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authorYonghong Song <yhs@fb.com>2020-06-30 19:12:41 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2020-06-30 22:21:29 +0200
commitd923021c2ce12acb50dc7086a1bf66eed82adf6a (patch)
treeab388fa92b8b8bf4d3be8683567ee1b3788ebbf9 /tools
parentbpf: Fix an incorrect branch elimination by verifier (diff)
downloadlinux-d923021c2ce12acb50dc7086a1bf66eed82adf6a.tar.xz
linux-d923021c2ce12acb50dc7086a1bf66eed82adf6a.zip
bpf: Add tests for PTR_TO_BTF_ID vs. null comparison
Add two tests for PTR_TO_BTF_ID vs. null ptr comparison, one for PTR_TO_BTF_ID in the ctx structure and the other for PTR_TO_BTF_ID after one level pointer chasing. In both cases, the test ensures condition is not removed. For example, for this test struct bpf_fentry_test_t { struct bpf_fentry_test_t *a; }; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) { if (arg == 0) test7_result = 1; return 0; } Before the previous verifier change, we have xlated codes: int test7(long long unsigned int * ctx): ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) 0: (79) r1 = *(u64 *)(r1 +0) ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) 1: (b4) w0 = 0 2: (95) exit After the previous verifier change, we have: int test7(long long unsigned int * ctx): ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) 0: (79) r1 = *(u64 *)(r1 +0) ; if (arg == 0) 1: (55) if r1 != 0x0 goto pc+4 ; test7_result = 1; 2: (18) r1 = map[id:6][0]+48 4: (b7) r2 = 1 5: (7b) *(u64 *)(r1 +0) = r2 ; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) 6: (b4) w0 = 0 7: (95) exit Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200630171241.2523875-1-yhs@fb.com
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/bpf/prog_tests/fentry_fexit.c2
-rw-r--r--tools/testing/selftests/bpf/progs/fentry_test.c22
-rw-r--r--tools/testing/selftests/bpf/progs/fexit_test.c22
3 files changed, 45 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c b/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c
index 83493bd5745c..109d0345a2be 100644
--- a/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c
+++ b/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c
@@ -36,7 +36,7 @@ void test_fentry_fexit(void)
fentry_res = (__u64 *)fentry_skel->bss;
fexit_res = (__u64 *)fexit_skel->bss;
printf("%lld\n", fentry_skel->bss->test1_result);
- for (i = 0; i < 6; i++) {
+ for (i = 0; i < 8; i++) {
CHECK(fentry_res[i] != 1, "result",
"fentry_test%d failed err %lld\n", i + 1, fentry_res[i]);
CHECK(fexit_res[i] != 1, "result",
diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
index 9365b686f84b..5f645fdaba6f 100644
--- a/tools/testing/selftests/bpf/progs/fentry_test.c
+++ b/tools/testing/selftests/bpf/progs/fentry_test.c
@@ -55,3 +55,25 @@ int BPF_PROG(test6, __u64 a, void *b, short c, int d, void * e, __u64 f)
e == (void *)20 && f == 21;
return 0;
}
+
+struct bpf_fentry_test_t {
+ struct bpf_fentry_test_t *a;
+};
+
+__u64 test7_result = 0;
+SEC("fentry/bpf_fentry_test7")
+int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
+{
+ if (arg == 0)
+ test7_result = 1;
+ return 0;
+}
+
+__u64 test8_result = 0;
+SEC("fentry/bpf_fentry_test8")
+int BPF_PROG(test8, struct bpf_fentry_test_t *arg)
+{
+ if (arg->a == 0)
+ test8_result = 1;
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
index bd1e17d8024c..0952affb22a6 100644
--- a/tools/testing/selftests/bpf/progs/fexit_test.c
+++ b/tools/testing/selftests/bpf/progs/fexit_test.c
@@ -56,3 +56,25 @@ int BPF_PROG(test6, __u64 a, void *b, short c, int d, void *e, __u64 f, int ret)
e == (void *)20 && f == 21 && ret == 111;
return 0;
}
+
+struct bpf_fentry_test_t {
+ struct bpf_fentry_test *a;
+};
+
+__u64 test7_result = 0;
+SEC("fexit/bpf_fentry_test7")
+int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
+{
+ if (arg == 0)
+ test7_result = 1;
+ return 0;
+}
+
+__u64 test8_result = 0;
+SEC("fexit/bpf_fentry_test8")
+int BPF_PROG(test8, struct bpf_fentry_test_t *arg)
+{
+ if (arg->a == 0)
+ test8_result = 1;
+ return 0;
+}