release: Add several security-related sysctls #435
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bcressey
reviewed
Oct 18, 2019
Add recommended settings from the Kernel Self Protection Project[0] wiki. Most of these are straightforward, some notes on the others: - kernel.perf_event_paranoid: Omitted since the Thar kernel does not include the required patch for '3' and the default is '2'. - kernel.yama.ptrace_scope: Omitted since Thar doesn't build the Yama LSM. - user.max_user_namespaces: Included since Kubernetes doesn't yet support user namespaces[1], but could be something to review later on. [0]: https://kernsec.org/wiki/index.php/Kernel_Self_Protection_Project/Recommended_Settings#sysctls [1]: kubernetes/enhancements#127 Signed-off-by: Samuel Mendoza-Jonas <[email protected]>
Enable the Yama LSM and set kernel.yama.ptrace_scope to 1; restricting how processes can use ptrace. For more information see https://www.kernel.org/doc/Documentation/security/Yama.txt Signed-off-by: Samuel Mendoza-Jonas <[email protected]>
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Updated to point to the KSPP wiki in the sysctl settings and added a new commit which enables the Yama LSM. |
bcressey
approved these changes
Oct 19, 2019
iliana
approved these changes
Oct 21, 2019
| kernel.yama.ptrace_scope = 1 | ||
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| # Disable User Namespaces, as it opens up a large attack surface to unprivileged users. | ||
| user.max_user_namespaces = 0 |
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This feels like something we're going to need to change eventually given the use of user namespaces in containers...
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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?
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Issue #, if available:
N/A
Description of changes:
Add recommended settings from the Kernel Self Protection Project
wiki. Most of these are straightforward, some notes on the others:
include the required patch for '3' and the default is '2'.
support user namespaces, but could be something to review later on.
Tested by building and launching an instance and confirming the values were correct under
/proc/sys/...Signed-off-by: Samuel Mendoza-Jonas [email protected]
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