selftests/bpf: Add pruning test case for bpf_spin_lock

Test that when reg->id is not same for the same register of type
PTR_TO_MAP_VALUE between current and old explored state, we currently
return false from regsafe and continue exploring.

Without the fix in prior commit, the test case fails.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20221209135733.28851-7-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/verifier/spin_lock.c b/tools/testing/selftests/bpf/verifier/spin_lock.c
index 781621facae48d4a460aa3839196b3f29a30dbbb..0a8dcfc37fc6e23b3d98ff1e86022a5dcd62cd04 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/spin_lock.c
+++ b/tools/testing/selftests/bpf/verifier/spin_lock.c
@@ -331,3 +331,42 @@
        .errstr = "inside bpf_spin_lock",
        .prog_type = BPF_PROG_TYPE_SCHED_CLS,
 },
+{
+       "spin_lock: regsafe compare reg->id for map value",
+       .insns = {
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+       BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_6, offsetof(struct __sk_buff, mark)),
+       BPF_LD_MAP_FD(BPF_REG_1, 0),
+       BPF_MOV64_REG(BPF_REG_9, BPF_REG_1),
+       BPF_ST_MEM(BPF_W, BPF_REG_10, -4, 0),
+       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_9),
+       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 4),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_spin_lock),
+       BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 1),
+       BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+       BPF_MOV64_REG(BPF_REG_7, BPF_REG_8),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_7),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 4),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_spin_unlock),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .fixup_map_spin_lock = { 2 },
+       .result = REJECT,
+       .errstr = "bpf_spin_unlock of different lock",
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       .flags = BPF_F_TEST_STATE_FREQ,
+},