/minimal-ebpf

Tiny repository containing work related to eBPF and Rust.

Primary LanguageC

minimal-ebpf

Tiny repository containing work related to eBPF and Rust. The medium to long term objective is to use this repository to learn more about eBPF and how to use it with Rust.

For the time being this is mostly a scratchpad.

generic_file_open_example

Simple eBPF program that uses bpftrace to hook to the generic_file_open kprobe and print out details regarding which file was opened and by who. This currently filters by uid being 1000 which generally refers to the current user.

Attaching 2 probes...
uid, gid, filename 
1000, 1000, HEAD

Moving away from bpftrace

Decided to start recreating the program without using bpftrace in order to get a better understanding of the internal representations of eBPF programs.

We recreate the generic_file_open example in C and compile it to byte-code using clang.

clang -target bpf -Wall -O2 -c generic_file_open_example.c -o generic_file_open_example.o

We can now use the Rust library, aya to load our program.

Using aya

Extended the generic_file_open example to now use Aya to load our program into the kernel.

cargo b
sudo ./target/debug/generic-file-open

We can then use bpftool prog to validate that our program has loaded.

❯ sudo bpftool prog
2: cgroup_skb  name egress  tag b9d9f7a5d9d7e087  gpl
        loaded_at 2022-06-08T13:03:02+0100  uid 0
        xlated 360B  jited 206B  memlock 4096B  map_ids 6,4,3