x86/include/asm/elf.h | 13 +++++++++++++ arch/x86/kernel/process_64.c | 29 +++++++++++++++++++++++++++++ 3 files changed, 44 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ac07e1f6a2bc..8b7b97ff5fb4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1970,6 +1970,8 @@ config X86_INTEL_SHADOW_STACK_USER select X86_INTEL_CET select ARCH_MAYBE_MKWRITE select ARCH_HAS_SHADOW_STACK + select ARCH_USE_GNU_PROPERTY + select ARCH_BINFMT_ELF_STATE help Shadow Stacks provides protection against program stack corruption. It's a hardware feature. This only matters diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 69c0f892e310..fac79b621e0a 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -367,6 +367,19 @@ extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp); #define compat_arch_setup_additional_pages compat_arch_setup_additional_pages +#ifdef CONFIG_ARCH_BINFMT_ELF_STATE +struct arch_elf_state { + unsigned int gnu_property; +}; + +#define INIT_ARCH_ELF_STATE { \ + .gnu_property = 0, \ +} + +#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state) (0) +#define arch_check_elf(ehdr, interp, interp_ehdr, state) (0) +#endif + /* Do not change the values. See get_align_mask() */ enum align_flags { ALIGN_VA_32 = BIT(0), diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 5ef9d8f25b0e..93ba4afd0c19 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -730,3 +730,32 @@ unsigned long KSTK_ESP(struct task_struct *task) { return task_pt_regs(task)->sp; } + +#ifdef CONFIG_ARCH_USE_GNU_PROPERTY +int arch_parse_elf_property(u32 type, const void *data, size_t datasz, + bool compat, struct arch_elf_state *state) +{ + if (type != GNU_PROPERTY_X86_FEATURE_1_AND) + return 0; + + if (datasz != sizeof(unsigned int)) + return -ENOEXEC; + + state->gnu_property = *(unsigned int *)data; + return 0; +} + +int arch_setup_elf_property(struct arch_elf_state *state) +{ + int r = 0; + + memset(¤t->thread.cet, 0, sizeof(struct cet_status)); + + if (static_cpu_has(X86_FEATURE_SHSTK)) { + if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_SHSTK) + r = cet_setup_shstk(); + } + + return r; +} +#endif -- 2.21.0
