Commit 75dcef8d authored by Feng Zhou's avatar Feng Zhou Committed by Daniel Borkmann
Browse files

selftests/bpf: Add test to access u32 ptr argument in tracing program 



Adding verifier test for accessing u32 pointer argument in
tracing programs.

The test program loads 1nd argument of bpf_fentry_test9 function
which is u32 pointer and checks that verifier allows that.

Co-developed-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarFeng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230410085908.98493-3-zhoufeng.zf@bytedance.com
parent 91f2dc68

net/bpf/test_run.c

+7 −1
Original line number Diff line number Diff line
@@ -541,6 +541,11 @@ int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg) 
	return (long)arg->a;

}



__bpf_kfunc u32 bpf_fentry_test9(u32 *a)

{

	return *a;

}



__bpf_kfunc int bpf_modify_return_test(int a, int *b)

{

	*b += 1;
@@ -855,7 +860,8 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, 
		    bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||

		    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)

		    bpf_fentry_test8(&arg) != 0 ||

		    bpf_fentry_test9(&retval) != 0)

			goto out;

		break;

	case BPF_MODIFY_RETURN:

tools/testing/selftests/bpf/verifier/btf_ctx_access.c

+13 −0
Original line number Diff line number Diff line
@@ -10,3 +10,16 @@ 
	.expected_attach_type = BPF_TRACE_FENTRY,

	.kfunc = "bpf_modify_return_test",

},



{

	"btf_ctx_access u32 pointer accept",

	.insns = {

	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),	/* load 1nd argument value (u32 pointer) */

	BPF_MOV64_IMM(BPF_REG_0, 0),

	BPF_EXIT_INSN(),

	},

	.result = ACCEPT,

	.prog_type = BPF_PROG_TYPE_TRACING,

	.expected_attach_type = BPF_TRACE_FENTRY,

	.kfunc = "bpf_fentry_test9",

},