diff options
| author | Dave Martin <Dave.Martin@arm.com> | 2020-03-16 17:50:47 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2020-03-16 18:19:48 +0100 |
| commit | ab7876a98a2160092133de4c648e94b18bc3f139 (patch) | |
| tree | 8c9a55d036f6e42dd7917860ad9d1fac9605c672 /arch/arm64/kernel | |
| parent | elf: Allow arch to tweak initial mmap prot flags (diff) | |
| download | linux-ab7876a98a2160092133de4c648e94b18bc3f139.tar.xz linux-ab7876a98a2160092133de4c648e94b18bc3f139.zip | |
arm64: elf: Enable BTI at exec based on ELF program properties
For BTI protection to be as comprehensive as possible, it is
desirable to have BTI enabled from process startup. If this is not
done, the process must use mprotect() to enable BTI for each of its
executable mappings, but this is painful to do in the libc startup
code. It's simpler and more sound to have the kernel do it
instead.
To this end, detect BTI support in the executable (or ELF
interpreter, as appropriate), via the
NT_GNU_PROGRAM_PROPERTY_TYPE_0 note, and tweak the initial prot
flags for the process' executable pages to include PROT_BTI as
appropriate.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/process.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 00626057a384..b8e3faa8d406 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -11,6 +11,7 @@ #include <linux/compat.h> #include <linux/efi.h> +#include <linux/elf.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/sched/debug.h> @@ -18,6 +19,7 @@ #include <linux/sched/task_stack.h> #include <linux/kernel.h> #include <linux/lockdep.h> +#include <linux/mman.h> #include <linux/mm.h> #include <linux/stddef.h> #include <linux/sysctl.h> @@ -654,3 +656,20 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) if (system_capabilities_finalized()) preempt_schedule_irq(); } + +#ifdef CONFIG_BINFMT_ELF +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, + bool has_interp, bool is_interp) +{ + if (is_interp != has_interp) + return prot; + + if (!(state->flags & ARM64_ELF_BTI)) + return prot; + + if (prot & PROT_EXEC) + prot |= PROT_BTI; + + return prot; +} +#endif |