| Message ID | 1463138436-5073-1-git-send-email-mark.rutland@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
On 13 May 2016 at 13:20, Mark Rutland <mark.rutland@arm.com> wrote: > The SET_MODULE_RONX protections are effectively the same as the > DEBUG_RODATA protections we enabled by default back in commit > 57efac2f7108e325 ("arm64: enable CONFIG_DEBUG_RODATA by default"). It > seems unusual to have one but not the other. > > As evidenced by the help text, the rationale appears to be that > SET_MODULE_RONX interacts poorly with tracing and patching, but both of > these make use of the insn framework, which takes SET_MODULE_RONX into > account. Any remaining issues are bugs which should be fixed regardless > of the default state of the option. > > This patch enables DEBUG_SET_MODULE_RONX by default, and replaces the > help text with a new wording derived from the DEBUG_RODATA help text, > which better describes the functionality. Previously, the DEBUG_RODATA > entry was inconsistently indented with spaces, which are replaced with > tabs as with the other Kconfig entries. > > Additionally, the wording of recommended defaults is made consistent for > all options. These are placed in a new paragraph, unquoted, as a full > sentence (with a period/full stop) as this appears to be the most common > form per $(git grep 'in doubt'). > > 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@fedoraproject.org> > Cc: Will Deacon <will.deacon@arm.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm64/Kconfig.debug | 25 +++++++++++++------------ > 1 file changed, 13 insertions(+), 12 deletions(-) > > diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug > index 710fde4..0cc758c 100644 > --- a/arch/arm64/Kconfig.debug > +++ b/arch/arm64/Kconfig.debug > @@ -12,7 +12,8 @@ config ARM64_PTDUMP > who are working in architecture specific areas of the kernel. > It is probably not a good idea to enable this feature in a production > kernel. > - If in doubt, say "N" > + > + If in doubt, say N. > > config PID_IN_CONTEXTIDR > bool "Write the current PID to the CONTEXTIDR register" > @@ -38,15 +39,15 @@ config ARM64_RANDOMIZE_TEXT_OFFSET > value. > > config DEBUG_SET_MODULE_RONX > - bool "Set loadable kernel module data as NX and text as RO" > - depends on MODULES > - help > - This option helps catch unintended modifications to loadable > - kernel module's text and read-only data. It also prevents execution > - of module data. Such protection may interfere with run-time code > - patching and dynamic kernel tracing - and they might also protect > - against certain classes of kernel exploits. > - If in doubt, say "N". > + bool "Set loadable kernel module data as NX and text as RO" > + depends on MODULES > + default y > + help > + Is this is set, kernel module 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_RODATA > bool "Make kernel text and rodata read-only" > @@ -56,7 +57,7 @@ config DEBUG_RODATA > is to help catch accidental or malicious attempts to change the > kernel's executable code. > > - If in doubt, say Y > + If in doubt, say Y. > > config DEBUG_ALIGN_RODATA > depends on DEBUG_RODATA > @@ -69,7 +70,7 @@ config DEBUG_ALIGN_RODATA > alignment and potentially wasted space. Turn on this option if > performance is more important than memory pressure. > > - If in doubt, say N > + If in doubt, say N. > > source "drivers/hwtracing/coresight/Kconfig" > > -- > 1.9.1 > _______________________________________________ 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.debug b/arch/arm64/Kconfig.debug index 710fde4..0cc758c 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -12,7 +12,8 @@ config ARM64_PTDUMP who are working in architecture specific areas of the kernel. It is probably not a good idea to enable this feature in a production kernel. - If in doubt, say "N" + + If in doubt, say N. config PID_IN_CONTEXTIDR bool "Write the current PID to the CONTEXTIDR register" @@ -38,15 +39,15 @@ config ARM64_RANDOMIZE_TEXT_OFFSET value. config DEBUG_SET_MODULE_RONX - bool "Set loadable kernel module data as NX and text as RO" - depends on MODULES - help - This option helps catch unintended modifications to loadable - kernel module's text and read-only data. It also prevents execution - of module data. Such protection may interfere with run-time code - patching and dynamic kernel tracing - and they might also protect - against certain classes of kernel exploits. - If in doubt, say "N". + bool "Set loadable kernel module data as NX and text as RO" + depends on MODULES + default y + help + Is this is set, kernel module 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_RODATA bool "Make kernel text and rodata read-only" @@ -56,7 +57,7 @@ config DEBUG_RODATA is to help catch accidental or malicious attempts to change the kernel's executable code. - If in doubt, say Y + If in doubt, say Y. config DEBUG_ALIGN_RODATA depends on DEBUG_RODATA @@ -69,7 +70,7 @@ config DEBUG_ALIGN_RODATA alignment and potentially wasted space. Turn on this option if performance is more important than memory pressure. - If in doubt, say N + If in doubt, say N. source "drivers/hwtracing/coresight/Kconfig"
The SET_MODULE_RONX protections are effectively the same as the DEBUG_RODATA protections we enabled by default back in commit 57efac2f7108e325 ("arm64: enable CONFIG_DEBUG_RODATA by default"). It seems unusual to have one but not the other. As evidenced by the help text, the rationale appears to be that SET_MODULE_RONX interacts poorly with tracing and patching, but both of these make use of the insn framework, which takes SET_MODULE_RONX into account. Any remaining issues are bugs which should be fixed regardless of the default state of the option. This patch enables DEBUG_SET_MODULE_RONX by default, and replaces the help text with a new wording derived from the DEBUG_RODATA help text, which better describes the functionality. Previously, the DEBUG_RODATA entry was inconsistently indented with spaces, which are replaced with tabs as with the other Kconfig entries. Additionally, the wording of recommended defaults is made consistent for all options. These are placed in a new paragraph, unquoted, as a full sentence (with a period/full stop) as this appears to be the most common form per $(git grep 'in doubt'). 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@fedoraproject.org> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/Kconfig.debug | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) -- 1.9.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel