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| author | Mark Rutland <mark.rutland@arm.com> | 2016-08-25 16:23:23 (GMT) |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2016-08-26 09:13:41 (GMT) |
| commit | 40982fd6b975de4a51ce5147bc1d698c3b075634 (patch) | |
| tree | 3021aa1627232dfcd14a00dea3f031008064eb50 /arch | |
| parent | e7cd190385d17790cc3eb3821b1094b00aacf325 (diff) | |
| download | linux-40982fd6b975de4a51ce5147bc1d698c3b075634.tar.xz | |
arm64: always enable DEBUG_RODATA and remove the Kconfig option
Follow the example set by x86 in commit 9ccaf77cf05915f5 ("x86/mm:
Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option"), and
make these protections a fundamental security feature rather than an
opt-in. This also results in a minor code simplification.
For those rare cases when users wish to disable this protection (e.g.
for debugging), this can be done by passing 'rodata=off' on the command
line.
As DEBUG_RODATA_ALIGN is only intended to address a performance/memory
tradeoff, and does not affect correctness, this is left user-selectable.
DEBUG_MODULE_RONX is also left user-selectable until the core code
provides a boot-time option to disable the protection for debugging
use-cases.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/Kconfig | 3 | ||||
| -rw-r--r-- | arch/arm64/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/arm64/kernel/insn.c | 2 |
3 files changed, 4 insertions, 11 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 9be0c16..1e49fbc4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -122,6 +122,9 @@ config ARCH_PHYS_ADDR_T_64BIT config MMU def_bool y +config DEBUG_RODATA + def_bool y + config ARM64_PAGE_SHIFT int default 16 if ARM64_64K_PAGES diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index 0cc758c..b661fe7 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -49,16 +49,6 @@ config DEBUG_SET_MODULE_RONX If in doubt, say Y. -config DEBUG_RODATA - bool "Make kernel text and rodata read-only" - default y - help - If this is set, kernel text and rodata will be made read-only. This - is to help catch accidental or malicious attempts to change the - kernel's executable code. - - If in doubt, say Y. - config DEBUG_ALIGN_RODATA depends on DEBUG_RODATA bool "Align linker sections up to SECTION_SIZE" diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index 63f9432..178488f 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -96,7 +96,7 @@ static void __kprobes *patch_map(void *addr, int fixmap) if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) page = vmalloc_to_page(addr); - else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA)) + else if (!module) page = pfn_to_page(PHYS_PFN(__pa(addr))); else return addr; |