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| author |   Alexander Popov <alex.popov@linux.com> | 2018-08-17 01:17:03 +0300 |
|---|---|---|
| committer |   Kees Cook <keescook@chromium.org> | 2018-09-04 10:35:48 -0700 |
| commit | 964c9dff0091893a9a74a88edf984c6da0b779f7 (patch) | |
| tree | 162d45af3ac44401db524294e67e396ddee476f4 /Documentation/sysctl | |
| parent | doc: self-protection: Add information about STACKLEAK feature (diff) | |
| download | linux-dev-964c9dff0091893a9a74a88edf984c6da0b779f7.tar.xz linux-dev-964c9dff0091893a9a74a88edf984c6da0b779f7.zip | |
stackleak: Allow runtime disabling of kernel stack erasing
Introduce CONFIG_STACKLEAK_RUNTIME_DISABLE option, which provides
'stack_erasing' sysctl. It can be used in runtime to control kernel
stack erasing for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Alexander Popov <alex.popov@linux.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'Documentation/sysctl')
| -rw-r--r-- | Documentation/sysctl/kernel.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 37a679501ddc..1b8775298cf7 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -89,6 +89,7 @@ show up in /proc/sys/kernel: - shmmni - softlockup_all_cpu_backtrace - soft_watchdog +- stack_erasing - stop-a [ SPARC only ] - sysrq ==> Documentation/admin-guide/sysrq.rst - sysctl_writes_strict @@ -987,6 +988,23 @@ detect a hard lockup condition. ============================================================== +stack_erasing + +This parameter can be used to control kernel stack erasing at the end +of syscalls for kernels built with CONFIG_GCC_PLUGIN_STACKLEAK. + +That erasing 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. + + 0: kernel stack erasing is disabled, STACKLEAK_METRICS are not updated. + + 1: kernel stack erasing is enabled (default), it is performed before + returning to the userspace at the end of syscalls. + +============================================================== + tainted: Non-zero if the kernel has been tainted. Numeric values, which can be |