[source] Add config symbols for kernel keyring support

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/39d817cf38cac58d4383012adc13dc2e3606f4f7

commit 39d817cf38cac58d4383012adc13dc2e3606f4f7
Author: Nathaniel Wesley Filardo <nwf at cs.jhu.edu>
AuthorDate: Sun Oct 19 03:28:13 2014 -0400

    Add config symbols for kernel keyring support
    
    Enable selection of the kernel key retention framework and some of its
    additional facilities; see Documentation/security/keys.txt and
    security/keys/Kconfig for details
    
    Signed-off-by: Nathaniel Wesley Filardo <nwfilardo at gmail.com>
---
 config/Config-kernel.in | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/config/Config-kernel.in b/config/Config-kernel.in
index b9aaac5..d8ca76c 100644
--- a/config/Config-kernel.in
+++ b/config/Config-kernel.in
@@ -251,6 +251,25 @@ if KERNEL_DEVTMPFS
 
 endif
 
+config KERNEL_KEYS
+    bool "Enable kernel access key retention support"
+    default n
+
+config KERNEL_PERSISTENT_KEYRINGS
+    bool "Enable kernel persistent keyrings"
+    depends on KERNEL_KEYS
+    default n
+
+config KERNEL_BIG_KEYS
+    bool "Enable large payload keys on kernel keyrings"
+    depends on KERNEL_KEYS
+    default n
+
+config KERNEL_ENCRYPTED_KEYS
+    tristate "Enable keys with encrypted payloads on kernel keyrings"
+    depends on KERNEL_KEYS
+    default n
+
 #
 # CGROUP support symbols
 #