TIP: 61
Title: Make TK_NO_SECURITY Run-Time Switchable
Version: $Revision: 1.4 $
Author: Jeff Hobbs <[email protected]>
Author: Donal K. Fellows <[email protected]>
State: Deferred
Type: Project
Vote: Pending
Created: 12-Sep-2001
Post-History:
Tcl-Version: 8.5
~ Abstract
This TIP changes the compile time Tk define TK_NO_SECURITY to be
switchable at run-time.
~ Rationale
The TK_NO_SECURITY compile time #define is available to disable some
security checking when send is used. The direct comments in the
Makefile are:
| # To turn off the security checks that disallow incoming sends when
| # the X server appears to be insecure, reverse the comments on the
| # following lines:
| SECURITY_FLAGS =
| #SECURITY_FLAGS = -DTK_NO_SECURITY
I propose to make this switch configurable at runtime through a ''tk
securesend'' option.
~ Benefits
Users would be able to debug between Tk applications on Unix using
''send'' without having to compile a special version of Tk or
manipulating the security settings of their X server to Tk's liking
(which can then conflict with other work). It is common for users in
internal ("safe") networks to open up access to an X server with
''xhost +machine''.
~ Drawbacks
By allowing security to be disabled, users do possibly open up their
system to attack. However, secure is the default setting, and any
paranoid users can ''rename send {}'' to ensure that it is not used at
all.
~ Reference Implementation
A full patch for this feature is available at:
http://sf.net/tracker/?func=detail&aid=456732&group_id=12997&atid=312997
The proposal adds one element to the private ''TkDisplay'' structure
(configuration for secure send is done per display), and creates the
Tcl level command:
| tk securesend ?-displayof window? ?boolean?
It leaves the TK_NO_SECURITY flag alone. If specified, send is
insecure by default, otherwise it is secure.
~ Comments
''DKF'' - It should be possible to control the setting of the
compile-time TK_NO_SECURITY flag from the ''configure'' script; having
to edit the Makefile by hand to adjust it makes it too easy to
inadvertently break something by introducing an unfortunate typo. Being
able to pass a ''--disable-security'' flag would make thing much easier
from a user's point of view, and will make it less likely that the Tk
maintainers will have to deal with bug reports that ultimately stem from
a dumb mistake made in a sensitive spot...
~ Copyright
This document has been placed in the public domain.