As suggested in [1], the kprobe_multi interface is to be fixed for 32-bit
architectures and compat, rather then disabled. As it turned out,
there are a couple of additional problems that are to be addressed:
- the absence of size overflow checks, leading to possible
out-of-bounds writes (addressed by the first patch);
- the assumption that long has the same size as u64, which would make
cookies arrays size calculation incorrect on 32-bit architectures
(addressed by the second patch);
- the addrs array passing API, that is incompatible with compat and has
to be changed (addressed in the fourth patch): those are kernel
addresses and not user ones (as was incorrectly stated in [2]);
this change is only semantical for 64-bit user/kernelspace,
so it shouldn't impact ABI there, at least.
[1] https://lore.kernel.org/lkml/CAADnVQ+2gwhcMht4PuDnDOFKY68Wsq8QFz4Y69NBX_TLaSexQQ@mail.gmail.com/
[2] https://lore.kernel.org/lkml/[email protected]/
Eugene Syromiatnikov (4):
bpf_trace: check size for overflow in bpf_kprobe_multi_link_attach
bpf_trace: support 32-bit kernels in bpf_kprobe_multi_link_attach
bpf_trace: handle compat in kprobe_multi_resolve_syms
bpf_trace: pass array of u64 values in kprobe_multi.addrs
kernel/trace/bpf_trace.c | 63 ++++++++++++++++------
tools/lib/bpf/bpf.h | 2 +-
tools/lib/bpf/libbpf.c | 8 +--
tools/lib/bpf/libbpf.h | 2 +-
.../testing/selftests/bpf/prog_tests/bpf_cookie.c | 2 +-
.../selftests/bpf/prog_tests/kprobe_multi_test.c | 2 +-
6 files changed, 54 insertions(+), 25 deletions(-)
--
2.1.4