diff mbox series

[v3,2/2] selftests/bpf: Add tests for alu on PTR_TO_FLOW_KEYS

Message ID 20240112152011.6264-2-sunhao.th@gmail.com
State New
Headers
Series None |

Commit Message

Hao Sun Jan. 12, 2024, 3:20 p.m. UTC 
  Add two cases for PTR_TO_FLOW_KEYS alu. One for rejecting alu with
variable offset, another for fixed offset.

Signed-off-by: Hao Sun <sunhao.th@gmail.com>
---
 .../bpf/progs/verifier_value_illegal_alu.c    | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)

Comments

Yonghong Song Jan. 12, 2024, 6:14 p.m. UTC | #1 
On 1/12/24 7:20 AM, Hao Sun wrote:
> Add two cases for PTR_TO_FLOW_KEYS alu. One for rejecting alu with
> variable offset, another for fixed offset.
>
> Signed-off-by: Hao Sun <sunhao.th@gmail.com>
> ---
>   .../bpf/progs/verifier_value_illegal_alu.c    | 36 +++++++++++++++++++
>   1 file changed, 36 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
> index 71814a753216..3bcccb4cbc85 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
> @@ -146,4 +146,40 @@ l0_%=:	exit;						\
>   	: __clobber_all);
>   }
>   
> +SEC("flow_dissector")
> +__description("flow_keys illegal alu op with variable offset")
> +__failure __msg("R7 pointer arithmetic on flow_keys prohibited")
> +__naked void flow_keys_illegal_variable_offset_alu(void)
> +{
> +	asm volatile("					\
> +	r6 = r1;					\
> +	r7 = *(u64*)(r6 + %[flow_keys_off]);		\
> +	r8 = 8;						\
> +	r8 /= 1;					\
> +	r8 &= 8;					\
> +	r7 += r8;					\
> +	r0 = *(u64*)(r7 + 0);				\
> +	exit;						\
> +"	:
> +	: __imm_const(flow_keys_off, offsetof(struct __sk_buff, flow_keys))
> +	: __clobber_all);
> +}
> +
> +SEC("flow_dissector")
> +__description("flow_keys valid alu op with fixed offset")
> +__success
> +__naked void flow_keys_legal_fixed_offset_alu(void)
> +{
> +	asm volatile("					\
> +	r6 = r1;					\
> +	r7 = *(u64*)(r6 + %[flow_keys_off]);		\
> +	r8 = 8;						\
> +	r7 += r8;					\
> +	r0 = *(u64*)(r7 + 0);				\
> +	exit;						\
> +"	:
> +	: __imm_const(flow_keys_off, offsetof(struct __sk_buff, flow_keys))
> +	: __clobber_all);
> +}

Please remove the above '__success' case from this file. This file,
verifier_value_illegal_alu.c, only contains failure cases.

For the fixed offset, we already have C code to verify,
e.g., in bpf_flow.c.
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
index 71814a753216..3bcccb4cbc85 100644
--- a/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
+++ b/tools/testing/selftests/bpf/progs/verifier_value_illegal_alu.c
@@ -146,4 +146,40 @@  l0_%=:	exit;						\
 	: __clobber_all);
 }
 
+SEC("flow_dissector")
+__description("flow_keys illegal alu op with variable offset")
+__failure __msg("R7 pointer arithmetic on flow_keys prohibited")
+__naked void flow_keys_illegal_variable_offset_alu(void)
+{
+	asm volatile("					\
+	r6 = r1;					\
+	r7 = *(u64*)(r6 + %[flow_keys_off]);		\
+	r8 = 8;						\
+	r8 /= 1;					\
+	r8 &= 8;					\
+	r7 += r8;					\
+	r0 = *(u64*)(r7 + 0);				\
+	exit;						\
+"	:
+	: __imm_const(flow_keys_off, offsetof(struct __sk_buff, flow_keys))
+	: __clobber_all);
+}
+
+SEC("flow_dissector")
+__description("flow_keys valid alu op with fixed offset")
+__success
+__naked void flow_keys_legal_fixed_offset_alu(void)
+{
+	asm volatile("					\
+	r6 = r1;					\
+	r7 = *(u64*)(r6 + %[flow_keys_off]);		\
+	r8 = 8;						\
+	r7 += r8;					\
+	r0 = *(u64*)(r7 + 0);				\
+	exit;						\
+"	:
+	: __imm_const(flow_keys_off, offsetof(struct __sk_buff, flow_keys))
+	: __clobber_all);
+}
+
 char _license[] SEC("license") = "GPL";