bpf: Factor out attach_type to prog_type mapping for attach/detach

Factor out logic mapping expected program attach type to program type and
subsequent handling of program attach/detach. Also list out all supported
cgroup BPF program types explicitly to prevent accidental bugs once more
program types are added to a mapping. Do the same for prog_query API.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200325065746.640559-3-andriin@fb.com

kernel/bpf/syscall.c

@@ -2535,36 +2535,18 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
 	}
 }
 
-#define BPF_PROG_ATTACH_LAST_FIELD replace_bpf_fd
-
-#define BPF_F_ATTACH_MASK \
-	(BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI | BPF_F_REPLACE)
-
-static int bpf_prog_attach(const union bpf_attr *attr)
+static enum bpf_prog_type
+attach_type_to_prog_type(enum bpf_attach_type attach_type)
 {
-	enum bpf_prog_type ptype;
-	struct bpf_prog *prog;
-	int ret;
-
-	if (!capable(CAP_NET_ADMIN))
-		return -EPERM;
-
-	if (CHECK_ATTR(BPF_PROG_ATTACH))
-		return -EINVAL;
-
-	if (attr->attach_flags & ~BPF_F_ATTACH_MASK)
-		return -EINVAL;
-
-	switch (attr->attach_type) {
+	switch (attach_type) {
 	case BPF_CGROUP_INET_INGRESS:
 	case BPF_CGROUP_INET_EGRESS:
-		ptype = BPF_PROG_TYPE_CGROUP_SKB;
+		return BPF_PROG_TYPE_CGROUP_SKB;
 		break;
 	case BPF_CGROUP_INET_SOCK_CREATE:
 	case BPF_CGROUP_INET4_POST_BIND:
 	case BPF_CGROUP_INET6_POST_BIND:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCK;
-		break;
+		return BPF_PROG_TYPE_CGROUP_SOCK;
 	case BPF_CGROUP_INET4_BIND:
 	case BPF_CGROUP_INET6_BIND:
 	case BPF_CGROUP_INET4_CONNECT:
@@ -2573,37 +2555,53 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_CGROUP_UDP6_SENDMSG:
 	case BPF_CGROUP_UDP4_RECVMSG:
 	case BPF_CGROUP_UDP6_RECVMSG:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
-		break;
+		return BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
 	case BPF_CGROUP_SOCK_OPS:
-		ptype = BPF_PROG_TYPE_SOCK_OPS;
-		break;
+		return BPF_PROG_TYPE_SOCK_OPS;
 	case BPF_CGROUP_DEVICE:
-		ptype = BPF_PROG_TYPE_CGROUP_DEVICE;
-		break;
+		return BPF_PROG_TYPE_CGROUP_DEVICE;
 	case BPF_SK_MSG_VERDICT:
-		ptype = BPF_PROG_TYPE_SK_MSG;
-		break;
+		return BPF_PROG_TYPE_SK_MSG;
 	case BPF_SK_SKB_STREAM_PARSER:
 	case BPF_SK_SKB_STREAM_VERDICT:
-		ptype = BPF_PROG_TYPE_SK_SKB;
-		break;
+		return BPF_PROG_TYPE_SK_SKB;
 	case BPF_LIRC_MODE2:
-		ptype = BPF_PROG_TYPE_LIRC_MODE2;
-		break;
+		return BPF_PROG_TYPE_LIRC_MODE2;
 	case BPF_FLOW_DISSECTOR:
-		ptype = BPF_PROG_TYPE_FLOW_DISSECTOR;
-		break;
+		return BPF_PROG_TYPE_FLOW_DISSECTOR;
 	case BPF_CGROUP_SYSCTL:
-		ptype = BPF_PROG_TYPE_CGROUP_SYSCTL;
-		break;
+		return BPF_PROG_TYPE_CGROUP_SYSCTL;
 	case BPF_CGROUP_GETSOCKOPT:
 	case BPF_CGROUP_SETSOCKOPT:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCKOPT;
-		break;
+		return BPF_PROG_TYPE_CGROUP_SOCKOPT;
 	default:
-		return -EINVAL;
+		return BPF_PROG_TYPE_UNSPEC;
 	}
+}
+
+#define BPF_PROG_ATTACH_LAST_FIELD replace_bpf_fd
+
+#define BPF_F_ATTACH_MASK \
+	(BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI | BPF_F_REPLACE)
+
+static int bpf_prog_attach(const union bpf_attr *attr)
+{
+	enum bpf_prog_type ptype;
+	struct bpf_prog *prog;
+	int ret;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (CHECK_ATTR(BPF_PROG_ATTACH))
+		return -EINVAL;
+
+	if (attr->attach_flags & ~BPF_F_ATTACH_MASK)
+		return -EINVAL;
+
+	ptype = attach_type_to_prog_type(attr->attach_type);
+	if (ptype == BPF_PROG_TYPE_UNSPEC)
+		return -EINVAL;
 
