* [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
@ 2018-06-29 20:04 ` Kamal Mostafa
0 siblings, 0 replies; 8+ messages in thread
From: Kamal Mostafa @ 2018-06-29 20:04 UTC (permalink / raw)
To: linux-security-module
Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
security/Kconfig | 1 -
1 file changed, 1 deletion(-)
diff --git a/security/Kconfig b/security/Kconfig
index c430206..7667774 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
- select BUG
imply STRICT_DEVMEM
help
This option checks for obviously wrong memory regions when
--
2.7.4
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
@ 2018-06-29 20:04 ` Kamal Mostafa
0 siblings, 0 replies; 8+ messages in thread
From: Kamal Mostafa @ 2018-06-29 20:04 UTC (permalink / raw)
To: linux-kernel, Kees Cook
Cc: Kamal Mostafa, James Morris, Serge E. Hallyn,
open list:SECURITY SUBSYSTEM
Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
security/Kconfig | 1 -
1 file changed, 1 deletion(-)
diff --git a/security/Kconfig b/security/Kconfig
index c430206..7667774 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
config HARDENED_USERCOPY
bool "Harden memory copies between kernel and userspace"
depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
- select BUG
imply STRICT_DEVMEM
help
This option checks for obviously wrong memory regions when
--
2.7.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
2018-06-29 20:04 ` Kamal Mostafa
@ 2018-06-29 20:27 ` Kees Cook
-1 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2018-06-29 20:27 UTC (permalink / raw)
To: linux-security-module
On Fri, Jun 29, 2018 at 1:04 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
>
> Signed-off-by: Kamal Mostafa <kamal@canonical.com>
> ---
> security/Kconfig | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/security/Kconfig b/security/Kconfig
> index c430206..7667774 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
> config HARDENED_USERCOPY
> bool "Harden memory copies between kernel and userspace"
> depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
> - select BUG
> imply STRICT_DEVMEM
> help
> This option checks for obviously wrong memory regions when
Do the lkdtm tests for usercopy correctly halt the kernel thread if
CONFIG_BUG is removed?
-Kees
--
Kees Cook
Pixel Security
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
@ 2018-06-29 20:27 ` Kees Cook
0 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2018-06-29 20:27 UTC (permalink / raw)
To: Kamal Mostafa
Cc: LKML, James Morris, Serge E. Hallyn, open list:SECURITY SUBSYSTEM
On Fri, Jun 29, 2018 at 1:04 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
>
> Signed-off-by: Kamal Mostafa <kamal@canonical.com>
> ---
> security/Kconfig | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/security/Kconfig b/security/Kconfig
> index c430206..7667774 100644
> --- a/security/Kconfig
> +++ b/security/Kconfig
> @@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
> config HARDENED_USERCOPY
> bool "Harden memory copies between kernel and userspace"
> depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
> - select BUG
> imply STRICT_DEVMEM
> help
> This option checks for obviously wrong memory regions when
Do the lkdtm tests for usercopy correctly halt the kernel thread if
CONFIG_BUG is removed?
-Kees
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
2018-06-29 20:27 ` Kees Cook
@ 2018-07-02 20:14 ` Kamal Mostafa
-1 siblings, 0 replies; 8+ messages in thread
From: Kamal Mostafa @ 2018-07-02 20:14 UTC (permalink / raw)
To: linux-security-module
On Fri, Jun 29, 2018 at 01:27:08PM -0700, Kees Cook wrote:
> On Fri, Jun 29, 2018 at 1:04 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
> >
> > Signed-off-by: Kamal Mostafa <kamal@canonical.com>
> > ---
> > security/Kconfig | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/security/Kconfig b/security/Kconfig
> > index c430206..7667774 100644
> > --- a/security/Kconfig
> > +++ b/security/Kconfig
> > @@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
> > config HARDENED_USERCOPY
> > bool "Harden memory copies between kernel and userspace"
> > depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
> > - select BUG
> > imply STRICT_DEVMEM
> > help
> > This option checks for obviously wrong memory regions when
>
> Do the lkdtm tests for usercopy correctly halt the kernel thread if
> CONFIG_BUG is removed?
>
Yes, they do...
With this config (specifically disabling 'FALLBACK'):
CONFIG_HARDENED_USERCOPY=y
# CONFIG_HARDENED_USERCOPY_FALLBACK is not set
# CONFIG_BUG is not set
I ran the usercopy tests as follows:
modprobe lkdtm
cd /sys/kernel/debug/provoke-crash
cat DIRECT | grep USERCOPY | while read x ; do echo $x | tee DIRECT || echo $?; done
Resulting in this command line output:
USERCOPY_HEAP_SIZE_TO
139
USERCOPY_HEAP_SIZE_FROM
139
USERCOPY_HEAP_WHITELIST_TO
139
USERCOPY_HEAP_WHITELIST_FROM
139
USERCOPY_STACK_FRAME_TO
139
USERCOPY_STACK_FRAME_FROM
139
USERCOPY_STACK_BEYOND
139
USERCOPY_KERNEL
139
Each test case yields kernel log output like:
lkdtm: Performing direct entry USERCOPY_HEAP_SIZE_TO
lkdtm: attempting good copy_to_user of correct size
lkdtm: attempting bad copy_to_user of too large size
usercopy: Kernel memory exposure attempt detected from SLUB object 'kmalloc-1024' (offset 16, size 1024)!
invalid opcode: 0000 [#17] SMP PTI
... {panic dump} ...
