Changes v1 => v2: 1. Make default mode of /dev/bpf 0220 (Greg); 2. Rename ioctl commands as BPF_DEV_IOCTL_ENABLE_SYS_BPF and BPF_DEV_IOCTL_DISABLE_SYS_BPF (Daniel); 3. Save space for task_struct by reusing free bit (Daniel); 4. Make the permission per process (Lorenz). 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 enable/disable the access. The permission to access sys_bpf() is marked by bit bpf_permitted in task_struct. During clone(), child will inherit this bit if CLONE_THREAD is set. Therefore, the permission is shared within same user process, but not via fork(). libbpf APIs libbpf_[enable|disable]_sys_bpf() 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_[enable|disable]_sys_bpf() bpftool: use libbpf_[enable|disable]_sys_bpf() Documentation/ioctl/ioctl-number.txt | 1 + include/linux/bpf.h | 11 +++++ include/linux/sched.h | 3 ++ include/uapi/linux/bpf.h | 6 +++ 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 | 71 +++++++++++++++++++++------- kernel/bpf/verifier.c | 2 +- kernel/bpf/xskmap.c | 2 +- kernel/fork.c | 5 ++ net/core/filter.c | 6 +-- tools/bpf/bpftool/feature.c | 2 +- tools/bpf/bpftool/main.c | 5 ++ tools/include/uapi/linux/bpf.h | 6 +++ tools/lib/bpf/libbpf.c | 54 +++++++++++++++++++++ tools/lib/bpf/libbpf.h | 7 +++ tools/lib/bpf/libbpf.map | 2 + 26 files changed, 174 insertions(+), 35 deletions(-) -- 2.17.1
