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@xxxxxxxxxx/ 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@xxxxxxxxxx/ Changes v2 => v3 1. Add kfuncs to set and remove xattr from BPF programs. v2: https://lore.kernel.org/bpf/20241016070955.375923-1-song@xxxxxxxxxx/ 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@xxxxxxxxxx/ 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
