]> www.infradead.org Git - users/jedix/linux-maple.git/commit
bpf: Ensure reg is PTR_TO_STACK in process_iter_arg
authorTao Lyu <tao.lyu@epfl.ch>
Tue, 3 Dec 2024 00:02:37 +0000 (16:02 -0800)
committerAlexei Starovoitov <ast@kernel.org>
Tue, 3 Dec 2024 01:47:56 +0000 (17:47 -0800)
commit12659d28615d606b36e382f4de2dd05550d202af
tree6198dadfa3fb8ce2bbda8c01f2542caab9605602
parent537a2525eaf76ea9b0dca62b994500d8670b39d5
bpf: Ensure reg is PTR_TO_STACK in process_iter_arg

Currently, KF_ARG_PTR_TO_ITER handling missed checking the reg->type and
ensuring it is PTR_TO_STACK. Instead of enforcing this in the caller of
process_iter_arg, move the check into it instead so that all callers
will gain the check by default. This is similar to process_dynptr_func.

An existing selftest in verifier_bits_iter.c fails due to this change,
but it's because it was passing a NULL pointer into iter_next helper and
getting an error further down the checks, but probably meant to pass an
uninitialized iterator on the stack (as is done in the subsequent test
below it). We will gain coverage for non-PTR_TO_STACK arguments in later
patches hence just change the declaration to zero-ed stack object.

Fixes: 06accc8779c1 ("bpf: add support for open-coded iterator loops")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Tao Lyu <tao.lyu@epfl.ch>
[ Kartikeya: move check into process_iter_arg, rewrite commit log ]
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241203000238.3602922-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel/bpf/verifier.c
tools/testing/selftests/bpf/progs/verifier_bits_iter.c