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authorYonghong Song <yhs@fb.com>2020-06-30 20:12:41 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2020-06-30 23:21:29 +0300
commitd923021c2ce12acb50dc7086a1bf66eed82adf6a (patch)
treeab388fa92b8b8bf4d3be8683567ee1b3788ebbf9 /net
parent01c66c48d4f0825a202d4163800b706a1d2ec7ad (diff)
downloadlinux-d923021c2ce12acb50dc7086a1bf66eed82adf6a.tar.xz
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 'net')
-rw-r--r--net/bpf/test_run.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index bfd4ccd80847..b03c469cd01f 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -147,6 +147,20 @@ int noinline bpf_fentry_test6(u64 a, void *b, short c, int d, void *e, u64 f)
return a + (long)b + c + d + (long)e + f;
}
+struct bpf_fentry_test_t {
+ struct bpf_fentry_test_t *a;
+};
+
+int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
+{
+ return (long)arg;
+}
+
+int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
+{
+ return (long)arg->a;
+}
+
int noinline bpf_modify_return_test(int a, int *b)
{
*b += 1;
@@ -185,6 +199,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
+ struct bpf_fentry_test_t arg = {};
u16 side_effect = 0, ret = 0;
int b = 2, err = -EFAULT;
u32 retval = 0;
@@ -197,7 +212,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
bpf_fentry_test3(4, 5, 6) != 15 ||
bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
- bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111)
+ bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
+ bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
+ bpf_fentry_test8(&arg) != 0)
goto out;
break;
case BPF_MODIFY_RETURN: