From patchwork Thu Nov 2 16:54:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13443998 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 70E456D3F; Thu, 2 Nov 2023 16:54:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U+2lyUEJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F588C433C8; Thu, 2 Nov 2023 16:54:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698944078; bh=QXWZ+ZXV/ZjQ7xnZ5Z2D0uIBcN/cO3LT8qEiFOk9iG4=; h=From:To:Cc:Subject:Date:From; b=U+2lyUEJ8Wsp+lfwdxtpWcBTmNV3MhfekYYyfB8G9cS3YHaOGrnfGmaWlMyiNukuY V2FTIs68YWXNol0rxwk4yVDGSvZniU1lXk53bBGl9O0Nw/PTB8RyOq4ivYEyx3z2mX ykS787Bi2SVQGoMmgz73bJT4zh7TvqS8980ZkisaJcDrN+YQG7/lAWTb/FqBVI3T0u y1wtJRbLnzZrmGvsbH4qGnzFkOP3jWy42I3TU8JSEI+KfdaBWACPUSSz9s6fMlKc7I ZW08aHtKDze2c0D9kCoDQI6MOnWU8RHVwkUsuqIEZA/w2+PHoxhmLU/EINdkz8dKxA OsPZwCoPcS6BQ== From: Song Liu To: bpf@vger.kernel.org, fsverity@lists.linux.dev Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, kernel-team@meta.com, ebiggers@kernel.org, tytso@mit.edu, roberto.sassu@huaweicloud.com, kpsingh@kernel.org, Song Liu Subject: [PATCH v7 bpf-next 0/9] bpf: File verification with LSM and fsverity Date: Thu, 2 Nov 2023 09:54:23 -0700 Message-Id: <20231102165432.1769965-1-song@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 (9): bpf: Expose bpf_dynptr_slice* kfuncs for in kernel use bpf: Factor out helper check_reg_const_str() bpf: Introduce KF_ARG_PTR_TO_CONST_STR 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 + Documentation/bpf/kfuncs.rst | 24 +++ fs/verity/fsverity_private.h | 10 ++ fs/verity/init.c | 1 + fs/verity/measure.c | 85 +++++++++ include/linux/bpf.h | 4 + kernel/bpf/helpers.c | 16 +- kernel/bpf/verifier.c | 104 +++++++---- kernel/trace/bpf_trace.c | 79 ++++++++- 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 +++ 19 files changed, 794 insertions(+), 57 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