From fdbaa0beb78b7c8847e261fe2c32816e9d1c54cc Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 19 Dec 2018 13:01:01 -0800 Subject: [PATCH] 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 Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index e0e77ffeefb8..5c64281d566e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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); -- 2.30.2