elf: freeze .kconfig map #1000
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elf: freeze .kconfig map #1000
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The verifier will only treat .kconfig as constants if the map is frozen, since otherwise modification from user space is possible. Always freeze the kconfig map. Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
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cc @eiffel-fl |
eiffel-fl
approved these changes
Apr 4, 2023
I think it actually turns the load from memory into a constant load (in the JITed BPF code) and can then use the constant value for deciding whether code is reachable or not! This might make it faster to verify a program, but the main benefit is that some programs start working at all because large chunks can be ignored by the verifier. |
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The verifier will only treat .kconfig as constants if the map is frozen, since otherwise modification from user space is possible.
Always freeze the kconfig map.