Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

release: Add several security-related sysctls #435

Merged
merged 2 commits into from
Oct 21, 2019
Merged

release: Add several security-related sysctls #435

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
0508365
release: Add several security-related sysctls
sam-aws Oct 18, 2019
b1f222f
kernel: Enable Yama security module.
sam-aws Oct 18, 2019
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 3 additions & 0 deletions packages/kernel/config-thar
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -21,3 +21,6 @@ CONFIG_BLK_DEV_DM=y
CONFIG_DAX=y
CONFIG_DM_INIT=y
CONFIG_DM_VERITY=y

# yama LSM for ptrace restrictions
CONFIG_SECURITY_YAMA=y
24 changes: 24 additions & 0 deletions packages/release/release-sysctl.conf
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,3 +25,27 @@ net.ipv4.ip_local_port_range = 1025 65000
# Connection tracking to prevent dropped connections
net.netfilter.nf_conntrack_max = 1048576
net.netfilter.nf_conntrack_generic_timeout = 120

## Kernel hardening settings
sam-aws marked this conversation as resolved.
Show resolved Hide resolved
## Settings & descriptions sourced from the KSPP wiki, see
## https://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project/Recommended_Settings#sysctls
# Try to keep kernel address exposures out of various /proc files (kallsyms, modules, etc).
kernel.kptr_restrict = 1

# Avoid kernel memory address exposures via dmesg.
kernel.dmesg_restrict = 1

# Turn off kexec, even if it's built in.
kernel.kexec_load_disabled = 1

# Avoid non-ancestor ptrace access to running processes and their credentials.
kernel.yama.ptrace_scope = 1

# Disable User Namespaces, as it opens up a large attack surface to unprivileged users.
user.max_user_namespaces = 0
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This feels like something we're going to need to change eventually given the use of user namespaces in containers...

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Right, it sounds like this isn't used too thoroughly yet but could be in the future - should we exclude it or wait until it's explicitly supported?


# Turn off unprivileged eBPF access.
kernel.unprivileged_bpf_disabled = 1

# Turn on BPF JIT hardening, if the JIT is enabled.
net.core.bpf_jit_harden = 2