Commit 744ea4e3 authored by Gilad Reti's avatar Gilad Reti Committed by Alexei Starovoitov
Browse files

bpf: Support PTR_TO_MEM{,_OR_NULL} register spilling 



Add support for pointer to mem register spilling, to allow the verifier
to track pointers to valid memory addresses. Such pointers are returned
for example by a successful call of the bpf_ringbuf_reserve helper.

The patch was partially contributed by CyberArk Software, Inc.

Fixes: 457f4436 ("bpf: Implement BPF ring buffer and verifier support for it")
Suggested-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarGilad Reti <gilad.reti@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarKP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210113053810.13518-1-gilad.reti@gmail.com
parent 7ac6ad05

kernel/bpf/verifier.c

+2 −0
Original line number Diff line number Diff line
@@ -2217,6 +2217,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type) 
	case PTR_TO_RDWR_BUF:

	case PTR_TO_RDWR_BUF_OR_NULL:

	case PTR_TO_PERCPU_BTF_ID:

	case PTR_TO_MEM:

	case PTR_TO_MEM_OR_NULL:

		return true;

	default:

		return false;