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| author | Peter Enderborg <peter.enderborg@sony.com> | 2020-07-16 10:15:11 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-23 18:10:25 +0300 |
| commit | a24c6f7bc923d5e2f3139855eb09b0d480d6b410 (patch) | |
| tree | f96b6939d66e6cb438690706dcb76b7e2a948f73 /Documentation/admin-guide/kernel-parameters.txt | |
| parent | 072e133d554bb74929f902582c8cf66d9fd12771 (diff) | |
| download | linux-a24c6f7bc923d5e2f3139855eb09b0d480d6b410.tar.xz | |
debugfs: Add access restriction option
Since debugfs include sensitive information it need to be treated
carefully. But it also has many very useful debug functions for userspace.
With this option we can have same configuration for system with
need of debugfs and a way to turn it off. This gives a extra protection
for exposure on systems where user-space services with system
access are attacked.
It is controlled by a configurable default value that can be override
with a kernel command line parameter. (debugfs=)
It can be on or off, but also internally on but not seen from user-space.
This no-mount mode do not register a debugfs as filesystem, but client can
register their parts in the internal structures. This data can be readed
with a debugger or saved with a crashkernel. When it is off clients
get EPERM error when accessing the functions for registering their
components.
Signed-off-by: Peter Enderborg <peter.enderborg@sony.com>
Link: https://lore.kernel.org/r/20200716071511.26864-3-peter.enderborg@sony.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb95fad81c79..6766a308ad96 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -827,6 +827,21 @@ useful to also enable the page_owner functionality. on: enable the feature + debugfs= [KNL] This parameter enables what is exposed to userspace + and debugfs internal clients. + Format: { on, no-mount, off } + on: All functions are enabled. + no-mount: + Filesystem is not registered but kernel clients can + access APIs and a crashkernel can be used to read + its content. There is nothing to mount. + off: Filesystem is not registered and clients + get a -EPERM as result when trying to register files + or directories within debugfs. + This is equivalent of the runtime functionality if + debugfs was not enabled in the kernel at all. + Default value is set in build-time with a kernel configuration. + debugpat [X86] Enable PAT debugging decnet.addr= [HW,NET] |