Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2022-12-16

We've added 7 non-merge commits during the last 2 day(s) which contain
a total of 9 files changed, 119 insertions(+), 36 deletions(-).

1) Fix for recent syzkaller XDP dispatcher update splat, from Jiri Olsa.

2) Fix BPF program refcount leak in LSM attachment failure path,
   from Milan Landaverde.

3) Fix BPF program type in map compatibility check for fext,
   from Toke Høiland-Jørgensen.

4) Fix a BPF selftest compilation error under !CONFIG_SMP config,
   from Yonghong Song.

5) Fix CI to enable CONFIG_FUNCTION_ERROR_INJECTION after it got changed
   to a prompt, from Song Liu.

6) Various BPF documentation fixes for socket local storage,
   from Donald Hunter.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Add a test for using a cpumap from an freplace-to-XDP program
  bpf: Resolve fext program type when checking map compatibility
  bpf: Synchronize dispatcher update with bpf_dispatcher_xdp_func
  bpf: prevent leak of lsm program after failed attach
  selftests/bpf: Select CONFIG_FUNCTION_ERROR_INJECTION
  selftests/bpf: Fix a selftest compilation error with CONFIG_SMP=n
  docs/bpf: Reword docs for BPF_MAP_TYPE_SK_STORAGE
====================

Link: https://lore.kernel.org/r/20221216174540.16598-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

5 files changed, 78 insertions, 5 deletions

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 612f699dc4f7..63cd4ab70171 100644
--- a/tools/testing/selftests/bpf/config
+++ b/tools/testing/selftests/bpf/config
@@ -16,6 +16,7 @@ CONFIG_CRYPTO_USER_API_HASH=y
 CONFIG_DYNAMIC_FTRACE=y
 CONFIG_FPROBE=y
 CONFIG_FTRACE_SYSCALLS=y
+CONFIG_FUNCTION_ERROR_INJECTION=y
 CONFIG_FUNCTION_TRACER=y
 CONFIG_GENEVE=y
 CONFIG_IKCONFIG=y
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index d1e32e792536..20f5fa0fcec9 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -4,6 +4,8 @@
 #include <network_helpers.h>
 #include <bpf/btf.h>
 #include "bind4_prog.skel.h"
+#include "freplace_progmap.skel.h"
+#include "xdp_dummy.skel.h"
 
 typedef int (*test_cb)(struct bpf_object *obj);
 
@@ -500,6 +502,50 @@ cleanup:
 	bind4_prog__destroy(skel);
 }
 
+static void test_func_replace_progmap(void)
+{
+	struct bpf_cpumap_val value = { .qsize = 1 };
+	struct freplace_progmap *skel = NULL;
+	struct xdp_dummy *tgt_skel = NULL;
+	__u32 key = 0;
+	int err;
+
+	skel = freplace_progmap__open();
+	if (!ASSERT_OK_PTR(skel, "prog_open"))
+		return;
+
+	tgt_skel = xdp_dummy__open_and_load();
+	if (!ASSERT_OK_PTR(tgt_skel, "tgt_prog_load"))
+		goto out;
+
+	err = bpf_program__set_attach_target(skel->progs.xdp_cpumap_prog,
+					     bpf_program__fd(tgt_skel->progs.xdp_dummy_prog),
+					     "xdp_dummy_prog");
+	if (!ASSERT_OK(err, "set_attach_target"))
+		goto out;
+
+	err = freplace_progmap__load(skel);
+	if (!ASSERT_OK(err, "obj_load"))
+		goto out;
+
+	/* Prior to fixing the kernel, loading the PROG_TYPE_EXT 'redirect'
+	 * program above will cause the map owner type of 'cpumap' to be set to
+	 * PROG_TYPE_EXT. This in turn will cause the bpf_map_update_elem()
+	 * below to fail, because the program we are inserting into the map is
+	 * of PROG_TYPE_XDP. After fixing the kernel, the initial ownership will
+	 * be correctly resolved to the *target* of the PROG_TYPE_EXT program
+	 * (i.e., PROG_TYPE_XDP) and the map update will succeed.
+	 */
+	value.bpf_prog.fd = bpf_program__fd(skel->progs.xdp_drop_prog);
+	err = bpf_map_update_elem(bpf_map__fd(skel->maps.cpu_map),
+				  &key, &value, 0);
+	ASSERT_OK(err, "map_update");
+
+out:
+	xdp_dummy__destroy(tgt_skel);
+	freplace_progmap__destroy(skel);
+}
+
 /* NOTE: affect other tests, must run in serial mode */
 void serial_test_fexit_bpf2bpf(void)
 {
@@ -525,4 +571,6 @@ void serial_test_fexit_bpf2bpf(void)
 		test_func_replace_global_func();
 	if (test__start_subtest("fentry_to_cgroup_bpf"))
 		test_fentry_to_cgroup_bpf();
+	if (test__start_subtest("func_replace_progmap"))
+		test_func_replace_progmap();
 }
diff --git a/tools/testing/selftests/bpf/progs/freplace_progmap.c b/tools/testing/selftests/bpf/progs/freplace_progmap.c
new file mode 100644
index 000000000000..81b56b9aa7d6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/freplace_progmap.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CPUMAP);
+	__type(key, __u32);
+	__type(value, struct bpf_cpumap_val);
+	__uint(max_entries, 1);
+} cpu_map SEC(".maps");
+
+SEC("xdp/cpumap")
+int xdp_drop_prog(struct xdp_md *ctx)
+{
+	return XDP_DROP;
+}
+
+SEC("freplace")
+int xdp_cpumap_prog(struct xdp_md *ctx)
+{
+	return bpf_redirect_map(&cpu_map, 0, XDP_PASS);
+}
+
+char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c
index 125f908024d3..5cecbdbbb16e 100644
--- a/tools/testing/selftests/bpf/progs/rcu_read_lock.c
+++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c
@@ -288,13 +288,13 @@ out:
 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
 int task_untrusted_non_rcuptr(void *ctx)
 {
-	struct task_struct *task, *last_wakee;
+	struct task_struct *task, *group_leader;
 
 	task = bpf_get_current_task_btf();
 	bpf_rcu_read_lock();
-	/* the pointer last_wakee marked as untrusted */
-	last_wakee = task->real_parent->last_wakee;
-	(void)bpf_task_storage_get(&map_a, last_wakee, 0, 0);
+	/* the pointer group_leader marked as untrusted */
+	group_leader = task->real_parent->group_leader;
+	(void)bpf_task_storage_get(&map_a, group_leader, 0, 0);
 	bpf_rcu_read_unlock();
 	return 0;
 }
diff --git a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
index 87fa1db9d9b5..1b47b94dbca0 100644
--- a/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
+++ b/tools/testing/selftests/bpf/progs/task_kfunc_failure.c
@@ -73,7 +73,7 @@ int BPF_PROG(task_kfunc_acquire_trusted_walked, struct task_struct *task, u64 cl
 	struct task_struct *acquired;
 
 	/* Can't invoke bpf_task_acquire() on a trusted pointer obtained from walking a struct. */
-	acquired = bpf_task_acquire(task->last_wakee);
+	acquired = bpf_task_acquire(task->group_leader);
 	bpf_task_release(acquired);
 
 	return 0;