Merge branch 'resolve_prog_type'

Udip Pant says:

====================
This patch series adds changes in verifier to make decisions such as granting
of read / write access or enforcement of return code status based on
the program type of the target program while using dynamic program
extension (of type BPF_PROG_TYPE_EXT).

The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
placeholder for those, we need this extended check for those extended
programs to actually work with proper access, while using this option.

Patch #1 includes changes in the verifier.
Patch #2 adds selftests to verify write access on a packet for a valid
extension program type
Patch #3 adds selftests to verify proper check for the return code
Patch #4 adds selftests to ensure access permissions and restrictions
for some map types such sockmap.

Changelogs:
  v2 -> v3:
    * more comprehensive resolution of the program type in the verifier
      based on the target program (and not just for the packet access)
    * selftests for checking return code and map access
    * Also moved this patch to 'bpf-next' from 'bpf' tree
  v1 -> v2:
    * extraction of the logic to resolve prog type into a separate method
    * selftests to check for packet access for a valid freplace prog
====================

Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 68 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index 197d0d217b56..a550dab9ba7a 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -123,6 +123,7 @@ static void test_func_replace(void)
 		"freplace/get_skb_len",
 		"freplace/get_skb_ifindex",
 		"freplace/get_constant",
+		"freplace/test_pkt_write_access_subprog",
 	};
 	test_fexit_bpf2bpf_common("./fexit_bpf2bpf.o",
 				  "./test_pkt_access.o",
@@ -141,10 +142,77 @@ static void test_func_replace_verify(void)
 				  prog_name, false);
 }
 
+static void test_func_sockmap_update(void)
+{
+	const char *prog_name[] = {
+		"freplace/cls_redirect",
+	};
+	test_fexit_bpf2bpf_common("./freplace_cls_redirect.o",
+				  "./test_cls_redirect.o",
+				  ARRAY_SIZE(prog_name),
+				  prog_name, false);
+}
+
+static void test_obj_load_failure_common(const char *obj_file,
+					  const char *target_obj_file)
+
+{
+	/*
+	 * standalone test that asserts failure to load freplace prog
+	 * because of invalid return code.
+	 */
+	struct bpf_object *obj = NULL, *pkt_obj;
+	int err, pkt_fd;
+	__u32 duration = 0;
+
+	err = bpf_prog_load(target_obj_file, BPF_PROG_TYPE_UNSPEC,
+			    &pkt_obj, &pkt_fd);
+	/* the target prog should load fine */
+	if (CHECK(err, "tgt_prog_load", "file %s err %d errno %d\n",
+		  target_obj_file, err, errno))
+		return;
+	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
+			    .attach_prog_fd = pkt_fd,
+			   );
+
+	obj = bpf_object__open_file(obj_file, &opts);
+	if (CHECK(IS_ERR_OR_NULL(obj), "obj_open",
+		  "failed to open %s: %ld\n", obj_file,
+		  PTR_ERR(obj)))
+		goto close_prog;
+
+	/* It should fail to load the program */
+	err = bpf_object__load(obj);
+	if (CHECK(!err, "bpf_obj_load should fail", "err %d\n", err))
+		goto close_prog;
+
+close_prog:
+	if (!IS_ERR_OR_NULL(obj))
+		bpf_object__close(obj);
+	bpf_object__close(pkt_obj);
+}
+
+static void test_func_replace_return_code(void)
+{
+	/* test invalid return code in the replaced program */
+	test_obj_load_failure_common("./freplace_connect_v4_prog.o",
+				     "./connect4_prog.o");
+}
+
+static void test_func_map_prog_compatibility(void)
+{
+	/* test with spin lock map value in the replaced program */
+	test_obj_load_failure_common("./freplace_attach_probe.o",
+				     "./test_attach_probe.o");
+}
+
 void test_fexit_bpf2bpf(void)
 {
 	test_target_no_callees();
 	test_target_yes_callees();
 	test_func_replace();
 	test_func_replace_verify();
+	test_func_sockmap_update();
+	test_func_replace_return_code();
+	test_func_map_prog_compatibility();
 }