* [PATCH] acpi: create CONFIG item for debugfs custom_method
@ 2011-02-22 19:32 Kees Cook
2011-04-13 0:20 ` Kees Cook
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Kees Cook @ 2011-02-22 19:32 UTC (permalink / raw)
To: linux-kernel; +Cc: Len Brown, linux-acpi
Since /sys/kernel/debug/acpi/custom_method can be used to write arbitrary
kernel memory (http://jon.oberheide.org/files/american-sign-language.c),
it should be able to be left out of the kernel for system owners that
want to be as defensive as possible to potential attacks, even from the
root user. See as examples: CONFIG_DEVKMEM, CONFIG_STRICT_DEVMEM, and
/proc/sys/kernel/modules_disabled.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
---
drivers/acpi/Kconfig | 10 ++++++++++
drivers/acpi/debugfs.c | 2 ++
2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 2aa042a..726b7ea 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -381,6 +381,16 @@ config ACPI_HED
which is used to report some hardware errors notified via
SCI, mainly the corrected errors.
+config ACPI_DEBUG_CUSTOM_METHOD
+ bool "Debugging: Custom Method Insertion"
+ depends on DEBUG_FS
+ default n
+ help
+ This creates the debugfs interface file "acpi/custom_method"
+ used for loading custom ACPI methods. Note that this allows
+ arbitrary kernel memory writing by the root user and is not
+ recommended for normal systems.
+
source "drivers/acpi/apei/Kconfig"
endif # ACPI
diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
index 5df67f1..0240b15 100644
--- a/drivers/acpi/debugfs.c
+++ b/drivers/acpi/debugfs.c
@@ -20,6 +20,7 @@ module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
MODULE_PARM_DESC(aml_debug_output,
"To enable/disable the ACPI Debug Object output.");
+#ifdef CONFIG_ACPI_DEBUG_CUSTOM_METHOD
/* /sys/kernel/debug/acpi/custom_method */
static ssize_t cm_write(struct file *file, const char __user * user_buf,
@@ -92,3 +93,4 @@ err:
debugfs_remove(acpi_dir);
return -EINVAL;
}
+#endif
--
1.7.2.3
--
Kees Cook
Ubuntu Security Team
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] acpi: create CONFIG item for debugfs custom_method
2011-02-22 19:32 [PATCH] acpi: create CONFIG item for debugfs custom_method Kees Cook
@ 2011-04-13 0:20 ` Kees Cook
2011-05-28 4:15 ` Kees Cook
2011-05-29 5:39 ` Len Brown
2 siblings, 0 replies; 6+ messages in thread
From: Kees Cook @ 2011-04-13 0:20 UTC (permalink / raw)
To: linux-kernel; +Cc: Len Brown, linux-acpi
Hi,
Any news on this? I think it's a no-brainer to let this be CONFIG-able.
Thanks!
-Kees
On Tue, Feb 22, 2011 at 11:32:50AM -0800, Kees Cook wrote:
> Since /sys/kernel/debug/acpi/custom_method can be used to write arbitrary
> kernel memory (http://jon.oberheide.org/files/american-sign-language.c),
> it should be able to be left out of the kernel for system owners that
> want to be as defensive as possible to potential attacks, even from the
> root user. See as examples: CONFIG_DEVKMEM, CONFIG_STRICT_DEVMEM, and
> /proc/sys/kernel/modules_disabled.
>
> Signed-off-by: Kees Cook <kees.cook@canonical.com>
> ---
> drivers/acpi/Kconfig | 10 ++++++++++
> drivers/acpi/debugfs.c | 2 ++
> 2 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 2aa042a..726b7ea 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -381,6 +381,16 @@ config ACPI_HED
> which is used to report some hardware errors notified via
> SCI, mainly the corrected errors.
>
> +config ACPI_DEBUG_CUSTOM_METHOD
> + bool "Debugging: Custom Method Insertion"
> + depends on DEBUG_FS
> + default n
> + help
> + This creates the debugfs interface file "acpi/custom_method"
> + used for loading custom ACPI methods. Note that this allows
> + arbitrary kernel memory writing by the root user and is not
> + recommended for normal systems.
> +
> source "drivers/acpi/apei/Kconfig"
>
> endif # ACPI
> diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
> index 5df67f1..0240b15 100644
> --- a/drivers/acpi/debugfs.c
> +++ b/drivers/acpi/debugfs.c
> @@ -20,6 +20,7 @@ module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
> MODULE_PARM_DESC(aml_debug_output,
> "To enable/disable the ACPI Debug Object output.");
>
> +#ifdef CONFIG_ACPI_DEBUG_CUSTOM_METHOD
> /* /sys/kernel/debug/acpi/custom_method */
>
> static ssize_t cm_write(struct file *file, const char __user * user_buf,
> @@ -92,3 +93,4 @@ err:
> debugfs_remove(acpi_dir);
> return -EINVAL;
> }
> +#endif
> --
> 1.7.2.3
>
> --
> Kees Cook
> Ubuntu Security Team
--
Kees Cook
Ubuntu Security Team
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] acpi: create CONFIG item for debugfs custom_method
2011-02-22 19:32 [PATCH] acpi: create CONFIG item for debugfs custom_method Kees Cook
2011-04-13 0:20 ` Kees Cook
@ 2011-05-28 4:15 ` Kees Cook
2011-05-28 9:03 ` Rafael J. Wysocki
2011-05-29 5:39 ` Len Brown
2 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2011-05-28 4:15 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel, Len Brown
Since /sys/kernel/debug/acpi/custom_method can be used to write arbitrary
kernel memory (http://jon.oberheide.org/files/american-sign-language.c),
it should be able to be left out of the kernel for system owners that
want to be as defensive as possible to potential attacks, even from the
root user. See as examples: CONFIG_DEVKMEM, CONFIG_STRICT_DEVMEM, and
/proc/sys/kernel/modules_disabled.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
---
Third time sending this, no response...
https://lkml.org/lkml/2011/2/22/369
drivers/acpi/Kconfig | 10 ++++++++++
drivers/acpi/debugfs.c | 2 ++
2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 2aa042a..726b7ea 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -381,6 +381,16 @@ config ACPI_HED
which is used to report some hardware errors notified via
SCI, mainly the corrected errors.
