hi,
first version of this patchset added helper for this functionality,
but based Alexei's feedback [1], changing it to kfunc.
With the current build_id_parse function as kfunc we can't effectively
check buffer size provided by user. Therefore adding new function as
bpf kfunc:
int bpf_vma_build_id_parse(struct vm_area_struct *vma,
unsigned char *build_id,
size_t build_id__sz);
that triggers kfunc's verifier check for build_id/build_id__sz buffer
size and calls build_id_parse.
v4 changes:
- vma object is now passed as trusted pointer argument [Alexei]
- marked bpf_vma_build_id_parse with KF_TRUSTED_ARGS flag
so it can be called only with PTR_TRUSTED args
- marked vma objects from task_vma iter and find_vma callback
as PTR_TRUSTED
- added test for task_vma iterator
v3 changes:
- restrict bpf_vma_build_id_parse to bpf_find_vma callback
- move bpf_vma_build_id_parse to kernel/trace/bpf_trace.c
and add new tracing_kfunc_set
thanks,
jirka
[1] https://lore.kernel.org/bpf/CAADnVQKyT4Mm4EdTCYK8c070E-BwPZS_FOkWKLJC80riSGmLTg@xxxxxxxxxxxxxx/
---
Jiri Olsa (4):
bpf: Mark vma objects as trusted for task_vma iter and find_vma callback
bpf: Add bpf_vma_build_id_parse function and kfunc
selftests/bpf: Add bpf_vma_build_id_parse find_vma callback test
selftests/bpf: Add bpf_vma_build_id_parse task vma iterator test
include/linux/bpf.h | 4 ++++
kernel/bpf/task_iter.c | 2 +-
kernel/bpf/verifier.c | 2 +-
kernel/trace/bpf_trace.c | 31 +++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/prog_tests/bpf_vma_build_id_parse.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/bpf_iter_build_id.c | 41 +++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/bpf_vma_build_id_parse.c | 40 ++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.c | 40 ++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
10 files changed, 258 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_vma_build_id_parse.c
create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_build_id.c
create mode 100644 tools/testing/selftests/bpf/progs/bpf_vma_build_id_parse.c
