diff options
| author | Andrii Nakryiko <andriin@fb.com> | 2020-08-19 23:14:08 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-08-20 16:45:09 +0200 |
| commit | 9b2f6fecf3b77d2457a13f77a563c07304f15775 (patch) | |
| tree | afc42c68923d9e671ccd9384ef1a0d52ecbf2d2b | |
| parent | 0bc23a1d1c8a1b4a5e4b973a7a80a6d067bd3eef (diff) | |
libbpf: Fix detection of BPF helper call instruction
BPF_CALL | BPF_JMP32 is explicitly not allowed by verifier for BPF helper
calls, so don't detect it as a valid call. Also drop the check on func_id
pointer, as it's currently always non-null.
Fixes: 109cea5a594f ("libbpf: Sanitize BPF program code for bpf_probe_read_{kernel, user}[_str]")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820061411.1755905-1-andriin@fb.com
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 829d62a3ad5f..0bc1fd813408 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5840,14 +5840,12 @@ static int bpf_object__collect_reloc(struct bpf_object *obj) static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) { - __u8 class = BPF_CLASS(insn->code); - - if ((class == BPF_JMP || class == BPF_JMP32) && + if (BPF_CLASS(insn->code) == BPF_JMP && BPF_OP(insn->code) == BPF_CALL && BPF_SRC(insn->code) == BPF_K && - insn->src_reg == 0 && insn->dst_reg == 0) { - if (func_id) - *func_id = insn->imm; + insn->src_reg == 0 && + insn->dst_reg == 0) { + *func_id = insn->imm; return true; } return false; |