ExecShield In C6 Or C7 Kernels?
I’m trying to figure out if the stock kernels for CentOS-6 and/or CentOS-7
have ExecShield compiled in, and if so, if it is turned on by default.
On my local C7 box I’ve been looking at/for indicators without a lot of success:
/usr/lib/sysctl.d/00-system.conf. does not mention ExecShield at all.
/proc/sys/kernel has no entries for exec_shield no mention of execshield in any of the files in /etc/grub.d
So, as far as I can see, there are no settings that I would expect to force ExecShield to an ON setting.
I DO see, in /proc/sys/kernel, a file named randomize_va_space, and it contains a value of “2”.
I’ve been googling (well, actually DuckDuckGo-ing) and most of the articles I find regarding ExecShield are 3-10 years old.
I’d appreciate pointers/guides/info on ExecShield in C6 or C7.
thanks in advance!
Fred
4 thoughts on - ExecShield In C6 Or C7 Kernels?
According to what I’ve read, Exec Shield is enabled in CentOS-6 and -7
by default. In CentOS-6, you can see it by:
sysctl -a | grep -i shield
The sysctl command also allows you to disable it. But in CentOS-7 you cannot change it any more.
Akemi
Thanks, Akemi!
I’ve also realized if you have No Execute(NX) or Execute Disable(XD)
protection enabled in your BIOS, you can’t access kernel.exec-shield sysctl parameter.
[root@CentOS7 ~]# dmesg | grep ‘[NX|DX]*protection’
[ 0.000000] NX (Execute Disable) protection: active
[root@CentOS7 ~]# sysctl kernel.exec-shield sysctl: cannot stat /proc/sys/kernel/exec-shield: No such file or directory
dmesg | grep “[NX|DX]*protection”