[PATCH bpf-next v2 2/3] selftests/bpf: test if pointer type is tracked for BPF_ST_MEM

Eduard Zingerman
2023-03-04T01:15:16Z

Check that verifier tracks pointer types for BPF_ST_MEM instructions
and reports error if pointer types do not match for different
execution branches.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
tools/testing/selftests/bpf/verifier/unpriv.c | 23 +++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/unpriv.c b/tools/testing/selftests/bpf/verifier/unpriv.c
index 878ca26c3f0a..af0c0f336625 100644
--- a/tools/testing/selftests/bpf/verifier/unpriv.c
+++ b/tools/testing/selftests/bpf/verifier/unpriv.c
@@ -239,6 +239,29 @@
.errstr = "same insn cannot be used with different pointers",
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
+{
+ /* Same as above, but use BPF_ST_MEM to save 42
+ * instead of BPF_STX_MEM.
+ */
+ "unpriv: spill/fill of different pointers st",
+ .insns = {
+ BPF_ALU64_REG(BPF_MOV, BPF_REG_6, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -8),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 3),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -16),
+ BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_2, 0),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 1),
+ BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 0),
+ BPF_ST_MEM(BPF_W, BPF_REG_1, offsetof(struct __sk_buff, mark), 42),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = REJECT,
+ .errstr = "same insn cannot be used with different pointers",
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+},
{
"unpriv: spill/fill of different pointers stx - ctx and sock",
.insns = {
--
2.39.1