From patchwork Fri Jan 10 01:13:35 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13933390 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 8749E15E90; Fri, 10 Jan 2025 01:13:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736471630; cv=none; b=MTrMBFzobi3XMwXlXD36B8GId2FizKOr93izTxXl+c/GHLoYE3Sn4vqzI0Al7kujzeNbotdKxsPVckk9mQY4l9rRLl4C9lwkOK4AvcFTKy7SCJTD0RieOy0ruVriPGFt8VkixCsJs5k5hkByZWPBrJl9d7p7ZNo7BveVnch6Aag= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736471630; c=relaxed/simple; bh=pps64vwUbYi5UZ6+Pylk6a522WsuprFvbViZdcmDoc0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=GPBCorgleC8TLMdOJiuYWZDtpp4g7+mE0g95OC5oAA6KoanSjtLLno4lYtuOgIJfs+M7l7jFbj38IU019czcmi0p0S5058m6Qzl5tbyYsbwdyNRYDayotbo9iATL8rUY9oaKCcg+Si4nBBChcuuzlQg5oBFm4lr9BhWXFrDa8aU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n6Za1sSz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="n6Za1sSz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CA99C4CED2; Fri, 10 Jan 2025 01:13:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736471629; bh=pps64vwUbYi5UZ6+Pylk6a522WsuprFvbViZdcmDoc0=; h=From:To:Cc:Subject:Date:From; b=n6Za1sSz/TE6cGyPBebTM8osOD0kFSoQkKAHmCPInnHaazbmk137hUVV8s7GQ+o7d twf5q40aApHjRQQfc0g6g4QQCg4P386+vTs5DphRtyE6DI5a4HOBGa228aA/oON5dG OT1bfv/PNbL6HNCxjn+Ydgw+dmgtSL4doBJx9LxxXSZ4dhOLB7V3m0azYGz7fk0nZb IPU2Rqo0Ecd05NIAlpbr4wQsjDWtya8sMllCO0GB6OkxnOwOP9fsaiXBGckJDAZdsK MetP/r49T/7bBWxK4jk+7j3mVbfeaTA5FUPNzT4NSYx5kA8pxx2fovynsQbfJ7iMtl H4wfflqzD5RRA== From: Song Liu To: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Cc: kernel-team@meta.com, andrii@kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, kpsingh@kernel.org, mattbobrowski@google.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, memxor@gmail.com, Song Liu Subject: [PATCH v9 bpf-next 0/7] Enable writing xattr from BPF programs Date: Thu, 9 Jan 2025 17:13:35 -0800 Message-ID: <20250110011342.2965136-1-song@kernel.org> X-Mailer: git-send-email 2.43.5 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Add support to set and remove xattr from BPF program. Also add security.bpf. xattr name prefix. kfuncs are added to set and remove xattrs with security.bpf. name prefix. Update kfuncs bpf_get_[file|dentry]_xattr to read xattrs with security.bpf. name prefix. Note that BPF programs can read user. xattrs, but not write and remove them. To pick the right version of kfunc to use, a remap logic is added to btf_kfunc_id_set. This helps move some kfunc specific logic off the verifier core code. Also use this remap logic to select bpf_dynptr_from_skb or bpf_dynptr_from_skb_rdonly. Cover letter of v1 and v2: Follow up discussion in LPC 2024 [1], that we need security.bpf xattr prefix. This set adds "security.bpf." xattr name prefix, and allows bpf kfuncs bpf_get_[file|dentry]_xattr() to read these xattrs. [1] https://lpc.events/event/18/contributions/1940/ Changes v8 => v9 1. Fix build for CONFIG_DEBUG_INFO_BTF=n case. (kernel test robot) v8: https://lore.kernel.org/bpf/20250108225140.3467654-1-song@kernel.org/ Changes v7 => v8 1. Rebase and resolve conflicts. v7: https://lore.kernel.org/bpf/20241219221439.2455664-1-song@kernel.org/ Changes v6 => v7 1. Move btf_kfunc_id_remap() to the right place. (Bug reported by CI) v6: https://lore.kernel.org/bpf/20241219202536.1625216-1-song@kernel.org/ Changes v5 => v6 1. Hide _locked version of the kfuncs from vmlinux.h (Alexei) 2. Add remap logic to btf_kfunc_id_set and use that to pick the correct version of kfuncs to use. 3. Also use the remap logic for bpf_dynptr_from_skb[|_rdonly]. v5: https://lore.kernel.org/bpf/20241218044711.1723221-1-song@kernel.org/ Changes v4 => v5 1. Let verifier pick proper kfunc (_locked or not _locked) based on the calling context. (Alexei) 2. Remove the __failure test (6/6 of v4). v4: https://lore.kernel.org/bpf/20241217063821.482857-1-song@kernel.org/ Changes v3 => v4 1. Do write permission check with inode locked. (Jan Kara) 2. Fix some source_inline warnings. v3: https://lore.kernel.org/bpf/20241210220627.2800362-1-song@kernel.org/ Changes v2 => v3 1. Add kfuncs to set and remove xattr from BPF programs. v2: https://lore.kernel.org/bpf/20241016070955.375923-1-song@kernel.org/ Changes v1 => v2 1. Update comment of bpf_get_[file|dentry]_xattr. (Jiri Olsa) 2. Fix comment for return value of bpf_get_[file|dentry]_xattr. v1: https://lore.kernel.org/bpf/20241002214637.3625277-1-song@kernel.org/ Song Liu (7): fs/xattr: bpf: Introduce security.bpf. xattr name prefix selftests/bpf: Extend test fs_kfuncs to cover security.bpf. xattr names bpf: lsm: Add two more sleepable hooks bpf: Extend btf_kfunc_id_set to handle kfunc polymorphism bpf: Use btf_kfunc_id_set.remap logic for bpf_dynptr_from_skb bpf: fs/xattr: Add BPF kfuncs to set and remove xattrs selftests/bpf: Test kfuncs that set and remove xattr from BPF programs fs/bpf_fs_kfuncs.c | 246 +++++++++++++++++- include/linux/bpf_lsm.h | 2 + include/linux/btf.h | 20 ++ include/linux/btf_ids.h | 4 + include/uapi/linux/xattr.h | 4 + kernel/bpf/bpf_lsm.c | 2 + kernel/bpf/btf.c | 117 +++++++-- kernel/bpf/verifier.c | 31 +-- net/core/filter.c | 49 +++- tools/testing/selftests/bpf/bpf_kfuncs.h | 5 + .../selftests/bpf/prog_tests/fs_kfuncs.c | 162 +++++++++++- .../selftests/bpf/progs/test_get_xattr.c | 28 +- .../bpf/progs/test_set_remove_xattr.c | 133 ++++++++++ 13 files changed, 740 insertions(+), 63 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_set_remove_xattr.c --- 2.43.5