bpf, selftests: Add a verifier test for assigning 32bit reg states to 64bit ones

Added a verifier test for assigning 32bit reg states to
64bit where 32bit reg holds a constant value of 0.

Without previous kernel verifier.c fix, the test in
this patch will fail.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/159077335867.6014.2075350327073125374.stgit@john-Precision-5820-Tower

diff --git a/tools/testing/selftests/bpf/verifier/bounds.c b/tools/testing/selftests/bpf/verifier/bounds.c
index fafa540..58f4aa5 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/bounds.c
+++ b/tools/testing/selftests/bpf/verifier/bounds.c
@@ -535,3 +535,25 @@
        },
        .result = ACCEPT
 },
+{
+       "assigning 32bit bounds to 64bit for wA = 0, wB = wA",
+       .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_MOV32_IMM(BPF_REG_9, 0),
+       BPF_MOV32_REG(BPF_REG_2, BPF_REG_9),
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_7),
+       BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_2),
+       BPF_MOV64_REG(BPF_REG_3, BPF_REG_6),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 8),
+       BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_8, 1),
+       BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_6, 0),
+       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,
+},