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| author | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2016-11-14 07:15:05 +0100 |
|---|---|---|
| committer | Jessica Yu <jeyu@redhat.com> | 2016-11-28 01:15:33 +0100 |
| commit | 39290b389ea2654f9190e3b48c57d27b24def83e (patch) | |
| tree | c56b3f6505001d9c4bf25d5588e79e79f2db0ea8 /kernel/module.c | |
| parent | module: Fix a comment above strong_try_module_get() (diff) | |
| download | linux-39290b389ea2654f9190e3b48c57d27b24def83e.tar.xz linux-39290b389ea2654f9190e3b48c57d27b24def83e.zip | |
module: extend 'rodata=off' boot cmdline parameter to module mappings
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>
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/kernel/module.c b/kernel/module.c index 6281c70683d3..039ce82803f7 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1902,6 +1902,9 @@ static void frob_writable_data(const struct module_layout *layout, /* 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); @@ -1911,6 +1914,9 @@ void module_disable_ro(const struct module *mod) 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); @@ -1943,6 +1949,9 @@ 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) @@ -1959,6 +1968,9 @@ 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) { /* @@ -1978,10 +1990,12 @@ 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); } |