Schannel: plug a memory-leak

[gvanem]

Building with DEBUGBUILD and issuing these commands:

c:\> set CURL_SSL_BACKEND=schannel
c:\> curl.exe https://www.vg.no > NUL
c:\> perl tests\memanalyze.pl \gv\tmp\memdebug.curl

This tool reports:

Leak detected: memory still allocated: 379 bytes
At d354420, there's 379 bytes.
 allocated by vtls/schannel_verify.c:446

I did not build with -DUNICODE. Hence that curlx_unicodefree(cert_hostname_buff) was a no-op and
responsible for the leak. Surely it should be free()'d regardless of -DUNICODE. No?

[bagder]

I think curlx_unicodefree() should only really be used if the variable doesn't exist in non-unicode builds because calling free() on a NULL pointer is defined and safe.

[bagder]

Hm not even that, because the macro assigns the variable to NULL in non-unicode... Can't we remove the macro completely?

[bagder]

No: because in non-unicode builds it is used for (or rather should be used for) pointing to data that isn't allocated.

[gvanem]

Speaking of such macros; it's IMHO more evident it's a macro if it was defined and used as CURLX_UNICODEFREE(ptr).
Just my ¥ 0.2.

[bagder]

I agree