 	prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
 	if (IS_ERR(prog))
@@ -2625,8 +2623,17 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 		ret = skb_flow_dissector_bpf_prog_attach(attr, prog);
 		break;
-	default:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_SOCK_OPS:
 		ret = cgroup_bpf_prog_attach(attr, ptype, prog);
+		break;
+	default:
+		ret = -EINVAL;
 	}
 
 	if (ret)
@@ -2646,53 +2653,27 @@ static int bpf_prog_detach(const union bpf_attr *attr)
 	if (CHECK_ATTR(BPF_PROG_DETACH))
 		return -EINVAL;
 
-	switch (attr->attach_type) {
-	case BPF_CGROUP_INET_INGRESS:
-	case BPF_CGROUP_INET_EGRESS:
-		ptype = BPF_PROG_TYPE_CGROUP_SKB;
-		break;
-	case BPF_CGROUP_INET_SOCK_CREATE:
-	case BPF_CGROUP_INET4_POST_BIND:
-	case BPF_CGROUP_INET6_POST_BIND:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCK;
-		break;
-	case BPF_CGROUP_INET4_BIND:
-	case BPF_CGROUP_INET6_BIND:
-	case BPF_CGROUP_INET4_CONNECT:
-	case BPF_CGROUP_INET6_CONNECT:
-	case BPF_CGROUP_UDP4_SENDMSG:
-	case BPF_CGROUP_UDP6_SENDMSG:
-	case BPF_CGROUP_UDP4_RECVMSG:
-	case BPF_CGROUP_UDP6_RECVMSG:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
-		break;
-	case BPF_CGROUP_SOCK_OPS:
-		ptype = BPF_PROG_TYPE_SOCK_OPS;
-		break;
-	case BPF_CGROUP_DEVICE:
-		ptype = BPF_PROG_TYPE_CGROUP_DEVICE;
-		break;
-	case BPF_SK_MSG_VERDICT:
-		return sock_map_get_from_fd(attr, NULL);
-	case BPF_SK_SKB_STREAM_PARSER:
-	case BPF_SK_SKB_STREAM_VERDICT:
+	ptype = attach_type_to_prog_type(attr->attach_type);
+
+	switch (ptype) {
+	case BPF_PROG_TYPE_SK_MSG:
+	case BPF_PROG_TYPE_SK_SKB:
 		return sock_map_get_from_fd(attr, NULL);
-	case BPF_LIRC_MODE2:
+	case BPF_PROG_TYPE_LIRC_MODE2:
 		return lirc_prog_detach(attr);
-	case BPF_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 		return skb_flow_dissector_bpf_prog_detach(attr);
-	case BPF_CGROUP_SYSCTL:
-		ptype = BPF_PROG_TYPE_CGROUP_SYSCTL;
-		break;
-	case BPF_CGROUP_GETSOCKOPT:
-	case BPF_CGROUP_SETSOCKOPT:
-		ptype = BPF_PROG_TYPE_CGROUP_SOCKOPT;
-		break;
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_SOCK_OPS:
+		return cgroup_bpf_prog_detach(attr, ptype);
 	default:
 		return -EINVAL;
 	}
-
-	return cgroup_bpf_prog_detach(attr, ptype);
 }
 
 #define BPF_PROG_QUERY_LAST_FIELD query.prog_cnt
@@ -2726,7 +2707,7 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	case BPF_CGROUP_SYSCTL:
 	case BPF_CGROUP_GETSOCKOPT:
 	case BPF_CGROUP_SETSOCKOPT:
-		break;
+		return cgroup_bpf_prog_query(attr, uattr);
 	case BPF_LIRC_MODE2:
 		return lirc_prog_query(attr, uattr);
 	case BPF_FLOW_DISSECTOR:
@@ -2734,8 +2715,6 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	default:
 		return -EINVAL;
 	}
-
-	return cgroup_bpf_prog_query(attr, uattr);
 }
 
 #define BPF_PROG_TEST_RUN_LAST_FIELD test.ctx_out