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Yonghong SongKernel Patches Daemon
Yonghong Song
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Kernel Patches Daemon
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selftests/bpf: Test ldsx with more complex cases
The following ldsx cases are tested: - signed readonly map value - read/write map value - probed memory - not-narrowed ctx field access - narrowed ctx field access. Without previous proper verifier/git handling, the test will fail. If cpuv4 is not supported either by compiler or by jit, the test will be skipped. # ./test_progs -t ldsx_insn #113/1 ldsx_insn/map_val and probed_memory:SKIP #113/2 ldsx_insn/ctx_member_sign_ext:SKIP #113/3 ldsx_insn/ctx_member_narrow_sign_ext:SKIP #113 ldsx_insn:SKIP Summary: 1/0 PASSED, 3 SKIPPED, 0 FAILED Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
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‎tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c‎

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -98,6 +98,12 @@ bpf_testmod_test_struct_arg_8(u64 a, void *b, short c, int d, void *e,
9898
return bpf_testmod_test_struct_arg_result;
9999
}
100100

101+
noinline int
102+
bpf_testmod_test_arg_ptr_to_struct(struct bpf_testmod_struct_arg_1 *a) {
103+
bpf_testmod_test_struct_arg_result = a->a;
104+
return bpf_testmod_test_struct_arg_result;
105+
}
106+
101107
__bpf_kfunc void
102108
bpf_testmod_test_mod_kfunc(int i)
103109
{
@@ -240,7 +246,7 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
240246
.off = off,
241247
.len = len,
242248
};
243-
struct bpf_testmod_struct_arg_1 struct_arg1 = {10};
249+
struct bpf_testmod_struct_arg_1 struct_arg1 = {10}, struct_arg1_2 = {-1};
244250
struct bpf_testmod_struct_arg_2 struct_arg2 = {2, 3};
245251
struct bpf_testmod_struct_arg_3 *struct_arg3;
246252
struct bpf_testmod_struct_arg_4 struct_arg4 = {21, 22};
@@ -259,6 +265,7 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
259265
(void)bpf_testmod_test_struct_arg_8(16, (void *)17, 18, 19,
260266
(void *)20, struct_arg4, 23);
261267

268+
(void)bpf_testmod_test_arg_ptr_to_struct(&struct_arg1_2);
262269

263270
struct_arg3 = kmalloc((sizeof(struct bpf_testmod_struct_arg_3) +
264271
sizeof(int)), GFP_KERNEL);

