From 7081a525902dcc4acf4f00a2a773b927e86ccbb7 Mon Sep 17 00:00:00 2001 From: "Rob Swindell (in GitKraken)" <rob@synchro.net> Date: Sat, 11 Mar 2023 17:16:37 -0800 Subject: [PATCH] Fix mysterious double overflow issue in parse_byte_count() It's possible that some values (e.g. "16384P") exceed the storage (count of bytes) of a 64-bit integer, and such values were causing floating point exceptions when running sbbsctrl.exe, e.g. Faulting application name: sbbsctrl.exe, version: 3.20.0.0, time stamp: 0x00000000 Faulting module name: gdi32full.dll, version: 10.0.19041.2604, time stamp: 0x2b5302d5 Exception code: 0xc0000090 but interesting (and perhaps a clue), not with sbbs.exe. Anyway, this added range checking, limiting the maximum value to INT64_MAX (after division by unit, though there was no division-unit in the problem case, the "min_dspace" value parsing in scfglib2.c). Using conditional/ternary return statement had the same floating point exception occurrences, so this if-statement shouldn't be removed/changed/optimized! I suspect this has something to do with mix of Borland and MSVC run-time libs and perhaps different expectations or setups with regards to floating point exceptions. I did notice that when stepping through read_file_cfg(), I would get different return values for the same call to iniGetBytes() depending on whether it was initiated from sbbsctrl.exe (built with C++Builder) or sbbs.dll (built with MSVC). Thanks to Codefenix for providing the sample file.ini file that demonstrated the issue. This problem would've been very hard to root-cause otherwise! --- src/xpdev/genwrap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/xpdev/genwrap.c b/src/xpdev/genwrap.c index cc7d151c50..c95dbcac0d 100644 --- a/src/xpdev/genwrap.c +++ b/src/xpdev/genwrap.c @@ -279,7 +279,11 @@ int64_t parse_byte_count(const char* str, ulong unit) break; } } - return((int64_t)(unit>1 ? (bytes/unit):bytes)); + if(unit > 1) + bytes /= unit; + if(bytes < 0 || bytes > INT64_MAX) + return INT64_MAX; + return (int64_t)bytes; } static const double one_pebibyte = 1024.0*1024.0*1024.0*1024.0*1024.0; -- GitLab