nfp: bpf: reject program on instructions unknown to the JIT compiler

If an eBPF instruction is unknown to the driver JIT compiler, we can
reject the program at verification time.
Signed-off-by: NQuentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NJiong Wang <jiong.wang@netronome.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

drivers/net/ethernet/netronome/nfp/bpf/jit.c

@@ -2907,6 +2907,11 @@ void nfp_bpf_jit_prepare(struct nfp_prog *nfp_prog, unsigned int cnt)
 	}
 }
 
+bool nfp_bpf_supported_opcode(u8 code)
+{
+	return !!instr_cb[code];
+}
+
 void *nfp_bpf_relo_for_vnic(struct nfp_prog *nfp_prog, struct nfp_bpf_vnic *bv)
 {
 	unsigned int i;

drivers/net/ethernet/netronome/nfp/bpf/main.h

@@ -324,6 +324,7 @@ struct nfp_bpf_vnic {
 
 void nfp_bpf_jit_prepare(struct nfp_prog *nfp_prog, unsigned int cnt);
 int nfp_bpf_jit(struct nfp_prog *prog);
+bool nfp_bpf_supported_opcode(u8 code);
 
 extern const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops;
 

drivers/net/ethernet/netronome/nfp/bpf/verifier.c

@@ -290,6 +290,12 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx)
 	meta = nfp_bpf_goto_meta(nfp_prog, meta, insn_idx, env->prog->len);
 	nfp_prog->verifier_meta = meta;
 
+	if (!nfp_bpf_supported_opcode(meta->insn.code)) {
+		pr_vlog(env, "instruction %#02x not supported\n",
+			meta->insn.code);
+		return -EINVAL;
+	}
+
 	if (meta->insn.src_reg >= MAX_BPF_REG ||
 	    meta->insn.dst_reg >= MAX_BPF_REG) {
 		pr_vlog(env, "program uses extended registers - jit hardening?\n");