94 lines
3.3 KiB
Plaintext
94 lines
3.3 KiB
Plaintext
menu "Kernel hardening options"
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config GCC_PLUGIN_STRUCTLEAK
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bool
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help
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While the kernel is built with warnings enabled for any missed
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stack variable initializations, this warning is silenced for
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anything passed by reference to another function, under the
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occasionally misguided assumption that the function will do
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the initialization. As this regularly leads to exploitable
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flaws, this plugin is available to identify and zero-initialize
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such variables, depending on the chosen level of coverage.
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This plugin was originally ported from grsecurity/PaX. More
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information at:
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* https://grsecurity.net/
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* https://pax.grsecurity.net/
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menu "Memory initialization"
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choice
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prompt "Initialize kernel stack variables at function entry"
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default GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if COMPILE_TEST && GCC_PLUGINS
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default INIT_STACK_NONE
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help
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This option enables initialization of stack variables at
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function entry time. This has the possibility to have the
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greatest coverage (since all functions can have their
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variables initialized), but the performance impact depends
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on the function calling complexity of a given workload's
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syscalls.
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This chooses the level of coverage over classes of potentially
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uninitialized variables. The selected class will be
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initialized before use in a function.
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config INIT_STACK_NONE
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bool "no automatic initialization (weakest)"
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help
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Disable automatic stack variable initialization.
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This leaves the kernel vulnerable to the standard
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classes of uninitialized stack variable exploits
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and information exposures.
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config GCC_PLUGIN_STRUCTLEAK_USER
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bool "zero-init structs marked for userspace (weak)"
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depends on GCC_PLUGINS
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any structures on the stack containing
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a __user attribute. This can prevent some classes of
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uninitialized stack variable exploits and information
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exposures, like CVE-2013-2141:
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https://git.kernel.org/linus/b9e146d8eb3b9eca
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config GCC_PLUGIN_STRUCTLEAK_BYREF
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bool "zero-init structs passed by reference (strong)"
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depends on GCC_PLUGINS
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any structures on the stack that may
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be passed by reference and had not already been
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explicitly initialized. This can prevent most classes
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of uninitialized stack variable exploits and information
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exposures, like CVE-2017-1000410:
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https://git.kernel.org/linus/06e7e776ca4d3654
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config GCC_PLUGIN_STRUCTLEAK_BYREF_ALL
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bool "zero-init anything passed by reference (very strong)"
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depends on GCC_PLUGINS
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select GCC_PLUGIN_STRUCTLEAK
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help
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Zero-initialize any stack variables that may be passed
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by reference and had not already been explicitly
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initialized. This is intended to eliminate all classes
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of uninitialized stack variable exploits and information
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exposures.
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endchoice
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config GCC_PLUGIN_STRUCTLEAK_VERBOSE
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bool "Report forcefully initialized variables"
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depends on GCC_PLUGIN_STRUCTLEAK
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depends on !COMPILE_TEST # too noisy
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help
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This option will cause a warning to be printed each time the
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structleak plugin finds a variable it thinks needs to be
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initialized. Since not all existing initializers are detected
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by the plugin, this can produce false positive warnings.
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endmenu
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endmenu
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