rhel 7
buffer weakness #24

5

Weakness Breakdown


Definition:

Buffer overflows are one of the most well-known software vulnerabilities. Even though most developers know what buffer overflows are, attacks against the vulnerabilities are common in both legacy and newer applications. A classic buffer overflow exploit begins with the attacker sending data to a program, which it then stores in an undersized stack buffer. Besides stack buffer overflows, other kinds of buffer overflows include heap overflows, off-by-one errors and many others. Learn more about buffer overflows on OWASP attack index.

Warning code(s):

Requires maximum length in CHARACTERS, not bytes.

File Name:

openwsman/openwsman-2.3.6/src/server/shttpd/compat_win32.c

Context:

The highlighted line of code below is the trigger point of this particular Red Hat Enterprise Linux 7 buffer weakness.

 	char	buf2[FILENAME_MAX];
	wchar_t	wbuf1[FILENAME_MAX];
	wchar_t	wbuf2[FILENAME_MAX];

	my_strlcpy(buf1, path1, sizeof(buf1));
	my_strlcpy(buf2, path2, sizeof(buf2));
	fix_directory_separators(buf1);
	fix_directory_separators(buf2);

	MultiByteToWideChar(CP_UTF8, 0, buf1, -1, wbuf1, sizeof(wbuf1));
	MultiByteToWideChar(CP_UTF8, 0, buf2, -1, wbuf2, sizeof(wbuf2));

	return (_wrename(wbuf1, wbuf2));
}

int
my_mkdir(const char *path, int mode)
{
	char	buf[FILENAME_MAX];
	wchar_t	wbuf[FILENAME_MAX];

	my_strlcpy(buf, path, sizeof(buf));
	fix_directory_separators(buf);

	MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, sizeof(wbuf));

	return (_wmkdir(wbuf));
}

static char *
wide_to_utf8(const wchar_t *str)
{
	char *buf = NULL;
	if (str) {
		int nchar = WideCharToMultiByte(CP_UTF8, 0, str, -1, NULL, 0, NULL, NULL);
		if (nchar > 0) {
			buf = malloc(nchar);
			if (!buf)
				errno = ENOMEM;
			else if (!WideCharToMultiByte(CP_UTF8, 0, str, -1, buf, nchar, NULL, NULL)) {
				free(buf);
				buf = NULL;
				errno = EINVAL;
			}
		} else
			errno = EINVAL;
	} else
		errno = EINVAL;
	return buf;
} 

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