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security: Move stackleak config to Kconfig.hardening

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This moves the stackleak plugin options to Kconfig.hardening's memory
initialization menu.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Alexander Popov <alex.popov@linux.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
This commit is contained in:
Kees Cook 2019-04-10 09:04:40 -07:00
parent 9f671e5815
commit b6a6a3772d
2 changed files with 57 additions and 51 deletions
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51
scripts/gcc-plugins/Kconfig
View File

@ -108,57 +108,6 @@ config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
in structures. This reduces the performance hit of RANDSTRUCT
at the cost of weakened randomization.
config GCC_PLUGIN_STACKLEAK
bool "Erase the kernel stack before returning from syscalls"
depends on GCC_PLUGINS
depends on HAVE_ARCH_STACKLEAK
help
This option makes the kernel erase the kernel stack before
returning from system calls. That reduces the information which
kernel stack leak bugs can reveal and blocks some uninitialized
stack variable attacks.
The tradeoff is the performance impact: on a single CPU system kernel
compilation sees a 1% slowdown, other systems and workloads may vary
and you are advised to test this feature on your expected workload
before deploying it.
This plugin was ported from grsecurity/PaX. More information at:
* https://grsecurity.net/
* https://pax.grsecurity.net/
config STACKLEAK_TRACK_MIN_SIZE
int "Minimum stack frame size of functions tracked by STACKLEAK"
default 100
range 0 4096
depends on GCC_PLUGIN_STACKLEAK
help
The STACKLEAK gcc plugin instruments the kernel code for tracking
the lowest border of the kernel stack (and for some other purposes).
It inserts the stackleak_track_stack() call for the functions with
a stack frame size greater than or equal to this parameter.
If unsure, leave the default value 100.
config STACKLEAK_METRICS
bool "Show STACKLEAK metrics in the /proc file system"
depends on GCC_PLUGIN_STACKLEAK
depends on PROC_FS
help
If this is set, STACKLEAK metrics for every task are available in
the /proc file system. In particular, /proc/<pid>/stack_depth
shows the maximum kernel stack consumption for the current and
previous syscalls. Although this information is not precise, it
can be useful for estimating the STACKLEAK performance impact for
your workloads.
config STACKLEAK_RUNTIME_DISABLE
bool "Allow runtime disabling of kernel stack erasing"
depends on GCC_PLUGIN_STACKLEAK
help
This option provides 'stack_erasing' sysctl, which can be used in
runtime to control kernel stack erasing for kernels built with
CONFIG_GCC_PLUGIN_STACKLEAK.
config GCC_PLUGIN_ARM_SSP_PER_TASK
bool
depends on GCC_PLUGINS && ARM

57
security/Kconfig.hardening
View File

@ -88,6 +88,63 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE
initialized. Since not all existing initializers are detected
by the plugin, this can produce false positive warnings.
config GCC_PLUGIN_STACKLEAK
bool "Poison kernel stack before returning from syscalls"
depends on GCC_PLUGINS
depends on HAVE_ARCH_STACKLEAK
help
This option makes the kernel erase the kernel stack before
returning from system calls. This has the effect of leaving
the stack initialized to the poison value, which both reduces
the lifetime of any sensitive stack contents and reduces
potential for uninitialized stack variable exploits or information
exposures (it does not cover functions reaching the same stack
depth as prior functions during the same syscall). This blocks
most uninitialized stack variable attacks, with the performance
impact being driven by the depth of the stack usage, rather than
the function calling complexity.
The performance impact on a single CPU system kernel compilation
sees a 1% slowdown, other systems and workloads may vary and you
are advised to test this feature on your expected workload before
deploying it.
This plugin was ported from grsecurity/PaX. More information at:
* https://grsecurity.net/
* https://pax.grsecurity.net/
config STACKLEAK_TRACK_MIN_SIZE
int "Minimum stack frame size of functions tracked by STACKLEAK"
default 100
range 0 4096
depends on GCC_PLUGIN_STACKLEAK
help
The STACKLEAK gcc plugin instruments the kernel code for tracking
the lowest border of the kernel stack (and for some other purposes).
It inserts the stackleak_track_stack() call for the functions with
a stack frame size greater than or equal to this parameter.
If unsure, leave the default value 100.
config STACKLEAK_METRICS
bool "Show STACKLEAK metrics in the /proc file system"
depends on GCC_PLUGIN_STACKLEAK
depends on PROC_FS
help
If this is set, STACKLEAK metrics for every task are available in
the /proc file system. In particular, /proc/<pid>/stack_depth
shows the maximum kernel stack consumption for the current and
previous syscalls. Although this information is not precise, it
can be useful for estimating the STACKLEAK performance impact for
your workloads.
config STACKLEAK_RUNTIME_DISABLE
bool "Allow runtime disabling of kernel stack erasing"
depends on GCC_PLUGIN_STACKLEAK
help
This option provides 'stack_erasing' sysctl, which can be used in
runtime to control kernel stack erasing for kernels built with
CONFIG_GCC_PLUGIN_STACKLEAK.
endmenu
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