RFC because the selftests in the 3rd patch is failing and I couldn't figure out what's going on, sending out for suggestion. This is a follow up of Xu Kuohai's "Add BPF LSM return value range check, BPF part" series[1], where the 5th patch "improve signed ranges inference for BPF_AND" was omitting because further changes were required. This series brough back that patch (with modifications as requested), removed workaround, and bring back 'test 3'[2] from Xu Kuohai that was also dropped. Patch 1 add reasoning of signed ranges directly from previous signed ranges during BPF_AND to the BPF verfier, which allowed better tracking of signed range for situation like [-1, 0] & -13. See the patch for complete detail. Patch 2 and 3 are corresponding tests. Patch 2 brings back an omitted test[2] from Xu Kuohai. Patch 3 add more specific test in verifier_and.c. 1: https://lore.kernel.org/bpf/20240719110059.797546-1-xukuohai@xxxxxxxxxxxxxxx/ 2: https://lore.kernel.org/bpf/20240719110059.797546-10-xukuohai@xxxxxxxxxxxxxxx/ Changes since v1: - address comments - add code comment in scalar*_min_max_and() to better explaining the reasoning (Eduard, Alexei) - point out unsigned range are still propagated to signed range later in __reg_deduce_bounds() (Edward) - point out the fls(~v) special case in negative_bit_floor() (Edward) - revert workaround added in 229d6db14942 - add additional tests - v1 can be found at both - https://lore.kernel.org/bpf/20240719110059.797546-6-xukuohai@xxxxxxxxxxxxxxx/ - https://lore.kernel.org/bpf/9505522b-de45-cf52-162b-76a3a52a6efe@xxxxxxxxx/ Shung-Hsi Yu (3): bpf, verifier: improve signed ranges inference for BPF_AND selftests/bpf: bring back verifier tests for bpf lsm selftests/bpf: add more verifier tests for signed range deduction of BPF_AND kernel/bpf/verifier.c | 105 ++++++++++++++---- .../bpf/progs/test_libbpf_get_fd_by_id_opts.c | 1 - .../selftests/bpf/progs/verifier_and.c | 56 ++++++++++ .../selftests/bpf/progs/verifier_lsm.c | 16 +++ 4 files changed, 157 insertions(+), 21 deletions(-) -- 2.47.0
