Commit fdbaa0be authored Dec 19, 2018 by Martin KaFai Lau Committed by Alexei Starovoitov Dec 19, 2018

bpf: Ensure line_info.insn_off cannot point to insn with zero code



This patch rejects a line_info if the bpf insn code referred by
line_info.insn_off is 0. F.e. a broken userspace tool might generate
a line_info.insn_off that points to the second 8 bytes of a BPF_LD_IMM64.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent 9e88b931

kernel/bpf/verifier.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -4980,6 +4980,14 @@ static int check_btf_line(struct bpf_verifier_env *env,
		goto err_free;
		}

		if (!prog->insnsi[linfo[i].insn_off].code) {
		verbose(env,
		"Invalid insn code at line_info[%u].insn_off\n",
		i);
		err = -EINVAL;
		goto err_free;
		}

		if (!btf_name_by_offset(btf, linfo[i].line_off) \|\|
		!btf_name_by_offset(btf, linfo[i].file_name_off)) {
		verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);