Fix filename detection in curl

[terriko]

Like with bug #383 , curl has broken filename detection and it's probably what inspired the other two:

cve-bin-tool/cve_bin_tool/checkers/curl.py

Line 30 in e4cca52

if filename[::-1].startswith(("curl")[::-1]):

This won't work in practice. The example below is with bluetooth but the same idea applies:

>>> filename = "bluetoothctl.so"
>>> filename[::-1]
'os.ltchtooteulb'
>>> filename[::-1].startswith(("bluetoothctl")[::-1])
False
>>>

Removing [::-1] in both places in that line should do the trick:

>>> filename.startswith(("bluetoothctl"))
True

If you're feeling ambitious, it would be nice to have a test for this.

[bigbird555]

I just thought the code below would resolve the bug but what do you think of it ?
if filename.find(("curl")) >= 0:

[bigbird555]

When you apply the above change, you will get the result below.
https://github.com/intel/cve-bin-tool/runs/462069846
I can not clearly understand what the message means and I do not know how to improve it more....
Is there any advice here ?

[Shrawan907]

if filename[::-1].startswith(("curl")[::-1]):
in place of it we can use
if filename.endswith(("curl")):