Hello,
While trying to implement an eBPF gatekeeper program, we ran into an issue whereas the LSM hooks are missing some relevant data.
Certain subcommands passed to the bpf() syscall can be invoked from either the kernel or userspace. Additionally, some fields in the bpf_attr struct contain pointers, and depending on where the subcommand was invoked, they could point to either user or kernel memory. One example of this is the bpf_prog_load subcommand and its fd_array. This data is made available and used by the verifier but not made available to the LSM subsystem. This patchset simply exposes that information to applicable LSM hooks.
Change list: - v4 -> v5 - merge v4 selftest breakout patch back into a single patch - change "is_kernel" to "kernel" - add selftest using new kernel flag - v3 -> v4 - split out selftest changes into a separate patch - v2 -> v3 - reorder params so that the new boolean flag is the last param - fixup function signatures in bpf selftests - v1 -> v2 - Pass a boolean flag in lieu of bpfptr_t
Revisions: - v4 https://lore.kernel.org/bpf/20250304203123.3935371-1-bboscaccy@linux.microso... - v3 https://lore.kernel.org/bpf/20250303222416.3909228-1-bboscaccy@linux.microso... - v2 https://lore.kernel.org/bpf/20250228165322.3121535-1-bboscaccy@linux.microso... - v1 https://lore.kernel.org/bpf/20250226003055.1654837-1-bboscaccy@linux.microso...
Blaise Boscaccy (2): security: Propagate caller information in bpf hooks selftests/bpf: Add a kernel flag test for LSM bpf hook
include/linux/lsm_hook_defs.h | 6 +-- include/linux/security.h | 12 +++--- kernel/bpf/syscall.c | 10 ++--- security/security.c | 15 ++++--- security/selinux/hooks.c | 6 +-- .../selftests/bpf/prog_tests/kernel_flag.c | 43 +++++++++++++++++++ .../selftests/bpf/progs/rcu_read_lock.c | 3 +- .../bpf/progs/test_cgroup1_hierarchy.c | 4 +- .../selftests/bpf/progs/test_kernel_flag.c | 32 ++++++++++++++ .../bpf/progs/test_kfunc_dynptr_param.c | 6 +-- .../selftests/bpf/progs/test_lookup_key.c | 2 +- .../selftests/bpf/progs/test_ptr_untrusted.c | 2 +- .../bpf/progs/test_task_under_cgroup.c | 2 +- .../bpf/progs/test_verify_pkcs7_sig.c | 2 +- 14 files changed, 112 insertions(+), 33 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/kernel_flag.c create mode 100644 tools/testing/selftests/bpf/progs/test_kernel_flag.c