elf: prevent overflow

[jackcmay]

Fuzzier found an overflow if bad section address or size.

• Update check_size to also check addr + size
• Use saturating addition to prevent overflow or a wrap-around region bound if check_size is not called on a created section.

[jackcmay]

Looks like CI is failing on something unrelated to my changes :-(

[m4b]

Yes looks like it's this: https://github.blog/changelog/2020-10-01-github-actions-deprecating-set-env-and-add-path-commands/

aside: i find it a bit sad that for nearly 4 years travis CI did not have a single CI involved regression with any of the github projects i had, and now, with not even 1 year into github actions, it's already breaking my code, and wasting developer time upgrading to some new api... This does not bode well.

[jackcmay]

:-(. Should I rebase once you have applied a fix?

[m4b]

I don't have the time right now to fix the issue; maybe this weekend; i can just merge without CI if you want

[m4b]

If you think you know how to fix, feel free to go for it in this PR, otherwise we can just merge

[m4b]

Ok i think i fixed it actually here: https://github.com/m4b/goblin/pull/244

can you rebase on top of that ?

[jackcmay]

Rebased and CI passed, woot!

[m4b]

sorrrryyyyy for spamming :D and thanks for the PR :heart:

[jackcmay]

@m4b When do you think these changes will be released so we can pick them up?

[m4b]

whoops, forgot about this, will release now!

[m4b]

ok this is released in 0.3, which rolls up several things from past few months; it's a breaking change because one part of the mach-o api changed, but otherwise it should be fine