Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
bpf-next 2022-02-17

We've added 29 non-merge commits during the last 8 day(s) which contain
a total of 34 files changed, 1502 insertions(+), 524 deletions(-).

The main changes are:

1) Add BTFGen support to bpftool which allows to use CO-RE in kernels without
   BTF info, from Mauricio Vásquez, Rafael David Tinoco, Lorenzo Fontana and
   Leonardo Di Donato. (Details: https://lpc.events/event/11/contributions/948/)

2) Prepare light skeleton to be used in both kernel module and user space
   and convert bpf_preload.ko to use light skeleton, from Alexei Starovoitov.

3) Rework bpftool's versioning scheme and align with libbpf's version number;
   also add linked libbpf version info to "bpftool version", from Quentin Monnet.

4) Add minimal C++ specific additions to bpftool's skeleton codegen to
   facilitate use of C skeletons in C++ applications, from Andrii Nakryiko.

5) Add BPF verifier sanity check whether relative offset on kfunc calls overflows
   desc->imm and reject the BPF program if the case, from Hou Tao.

6) Fix libbpf to use a dynamically allocated buffer for netlink messages to
   avoid receiving truncated messages on some archs, from Toke Høiland-Jørgensen.

7) Various follow-up fixes to the JIT bpf_prog_pack allocator, from Song Liu.

8) Various BPF selftest and vmtest.sh fixes, from Yucong Sun.

9) Fix bpftool pretty print handling on dumping map keys/values when no BTF
   is available, from Jiri Olsa and Yinjun Zhang.

10) Extend XDP frags selftest to check for invalid length, from Lorenzo Bianconi.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (29 commits)
  bpf: bpf_prog_pack: Set proper size before freeing ro_header
  selftests/bpf: Fix crash in core_reloc when bpftool btfgen fails
  selftests/bpf: Fix vmtest.sh to launch smp vm.
  libbpf: Fix memleak in libbpf_netlink_recv()
  bpftool: Fix C++ additions to skeleton
  bpftool: Fix pretty print dump for maps without BTF loaded
  selftests/bpf: Test "bpftool gen min_core_btf"
  bpftool: Gen min_core_btf explanation and examples
  bpftool: Implement btfgen_get_btf()
  bpftool: Implement "gen min_core_btf" logic
  bpftool: Add gen min_core_btf command
  libbpf: Expose bpf_core_{add,free}_cands() to bpftool
  libbpf: Split bpf_core_apply_relo()
  bpf: Reject kfunc calls that overflow insn->imm
  selftests/bpf: Add Skeleton templated wrapper as an example
  bpftool: Add C++-specific open/load/etc skeleton wrappers
  selftests/bpf: Fix GCC11 compiler warnings in -O2 mode
  bpftool: Fix the error when lookup in no-btf maps
  libbpf: Use dynamically allocated buffer when receiving netlink messages
  libbpf: Fix libbpf.map inheritance chain for LIBBPF_0.7.0
  ...
====================

Link: https://lore.kernel.org/r/20220217232027.29831-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

6 files changed, 174 insertions, 9 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
index 8b652f5ce423..ec823561b912 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf.c
@@ -6556,7 +6556,7 @@ done:
 static void do_test_info_raw(unsigned int test_num)
 {
 	const struct prog_info_raw_test *test = &info_raw_tests[test_num - 1];
-	unsigned int raw_btf_size, linfo_str_off, linfo_size;
+	unsigned int raw_btf_size, linfo_str_off, linfo_size = 0;
 	int btf_fd = -1, prog_fd = -1, err = 0;
 	void *raw_btf, *patched_linfo = NULL;
 	const char *ret_next_str;
diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index b8bdd1c3efca..8fbb40a832d5 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -2,6 +2,7 @@
 #include <test_progs.h>
 #include "progs/core_reloc_types.h"
 #include "bpf_testmod/bpf_testmod.h"
+#include <linux/limits.h>
 #include <sys/mman.h>
 #include <sys/syscall.h>
 #include <bpf/btf.h>
@@ -836,13 +837,27 @@ static size_t roundup_page(size_t sz)
 	return (sz + page_size - 1) / page_size * page_size;
 }
 
