Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
Rusty, Jessica On Wed, Oct 26, 2016 at 10:43:32AM +1030, Rusty Russell wrote: > AKASHI Takahirowrites: > > On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: > >> On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro > >> wrote: > >> > 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 patch looks good (except the minor issues noted by Kees); please CC > the followup version to Jessica as new module maintainer. I think that the new version (v2)[1] addresses Kees' comments already. [1] http://lkml.iu.edu//hypermail/linux/kernel/1610.2/04163.html Thanks, -Takahiro AKASHI > Thanks! > Rusty. > > >> > > >> > 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: Mark Rutland > >> > Signed-off-by: AKASHI Takahiro > >> > Cc: Rusty Russell > >> > --- > >> > v1: > >> > * remove RFC's "module_ronx=" and merge it with "rodata=" > >> > * always keep NX set if CONFIG_SET_MODULE_RONX > >> > > >> > include/linux/init.h | 3 ++- > >> > init/main.c | 2 +- > >> > kernel/module.c | 21 ++--- > >> > 3 files changed, 21 insertions(+), 5 deletions(-) > >> > > >> > diff --git a/include/linux/init.h b/include/linux/init.h > >> > index e30104c..20aa2eb 100644 > >> > --- a/include/linux/init.h > >> > +++ b/include/linux/init.h > >> > @@ -126,7 +126,8 @@ void prepare_namespace(void); > >> > void __init load_default_modules(void); > >> > int __init init_rootfs(void); > >> > > >> > -#ifdef CONFIG_DEBUG_RODATA > >> > +#if defined(CONFIG_DEBUG_RODATA) || > >> > defined(CONFIG_DEBUG_SET_MODULE_RONX) > >> > +extern bool rodata_enabled; > >> > void mark_rodata_ro(void); > >> > #endif > >> > > >> > diff --git a/init/main.c b/init/main.c > >> > index 2858be7..92db2f3 100644 > >> > --- a/init/main.c > >> > +++ b/init/main.c > >> > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > >> > *init_filename) > >> > static noinline void __init kernel_init_freeable(void); > >> > > >> > #ifdef CONFIG_DEBUG_RODATA > >> > -static bool rodata_enabled = true; > >> > +bool rodata_enabled = true; > >> > >> Is there a mismatch here between the extern ifdef and the bool ifdef? > >> I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? > > > > Yes. > > > >> Also, can you mark this as __ro_after_init, since nothing changes it > >> after the kernel command line is parsed? > > > > Yes, yes. > > > > Thanks, > > -Takahiro AKASHI > > > >> Otherwise, this looks fine to me. > >> > >> -Kees > >> > >> > >> -- > >> Kees Cook > >> Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
Rusty, Jessica On Wed, Oct 26, 2016 at 10:43:32AM +1030, Rusty Russell wrote: > AKASHI Takahiro writes: > > On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: > >> On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro > >> wrote: > >> > 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 patch looks good (except the minor issues noted by Kees); please CC > the followup version to Jessica as new module maintainer. I think that the new version (v2)[1] addresses Kees' comments already. [1] http://lkml.iu.edu//hypermail/linux/kernel/1610.2/04163.html Thanks, -Takahiro AKASHI > Thanks! > Rusty. > > >> > > >> > 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: Mark Rutland > >> > Signed-off-by: AKASHI Takahiro > >> > Cc: Rusty Russell > >> > --- > >> > v1: > >> > * remove RFC's "module_ronx=" and merge it with "rodata=" > >> > * always keep NX set if CONFIG_SET_MODULE_RONX > >> > > >> > include/linux/init.h | 3 ++- > >> > init/main.c | 2 +- > >> > kernel/module.c | 21 ++--- > >> > 3 files changed, 21 insertions(+), 5 deletions(-) > >> > > >> > diff --git a/include/linux/init.h b/include/linux/init.h > >> > index e30104c..20aa2eb 100644 > >> > --- a/include/linux/init.h > >> > +++ b/include/linux/init.h > >> > @@ -126,7 +126,8 @@ void prepare_namespace(void); > >> > void __init load_default_modules(void); > >> > int __init