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MXS-1396: Fix persistent connection hangs

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When a COM_CHANGE_USER was executed, it is possible that the server
responds with a AuthSwitchRequest packet instead of an OK packet. In this
case, the server sends a new scramble which must be used to create the 20
byte hash that is expected as the response.
This commit is contained in:
Markus Mäkelä
2017-09-07 17:19:16 +03:00
parent faa1cc815d
commit 9ceb23dd65
3 changed files with 85 additions and 29 deletions
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50
server/modules/protocol/MySQL/MySQLBackend/mysql_backend.c
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@ -766,6 +766,43 @@ gw_read_and_write(DCB *dcb)
MXS_INFO("Response to COM_CHANGE_USER is OK, writing stored query");
rval = query ? dcb->func.write(dcb, query) : 1;
}
else if (result == MYSQL_REPLY_AUTHSWITCHREQUEST &&
gwbuf_length(reply) > MYSQL_EOF_PACKET_LEN)
{
/**
* The server requested a change of authentication methods.
* If we're changing the authentication method to the same one we
* are using now, it means that the server is simply generating
* a new scramble for the re-authentication process.
*/
if (strcmp((char*)GWBUF_DATA(reply) + 5, DEFAULT_MYSQL_AUTH_PLUGIN) == 0)
{
/** Load the new scramble into the protocol... */
gwbuf_copy_data(reply, 5 + strlen(DEFAULT_MYSQL_AUTH_PLUGIN) + 1,
GW_MYSQL_SCRAMBLE_SIZE, proto->scramble);
/** ... and use it to send the encrypted password to the server */
rval = send_mysql_native_password_response(dcb);
/** Store the query until we know the result of the authentication
* method switch. */
proto->stored_query = query;
proto->ignore_reply = true;
return rval;
}
else
{
/** The server requested a change to something other than
* the default auth plugin */
gwbuf_free(query);
poll_fake_hangup_event(dcb);
// TODO: Use the authenticators to handle COM_CHANGE_USER responses
MXS_ERROR("Received AuthSwitchRequest to '%s' when '%s' was expected",
(char*)GWBUF_DATA(reply) + 5, DEFAULT_MYSQL_AUTH_PLUGIN);
}
}
else
{
if (result == MYSQL_REPLY_ERR)
@ -774,22 +811,13 @@ gw_read_and_write(DCB *dcb)
* close the DCB and send an error to the client. */
log_error_response(dcb, reply);
}
else if (result == MYSQL_REPLY_AUTHSWITCHREQUEST &&
gwbuf_length(reply) > MYSQL_EOF_PACKET_LEN)
{
MXS_ERROR("Received AuthSwitchRequest to '%s' when '%s' was expected",
(char*)GWBUF_DATA(reply) + 5, DEFAULT_MYSQL_AUTH_PLUGIN);
}
else
{
/** This should never happen */
MXS_ERROR("Unknown response to COM_CHANGE_USER (0x%02hhx), "
"ignoring and waiting for correct result", result);
gwbuf_free(reply);
proto->stored_query = query;
proto->ignore_reply = true;
return 1;
"closing connection", result);
}
gwbuf_free(query);
poll_fake_hangup_event(dcb);
}