This patch set follows recent changes that added btf_decl_tag-based argument
annotation support for global subprogs. This time we add ability to pass
PTR_TO_BTF_ID (BTF-aware kernel pointers) arguments into global subprograms.
We support explicitly trusted arguments only, for now.
Patch #1 adds logic for arg:trusted tag support on the verifier side. Default
semantic of such arguments is non-NULL, enforced on caller side. But patch #2
adds arg:nullable tag that can be combined with arg:trusted to make callee
explicitly do the NULL check, which helps implement "optional" PTR_TO_BTF_ID
arguments.
Patch #3 adds libbpf-side __arg_trusted and __arg_nullable macros.
Patch #4 adds a bunch of tests validating __arg_trusted in combination with
__arg_nullable.
v2->v3:
- went back to arg:nullable and __arg_nullable naming;
- rebased on latest bpf-next after prepartory patches landed;
v1->v2:
- added fix up to type enforcement changes, landed earlier;
- dropped bpf_core_cast() changes, will post them separately, as they now
are not used in added tests;
- dropped arg:untrusted support (Alexei);
- renamed arg:nullable to arg:maybe_null (Alexei);
- and also added task_struct___local flavor tests (Alexei).
Andrii Nakryiko (4):
bpf: add __arg_trusted global func arg tag
bpf: add arg:nullable tag to be combined with trusted pointers
libbpf: add __arg_trusted and __arg_nullable tag macros
selftests/bpf: add trusted global subprog arg tests
include/linux/bpf_verifier.h | 1 +
kernel/bpf/btf.c | 109 ++++++++++--
kernel/bpf/verifier.c | 24 +++
tools/lib/bpf/bpf_helpers.h | 2 +
.../selftests/bpf/prog_tests/verifier.c | 2 +
.../bpf/progs/verifier_global_ptr_args.c | 156 ++++++++++++++++++
6 files changed, 281 insertions(+), 13 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c
--
2.34.1
