This patch series contains two patches that add support for a probe_write helper to BPF programs. This allows them to manipulate user memory during the course of tracing. The second patch in the series has an example that uses it, in one the intended ways to divert execution.
Thanks to Alexei Starovoitov, and Daniel Borkmann for review, I've made changes based on their recommendations. This helper should be considered experimental, so we print a warning to dmesg when it is along with the command and pid. A follow-up patchset will contain a mechanism to verify the safety of the probe beyond what was done by hand. Sargun Dhillon (2): bpf: Add bpf_probe_write_user BPF helper to be called in tracers samples/bpf: Add test/example of using bpf_probe_write_user bpf helper include/uapi/linux/bpf.h | 10 ++++ kernel/trace/bpf_trace.c | 48 ++++++++++++++++++++ samples/bpf/Makefile | 4 ++ samples/bpf/bpf_helpers.h | 2 + samples/bpf/test_probe_write_user_kern.c | 52 +++++++++++++++++++++ samples/bpf/test_probe_write_user_user.c | 78 ++++++++++++++++++++++++++++++++ 6 files changed, 194 insertions(+) create mode 100644 samples/bpf/test_probe_write_user_kern.c create mode 100644 samples/bpf/test_probe_write_user_user.c -- 2.7.4
