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Fix buffer overflows due to incorrect use of sizeof

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A snippet of example code:

UTF16 pszFilter[1024];
...
convertUTF8toUTF16((UTF8 *)mData.mFilters, pszFilter, sizeof(pszFilter));

Since the conversion function is expecting the third parameter to be the
length in 16-bit characters, *not* bytes, this results in the function
writing outside the bounds of the output array.

To make this less likely to happen in the future (I hope), I've provided a
template function that infers the correct size of a static array, so it's
no longer necessary to pass the size in most cases. The sized function has
been renamed with an "N" suffix to hopefully encourage this use.

This bug was caught due to a warning from MSVC about stack corruption
occurring in codeBlock::exec(), after opening a file open dialog twice in
succession. After some hunting, I found that this was due to
FileDialog::Execute() passing incorrect buffer sizes to the conversion
function, which resulted in the function writing a null terminator into
some memory that happened to be in the stack frame of codeBlock::exec()!
This commit is contained in:
Ben Payne 2015-01-20 16:21:56 -05:00
parent d6beb3594a
commit a88339c219
11 changed files with 55 additions and 49 deletions
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2
Engine/source/core/stringBuffer.cpp
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@ -141,7 +141,7 @@ void StringBuffer::set(const UTF8 *in)
incRequestCount8();
// Convert and store. Note that a UTF16 version of the string cannot be longer.
FrameTemp<UTF16> tmpBuff(dStrlen(in)+1);
if(!in || in[0] == 0 || !convertUTF8toUTF16(in, tmpBuff, dStrlen(in)+1))
if(!in || in[0] == 0 || !convertUTF8toUTF16N(in, tmpBuff, dStrlen(in)+1))
{
// Easy out, it's a blank string, or a bad string.
mBuffer.clear();