tools: bpftool: teach cfg code about JMP32

mainline inclusion
from mainline-v5.1-rc1
commit df791dc167603efb676447a2d7b769a19e8fd722
category: bugfix
bugzilla: NA
CVE: CVE-2021-3444

--------------------------------

The cfg code need to be aware of the new JMP32 instruction class so it
could partition functions correctly.
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NJiong Wang <jiong.wang@netronome.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: He Fengqing<hefengqing@huawei.com>
Reviewed-by: NKuohai Xu <xukuohai@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NYu Changchun <yuchangchun1@huawei.com>

tools/bpf/bpftool/cfg.c

@@ -191,6 +191,11 @@ static bool cfg_partition_funcs(struct cfg *cfg, struct bpf_insn *cur,
 	return false;
 }
 
+static bool is_jmp_insn(u8 code)
+{
+	return BPF_CLASS(code) == BPF_JMP || BPF_CLASS(code) == BPF_JMP32;
+}
+
 static bool func_partition_bb_head(struct func_node *func)
 {
 	struct bpf_insn *cur, *end;
@@ -204,7 +209,7 @@ static bool func_partition_bb_head(struct func_node *func)
 		return true;
 
 	for (; cur <= end; cur++) {
-		if (BPF_CLASS(cur->code) == BPF_JMP) {
+		if (is_jmp_insn(cur->code)) {
 			u8 opcode = BPF_OP(cur->code);
 
 			if (opcode == BPF_EXIT || opcode == BPF_CALL)
@@ -330,7 +335,7 @@ static bool func_add_bb_edges(struct func_node *func)
 		e->src = bb;
 
 		insn = bb->tail;
-		if (BPF_CLASS(insn->code) != BPF_JMP ||
+		if (!is_jmp_insn(insn->code) ||
 		    BPF_OP(insn->code) == BPF_EXIT) {
 			e->dst = bb_next(bb);
 			e->flags |= EDGE_FLAG_FALLTHROUGH;