_php_ibase_attach_db() does not check buffer overflow

[mlazdans]

php-firebird/interbase.c

Line 998 in e1a3253

dpb_len = slprintf(dpb, buf_len, "%c%c%s", dpb_args[i],(unsigned char)len[i],args[i]);

Use snprintf() instead slprintf()

https://www.phpinternalsbook.com/php7/internal_types/strings/printing_functions.html

snprintf() returns the number of characters that could have been used, whereas slprintf() returns the number of characters that have effectively been used, thus enabling to detect too-small buffers and string truncation. This, is not counting the final ‘\0’.