test_bpf.ko blinding fixes #8015
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Constant blinding may expand instructions that make use of immediate values into multiple, resulting in preceding jump instructions to get a bigger target offset. The "max jump" tests specifically attempt to test the biggest possible jump offset, requiring to take special care about the final (after blinding) offset while crafting the input program. To make these tests independent of constant blinding's instruction expansion, use a register-only operation to load R0 with the intended value. This fixes the "Long conditional jump" tests with enabled blinding. Fixes: f1517eb ("bpf/tests: Expand branch conversion JIT test") Cc: Johan Almbladh <[email protected]> Signed-off-by: Mathias Krause <[email protected]>
To allow probing if constant blinding will be applied, support calling bpf_jit_blinding_enabled() with a NULL program. This allows to tailor the creation of a BPF program accordingly. Signed-off-by: Mathias Krause <[email protected]>
The "staggered jumps" tests currently fail with constant blinding enabled as the increased program size makes jump offsets overflow. Fix that by decreasing the number of jumps depending on the expected size increase caused by blinding the program. As the test for JIT blinding makes use of bpf_jit_blinding_enabled(NULL) and test_bpf.ko is a kernel modules, 'bpf_token_capable' and 'bpf_jit_harden' need to be exported. Fixes: a7d2e75 ("bpf/tests: Add staggered JMP and JMP32 tests") Cc: Johan Almbladh <[email protected]> Signed-off-by: Mathias Krause <[email protected]>
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Upstream branch: 1850ce1 |
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Pull request for series with
subject: test_bpf.ko blinding fixes
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=906240