Verify that the following example is rejected by verifier:
r9 = ... some pointer with range X ...
r6 = ... unbound scalar ID=a ...
r7 = ... unbound scalar ID=b ...
if (r6 > r7) goto +1
r7 = r6
if (r7 > X) goto exit
r9 += r6
*(u64 *)r9 = Y
Also add test cases to:
- check that check_alu_op() for BPF_MOV instruction does not allocate
scalar ID if source register is a constant;
- check that unique scalar IDs are ignored when new verifier state is
compared to cached verifier state;
- check that two different scalar IDs in a verified state can't be
mapped to the same scalar ID in current state.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230613153824.3324830-5-eddyz87@gmail.com
Check __mark_chain_precision() log to verify that scalars with same
IDs are marked as precise. Use several scenarios to test that
precision marks are propagated through:
- registers of scalar type with the same ID within one state;
- registers of scalar type with the same ID cross several states;
- registers of scalar type with the same ID cross several stack frames;
- stack slot of scalar type with the same ID;
- multiple scalar IDs are tracked independently.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230613153824.3324830-3-eddyz87@gmail.com
