Bug #69354 [Opn->Fbk]: Incorrect use of SQLColAttributes with ODBC 3.0

Edit report at https://bugs.php.net/bug.php?id=69354&edit=1 ID: 69354 Updated by: ab@php.net Reported by: php at mdjnet dot dk Summary: Incorrect use of SQLColAttributes with ODBC 3.0 -Status: Open +Status: Feedback Type: Bug Package: ODBC related Operating System: All PHP Version: 5.6.7 -Assigned To: +Assigned To: ab Block user comment: N Private report: N New Comment: Hi, please supply a code snippet illustrating the broken behavior. Are you using the ADS driver, or which exactly? Thanks. Previous Comments: ------------------------------------------------------------------------ [2015-04-02 08:35:28] php at mdjnet dot dk Description: ------------ Since php was changed to odbc 3.0 (#68964), an old hidden bug has surfaced. This bug is related to both #68350 "SQL_DESC_OCTET_LENGTH not supported by ADS ODBC driver" and #68014 "Result data values can be truncated because of incorrect column display sizes". In odbc 3.0, SQLColAttributes is deprecated, instead SQLColAttribute should be used, which in turn supports SQL_DESC_OCTET_LENGTH, introduced with odbc 3.0. The bug is in ext/odbc/php_odbc.c, the function odbc_bindcols, in the middle of the big switch. With ODBCVER set to 0x0300 as of php 5.6.7, the extra cases of SQL_WCHAR and SQL_WVARCHAR come into effect, setting colfieldid to SQL_DESC_OCTET_LENGTH also for SQL_CHAR and SQL_VARCHAR due to a rather suspiscious fall-through strategy, that worked well for ODBCVER < 0x0300. However, not all odbc drivers allow for SQLColAttributes to be called with SQL_DESC_OCTET_LENGTH. If SQLColAttributes fails, the effect is that strings lifted from subsequent calls to odbc_result become truncated, probably because of uninitialized variables, as the code doesn't even look at the return value of SQLColAttributes (same effect as in #68014, which appears to be fixed judging from looking at the code). The correct fix would be to call SQLColAttribute instead of SQLColAttributes, if ODBCVER >= 0x0300, and to actually check the return value before using the result of the call (displaysize). I have never figured out how to build my own php, so I have not tried to fix it directly in php_odbc.c, but I have tried to fix my odbc driver to support SQL_DESC_OCTET_LENGTH in SQLColAttributes, and that does indeed fix the problem. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=69354&edit=1