bpf: Refuse unused attributes in bpf_prog_{attach,detach}
authorLorenz Bauer <lmb@isovalent.com>
Fri, 6 Oct 2023 22:06:51 +0000 (00:06 +0200)
committerMartin KaFai Lau <martin.lau@kernel.org>
Sat, 7 Oct 2023 00:11:21 +0000 (17:11 -0700)
commitba62d61128bda71fd02622f320ac59d861fc4baa
tree8348cb7a82865b577e7ddf7b6cf267416b13264f
parentedfa9af0a73ecc2000d7bb81d0b0fd3158cc9a65
bpf: Refuse unused attributes in bpf_prog_{attach,detach}

The recently added tcx attachment extended the BPF UAPI for attaching and
detaching by a couple of fields. Those fields are currently only supported
for tcx, other types like cgroups and flow dissector silently ignore the
new fields except for the new flags.

This is problematic once we extend bpf_mprog to older attachment types, since
it's hard to figure out whether the syscall really was successful if the
kernel silently ignores non-zero values.

Explicitly reject non-zero fields relevant to bpf_mprog for attachment types
which don't use the latter yet.

Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20231006220655.1653-3-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
kernel/bpf/syscall.c