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From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
	Yonghong Song <yhs@fb.com>
Subject: [PATCH bpf-next 4/4] bpf: selftest: Add verifier tests for <8-byte scalar spill and refill
Date: Mon, 20 Sep 2021 18:31:29 -0700	[thread overview]
Message-ID: <20210921013129.1037825-1-kafai@fb.com> (raw)
In-Reply-To: <20210921013102.1035356-1-kafai@fb.com>

This patch adds a few verifier tests for <8-byte spill and refill.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
 .../selftests/bpf/verifier/spill_fill.c       | 161 ++++++++++++++++++
 1 file changed, 161 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/spill_fill.c b/tools/testing/selftests/bpf/verifier/spill_fill.c
index 0b943897aaf6..c9991c3f3bd2 100644
--- a/tools/testing/selftests/bpf/verifier/spill_fill.c
+++ b/tools/testing/selftests/bpf/verifier/spill_fill.c
@@ -104,3 +104,164 @@
 	.result = ACCEPT,
 	.retval = POINTER_VALUE,
 },
+{
+	"Spill and refill a u32 const scalar.  Offset to skb->data",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	/* r4 = 20 */
+	BPF_MOV32_IMM(BPF_REG_4, 20),
+	/* *(u32 *)(r10 -8) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* r4 = *(u32 *)(r10 -8) */
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -8),
+	/* r0 = r2 */
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+	/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv20 */
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
+	/* if (r0 > r3) R0=pkt,off=20 R2=pkt R3=pkt_end R4=inv20 */
+	BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+	/* r0 = *(u32 *)r2 R0=pkt,off=20,r=20 R2=pkt,r=20 R3=pkt_end R4=inv20 */
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"Spill a u32 const, refill from another half of the uninit u32 from the stack",
+	.insns = {
+	/* r4 = 20 */
+	BPF_MOV32_IMM(BPF_REG_4, 20),
+	/* *(u32 *)(r10 -8) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* r4 = *(u32 *)(r10 -4) fp-8=????rrrr*/
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -4),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "invalid read from stack off -4+0 size 4",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"Spill a u32 const scalar.  Refill as u16.  Offset to skb->data",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	/* r4 = 20 */
+	BPF_MOV32_IMM(BPF_REG_4, 20),
+	/* *(u32 *)(r10 -8) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* r4 = *(u16 *)(r10 -8) */
+	BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_10, -8),
+	/* r0 = r2 */
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+	/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=65535 */
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
+	/* if (r0 > r3) R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv,umax=65535 */
+	BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+	/* r0 = *(u32 *)r2 R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv20 */
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "invalid access to packet",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"Spill a u32 const scalar.  Refill as u16 from fp-6.  Offset to skb->data",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	/* r4 = 20 */
+	BPF_MOV32_IMM(BPF_REG_4, 20),
+	/* *(u32 *)(r10 -8) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* r4 = *(u16 *)(r10 -6) */
+	BPF_LDX_MEM(BPF_H, BPF_REG_4, BPF_REG_10, -6),
+	/* r0 = r2 */
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+	/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=65535 */
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
+	/* if (r0 > r3) R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv,umax=65535 */
+	BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+	/* r0 = *(u32 *)r2 R0=pkt,umax=65535 R2=pkt R3=pkt_end R4=inv20 */
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "invalid access to packet",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"Spill and refill a u32 const scalar at non 8byte aligned stack addr.  Offset to skb->data",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	/* r4 = 20 */
+	BPF_MOV32_IMM(BPF_REG_4, 20),
+	/* *(u32 *)(r10 -8) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* *(u32 *)(r10 -4) = r4 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -4),
+	/* r4 = *(u32 *)(r10 -4),  */
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -4),
+	/* r0 = r2 */
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+	/* r0 += r4 R0=pkt R2=pkt R3=pkt_end R4=inv,umax=U32_MAX */
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_4),
+	/* if (r0 > r3) R0=pkt,umax=U32_MAX R2=pkt R3=pkt_end R4=inv */
+	BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
+	/* r0 = *(u32 *)r2 R0=pkt,umax=U32_MAX R2=pkt R3=pkt_end R4=inv */
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.errstr = "invalid access to packet",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
+{
+	"Spill and refill a umax=40 bounded scalar.  Offset to skb->data",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_1,
+		    offsetof(struct __sk_buff, tstamp)),
+	BPF_JMP_IMM(BPF_JLE, BPF_REG_4, 40, 2),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	/* *(u32 *)(r10 -8) = r4 R4=inv,umax=40 */
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_4, -8),
+	/* r4 = (*u32 *)(r10 - 8) */
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_10, -8),
+	/* r2 += r4 R2=pkt R4=inv,umax=40 */
+	BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_4),
+	/* r0 = r2 R2=pkt,umax=40 R4=inv,umax=40 */
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
+	/* r2 += 20 R0=pkt,umax=40 R2=pkt,umax=40 */
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 20),
+	/* if (r2 > r3) R0=pkt,umax=40 R2=pkt,off=20,umax=40 */
+	BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_3, 1),
+	/* r0 = *(u32 *)r0 R0=pkt,r=20,umax=40 R2=pkt,off=20,r=20,umax=40 */
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
-- 
2.30.2


      parent reply	other threads:[~2021-09-21  1:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21  1:31 [PATCH bpf-next 0/4] bpf: Support <8-byte scalar spill and refill Martin KaFai Lau
2021-09-21  1:31 ` [PATCH bpf-next 1/4] bpf: Check the other end of slot_type for STACK_SPILL Martin KaFai Lau
2021-09-21  1:31 ` [PATCH bpf-next 2/4] bpf: Support <8-byte scalar spill and refill Martin KaFai Lau
2021-09-21  1:31 ` [PATCH bpf-next 3/4] bpf: selftest: A bpf prog that has a 32bit scalar spill Martin KaFai Lau
2021-09-21  2:32   ` Alexei Starovoitov
2021-09-21 23:52     ` Martin KaFai Lau
2021-09-21  1:31 ` Martin KaFai Lau [this message]

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