init_rootfs(void); > >> > > >> > -#ifdef CONFIG_DEBUG_RODATA > >> > +#if defined(CONFIG_DEBUG_RODATA) || > >> > defined(CONFIG_DEBUG_SET_MODULE_RONX) > >> > +extern bool rodata_enabled; > >> > void mark_rodata_ro(void); > >> > #endif > >> > > >> > diff --git a/init/main.c b/init/main.c > >> > index 2858be7..92db2f3 100644 > >> > --- a/init/main.c > >> > +++ b/init/main.c > >> > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > >> > *init_filename) > >> > static noinline void __init kernel_init_freeable(void); > >> > > >> > #ifdef CONFIG_DEBUG_RODATA > >> > -static bool rodata_enabled = true; > >> > +bool rodata_enabled = true; > >> > >> Is there a mismatch here between the extern ifdef and the bool ifdef? > >> I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? > > > > Yes. > > > >> Also, can you mark this as __ro_after_init, since nothing changes it > >> after the kernel command line is parsed? > > > > Yes, yes. > > > > Thanks, > > -Takahiro AKASHI > > > >> Otherwise, this looks fine to me. > >> > >> -Kees > >> > >> > >> -- > >> Kees Cook > >> Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
AKASHI Takahirowrites: > On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: >> On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro >> wrote: >> > 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 patch looks good (except the minor issues noted by Kees); please CC the followup version to Jessica as new module maintainer. Thanks! Rusty. >> > >> > 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: Mark Rutland >> > Signed-off-by: AKASHI Takahiro >> > Cc: Rusty Russell >> > --- >> > v1: >> > * remove RFC's "module_ronx=" and merge it with "rodata=" >> > * always keep NX set if CONFIG_SET_MODULE_RONX >> > >> > include/linux/init.h | 3 ++- >> > init/main.c | 2 +- >> > kernel/module.c | 21 ++--- >> > 3 files changed, 21 insertions(+), 5 deletions(-) >> > >> > diff --git a/include/linux/init.h b/include/linux/init.h >> > index e30104c..20aa2eb 100644 >> > --- a/include/linux/init.h >> > +++ b/include/linux/init.h >> > @@ -126,7 +126,8 @@ void prepare_namespace(void); >> > void __init load_default_modules(void); >> > int __init init_rootfs(void); >> > >> > -#ifdef CONFIG_DEBUG_RODATA >> > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) >> > +extern bool rodata_enabled; >> > void mark_rodata_ro(void); >> > #endif >> > >> > diff --git a/init/main.c b/init/main.c >> > index 2858be7..92db2f3 100644 >> > --- a/init/main.c >> > +++ b/init/main.c >> > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char >> > *init_filename) >> > static noinline void __init kernel_init_freeable(void); >> > >> > #ifdef CONFIG_DEBUG_RODATA >> > -static bool rodata_enabled = true; >> > +bool rodata_enabled = true; >> >> Is there a mismatch here between the extern ifdef and the bool ifdef? >> I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? > > Yes. > >> Also, can you mark this as __ro_after_init, since nothing changes it >> after the kernel command line is parsed? > > Yes, yes. > > Thanks, > -Takahiro AKASHI > >> Otherwise, this looks fine to me. >> >> -Kees >> >> >> -- >> Kees Cook >> Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
AKASHI Takahiro writes: > On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: >> On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro >> wrote: >> > 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 patch looks good (except the minor issues noted by Kees); please CC the followup version to Jessica as new module maintainer. Thanks! Rusty. >> > >> > 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: Mark Rutland >> > Signed-off-by: AKASHI Takahiro >> > Cc: Rusty Russell >> > --- >> > v1: >> > * remove RFC's "module_ronx=" and merge it with "rodata=" >> > * always keep NX set if CONFIG_SET_MODULE_RONX >> > >> > include/linux/init.h | 3 ++- >> > init/main.c | 2 +- >> > kernel/module.c | 21 ++--- >> > 3 files changed, 21 insertions(+), 5 deletions(-) >> > >> > diff --git a/include/linux/init.h b/include/linux/init.h >> > index e30104c..20aa2eb 100644 >> > --- a/include/linux/init.h >> > +++ b/include/linux/init.h >> > @@ -126,7 +126,8 @@ void prepare_namespace(void); >> > void __init load_default_modules(void); >> > int __init init_rootfs(void); >> > >> > -#ifdef CONFIG_DEBUG_RODATA >> > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) >> > +extern bool rodata_enabled; >> > void mark_rodata_ro(void); >> > #endif >> > >> > diff --git a/init/main.c b/init/main.c >> > index 2858be7..92db2f3 100644 >> > --- a/init/main.c >> > +++ b/init/main.c >> > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char >> > *init_filename) >> > static noinline void __init kernel_init_freeable(void); >> > >> > #ifdef CONFIG_DEBUG_RODATA >> > -static bool rodata_enabled = true; >> > +bool rodata_enabled = true; >> >> Is there a mismatch here between the extern ifdef and the bool ifdef? >> I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? > > Yes. > >> Also, can you mark this as __ro_after_init, since nothing changes it >> after the kernel command line is parsed? > > Yes, yes. > > Thanks, > -Takahiro AKASHI > >> Otherwise, this looks fine to me. >> >> -Kees >> >> >> -- >> Kees Cook >> Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: > On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro >wrote: > > 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: Mark Rutland > > Signed-off-by: AKASHI Takahiro > > Cc: Rusty Russell > > --- > > v1: > > * remove RFC's "module_ronx=" and merge it with "rodata=" > > * always keep NX set if CONFIG_SET_MODULE_RONX > > > > include/linux/init.h | 3 ++- > > init/main.c | 2 +- > > kernel/module.c | 21 ++--- > > 3 files changed, 21 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/init.h b/include/linux/init.h > > index e30104c..20aa2eb 100644 > > --- a/include/linux/init.h > > +++ b/include/linux/init.h > > @@ -126,7 +126,8 @@ void prepare_namespace(void); > > void __init load_default_modules(void); > > int __init init_rootfs(void); > > > > -#ifdef CONFIG_DEBUG_RODATA > > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) > > +extern bool rodata_enabled; > > void mark_rodata_ro(void); > > #endif > > > > diff --git a/init/main.c b/init/main.c > > index 2858be7..92db2f3 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > > *init_filename) > > static noinline void __init kernel_init_freeable(void); > > > > #ifdef CONFIG_DEBUG_RODATA > > -static bool rodata_enabled = true; > > +bool rodata_enabled = true; > > Is there a mismatch here between the extern ifdef and the bool ifdef? > I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? Yes. > Also, can you mark this as __ro_after_init, since nothing changes it > after the kernel command line is parsed? Yes, yes. Thanks, -Takahiro AKASHI > Otherwise, this looks fine to me. > > -Kees > > > -- > Kees Cook > Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
On Thu, Oct 20, 2016 at 01:48:15PM -0700, Kees Cook wrote: > On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro > wrote: > > 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: Mark Rutland > > Signed-off-by: AKASHI Takahiro > > Cc: Rusty Russell > > --- > > v1: > > * remove RFC's "module_ronx=" and merge it with "rodata=" > > * always keep NX set if CONFIG_SET_MODULE_RONX > > > > include/linux/init.h | 3 ++- > > init/main.c | 2 +- > > kernel/module.c | 21 ++--- > > 3 files changed, 21 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/init.h b/include/linux/init.h > > index e30104c..20aa2eb 100644 > > --- a/include/linux/init.h > > +++ b/include/linux/init.h > > @@ -126,7 +126,8 @@ void prepare_namespace(void); > > void __init load_default_modules(void); > > int __init init_rootfs(void); > > > > -#ifdef CONFIG_DEBUG_RODATA > > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) > > +extern bool rodata_enabled; > > void mark_rodata_ro(void); > > #endif > > > > diff --git a/init/main.c b/init/main.c > > index 2858be7..92db2f3 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > > *init_filename) > > static noinline void __init kernel_init_freeable(void); > > > > #ifdef CONFIG_DEBUG_RODATA > > -static bool rodata_enabled = true; > > +bool rodata_enabled = true; > > Is there a mismatch here between the extern ifdef and the bool ifdef? > I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? Yes. > Also, can you mark this as __ro_after_init, since nothing changes it > after the kernel command line is parsed? Yes, yes. Thanks, -Takahiro AKASHI > Otherwise, this looks fine to me. > > -Kees > > > -- > Kees Cook > Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahirowrote: > 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: Mark Rutland > Signed-off-by: AKASHI Takahiro > Cc: Rusty Russell > --- > v1: > * remove RFC's "module_ronx=" and merge it with "rodata=" > * always keep NX set if CONFIG_SET_MODULE_RONX > > include/linux/init.h | 3 ++- > init/main.c | 2 +- > kernel/module.c | 21 ++--- > 3 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/include/linux/init.h b/include/linux/init.h > index e30104c..20aa2eb 100644 > --- a/include/linux/init.h > +++ b/include/linux/init.h > @@ -126,7 +126,8 @@ void prepare_namespace(void); > void __init load_default_modules(void); > int __init init_rootfs(void); > > -#ifdef CONFIG_DEBUG_RODATA > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) > +extern bool rodata_enabled; > void mark_rodata_ro(void); > #endif > > diff --git a/init/main.c b/init/main.c > index 2858be7..92db2f3 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > *init_filename) > static noinline void __init kernel_init_freeable(void); > > #ifdef CONFIG_DEBUG_RODATA > -static bool rodata_enabled = true; > +bool rodata_enabled = true; Is there a mismatch here between the extern ifdef and the bool ifdef? I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? Also, can you mark this as __ro_after_init, since nothing changes it after the kernel command line is parsed? Otherwise, this looks fine to me. -Kees -- Kees Cook Nexus Security
Re: [kernel-hardening] [PATCH] module: extend 'rodata=off' boot cmdline parameter to module mappings
On Wed, Oct 19, 2016 at 11:24 PM, AKASHI Takahiro wrote: > 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: Mark Rutland > Signed-off-by: AKASHI Takahiro > Cc: Rusty Russell > --- > v1: > * remove RFC's "module_ronx=" and merge it with "rodata=" > * always keep NX set if CONFIG_SET_MODULE_RONX > > include/linux/init.h | 3 ++- > init/main.c | 2 +- > kernel/module.c | 21 ++--- > 3 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/include/linux/init.h b/include/linux/init.h > index e30104c..20aa2eb 100644 > --- a/include/linux/init.h > +++ b/include/linux/init.h > @@ -126,7 +126,8 @@ void prepare_namespace(void); > void __init load_default_modules(void); > int __init init_rootfs(void); > > -#ifdef CONFIG_DEBUG_RODATA > +#if defined(CONFIG_DEBUG_RODATA) || defined(CONFIG_DEBUG_SET_MODULE_RONX) > +extern bool rodata_enabled; > void mark_rodata_ro(void); > #endif > > diff --git a/init/main.c b/init/main.c > index 2858be7..92db2f3 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -915,7 +915,7 @@ static int try_to_run_init_process(const char > *init_filename) > static noinline void __init kernel_init_freeable(void); > > #ifdef CONFIG_DEBUG_RODATA > -static bool rodata_enabled = true; > +bool rodata_enabled = true; Is there a mismatch here between the extern ifdef and the bool ifdef? I.e. shouldn't the ifdef here be || DEBUG_SET_MODULE_RONX too? Also, can you mark this as __ro_after_init, since nothing changes it after the kernel command line is parsed? Otherwise, this looks fine to me. -Kees -- Kees Cook Nexus Security