Each 'tee' gets terminated with SIGSEGV and no instances appear of the
lkdtm/usercopy.c warning "copy_{to/from}_user failed, but lacked Oops".
If I leave CONFIG_HARDENED_USERCOPY_FALLBACK=y then the pair of
WHITELIST tests don't trigger a panic or SIGSEGV, as expected.
-Kamal
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
@ 2018-07-02 20:14 ` Kamal Mostafa
0 siblings, 0 replies; 8+ messages in thread
From: Kamal Mostafa @ 2018-07-02 20:14 UTC (permalink / raw)
To: Kees Cook
Cc: LKML, James Morris, Serge E. Hallyn, open list:SECURITY SUBSYSTEM
On Fri, Jun 29, 2018 at 01:27:08PM -0700, Kees Cook wrote:
> On Fri, Jun 29, 2018 at 1:04 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> > Allows for CONFIG_HARDENED_USERCOPY without CONFIG_BUG.
> >
> > Signed-off-by: Kamal Mostafa <kamal@canonical.com>
> > ---
> > security/Kconfig | 1 -
> > 1 file changed, 1 deletion(-)
> >
> > diff --git a/security/Kconfig b/security/Kconfig
> > index c430206..7667774 100644
> > --- a/security/Kconfig
> > +++ b/security/Kconfig
> > @@ -153,7 +153,6 @@ config HAVE_HARDENED_USERCOPY_ALLOCATOR
> > config HARDENED_USERCOPY
> > bool "Harden memory copies between kernel and userspace"
> > depends on HAVE_HARDENED_USERCOPY_ALLOCATOR
> > - select BUG
> > imply STRICT_DEVMEM
> > help
> > This option checks for obviously wrong memory regions when
>
> Do the lkdtm tests for usercopy correctly halt the kernel thread if
> CONFIG_BUG is removed?
>
Yes, they do...
With this config (specifically disabling 'FALLBACK'):
CONFIG_HARDENED_USERCOPY=y
# CONFIG_HARDENED_USERCOPY_FALLBACK is not set
# CONFIG_BUG is not set
I ran the usercopy tests as follows:
modprobe lkdtm
cd /sys/kernel/debug/provoke-crash
cat DIRECT | grep USERCOPY | while read x ; do echo $x | tee DIRECT || echo $?; done
Resulting in this command line output:
USERCOPY_HEAP_SIZE_TO
139
USERCOPY_HEAP_SIZE_FROM
139
USERCOPY_HEAP_WHITELIST_TO
139
USERCOPY_HEAP_WHITELIST_FROM
139
USERCOPY_STACK_FRAME_TO
139
USERCOPY_STACK_FRAME_FROM
139
USERCOPY_STACK_BEYOND
139
USERCOPY_KERNEL
139
Each test case yields kernel log output like:
lkdtm: Performing direct entry USERCOPY_HEAP_SIZE_TO
lkdtm: attempting good copy_to_user of correct size
lkdtm: attempting bad copy_to_user of too large size
usercopy: Kernel memory exposure attempt detected from SLUB object 'kmalloc-1024' (offset 16, size 1024)!
invalid opcode: 0000 [#17] SMP PTI
... {panic dump} ...
Each 'tee' gets terminated with SIGSEGV and no instances appear of the
lkdtm/usercopy.c warning "copy_{to/from}_user failed, but lacked Oops".
If I leave CONFIG_HARDENED_USERCOPY_FALLBACK=y then the pair of
WHITELIST tests don't trigger a panic or SIGSEGV, as expected.
-Kamal
^ permalink raw reply [flat|nested] 8+ messages in thread* [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
2018-07-02 20:14 ` Kamal Mostafa
@ 2018-07-02 20:46 ` Kees Cook
-1 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2018-07-02 20:46 UTC (permalink / raw)
To: linux-security-module
Hi Kamal,
On Mon, Jul 2, 2018 at 1:14 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> On Fri, Jun 29, 2018 at 01:27:08PM -0700, Kees Cook wrote:
>> Do the lkdtm tests for usercopy correctly halt the kernel thread if
>> CONFIG_BUG is removed?
>
> Yes, they do...
Perfect, thanks for double-checking! I'll apply this to my tree.
-Kees
--
Kees Cook
Pixel Security
--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG
@ 2018-07-02 20:46 ` Kees Cook
0 siblings, 0 replies; 8+ messages in thread
From: Kees Cook @ 2018-07-02 20:46 UTC (permalink / raw)
To: Kamal Mostafa
Cc: LKML, James Morris, Serge E. Hallyn, open list:SECURITY SUBSYSTEM
Hi Kamal,
On Mon, Jul 2, 2018 at 1:14 PM, Kamal Mostafa <kamal@canonical.com> wrote:
> On Fri, Jun 29, 2018 at 01:27:08PM -0700, Kees Cook wrote:
>> Do the lkdtm tests for usercopy correctly halt the kernel thread if
>> CONFIG_BUG is removed?
>
> Yes, they do...
Perfect, thanks for double-checking! I'll apply this to my tree.
-Kees
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-07-02 20:46 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-06-29 20:04 [PATCH] security: CONFIG_HARDENED_USERCOPY does not need to select BUG Kamal Mostafa
2018-06-29 20:04 ` Kamal Mostafa
2018-06-29 20:27 ` Kees Cook
2018-06-29 20:27 ` Kees Cook
2018-07-02 20:14 ` Kamal Mostafa
2018-07-02 20:14 ` Kamal Mostafa
2018-07-02 20:46 ` Kees Cook
2018-07-02 20:46 ` Kees Cook
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.