From: "Peter Müller" <peter.mueller@ipfire.org>
To: development@lists.ipfire.org
Subject: [PATCH] sysctl: improve KASLR effectiveness for mmap
Date: Thu, 04 Jul 2019 19:15:00 +0000 [thread overview]
Message-ID: <5e1acef7-1037-f621-0bd5-123519625c50@ipfire.org> (raw)
[-- Attachment #1: Type: text/plain, Size: 947 bytes --]
By feeding more random bits into mmap allocation, the
effectiveness of KASLR will be improved, making attacks
trying to bypass address randomisation more difficult.
Changed sysctl values are:
vm.mmap_rnd_bits = 32 (default: 28)
vm.mmap_rnd_compat_bits = 16 (default: 8)
Signed-off-by: Peter Müller <peter.mueller(a)ipfire.org>
---
config/etc/sysctl.conf | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/config/etc/sysctl.conf b/config/etc/sysctl.conf
index 9a943fffa..5a67f1795 100644
--- a/config/etc/sysctl.conf
+++ b/config/etc/sysctl.conf
@@ -45,6 +45,10 @@ kernel.kptr_restrict = 2
# Avoid kernel memory address exposures via dmesg.
kernel.dmesg_restrict = 1
+# Improve KASLR effectiveness for mmap
+vm.mmap_rnd_bits = 32
+vm.mmap_rnd_compat_bits = 16
+
# Minimal preemption granularity for CPU-bound tasks:
# (default: 1 msec# (1 + ilog(ncpus)), units: nanoseconds)
kernel.sched_min_granularity_ns = 10000000
--
2.16.4
next reply other threads:[~2019-07-04 19:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-04 19:15 Peter Müller [this message]
2019-07-04 19:17 ` Michael Tremer
2019-07-04 19:28 ` Peter Müller
2019-07-06 9:38 Peter Müller
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