Messages in this thread | | | Subject | Re: [PATCH] modules: fix compile error if don't have strict module rwx | From | Yang Yingliang <> | Date | Wed, 26 Jun 2019 11:36:27 +0800 |
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On 2019/6/26 3:21, Jessica Yu wrote: > +++ Yang Yingliang [25/06/19 17:40 +0800]: >> If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is not defined, >> we need stub for module_enable_nx() and module_enable_x(). >> >> If CONFIG_ARCH_HAS_STRICT_MODULE_RWX is defined, but >> CONFIG_STRICT_MODULE_RWX is disabled, we need stub for >> module_enable_nx. >> >> Move frob_text() outside of the CONFIG_STRICT_MODULE_RWX, >> because it is needed anyway. > > Maybe include a fixes tag? > > Fixes: 2eef1399a866 ("modules: fix BUG when load module with rodata=n") OK, I will add it in v2. > >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> >> --- >> kernel/module.c | 13 +++++++++---- >> 1 file changed, 9 insertions(+), 4 deletions(-) >> >> diff --git a/kernel/module.c b/kernel/module.c >> index c3ae34c..cfff441 100644 >> --- a/kernel/module.c >> +++ b/kernel/module.c >> @@ -1875,7 +1875,7 @@ static void mod_sysfs_teardown(struct module *mod) >> mod_sysfs_fini(mod); >> } >> >> -#ifdef CONFIG_STRICT_MODULE_RWX >> +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX > > Could you please explain why you introduced a new > CONFIG_ARCH_HAS_STRICT_MODULE_RWX #ifdef block instead of just moving > frob_text() and module_enable_x() outside of CONFIG_STRICT_MODULE_RWX? If CONFIG_STRICT_MODULE_RWX is not defined, it has two reasons, one is that the arch don't have strict module rwx and the other reason is that CONFIG_STRICT_MODULE_RWX is disabled. So I introduce CONFIG_ARCH_HAS_STRICT_MODULE_RWX #ifdef block to distinguish this two cases.
> > I do not have anything against it, although the nested #ifdef's are a > bit painful to read. But I could not find a better way to do it :/ > It's awkward because we need module_enable_x() and frob_text() > regardless of of CONFIG_STRICT_MODULE_RWX for x86, but other arches > don't need to call module_enable_x(), they usually just call the empty > stub. Yes, you are right. Actually, I was thinking moving all frob_* outside of CONFIG_STRICT_MODULE_RWX, because they all should be regardless of of CONFIG_STRICT_MODULE_RWX. But current only frob_next() is used, move other frob_* outside of CONFIG_STRICT_MODULE_RWX will cause a compile warning if CONFIG_STRICT_MODULE_RWX is disabled, so I left them in CONFIG_STRICT_MODULE_RWX. We can move them outside of CONFIG_STRICT_MODULE_RWX if they are used in future. > > But I think having the CONFIG_ARCH_HAS_STRICT_MODULE_RWX block is OK, > for the reason of limiting the scope of the calls rather than > blanketly calling frob_text() andd module_enable_x() for arches that > don't need to call them. Was that your reasoning as well? Yes, it's my reasoning.
Thanks, Yang > > Thanks, > > Jessica > > >> /* >> * LKM RO/NX protection: protect module's text/ro-data >> * from modification and any data from execution. >> @@ -1898,6 +1898,7 @@ static void frob_text(const struct >> module_layout *layout, >> layout->text_size >> PAGE_SHIFT); >> } >> >> +#ifdef CONFIG_STRICT_MODULE_RWX >> static void frob_rodata(const struct module_layout *layout, >> int (*set_memory)(unsigned long start, int num_pages)) >> { >> @@ -2010,15 +2011,19 @@ void set_all_modules_text_ro(void) >> } >> mutex_unlock(&module_mutex); >> } >> -#else >> +#else /* !CONFIG_STRICT_MODULE_RWX */ >> static void module_enable_nx(const struct module *mod) { } >> -#endif >> - >> +#endif /* CONFIG_STRICT_MODULE_RWX */ >> static void module_enable_x(const struct module *mod) >> { >> frob_text(&mod->core_layout, set_memory_x); >> frob_text(&mod->init_layout, set_memory_x); >> } >> +#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ >> +static void module_enable_nx(const struct module *mod) { } >> +static void module_enable_x(const struct module *mod) { } >> +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ >> + >> >> #ifdef CONFIG_LIVEPATCH >> /* >> -- >> 1.8.3 >> > > . >
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