diff mbox series

[bpf-next,v3,4/6] selftests/bpf: add a selftest with __user tag

Message ID 20220127154616.659314-1-yhs@fb.com (mailing list archive)
State Accepted
Delegated to: BPF
Headers show
Series bpf: add __user tagging support in vmlinux BTF | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 12 maintainers not CCed: mcoquelin.stm32@gmail.com linux-kselftest@vger.kernel.org linux-stm32@st-md-mailman.stormreply.com linux-arm-kernel@lists.infradead.org alexandre.torgue@foss.st.com kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com shuah@kernel.org netdev@vger.kernel.org memxor@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 81 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next success VM_Test

Commit Message

Yonghong Song Jan. 27, 2022, 3:46 p.m. UTC 
Added a selftest with three__user usages: a __user pointer-type argument
in bpf_testmod, a __user pointer-type struct member in bpf_testmod,
and a __user pointer-type struct member in vmlinux. In all cases,
directly accessing the user memory will result verification failure.

  $ ./test_progs -v -n 22/3
  ...
  libbpf: prog 'test_user1': BPF program load failed: Permission denied
  libbpf: prog 'test_user1': -- BEGIN PROG LOAD LOG --
  R1 type=ctx expected=fp
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  ; int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg)
  0: (79) r1 = *(u64 *)(r1 +0)
  func 'bpf_testmod_test_btf_type_tag_user_1' arg0 has btf_id 136561 type STRUCT 'bpf_testmod_btf_type_tag_1'
  1: R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0)
  ; g = arg->a;
  1: (61) r1 = *(u32 *)(r1 +0)
  R1 invalid mem access 'user_ptr_'
  ...
  #22/3 btf_tag/btf_type_tag_user_mod1:OK

  $ ./test_progs -v -n 22/4
  ...
  libbpf: prog 'test_user2': BPF program load failed: Permission denied
  libbpf: prog 'test_user2': -- BEGIN PROG LOAD LOG --
  R1 type=ctx expected=fp
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  ; int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg)
  0: (79) r1 = *(u64 *)(r1 +0)
  func 'bpf_testmod_test_btf_type_tag_user_2' arg0 has btf_id 136563 type STRUCT 'bpf_testmod_btf_type_tag_2'
  1: R1_w=ptr_bpf_testmod_btf_type_tag_2(id=0,off=0,imm=0)
  ; g = arg->p->a;
  1: (79) r1 = *(u64 *)(r1 +0)          ; R1_w=user_ptr_bpf_testmod_btf_type_tag_1(id=0,off=0,imm=0)
  ; g = arg->p->a;
  2: (61) r1 = *(u32 *)(r1 +0)
  R1 invalid mem access 'user_ptr_'
  ...
  #22/4 btf_tag/btf_type_tag_user_mod2:OK

  $ ./test_progs -v -n 22/5
  ...
  libbpf: prog 'test_sys_getsockname': BPF program load failed: Permission denied
  libbpf: prog 'test_sys_getsockname': -- BEGIN PROG LOAD LOG --
  R1 type=ctx expected=fp
  0: R1=ctx(id=0,off=0,imm=0) R10=fp0
  ; int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr,
  0: (79) r1 = *(u64 *)(r1 +8)
  func '__sys_getsockname' arg1 has btf_id 2319 type STRUCT 'sockaddr'
  1: R1_w=user_ptr_sockaddr(id=0,off=0,imm=0)
  ; g = usockaddr->sa_family;
  1: (69) r1 = *(u16 *)(r1 +0)
  R1 invalid mem access 'user_ptr_'
  ...
  #22/5 btf_tag/btf_type_tag_user_vmlinux:OK

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 18 ++++
 .../selftests/bpf/prog_tests/btf_tag.c        | 93 +++++++++++++++++++
 .../selftests/bpf/progs/btf_type_tag_user.c   | 40 ++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/btf_type_tag_user.c
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index bdbacf5adcd2..595d32ab285a 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -21,6 +21,24 @@  bpf_testmod_test_mod_kfunc(int i)
 	*(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i;
 }
 
+struct bpf_testmod_btf_type_tag_1 {
+	int a;
+};
+
+struct bpf_testmod_btf_type_tag_2 {
+	struct bpf_testmod_btf_type_tag_1 __user *p;
+};
+
+noinline int
+bpf_testmod_test_btf_type_tag_user_1(struct bpf_testmod_btf_type_tag_1 __user *arg) {
+	return arg->a;
+}
+
+noinline int
+bpf_testmod_test_btf_type_tag_user_2(struct bpf_testmod_btf_type_tag_2 *arg) {
+	return arg->p->a;
+}
+
 noinline int bpf_testmod_loop_test(int n)
 {
 	int i, sum = 0;
diff --git a/tools/testing/selftests/bpf/prog_tests/btf_tag.c b/tools/testing/selftests/bpf/prog_tests/btf_tag.c
index c4cf27777ff7..f7560b54a6bb 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_tag.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_tag.c
@@ -1,6 +1,7 @@ 
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021 Facebook */
 #include <test_progs.h>
+#include <bpf/btf.h>
 #include "test_btf_decl_tag.skel.h"
 
