On 06/25, Song Liu wrote: > Currently, most access to sys_bpf() is limited to root. However, there are > use cases that would benefit from non-privileged use of sys_bpf(), e.g. > systemd. > > This set introduces a new model to control the access to sys_bpf(). A > special device, /dev/bpf, is introduced to manage access to sys_bpf(). > Users with access to open /dev/bpf will be able to access most of > sys_bpf() features. The use can get access to sys_bpf() by opening /dev/bpf > and use ioctl to get/put permission. > > The permission to access sys_bpf() is marked by bit TASK_BPF_FLAG_PERMITTED > in task_struct. During fork(), child will not inherit this bit. 2c: if we are going to have an fd, I'd vote for a proper fd based access checks instead of a per-task flag, so we can do: ioctl(fd, BPF_MAP_CREATE, uattr, sizeof(uattr)) (and pass this fd around) I do understand that it breaks current assumptions that libbpf has, but maybe we can extend _xattr variants to accept optinal fd (and try to fallback to sysctl if it's absent/not working)? > libbpf APIs libbpf_[get|put]_bpf_permission() are added to help get and > put the permission. bpftool is updated to use these APIs. > > Song Liu (4): > bpf: unprivileged BPF access via /dev/bpf > bpf: sync tools/include/uapi/linux/bpf.h > libbpf: add libbpf_[get|put]_bpf_permission() > bpftool: use libbpf_[get|put]_bpf_permission() > > Documentation/ioctl/ioctl-number.txt | 1 + > include/linux/bpf.h | 12 +++++ > include/linux/sched.h | 8 ++++ > include/uapi/linux/bpf.h | 5 ++ > kernel/bpf/arraymap.c | 2 +- > kernel/bpf/cgroup.c | 2 +- > kernel/bpf/core.c | 4 +- > kernel/bpf/cpumap.c | 2 +- > kernel/bpf/devmap.c | 2 +- > kernel/bpf/hashtab.c | 4 +- > kernel/bpf/lpm_trie.c | 2 +- > kernel/bpf/offload.c | 2 +- > kernel/bpf/queue_stack_maps.c | 2 +- > kernel/bpf/reuseport_array.c | 2 +- > kernel/bpf/stackmap.c | 2 +- > kernel/bpf/syscall.c | 72 +++++++++++++++++++++------- > kernel/bpf/verifier.c | 2 +- > kernel/bpf/xskmap.c | 2 +- > kernel/fork.c | 4 ++ > net/core/filter.c | 6 +-- > tools/bpf/bpftool/feature.c | 2 +- > tools/bpf/bpftool/main.c | 5 ++ > tools/include/uapi/linux/bpf.h | 5 ++ > tools/lib/bpf/libbpf.c | 54 +++++++++++++++++++++ > tools/lib/bpf/libbpf.h | 7 +++ > tools/lib/bpf/libbpf.map | 2 + > 26 files changed, 178 insertions(+), 35 deletions(-) > > -- > 2.17.1