-void test_core_reloc(void)
+static int run_btfgen(const char *src_btf, const char *dst_btf, const char *objpath)
+{
+	char command[4096];
+	int n;
+
+	n = snprintf(command, sizeof(command),
+		     "./tools/build/bpftool/bpftool gen min_core_btf %s %s %s",
+		     src_btf, dst_btf, objpath);
+	if (n < 0 || n >= sizeof(command))
+		return -1;
+
+	return system(command);
+}
+
+static void run_core_reloc_tests(bool use_btfgen)
 {
 	const size_t mmap_sz = roundup_page(sizeof(struct data));
 	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts);
 	struct core_reloc_test_case *test_case;
 	const char *tp_name, *probe_name;
-	int err, i, equal;
+	int err, i, equal, fd;
 	struct bpf_link *link = NULL;
 	struct bpf_map *data_map;
 	struct bpf_program *prog;
@@ -854,6 +869,7 @@ void test_core_reloc(void)
 	my_pid_tgid = getpid() | ((uint64_t)syscall(SYS_gettid) << 32);
 
 	for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
+		char btf_file[] = "/tmp/core_reloc.btf.XXXXXX";
 		test_case = &test_cases[i];
 		if (!test__start_subtest(test_case->case_name))
 			continue;
@@ -863,6 +879,25 @@ void test_core_reloc(void)
 			continue;
 		}
 
+		/* generate a "minimal" BTF file and use it as source */
+		if (use_btfgen) {
+			if (!test_case->btf_src_file || test_case->fails) {
+				test__skip();
+				continue;
+			}
+
+			fd = mkstemp(btf_file);
+			if (!ASSERT_GE(fd, 0, "btf_tmp"))
+				continue;
+			close(fd); /* we only need the path */
+			err = run_btfgen(test_case->btf_src_file, btf_file,
+					 test_case->bpf_obj_file);
+			if (!ASSERT_OK(err, "run_btfgen"))
+				continue;
+
+			test_case->btf_src_file = btf_file;
+		}
+
 		if (test_case->setup) {
 			err = test_case->setup(test_case);
 			if (CHECK(err, "test_setup", "test #%d setup failed: %d\n", i, err))
@@ -872,7 +907,7 @@ void test_core_reloc(void)
 		if (test_case->btf_src_file) {
 			err = access(test_case->btf_src_file, R_OK);
 			if (!ASSERT_OK(err, "btf_src_file"))
-				goto cleanup;
+				continue;
 		}
 
 		open_opts.btf_custom_path = test_case->btf_src_file;
@@ -954,8 +989,19 @@ cleanup:
 			CHECK_FAIL(munmap(mmap_data, mmap_sz));
 			mmap_data = NULL;
 		}
+		remove(btf_file);
 		bpf_link__destroy(link);
 		link = NULL;
 		bpf_object__close(obj);
 	}
 }
+
+void test_core_reloc(void)
+{
+	run_core_reloc_tests(false);
+}
+
+void test_core_btfgen(void)
+{
+	run_core_reloc_tests(true);
+}
diff --git a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
index c2426df58e17..647b0a833628 100644
--- a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
+++ b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
@@ -140,7 +140,7 @@ static struct nstoken *open_netns(const char *name)
 	int err;
 	struct nstoken *token;
 
-	token = malloc(sizeof(struct nstoken));
+	token = calloc(1, sizeof(struct nstoken));
 	if (!ASSERT_OK_PTR(token, "malloc token"))
 		return NULL;
 
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
index d18e6f343c48..2f033da4cd45 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_frags.c
@@ -5,11 +5,12 @@
 static void test_xdp_update_frags(void)
 {
 	const char *file = "./test_xdp_update_frags.o";
+	int err, prog_fd, max_skb_frags, buf_size, num;
 	struct bpf_program *prog;
 	struct bpf_object *obj;
-	int err, prog_fd;
 	__u32 *offset;
 	__u8 *buf;
+	FILE *f;
 	LIBBPF_OPTS(bpf_test_run_opts, topts);
 
 	obj = bpf_object__open(file);
@@ -99,6 +100,41 @@ static void test_xdp_update_frags(void)
 	ASSERT_EQ(buf[7621], 0xbb, "xdp_update_frag buf[7621]");
 
 	free(buf);
+
+	/* test_xdp_update_frags: unsupported buffer size */
+	f = fopen("/proc/sys/net/core/max_skb_frags", "r");
+	if (!ASSERT_OK_PTR(f, "max_skb_frag file pointer"))
+		goto out;
+
+	num = fscanf(f, "%d", &max_skb_frags);
+	fclose(f);
+
+	if (!ASSERT_EQ(num, 1, "max_skb_frags read failed"))
+		goto out;
+
+	/* xdp_buff linear area size is always set to 4096 in the
+	 * bpf_prog_test_run_xdp routine.
+	 */
+	buf_size = 4096 + (max_skb_frags + 1) * sysconf(_SC_PAGE_SIZE);
+	buf = malloc(buf_size);
+	if (!ASSERT_OK_PTR(buf, "alloc buf"))
+		goto out;
+
+	memset(buf, 0, buf_size);
+	offset = (__u32 *)buf;
+	*offset = 16;
+	buf[*offset] = 0xaa;
+	buf[*offset + 15] = 0xaa;
+
+	topts.data_in = buf;
+	topts.data_out = buf;
+	topts.data_size_in = buf_size;
+	topts.data_size_out = buf_size;
+
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_EQ(err, -ENOMEM,
+		  "unsupported buf size, possible non-default /proc/sys/net/core/max_skb_flags?");
+	free(buf);
 out:
 	bpf_object__close(obj);
 }
diff --git a/tools/testing/selftests/bpf/test_cpp.cpp b/tools/testing/selftests/bpf/test_cpp.cpp
index e00201de2890..773f165c4898 100644
--- a/tools/testing/selftests/bpf/test_cpp.cpp
+++ b/tools/testing/selftests/bpf/test_cpp.cpp
@@ -5,18 +5,100 @@
 #include <bpf/btf.h>
 #include "test_core_extern.skel.h"
 
