[PATCH 01/11] Secure boot: Add new capability

From: Matthew Garrett
Date: Tue Sep 04 2012 - 11:57:02 EST


Secure boot adds certain policy requirements, including that root must not
be able to do anything that could cause the kernel to execute arbitrary code.
The simplest way to handle this would seem to be to add a new capability
and gate various functionality on that. We'll then strip it from the initial
capability set if required.

Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
---
include/linux/capability.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/capability.h b/include/linux/capability.h
index d10b7ed..6a39163 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -364,7 +364,11 @@ struct cpu_vfs_cap_data {

#define CAP_BLOCK_SUSPEND 36

-#define CAP_LAST_CAP CAP_BLOCK_SUSPEND
+/* Allow things that are dangerous under secure boot */
+
+#define CAP_SECURE_FIRMWARE 37
+
+#define CAP_LAST_CAP CAP_SECURE_FIRMWARE

#define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)

--
1.7.11.4

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