linux-kernel - [PATCH v5 bpf-next 0/5] Enable writing xattr from BPF programs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241218044711.1723221-1-song@kernel.org>
Date: Tue, 17 Dec 2024 20:47:06 -0800
From: Song Liu <song@...nel.org>
To: bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org
Cc: kernel-team@...a.com,
	andrii@...nel.org,
	ast@...nel.org,
	daniel@...earbox.net,
	martin.lau@...ux.dev,
	kpsingh@...nel.org,
	mattbobrowski@...gle.com,
	paul@...l-moore.com,
	jmorris@...ei.org,
	serge@...lyn.com,
	memxor@...il.com,
	Song Liu <song@...nel.org>
Subject: [PATCH v5 bpf-next 0/5] Enable writing xattr from BPF programs

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.

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 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 (5):
  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: 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                            | 214 +++++++++++++++++-
 include/linux/bpf_lsm.h                       |   8 +
 include/uapi/linux/xattr.h                    |   4 +
 kernel/bpf/bpf_lsm.c                          |   2 +
 kernel/bpf/verifier.c                         |  55 ++++-
 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 +++++++++++
 9 files changed, 590 insertions(+), 21 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/test_set_remove_xattr.c

--
2.43.5