[Vulnerability] It is dangerous not to restrict the use of the opt_level

Development
1

When I set opt_level to a very large value (such as 10000) in statement tvm.transform.PassContext(), TVM can run well and generated a compiled model without any warning messages. I think it should be a vulnerability.

Hackers can attack TVM by tampering with the unused internal code of opt_level. Due to the lack of warning information, it is difficult for users to notice that they have been attacked.

I think a warning message should be given to remind users when using invalid opt_level.

2

@tqchen @comaniac @FrozenGene
Do we need to fix this vulnerability?

3

I’m not familiar with the open source system vulnerability so I’m not sure if it is needed. It doesn’t hurt to add the checks and warnings tho.

4

Thanks for bringing this up. Right now the API allows opt_level to be the threshold to toggle the passes being enabled. So the API right now also works for opt_level=10000 as intended.

While the exact API design can be discussed(e.g. whether or not we should bring more friendly message for recommended opt_level. The particular issue is more of an usabilty improvement rather than a security issue.

5

I think add one warning message is enough, which is the common way taken by traditional compiler.

Example: warning: optimization level '-O5' is not supported; using '-O3' instead