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[bpf-next,2/2] tools/bpf: add verifier tests for 32bit pointer/scalar arithmetic

Message ID 20200618234632.3321367-1-yhs@fb.com
State Accepted
Delegated to: BPF Maintainers
Headers show
Series bpf: avoid verifier failure for 32bit pointer arithmetic | expand

Commit Message

Yonghong Song June 18, 2020, 11:46 p.m. UTC 
Added two test_verifier subtests for 32bit pointer/scalar arithmetic
with BPF_SUB operator. They are passing verifier now.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 .../selftests/bpf/verifier/value_ptr_arith.c  | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
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Patch

diff --git a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
index 97ee658e1242..ed4e76b24649 100644
--- a/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
+++ b/tools/testing/selftests/bpf/verifier/value_ptr_arith.c
@@ -836,3 +836,41 @@ 
 	.errstr = "R0 invalid mem access 'inv'",
 	.errstr_unpriv = "R0 pointer -= pointer prohibited",
 },
+{
+	"32bit pkt_ptr -= scalar",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_MOV64_REG(BPF_REG_6, BPF_REG_7),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 40),
+	BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_8, 2),
+	BPF_ALU32_REG(BPF_MOV, BPF_REG_4, BPF_REG_7),
+	BPF_ALU32_REG(BPF_SUB, BPF_REG_6, BPF_REG_4),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	.result = ACCEPT,
+	.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+},
+{
+	"32bit scalar -= pkt_ptr",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
+		    offsetof(struct __sk_buff, data_end)),
+	BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
+		    offsetof(struct __sk_buff, data)),
+	BPF_MOV64_REG(BPF_REG_6, BPF_REG_7),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 40),
+	BPF_JMP_REG(BPF_JGT, BPF_REG_6, BPF_REG_8, 2),
+	BPF_ALU32_REG(BPF_MOV, BPF_REG_4, BPF_REG_6),
+	BPF_ALU32_REG(BPF_SUB, BPF_REG_4, BPF_REG_7),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	.result = ACCEPT,
+	.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
+},