On Fri, Dec 28, 2018 at 2:00 PM Igor Korot <ikorot01@xxxxxxxxx> wrote:
Hi, ALL,
Following code:
int PostgresDatabase::GetTableOwner (const std::wstring &schemaName,
const std::wstring &tableName, std::wstring &owner,
std::vector<std::wstring> &errorMsg)
{
int result = 0;
std::wstring query = L"SELECT u.usename FROM pg_class c, pg_user
u, pg_namespace n WHERE n.oid = c.relnamespace AND u.usesysid =
c.relowner AND n.nspname = $1 AND relname = $2";
char *values[2];
values[0] = NULL, values[1] = NULL;
values[0] = new char[schemaName.length() + 1];
values[1] = new char[tableName.length() + 1];
memset( values[0], '\0', schemaName.length() + 1 );
memset( values[1], '\0', tableName.length() + 1 );
strcpy( values[0], m_pimpl->m_myconv.to_bytes( schemaName.c_str()
).c_str() );
strcpy( values[1], m_pimpl->m_myconv.to_bytes( tableName.c_str()
).c_str() );
int len1 = (int) schemaName.length();
int len2 = (int) tableName.length();
int length[2] = { len1, len2 };
int formats[2] = { 1, 1 };
PGresult *res = PQexecParams( m_db, m_pimpl->m_myconv.to_bytes(
query.c_str() ).c_str(), 2, NULL, values, length, formats, 1 );
ExecStatusType status = PQresultStatus( res );
if( status != PGRES_COMMAND_OK && status != PGRES_TUPLES_OK )
{
result = 1;
std::wstring err = m_pimpl->m_myconv.from_bytes(
PQerrorMessage( m_db ) );
errorMsg.push_back( L"Error executing query: " + err );
PQclear( res );
}
else
{
owner = m_pimpl->m_myconv.from_bytes( PQgetvalue( res, 0, 0 ) );
}
return result;
}
when ran with the call of
GetTableOwner( "public", "abcß", owner, errorMsg );
returns:
ERROR: Invalid byte sequence for encoding UTF8.
Does this mean I found the bug in the library?
The bug is in your C++ code. "abcß" as tableName.lenght() (wstring) returns 4 (as in four characters) not number of bytes required to represent the intended string: 61 62 63 c3 9f
Since the last character is a 2 bytes in length. Therefore, your call to PQexecParams() specifies a shorter length and hence an invalid UTF-8 sequence.
Furthermore, your value[] array allocation is in error since wstring::length returns number of characters, not number of bytes. so you will end up with buffer-overflows.
HTH,
--patrick
Any idea what I can do?
Thank you.
