Changes v12 => v13:
1. Only keep 4/9 through 9/9 of v12, as the first 3 patches already
applied;
2. Use new macro __bpf_kfunc_[start|end]_defs().
Changes v11 => v12:
1. Fix typo (data_ptr => sig_ptr) in bpf_get_file_xattr().
Changes v10 => v11:
1. Let __bpf_dynptr_data() return const void *. (Andrii)
2. Optimize code to reuse output from __bpf_dynptr_size(). (Andrii)
3. Add __diag_ignore_all("-Wmissing-declarations") for kfunc definition.
4. Fix an off indentation. (Andrii)
Changes v9 => v10:
1. Remove WARN_ON_ONCE() from check_reg_const_str. (Alexei)
Changes v8 => v9:
1. Fix test_progs kfunc_dynptr_param/dynptr_data_null.
Changes v7 => v8:
1. Do not use bpf_dynptr_slice* in the kernel. Add __bpf_dynptr_data* and
use them in ther kernel. (Andrii)
Changes v6 => v7:
1. Change "__const_str" annotation to "__str". (Alexei, Andrii)
2. Add KF_TRUSTED_ARGS flag for both new kfuncs. (KP)
3. Only allow bpf_get_file_xattr() to read xattr with "user." prefix.
4. Add Acked-by from Eric Biggers.
Changes v5 => v6:
1. Let fsverity_init_bpf() return void. (Eric Biggers)
2. Sort things in alphabetic orders. (Eric Biggers)
Changes v4 => v5:
1. Revise commit logs. (Alexei)
Changes v3 => v4:
1. Fix error reported by CI.
2. Update comments of bpf_dynptr_slice* that they may return error pointer.
Changes v2 => v3:
1. Rebase and resolve conflicts.
Changes v1 => v2:
1. Let bpf_get_file_xattr() use const string for arg "name". (Alexei)
2. Add recursion prevention with allowlist. (Alexei)
3. Let bpf_get_file_xattr() use __vfs_getxattr() to avoid recursion,
as vfs_getxattr() calls into other LSM hooks.
4. Do not use dynptr->data directly, use helper insteadd. (Andrii)
5. Fixes with bpf_get_fsverity_digest. (Eric Biggers)
6. Add documentation. (Eric Biggers)
7. Fix some compile warnings. (kernel test robot)
This set enables file verification with BPF LSM and fsverity.
In this solution, fsverity is used to provide reliable and efficient hash
of files; and BPF LSM is used to implement signature verification (against
asymmetric keys), and to enforce access control.
This solution can be used to implement access control in complicated cases.
For example: only signed python binary and signed python script and access
special files/devices/ports.
Thanks,
Song
Song Liu (6):
bpf: Add kfunc bpf_get_file_xattr
bpf, fsverity: Add kfunc bpf_get_fsverity_digest
Documentation/bpf: Add documentation for filesystem kfuncs
selftests/bpf: Sort config in alphabetic order
selftests/bpf: Add tests for filesystem kfuncs
selftests/bpf: Add test that uses fsverity and xattr to sign a file
Documentation/bpf/fs_kfuncs.rst | 21 +++
Documentation/bpf/index.rst | 1 +
fs/verity/fsverity_private.h | 10 ++
fs/verity/init.c | 1 +
fs/verity/measure.c | 84 +++++++++
kernel/trace/bpf_trace.c | 63 +++++++
tools/testing/selftests/bpf/bpf_kfuncs.h | 10 ++
tools/testing/selftests/bpf/config | 3 +-
.../selftests/bpf/prog_tests/fs_kfuncs.c | 132 ++++++++++++++
.../bpf/prog_tests/verify_pkcs7_sig.c | 163 +++++++++++++++++-
.../selftests/bpf/progs/test_fsverity.c | 46 +++++
.../selftests/bpf/progs/test_get_xattr.c | 37 ++++
.../selftests/bpf/progs/test_sig_in_xattr.c | 82 +++++++++
.../bpf/progs/test_verify_pkcs7_sig.c | 8 +-
.../testing/selftests/bpf/verify_sig_setup.sh | 25 +++
15 files changed, 677 insertions(+), 9 deletions(-)
create mode 100644 Documentation/bpf/fs_kfuncs.rst
create mode 100644 tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c
create mode 100644 tools/testing/selftests/bpf/progs/test_fsverity.c
create mode 100644 tools/testing/selftests/bpf/progs/test_get_xattr.c
create mode 100644 tools/testing/selftests/bpf/progs/test_sig_in_xattr.c
--
2.34.1