-/* do nothing, just make sure we can link successfully */
+template <typename T>
+class Skeleton {
+private:
+	T *skel;
+public:
+	Skeleton(): skel(nullptr) { }
+
+	~Skeleton() { if (skel) T::destroy(skel); }
+
+	int open(const struct bpf_object_open_opts *opts = nullptr)
+	{
+		int err;
+
+		if (skel)
+			return -EBUSY;
+
+		skel = T::open(opts);
+		err = libbpf_get_error(skel);
+		if (err) {
+			skel = nullptr;
+			return err;
+		}
+
+		return 0;
+	}
+
+	int load() { return T::load(skel); }
+
+	int attach() { return T::attach(skel); }
+
+	void detach() { return T::detach(skel); }
+
+	const T* operator->() const { return skel; }
+
+	T* operator->() { return skel; }
+
+	const T *get() const { return skel; }
+};
 
 static void dump_printf(void *ctx, const char *fmt, va_list args)
 {
 }
 
+static void try_skeleton_template()
+{
+	Skeleton<test_core_extern> skel;
+	std::string prog_name;
+	int err;
+	LIBBPF_OPTS(bpf_object_open_opts, opts);
+
+	err = skel.open(&opts);
+	if (err) {
+		fprintf(stderr, "Skeleton open failed: %d\n", err);
+		return;
+	}
+
+	skel->data->kern_ver = 123;
+	skel->data->int_val = skel->data->ushort_val;
+
+	err = skel.load();
+	if (err) {
+		fprintf(stderr, "Skeleton load failed: %d\n", err);
+		return;
+	}
+
+	if (!skel->kconfig->CONFIG_BPF_SYSCALL)
+		fprintf(stderr, "Seems like CONFIG_BPF_SYSCALL isn't set?!\n");
+
+	err = skel.attach();
+	if (err) {
+		fprintf(stderr, "Skeleton attach failed: %d\n", err);
+		return;
+	}
+
+	prog_name = bpf_program__name(skel->progs.handle_sys_enter);
+	if (prog_name != "handle_sys_enter")
+		fprintf(stderr, "Unexpected program name: %s\n", prog_name.c_str());
+
+	bpf_link__destroy(skel->links.handle_sys_enter);
+	skel->links.handle_sys_enter = bpf_program__attach(skel->progs.handle_sys_enter);
+
+	skel.detach();
+
+	/* destructor will destory underlying skeleton */
+}
+
 int main(int argc, char *argv[])
 {
 	struct btf_dump_opts opts = { };
 	struct test_core_extern *skel;
 	struct btf *btf;
 
+	try_skeleton_template();
+
 	/* libbpf.h */
 	libbpf_set_print(NULL);
 
@@ -25,7 +107,8 @@ int main(int argc, char *argv[])
 
 	/* btf.h */
 	btf = btf__new(NULL, 0);
-	btf_dump__new(btf, dump_printf, nullptr, &opts);
+	if (!libbpf_get_error(btf))
+		btf_dump__new(btf, dump_printf, nullptr, &opts);
 
 	/* BPF skeleton */
 	skel = test_core_extern__open_and_load();
diff --git a/tools/testing/selftests/bpf/vmtest.sh b/tools/testing/selftests/bpf/vmtest.sh
index b3afd43549fa..e0bb04a97e10 100755
--- a/tools/testing/selftests/bpf/vmtest.sh
+++ b/tools/testing/selftests/bpf/vmtest.sh
@@ -241,7 +241,7 @@ EOF
 		-nodefaults \
 		-display none \
 		-serial mon:stdio \
-		"${qemu_flags[@]}" \
+		"${QEMU_FLAGS[@]}" \
 		-enable-kvm \
 		-m 4G \
 		-drive file="${rootfs_img}",format=raw,index=1,media=disk,if=virtio,cache=none \