| Message ID | 1472142204-14258-1-git-send-email-mark.rutland@arm.com |
|---|---|
| State | Accepted |
| Commit | 40982fd6b975de4a51ce5147bc1d698c3b075634 |
| Headers | show |
On 25 August 2016 at 18:23, Mark Rutland <mark.rutland@arm.com> wrote: > 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. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> About time! > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Laura Abbott <labbott@redhat.com> > Cc: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/Kconfig.debug | 10 ---------- > arch/arm64/kernel/insn.c | 2 +- > 3 files changed, 4 insertions(+), 11 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index bc3f00f..43d6134 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; > -- > 2.7.4 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Thu, Aug 25, 2016 at 05:23:23PM +0100, Mark Rutland wrote: > 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. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Laura Abbott <labbott@redhat.com> > Cc: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/Kconfig.debug | 10 ---------- > arch/arm64/kernel/insn.c | 2 +- > 3 files changed, 4 insertions(+), 11 deletions(-) This is a very popular patch. Applied for 4.9. Perhaps it makes up for all the unpopular patches I've applied in the past. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index bc3f00f..43d6134 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;
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. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/Kconfig | 3 +++ arch/arm64/Kconfig.debug | 10 ---------- arch/arm64/kernel/insn.c | 2 +- 3 files changed, 4 insertions(+), 11 deletions(-) -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel