Silent truncation of 'long' diagnostic messages in SQLGetDiagRec

[matthew-wozniczka]

See

iODBC/iodbc/herr.c

Line 1031 in d6481a8

snprintf (msgbuf, sizeof (msgbuf), "%s%s", sqlerrhd, errmsg);

It's using a fixed size buffer, and there's no checks I could find on the size of a diagnostic message when being added via _iodbcdm_pushsqlerr(), so this will just silently truncate it

[matthew-wozniczka]

This could happen from

iODBC/iodbc/connect.c

Line 1181 in d6481a8

PUSHSYSERR (pdbc->herr, _iodbcdm_dllerror ());

for instance

[matthew-wozniczka]

I'm investigating a test failure where our driver fails to connect, and it seems (haven't verified yet) that iODBC is truncating the diagnostic message to "[iODBC][Driver Manager]dlopen(/Users/bamboo/bamboo-agent-home/x". The fact that it's 63 characters makes me think there's a 64 * CODEUNIT_SIZE limit somewhere. Looking more closely at what I pointed out, the 256 char buffer doesn't seem like it would be the cause... But I think it's still a possible issue.

Our driver is a unicode driver btw, and the application is calling into SQLGetDiagRecW, and we're using 3.52.15