 /* struct btf_type_tag_test is referenced in btf_type_tag.skel.h */
@@ -8,6 +9,7 @@  struct btf_type_tag_test {
         int **p;
 };
 #include "btf_type_tag.skel.h"
+#include "btf_type_tag_user.skel.h"
 
 static void test_btf_decl_tag(void)
 {
@@ -41,10 +43,101 @@  static void test_btf_type_tag(void)
 	btf_type_tag__destroy(skel);
 }
 
+static void test_btf_type_tag_mod_user(bool load_test_user1)
+{
+	const char *module_name = "bpf_testmod";
+	struct btf *vmlinux_btf, *module_btf;
+	struct btf_type_tag_user *skel;
+	__s32 type_id;
+	int err;
+
+	if (!env.has_testmod) {
+		test__skip();
+		return;
+	}
+
+	/* skip the test if the module does not have __user tags */
+	vmlinux_btf = btf__load_vmlinux_btf();
+	if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF"))
+		return;
+
+	module_btf = btf__load_module_btf(module_name, vmlinux_btf);
+	if (!ASSERT_OK_PTR(module_btf, "could not load module BTF"))
+		goto free_vmlinux_btf;
+
+	type_id = btf__find_by_name_kind(module_btf, "user", BTF_KIND_TYPE_TAG);
+	if (type_id <= 0) {
+		printf("%s:SKIP: btf_type_tag attribute not in %s", __func__, module_name);
+		test__skip();
+		goto free_module_btf;
+	}
+
+	skel = btf_type_tag_user__open();
+	if (!ASSERT_OK_PTR(skel, "btf_type_tag_user"))
+		goto free_module_btf;
+
+	bpf_program__set_autoload(skel->progs.test_sys_getsockname, false);
+	if (load_test_user1)
+		bpf_program__set_autoload(skel->progs.test_user2, false);
+	else
+		bpf_program__set_autoload(skel->progs.test_user1, false);
+
+	err = btf_type_tag_user__load(skel);
+	ASSERT_ERR(err, "btf_type_tag_user");
+
+	btf_type_tag_user__destroy(skel);
+
+free_module_btf:
+	btf__free(module_btf);
+free_vmlinux_btf:
+	btf__free(vmlinux_btf);
+}
+
+static void test_btf_type_tag_vmlinux_user(void)
+{
+	struct btf_type_tag_user *skel;
+	struct btf *vmlinux_btf;
+	__s32 type_id;
+	int err;
+
+	/* skip the test if the vmlinux does not have __user tags */
+	vmlinux_btf = btf__load_vmlinux_btf();
+	if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF"))
+		return;
+
+	type_id = btf__find_by_name_kind(vmlinux_btf, "user", BTF_KIND_TYPE_TAG);
+	if (type_id <= 0) {
+		printf("%s:SKIP: btf_type_tag attribute not in vmlinux btf", __func__);
+		test__skip();
+		goto free_vmlinux_btf;
+	}
+
+	skel = btf_type_tag_user__open();
+	if (!ASSERT_OK_PTR(skel, "btf_type_tag_user"))
+		goto free_vmlinux_btf;
+
+	bpf_program__set_autoload(skel->progs.test_user2, false);
+	bpf_program__set_autoload(skel->progs.test_user1, false);
+
+	err = btf_type_tag_user__load(skel);
+	ASSERT_ERR(err, "btf_type_tag_user");
+
+	btf_type_tag_user__destroy(skel);
+
+free_vmlinux_btf:
+	btf__free(vmlinux_btf);
+}
+
 void test_btf_tag(void)
 {
 	if (test__start_subtest("btf_decl_tag"))
 		test_btf_decl_tag();
 	if (test__start_subtest("btf_type_tag"))
 		test_btf_type_tag();
+	if (test__start_subtest("btf_type_tag_user_mod1"))
+		test_btf_type_tag_mod_user(true);
+	if (test__start_subtest("btf_type_tag_user_mod2"))
+		test_btf_type_tag_mod_user(false);
+	if (test__start_subtest("btf_type_tag_sys_user_vmlinux"))
+		test_btf_type_tag_vmlinux_user();
 }
diff --git a/tools/testing/selftests/bpf/progs/btf_type_tag_user.c b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c
new file mode 100644
index 000000000000..5523f77c5a44
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/btf_type_tag_user.c
@@ -0,0 +1,40 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Facebook */
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+struct bpf_testmod_btf_type_tag_1 {
+	int a;
+};
+
+struct bpf_testmod_btf_type_tag_2 {
+	struct bpf_testmod_btf_type_tag_1 *p;
+};
+
+int g;
+
+SEC("fentry/bpf_testmod_test_btf_type_tag_user_1")
+int BPF_PROG(test_user1, struct bpf_testmod_btf_type_tag_1 *arg)
+{
+	g = arg->a;
+	return 0;
+}
+
+SEC("fentry/bpf_testmod_test_btf_type_tag_user_2")
+int BPF_PROG(test_user2, struct bpf_testmod_btf_type_tag_2 *arg)
+{
+	g = arg->p->a;
+	return 0;
+}
+
+/* int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,
+ *                       int __user *usockaddr_len);
+ */
+SEC("fentry/__sys_getsockname")
+int BPF_PROG(test_sys_getsockname, int fd, struct sockaddr *usockaddr,
+	     int *usockaddr_len)
+{
+	g = usockaddr->sa_family;
+	return 0;
+}