[PATCH v3 0/9] bpf-lsm: Extend interoperability with IMA

Roberto Sassu
2022-03-02T11:15:21Z

Extend the interoperability with IMA, to give wider flexibility for the
implementation of integrity-focused LSMs based on eBPF.

Patch 1 fixes some style issues.

Patches 2-6 give the ability to eBPF-based LSMs to take advantage of the
measurement capability of IMA without needing to setup a policy in IMA
(those LSMs might implement the policy capability themselves).

Patches 7-9 allow eBPF-based LSMs to evaluate files read by the kernel.

Changelog

v2:
- Add better description to patch 1 (suggested by Shuah)
- Recalculate digest if it is not fresh (when IMA_COLLECTED flag not set)
- Move declaration of bpf_ima_file_hash() at the end (suggested by
Yonghong)
- Add tests to check if the digest has been recalculated
- Add deny test for bpf_kernel_read_file()
- Add description to tests

v1:
- Modify ima_file_hash() only and allow the usage of the function with the
modified behavior by eBPF-based LSMs through the new function
bpf_ima_file_hash() (suggested by Mimi)
- Make bpf_lsm_kernel_read_file() sleepable so that bpf_ima_inode_hash()
and bpf_ima_file_hash() can be called inside the implementation of
eBPF-based LSMs for this hook

Roberto Sassu (9):
ima: Fix documentation-related warnings in ima_main.c
ima: Always return a file measurement in ima_file_hash()
bpf-lsm: Introduce new helper bpf_ima_file_hash()
selftests/bpf: Move sample generation code to ima_test_common()
selftests/bpf: Add test for bpf_ima_file_hash()
selftests/bpf: Check if the digest is refreshed after a file write
bpf-lsm: Make bpf_lsm_kernel_read_file() as sleepable
selftests/bpf: Add test for bpf_lsm_kernel_read_file()
selftests/bpf: Check that bpf_kernel_read_file() denies reading IMA
policy

include/uapi/linux/bpf.h | 11 ++
kernel/bpf/bpf_lsm.c | 21 +++
security/integrity/ima/ima_main.c | 57 ++++---
tools/include/uapi/linux/bpf.h | 11 ++
tools/testing/selftests/bpf/ima_setup.sh | 35 +++-
.../selftests/bpf/prog_tests/test_ima.c | 149 +++++++++++++++++-
tools/testing/selftests/bpf/progs/ima.c | 66 +++++++-
7 files changed, 321 insertions(+), 29 deletions(-)

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2.32.0