[PATCH 3/8] UBUNTU: [Config] Enable cred sanity checks

[Tyler Hicks]

BugLink: https://launchpad.net/bugs/1855335

Enable CONFIG_DEBUG_CREDENTIALS to perform sanity checks, such as
verifying usage counts and proper magic values, when handling cred
structs. If a cred sanity check fails a loud warning is printed to the
logs.

This change raises the bar on the effort required to implement an
exploit based on cred manipulation. CONFIG_DEBUG_CREDENTIALS will not
prevent the attack but may aide an administrator in discovering such an
attack on the system.

Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
---
 debian.master/config/annotations          | 3 ++-
 debian.master/config/config.common.ubuntu | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/debian.master/config/annotations b/debian.master/config/annotations
index c8781797bfe8..3ce3a62a8d7d 100644
--- a/debian.master/config/annotations
+++ b/debian.master/config/annotations
@@ -10625,13 +10625,14 @@ CONFIG_DEBUG_LIST                               policy<{'amd64': 'y', 'arm64': '
 CONFIG_DEBUG_PLIST                              policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 CONFIG_DEBUG_SG                                 policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 CONFIG_DEBUG_NOTIFIERS                          policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
-CONFIG_DEBUG_CREDENTIALS                        policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
+CONFIG_DEBUG_CREDENTIALS                        policy<{'amd64': 'y', 'arm64': 'y', 'armhf': 'y', 'i386': 'y', 'ppc64el': 'y', 's390x': 'y'}>
 CONFIG_DEBUG_WQ_FORCE_RR_CPU                    policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 CONFIG_DEBUG_BLOCK_EXT_DEVT                     policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 CONFIG_CPU_HOTPLUG_STATE_CONTROL                policy<{'amd64': 'n', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 CONFIG_LATENCYTOP                               policy<{'amd64-generic': 'n', 'amd64-lowlatency': 'y', 'arm64': 'n', 'armhf': 'n', 'i386': 'n', 'ppc64el': 'n', 's390x': 'n'}>
 #
 CONFIG_DEBUG_LIST                               mark<ENFORCED> note<LP:1855334>
+CONFIG_DEBUG_CREDENTIALS                        mark<ENFORCED> note<LP:1855335>
 CONFIG_LATENCYTOP                               mark<ENFORCED> note<https://lists.ubuntu.com/archives/kernel-team/2014-July/045006.html, LP#1655986>
 
 # Menu: Kernel hacking >> Kernel debugging >> Architecture: arm
diff --git a/debian.master/config/config.common.ubuntu b/debian.master/config/config.common.ubuntu
index b0b3b98cfa6f..f989a8ba30ca 100644
--- a/debian.master/config/config.common.ubuntu
+++ b/debian.master/config/config.common.ubuntu
@@ -2304,7 +2304,7 @@ CONFIG_DEBUGGER=y
 # CONFIG_DEBUG_BLOCK_EXT_DEVT is not set
 # CONFIG_DEBUG_BOOT_PARAMS is not set
 CONFIG_DEBUG_BUGVERBOSE=y
-# CONFIG_DEBUG_CREDENTIALS is not set
+CONFIG_DEBUG_CREDENTIALS=y
 # CONFIG_DEBUG_DEVRES is not set
 # CONFIG_DEBUG_DRIVER is not set
 # CONFIG_DEBUG_EFI is not set
-- 
2.17.1