do not expose kernel address spaces even to privileged users

Change this setting from 1 to 2 so kernel addresses are not
displayed even if a user has CAPS_SYSLOG privileges.

See also:
- https://lwn.net/Articles/420403/
- https://tails.boum.org/contribute/design/kernel_hardening/

Signed-off-by: Peter Müller <peter.mueller@link38.eu>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/config/etc/sysctl.conf b/config/etc/sysctl.conf
index 011c4287ea04f7194548ac9a27e88b9e2701bf53..345f8f52a4b86cd3c0edda0ac96125dda835e108 100644 (file)
--- a/config/etc/sysctl.conf
+++ b/config/etc/sysctl.conf
@@ -44,7 +44,7 @@ net.bridge.bridge-nf-call-iptables = 0
 net.bridge.bridge-nf-call-arptables = 0
 
 # Try to keep kernel address exposures out of various /proc files (kallsyms, modules, etc).
-kernel.kptr_restrict = 1
+kernel.kptr_restrict = 2
 
 # Avoid kernel memory address exposures via dmesg.
 kernel.dmesg_restrict = 1