‎tools/testing/selftests/bpf/prog_tests/test_ldsx_insn.c‎

Lines changed: 139 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,139 @@
1+
// SPDX-License-Identifier: GPL-2.0
2+
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates.*/
3+
4+
#include <test_progs.h>
5+
#include <network_helpers.h>
6+
#include "test_ldsx_insn.skel.h"
7+
8+
static void test_map_val_and_probed_memory(void)
9+
{
10+
struct test_ldsx_insn *skel;
11+
int err;
12+
13+
skel = test_ldsx_insn__open();
14+
if (!ASSERT_OK_PTR(skel, "test_ldsx_insn__open"))
15+
return;
16+
17+
if (skel->rodata->skip) {
18+
test__skip();
19+
goto out;
20+
}
21+
22+
bpf_program__set_autoload(skel->progs.rdonly_map_prog, true);
23+
bpf_program__set_autoload(skel->progs.map_val_prog, true);
24+
bpf_program__set_autoload(skel->progs.test_ptr_struct_arg, true);
25+
26+
err = test_ldsx_insn__load(skel);
27+
if (!ASSERT_OK(err, "test_ldsx_insn__load"))
28+
goto out;
29+
30+
err = test_ldsx_insn__attach(skel);
31+
if (!ASSERT_OK(err, "test_ldsx_insn__attach"))
32+
goto out;
33+
34+
ASSERT_OK(trigger_module_test_read(256), "trigger_read");
35+
36+
ASSERT_EQ(skel->bss->done1, 1, "done1");
37+
ASSERT_EQ(skel->bss->ret1, 1, "ret1");
38+
ASSERT_EQ(skel->bss->done2, 1, "done2");
39+
ASSERT_EQ(skel->bss->ret2, 1, "ret2");
40+
ASSERT_EQ(skel->bss->int_member, -1, "int_member");
41+
42+
out:
43+
test_ldsx_insn__destroy(skel);
44+
}
45+
46+
static void test_ctx_member_sign_ext(void)
47+
{
48+
struct test_ldsx_insn *skel;
49+
int err, fd, cgroup_fd;
50+
char buf[16] = {0};
51+
socklen_t optlen;
52+
53+
cgroup_fd = test__join_cgroup("/ldsx_test");
54+
if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /ldsx_test"))
55+
return;
56+
57+
skel = test_ldsx_insn__open();
58+
if (!ASSERT_OK_PTR(skel, "test_ldsx_insn__open"))
59+
goto close_cgroup_fd;
60+
61+
if (skel->rodata->skip) {
62+
test__skip();
63+
goto destroy_skel;
64+
}
65+
66+
bpf_program__set_autoload(skel->progs._getsockopt, true);
67+
68+
err = test_ldsx_insn__load(skel);
69+
if (!ASSERT_OK(err, "test_ldsx_insn__load"))
70+
goto destroy_skel;
71+
72+
skel->links._getsockopt =
73+
bpf_program__attach_cgroup(skel->progs._getsockopt, cgroup_fd);
74+
if (!ASSERT_OK_PTR(skel->links._getsockopt, "getsockopt_link"))
75+
goto destroy_skel;
76+
77+
fd = socket(AF_INET, SOCK_STREAM, 0);
78+
if (!ASSERT_GE(fd, 0, "socket"))
79+
goto destroy_skel;
80+
81+
optlen = sizeof(buf);
82+
(void)getsockopt(fd, SOL_IP, IP_TTL, buf, &optlen);
83+
84+
ASSERT_EQ(skel->bss->set_optlen, -1, "optlen");
85+
ASSERT_EQ(skel->bss->set_retval, -1, "retval");
86+
87+
close(fd);
88+
destroy_skel:
89+
test_ldsx_insn__destroy(skel);
90+
close_cgroup_fd:
91+
close(cgroup_fd);
92+
}
93+
94+
static void test_ctx_member_narrow_sign_ext(void)
95+
{
96+
struct test_ldsx_insn *skel;
97+
struct __sk_buff skb = {};
98+
LIBBPF_OPTS(bpf_test_run_opts, topts,
99+
.data_in = &pkt_v4,
100+
.data_size_in = sizeof(pkt_v4),
101+
.ctx_in = &skb,
102+
.ctx_size_in = sizeof(skb),
103+
);
104+
int err, prog_fd;
105+
106+
skel = test_ldsx_insn__open();
107+
if (!ASSERT_OK_PTR(skel, "test_ldsx_insn__open"))
108+
return;
109+
110+
if (skel->rodata->skip) {
111+
test__skip();
112+
goto out;
113+
}
114+
115+
bpf_program__set_autoload(skel->progs._tc, true);
116+
117+
err = test_ldsx_insn__load(skel);
118+
if (!ASSERT_OK(err, "test_ldsx_insn__load"))
119+
goto out;
120+
121+
prog_fd = bpf_program__fd(skel->progs._tc);
122+
err = bpf_prog_test_run_opts(prog_fd, &topts);
123+
ASSERT_OK(err, "test_run");
124+
125+
ASSERT_EQ(skel->bss->set_mark, -2, "set_mark");
126+
127+
out:
128+
test_ldsx_insn__destroy(skel);
129+
}
130+
131+
void test_ldsx_insn(void)
132+
{
133+
if (test__start_subtest("map_val and probed_memory"))
134+
test_map_val_and_probed_memory();
135+
if (test__start_subtest("ctx_member_sign_ext"))
136+
test_ctx_member_sign_ext();
137+
if (test__start_subtest("ctx_member_narrow_sign_ext"))
138+
test_ctx_member_narrow_sign_ext();
139+
}

