Gas cost, msg.sender.call and re-entrancy

[raphbaph]

I have a few doubts about using msg.sender.call to transfer ETH.
While it makes sense that this is more future proof in the face of changing gas costs, I wonder:

If msg.sender.call sends all the remaining gas, and then this gas can be used by re-entrancy wouldn’t that still be a way to render my contract unusable (no gas left) and broke (multiple calls).

It could be done simply for malice…

What am I missing here? Does the gas come from the original contract?
Like Contract B calling Contract_A.withdraw() and sending gas B->A?
That would of course mean that B can’t abuse A.withdraw() because the Gas comes out of its own pocket.

[REGO350]

Yes, the gas comes from Contract B. The user(msg.sender) executes Contract B’s function so if the user tries to do a re-entrancy attack, assuming that Contract A uses check-effect-interaction pattern, the user will just lose the paid gas.

[raphbaph]

excellent! thanks a lot! now its much clearer to me.