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[v2,38/57,X] Annotate hardware config module parameters in fs/pstore/

Message ID 20200619165010.645925-39-seth.forshee@canonical.com
State New
Headers show
Series Lockdown updates | expand

Commit Message

Seth Forshee June 19, 2020, 4:49 p.m. UTC 
From: David Howells <dhowells@redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1884159

When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in fs/pstore/.

Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
cc: Anton Vorontsov <anton@enomsg.org>
cc: Colin Cross <ccross@android.com>
cc: Tony Luck <tony.luck@intel.com>
(backported from commit b90fe0c4e0ceb52c78c17f3cfa1ff8e79275028d)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 fs/pstore/ram.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index fa0e89edb62d..10b0302c4d57 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -56,7 +56,7 @@  module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400);
 MODULE_PARM_DESC(pmsg_size, "size of user space message log");
 
 static ulong mem_address;
-module_param(mem_address, ulong, 0400);
+module_param_hw(mem_address, ulong, other, 0400);
 MODULE_PARM_DESC(mem_address,
 		"start of reserved RAM used to store oops/panic logs");