| Message ID | 20240725001411.39614-2-technoboy85@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | bpf: enable some functions in cgroup programs | expand |
Il giorno gio 25 lug 2024 alle ore 02:14 <technoboy85@gmail.com> ha scritto: > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -3052,6 +3052,12 @@ static int __init kfunc_init(void) > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &generic_kfunc_set); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SKB, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_DEVICE, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SYSCTL, &generic_kfunc_set); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCKOPT, &generic_kfunc_set); > ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors, > ARRAY_SIZE(generic_dtors), > THIS_MODULE); This seems not enough, some kfuncs like bpf_cgroup_from_id are still rejected. To fix this we need also this chunk: --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -8309,7 +8319,11 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) case BPF_PROG_TYPE_SYSCALL: return BTF_KFUNC_HOOK_SYSCALL; case BPF_PROG_TYPE_CGROUP_SKB: + case BPF_PROG_TYPE_CGROUP_SOCK: + case BPF_PROG_TYPE_CGROUP_DEVICE: case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: + case BPF_PROG_TYPE_CGROUP_SYSCTL: + case BPF_PROG_TYPE_CGROUP_SOCKOPT: return BTF_KFUNC_HOOK_CGROUP_SKB; case BPF_PROG_TYPE_SCHED_ACT: return BTF_KFUNC_HOOK_SCHED_ACT; but even with this it won't work, because bpf_prog_type_to_kfunc_hook() aliases many program types with a single hook, and btf_kfunc_id_set_contains() will fail to check if the kfunc is in the set. One solution could be to extend the btf_kfunc_hook enum with an entry for every CGROUP program type, but a thing I wanted to avoid is to let this enum proliferate in this way. I wish to group all the CGROUP_ program types into a single hook, and perhaps drop the "SKB" in "BTF_KFUNC_HOOK_CGROUP_SKB" which will have no meaning anymore. Ideas?
On Mon, Aug 12, 2024 at 9:49 AM Matteo Croce <technoboy85@gmail.com> wrote: > > Il giorno gio 25 lug 2024 alle ore 02:14 <technoboy85@gmail.com> ha scritto: > > --- a/kernel/bpf/helpers.c > > +++ b/kernel/bpf/helpers.c > > @@ -3052,6 +3052,12 @@ static int __init kfunc_init(void) > > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &generic_kfunc_set); > > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set); > > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SKB, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_DEVICE, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SYSCTL, &generic_kfunc_set); > > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCKOPT, &generic_kfunc_set); > > ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors, > > ARRAY_SIZE(generic_dtors), > > THIS_MODULE); > > This seems not enough, some kfuncs like bpf_cgroup_from_id are still rejected. > To fix this we need also this chunk: > > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -8309,7 +8319,11 @@ static int bpf_prog_type_to_kfunc_hook(enum > bpf_prog_type prog_type) > case BPF_PROG_TYPE_SYSCALL: > return BTF_KFUNC_HOOK_SYSCALL; > case BPF_PROG_TYPE_CGROUP_SKB: > + case BPF_PROG_TYPE_CGROUP_SOCK: > + case BPF_PROG_TYPE_CGROUP_DEVICE: > case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: > + case BPF_PROG_TYPE_CGROUP_SYSCTL: > + case BPF_PROG_TYPE_CGROUP_SOCKOPT: > return BTF_KFUNC_HOOK_CGROUP_SKB; > case BPF_PROG_TYPE_SCHED_ACT: > return BTF_KFUNC_HOOK_SCHED_ACT; > > but even with this it won't work, because > bpf_prog_type_to_kfunc_hook() aliases many program types with a single > hook, and btf_kfunc_id_set_contains() will fail to check if the kfunc > is in the set. > > One solution could be to extend the btf_kfunc_hook enum with an entry > for every CGROUP program type, but a thing I wanted to avoid is to let > this enum proliferate in this way. > I wish to group all the CGROUP_ program types into a single hook, and > perhaps drop the "SKB" in "BTF_KFUNC_HOOK_CGROUP_SKB" which will have > no meaning anymore. > > Ideas? Given BPF_PROG_TYPE_CGROUP_SKB and BPF_PROG_TYPE_CGROUP_SOCK_ADDR are already grouped into the same hook type, and bpf_sock_addr_set_sun_path() is meant to be enabled for BPF_PROG_TYPE_CGROUP_SOCK_ADDR (but really it's enabled for BPF_PROG_TYPE_CGROUP_SKB as well), I guess it's fine to just have one CGROUP hook type for all those cgroup-related program types and just rely on BTF type matching logic. I'd say that register_btf_kfunc_id_set() should just accept enum bpf_kfunc_hook instead of enum bpf_prog_type (I don't see where we remember or use prog_type beyond just translating that to bpf_kfunc_hook), but that can be left for follow up clean ups. > > -- > Matteo Croce > > perl -e 'for($t=0;;$t++){print chr($t*($t>>8|$t>>13)&255)}' |aplay
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index d02ae323996b..0d1d97d968b0 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3052,6 +3052,12 @@ static int __init kfunc_init(void) ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &generic_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &generic_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SKB, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_DEVICE, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SYSCTL, &generic_kfunc_set); + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCKOPT, &generic_kfunc_set); ret = ret ?: register_btf_id_dtor_kfuncs(generic_dtors, ARRAY_SIZE(generic_dtors), THIS_MODULE);