‎tools/testing/selftests/bpf/progs/test_ldsx_insn.c‎

Lines changed: 118 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,118 @@
1+
// SPDX-License-Identifier: GPL-2.0
2+
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
3+
4+
#include "vmlinux.h"
5+
#include <bpf/bpf_helpers.h>
6+
#include <bpf/bpf_tracing.h>
7+
8+
#if defined(__TARGET_ARCH_x86) && __clang_major__ >= 18
9+
const volatile int skip = 0;
10+
#else
11+
const volatile int skip = 1;
12+
#endif
13+
14+
volatile const short val1 = -1;
15+
volatile const int val2 = -1;
16+
short val3 = -1;
17+
int val4 = -1;
18+
int done1, done2, ret1, ret2;
19+
20+
SEC("?raw_tp/sys_enter")
21+
int rdonly_map_prog(const void *ctx)
22+
{
23+
if (done1)
24+
return 0;
25+
26+
done1 = 1;
27+
/* val1/val2 readonly map */
28+
if (val1 == val2)
29+
ret1 = 1;
30+
return 0;
31+
32+
}
33+
34+
SEC("?raw_tp/sys_enter")
35+
int map_val_prog(const void *ctx)
36+
{
37+
if (done2)
38+
return 0;
39+
40+
done2 = 1;
41+
/* val1/val2 regular read/write map */
42+
if (val3 == val4)
43+
ret2 = 1;
44+
return 0;
45+
46+
}
47+
48+
struct bpf_testmod_struct_arg_1 {
49+
int a;
50+
};
51+
52+
long long int_member;
53+
54+
SEC("?fentry/bpf_testmod_test_arg_ptr_to_struct")
55+
int BPF_PROG2(test_ptr_struct_arg, struct bpf_testmod_struct_arg_1 *, p)
56+
{
57+
/* probed memory access */
58+
int_member = p->a;
59+
return 0;
60+
}
61+
62+
long long set_optlen, set_retval;
63+
64+
SEC("?cgroup/getsockopt")
65+
int _getsockopt(volatile struct bpf_sockopt *ctx)
66+
{
67+
int old_optlen, old_retval;
68+
69+
old_optlen = ctx->optlen;
70+
old_retval = ctx->retval;
71+
72+
ctx->optlen = -1;
73+
ctx->retval = -1;
74+
75+
/* sign extension for ctx member */
76+
set_optlen = ctx->optlen;
77+
set_retval = ctx->retval;
78+
79+
ctx->optlen = old_optlen;
80+
ctx->retval = old_retval;
81+
82+
return 0;
83+
}
84+
85+
long long set_mark;
86+
87+
SEC("?tc")
88+
int _tc(volatile struct __sk_buff *skb)
89+
{
90+
long long tmp_mark;
91+
int old_mark;
92+
93+
old_mark = skb->mark;
94+
95+
skb->mark = 0xf6fe;
96+
97+
/* narrowed sign extension for ctx member */
98+
#if __clang_major__ >= 18
99+
/* force narrow one-byte signed load. Otherwise, compiler may
100+
* generate a 32-bit unsigned load followed by an s8 movsx.
101+
*/
102+
asm volatile ("r1 = *(s8 *)(%[ctx] + %[off_mark])\n\t"
103+
"%[tmp_mark] = r1"
104+
: [tmp_mark]"=r"(tmp_mark)
105+
: [ctx]"r"(skb),
106+
[off_mark]"i"(offsetof(struct __sk_buff, mark))
107+
: "r1");
108+
#else
109+
tmp_mark = (char)skb->mark;
110+
#endif
111+
set_mark = tmp_mark;
112+
113+
skb->mark = old_mark;
114+
115+
return 0;
116+
}
117+
118+
char _license[] SEC("license") = "GPL";

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