Commit 42be23e8 authored by Eduard Zingerman's avatar Eduard Zingerman Committed by Andrii Nakryiko
Browse files

libbpf: Verify that arena map exists when adding arena relocations 

Fuzzer reported a memory access error in bpf_program__record_reloc()
that happens when:
- ".addr_space.1" section exists
- there is a relocation referencing this section
- there are no arena maps defined in BTF.

Sanity checks for maps existence are already present in
bpf_program__record_reloc(), hence this commit adds another one.

[1] https://github.com/libbpf/libbpf/actions/runs/16375110681/job/46272998064



Signed-off-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250718222059.281526-1-eddyz87@gmail.com
parent beb1097e

tools/lib/bpf/libbpf.c

+5 −0
Original line number Diff line number Diff line
@@ -4582,6 +4582,11 @@ static int bpf_program__record_reloc(struct bpf_program *prog, 


	/* arena data relocation */

	if (shdr_idx == obj->efile.arena_data_shndx) {

		if (obj->arena_map_idx < 0) {

			pr_warn("prog '%s': bad arena data relocation at insn %u, no arena maps defined\n",

				prog->name, insn_idx);

			return -LIBBPF_ERRNO__RELOC;

		}

		reloc_desc->type = RELO_DATA;

		reloc_desc->insn_idx = insn_idx;

		reloc_desc->map_idx = obj->arena_map_idx;