+config ACPI_DEBUG_CUSTOM_METHOD
+ bool "Debugging: Custom Method Insertion"
+ depends on DEBUG_FS
+ default n
+ help
+ This creates the debugfs interface file "acpi/custom_method"
+ used for loading custom ACPI methods. Note that this allows
+ arbitrary kernel memory writing by the root user and is not
+ recommended for normal systems.
+
source "drivers/acpi/apei/Kconfig"
endif # ACPI
diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
index 5df67f1..0240b15 100644
--- a/drivers/acpi/debugfs.c
+++ b/drivers/acpi/debugfs.c
@@ -20,6 +20,7 @@ module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
MODULE_PARM_DESC(aml_debug_output,
"To enable/disable the ACPI Debug Object output.");
+#ifdef CONFIG_ACPI_DEBUG_CUSTOM_METHOD
/* /sys/kernel/debug/acpi/custom_method */
static ssize_t cm_write(struct file *file, const char __user * user_buf,
@@ -92,3 +93,4 @@ err:
debugfs_remove(acpi_dir);
return -EINVAL;
}
+#endif
--
1.7.2.3
--
Kees Cook
Ubuntu Security Team
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] acpi: create CONFIG item for debugfs custom_method
2011-05-28 4:15 ` Kees Cook
@ 2011-05-28 9:03 ` Rafael J. Wysocki
0 siblings, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2011-05-28 9:03 UTC (permalink / raw)
To: Kees Cook; +Cc: Andrew Morton, linux-kernel, Len Brown, Thomas Renninger
On Saturday, May 28, 2011, Kees Cook wrote:
> Since /sys/kernel/debug/acpi/custom_method can be used to write arbitrary
> kernel memory (http://jon.oberheide.org/files/american-sign-language.c),
> it should be able to be left out of the kernel for system owners that
> want to be as defensive as possible to potential attacks, even from the
> root user. See as examples: CONFIG_DEVKMEM, CONFIG_STRICT_DEVMEM, and
> /proc/sys/kernel/modules_disabled.
I believe Thomas Renninger sent patches to address this issue too.
Thanks,
Rafael
> Signed-off-by: Kees Cook <kees.cook@canonical.com>
> ---
> Third time sending this, no response...
> https://lkml.org/lkml/2011/2/22/369
>
> drivers/acpi/Kconfig | 10 ++++++++++
> drivers/acpi/debugfs.c | 2 ++
> 2 files changed, 12 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 2aa042a..726b7ea 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -381,6 +381,16 @@ config ACPI_HED
> which is used to report some hardware errors notified via
> SCI, mainly the corrected errors.
>
> +config ACPI_DEBUG_CUSTOM_METHOD
> + bool "Debugging: Custom Method Insertion"
> + depends on DEBUG_FS
> + default n
> + help
> + This creates the debugfs interface file "acpi/custom_method"
> + used for loading custom ACPI methods. Note that this allows
> + arbitrary kernel memory writing by the root user and is not
> + recommended for normal systems.
> +
> source "drivers/acpi/apei/Kconfig"
>
> endif # ACPI
> diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
> index 5df67f1..0240b15 100644
> --- a/drivers/acpi/debugfs.c
> +++ b/drivers/acpi/debugfs.c
> @@ -20,6 +20,7 @@ module_param_named(aml_debug_output, acpi_gbl_enable_aml_debug_object,
> MODULE_PARM_DESC(aml_debug_output,
> "To enable/disable the ACPI Debug Object output.");
>
> +#ifdef CONFIG_ACPI_DEBUG_CUSTOM_METHOD
> /* /sys/kernel/debug/acpi/custom_method */
>
> static ssize_t cm_write(struct file *file, const char __user * user_buf,
> @@ -92,3 +93,4 @@ err:
> debugfs_remove(acpi_dir);
> return -EINVAL;
> }
> +#endif
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] acpi: create CONFIG item for debugfs custom_method
2011-02-22 19:32 [PATCH] acpi: create CONFIG item for debugfs custom_method Kees Cook
2011-04-13 0:20 ` Kees Cook
2011-05-28 4:15 ` Kees Cook
@ 2011-05-29 5:39 ` Len Brown
2011-05-29 5:51 ` Len Brown
2 siblings, 1 reply; 6+ messages in thread
From: Len Brown @ 2011-05-29 5:39 UTC (permalink / raw)
To: Kees Cook; +Cc: linux-kernel, linux-acpi
applied
thanks,
Len Brown, Intel Open Source Technology Center
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-05-29 5:51 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2011-02-22 19:32 [PATCH] acpi: create CONFIG item for debugfs custom_method Kees Cook
2011-04-13 0:20 ` Kees Cook
2011-05-28 4:15 ` Kees Cook
2011-05-28 9:03 ` Rafael J. Wysocki
2011-05-29 5:39 ` Len Brown
2011-05-29 5:51 ` Len Brown
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