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This LSM enforces that kernel-loaded files (modules, firmware, etc) must all come from the same filesystem, with the expectation that such a filesystem is backed by a read-only device such as dm-verity or CDROM. This allows systems that have a verified and/or unchangeable filesystem to enforce module and firmware loading restrictions without needing to sign the files individually. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
18 lines
986 B
Plaintext
18 lines
986 B
Plaintext
LoadPin is a Linux Security Module that ensures all kernel-loaded files
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(modules, firmware, etc) all originate from the same filesystem, with
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the expectation that such a filesystem is backed by a read-only device
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such as dm-verity or CDROM. This allows systems that have a verified
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and/or unchangeable filesystem to enforce module and firmware loading
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restrictions without needing to sign the files individually.
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The LSM is selectable at build-time with CONFIG_SECURITY_LOADPIN, and
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can be controlled at boot-time with the kernel command line option
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"loadpin.enabled". By default, it is enabled, but can be disabled at
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boot ("loadpin.enabled=0").
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LoadPin starts pinning when it sees the first file loaded. If the
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block device backing the filesystem is not read-only, a sysctl is
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created to toggle pinning: /proc/sys/kernel/loadpin/enabled. (Having
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a mutable filesystem means pinning is mutable too, but having the
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sysctl allows for easy testing on systems with a mutable filesystem.)
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