This is a note to let you know that I've just added the patch titled
module: extend 'rodata=off' boot cmdline parameter to module mappings
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: module-extend-rodata-off-boot-cmdline-parameter-to-module-mappings.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Thu Apr 5 21:39:27 CEST 2018
From: Mark Rutland mark.rutland@arm.com Date: Tue, 3 Apr 2018 12:09:03 +0100 Subject: module: extend 'rodata=off' boot cmdline parameter to module mappings To: stable@vger.kernel.org Cc: mark.brown@linaro.org, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, will.deacon@arm.com Message-ID: 20180403110923.43575-8-mark.rutland@arm.com
From: AKASHI Takahiro takahiro.akashi@linaro.org
commit 39290b389ea upstream.
The current "rodata=off" parameter disables read-only kernel mappings under CONFIG_DEBUG_RODATA: commit d2aa1acad22f ("mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings")
This patch is a logical extension to module mappings ie. read-only mappings at module loading can be disabled even if CONFIG_DEBUG_SET_MODULE_RONX (mainly for debug use). Please note, however, that it only affects RO/RW permissions, keeping NX set.
This is the first step to make CONFIG_DEBUG_SET_MODULE_RONX mandatory (always-on) in the future as CONFIG_DEBUG_RODATA on x86 and arm64.
Suggested-by: and Acked-by: Mark Rutland mark.rutland@arm.com Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org Reviewed-by: Kees Cook keescook@chromium.org Acked-by: Rusty Russell rusty@rustcorp.com.au Link: http://lkml.kernel.org/r/20161114061505.15238-1-takahiro.akashi@linaro.org Signed-off-by: Jessica Yu jeyu@redhat.com Signed-off-by: Alex Shi alex.shi@linaro.org [v4.9 backport] Signed-off-by: Mark Rutland mark.rutland@arm.com [v4.9 backport] Tested-by: Will Deacon will.deacon@arm.com Tested-by: Greg Hackmann ghackmann@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/init.h | 3 +++ init/main.c | 7 +++++-- kernel/module.c | 20 +++++++++++++++++--- 3 files changed, 25 insertions(+), 5 deletions(-)
--- a/include/linux/init.h +++ b/include/linux/init.h @@ -133,6 +133,9 @@ void prepare_namespace(void); void __init load_default_modules(void); int __init init_rootfs(void);
+#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) +extern bool rodata_enabled; +#endif #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void); #endif --- a/init/main.c +++ b/init/main.c @@ -81,6 +81,7 @@ #include <linux/proc_ns.h> #include <linux/io.h> #include <linux/kaiser.h> +#include <linux/cache.h>
#include <asm/io.h> #include <asm/bugs.h> @@ -914,14 +915,16 @@ static int try_to_run_init_process(const
static noinline void __init kernel_init_freeable(void);
-#ifdef CONFIG_DEBUG_RODATA -static bool rodata_enabled = true; +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_SET_MODULE_RONX) +bool rodata_enabled __ro_after_init = true; static int __init set_debug_rodata(char *str) { return strtobool(str, &rodata_enabled); } __setup("rodata=", set_debug_rodata); +#endif
+#ifdef CONFIG_DEBUG_RODATA static void mark_readonly(void) { if (rodata_enabled) --- a/kernel/module.c +++ b/kernel/module.c @@ -1911,6 +1911,9 @@ static void frob_writable_data(const str /* livepatching wants to disable read-only so it can frob module. */ void module_disable_ro(const struct module *mod) { + if (!rodata_enabled) + return; + frob_text(&mod->core_layout, set_memory_rw); frob_rodata(&mod->core_layout, set_memory_rw); frob_ro_after_init(&mod->core_layout, set_memory_rw); @@ -1920,6 +1923,9 @@ void module_disable_ro(const struct modu
void module_enable_ro(const struct module *mod, bool after_init) { + if (!rodata_enabled) + return; + frob_text(&mod->core_layout, set_memory_ro); frob_rodata(&mod->core_layout, set_memory_ro); frob_text(&mod->init_layout, set_memory_ro); @@ -1952,6 +1958,9 @@ void set_all_modules_text_rw(void) { struct module *mod;
+ if (!rodata_enabled) + return; + mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) @@ -1968,6 +1977,9 @@ void set_all_modules_text_ro(void) { struct module *mod;
+ if (!rodata_enabled) + return; + mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) @@ -1981,10 +1993,12 @@ void set_all_modules_text_ro(void)
static void disable_ro_nx(const struct module_layout *layout) { - frob_text(layout, set_memory_rw); - frob_rodata(layout, set_memory_rw); + if (rodata_enabled) { + frob_text(layout, set_memory_rw); + frob_rodata(layout, set_memory_rw); + frob_ro_after_init(layout, set_memory_rw); + } frob_rodata(layout, set_memory_x); - frob_ro_after_init(layout, set_memory_rw); frob_ro_after_init(layout, set_memory_x); frob_writable_data(layout, set_memory_x); }
Patches currently in stable-queue which might be from mark.rutland@arm.com are
queue-4.9/arm64-mm-add-arm64_kernel_unmapped_at_el0-helper.patch queue-4.9/arm64-entry-reword-comment-about-post_ttbr_update_workaround.patch queue-4.9/arm64-kaslr-put-kernel-vectors-address-in-separate-data-page.patch queue-4.9/arm64-turn-on-kpti-only-on-cpus-that-need-it.patch queue-4.9/arm64-force-kpti-to-be-disabled-on-cavium-thunderx.patch queue-4.9/arm64-mm-allocate-asids-in-pairs.patch queue-4.9/arm64-tls-avoid-unconditional-zeroing-of-tpidrro_el0-for-native-tasks.patch queue-4.9/arm64-use-ret-instruction-for-exiting-the-trampoline.patch queue-4.9/arm64-entry-explicitly-pass-exception-level-to-kernel_ventry-macro.patch queue-4.9/arm64-kpti-make-use-of-ng-dependent-on-arm64_kernel_unmapped_at_el0.patch queue-4.9/arm64-mm-use-non-global-mappings-for-kernel-space.patch queue-4.9/arm64-capabilities-handle-duplicate-entries-for-a-capability.patch queue-4.9/arm64-entry-hook-up-entry-trampoline-to-exception-vectors.patch queue-4.9/arm64-mm-invalidate-both-kernel-and-user-asids-when-performing-tlbi.patch queue-4.9/arm64-mm-map-entry-trampoline-into-trampoline-and-kernel-page-tables.patch queue-4.9/module-extend-rodata-off-boot-cmdline-parameter-to-module-mappings.patch queue-4.9/arm64-kconfig-reword-unmap_kernel_at_el0-kconfig-entry.patch queue-4.9/arm64-mm-move-asid-from-ttbr0-to-ttbr1.patch queue-4.9/arm64-allow-checking-of-a-cpu-local-erratum.patch queue-4.9/arm64-take-into-account-id_aa64pfr0_el1.csv3.patch queue-4.9/arm64-kconfig-add-config_unmap_kernel_at_el0.patch queue-4.9/arm64-idmap-use-awx-flags-for-.idmap.text-.pushsection-directives.patch queue-4.9/arm64-factor-out-entry-stack-manipulation.patch queue-4.9/arm64-entry-add-exception-trampoline-page-for-exceptions-from-el0.patch queue-4.9/arm64-kpti-add-enable-callback-to-remap-swapper-using-ng-mappings.patch queue-4.9/arm64-entry-add-fake-cpu-feature-for-unmapping-the-kernel-at-el0.patch queue-4.9/arm64-cputype-add-midr-values-for-cavium-thunderx2-cpus.patch