| Type | Issue | Status | tested | Date | 14-Aug-2009 09:57 |
|---|---|---|---|---|---|
| Version | alpha 77 | Category | Security | Submitted by | Sunanda |
| Platform | All | Severity | minor | Priority | normal |
| Summary | SELF seems insufficiently protected |
|---|---|
| Description |
Not sure if SELF needs protection -- perhaps it can be happily overwritten. But, if it needs it, it needs better than this: self: 'oops ** Script error: cannot set self - it is protected Okay so far. But: set self 'oops == oops probe self make object! [ system: 'oops oops: 'oops set: 'oops probe: make function! [[ {Debug print a molded value and returns that same value.} value [any-type!] ][ print mold :value :value ]] ] |
| Example code |
set self 'oops |
| Assigned to | n/a | Fixed in | alpha 79 | Last Update | 21-Aug-2009 20:41 |
|---|
| Comments | |
|---|---|
|
(0001487)
meijeru 14-Aug-2009 11:59 |
Your code does not set self (for that you need to write 'self) but it sets system/context/user (which is the value of self). According to http://www.rebol.net/r3blogs/0232.html , system/contexts is protected, but apparently not via self. |
|
(0001488)
BrianH 14-Aug-2009 13:50 |
You can't protect the system/contexts/user object itself - it gets modified with every new user script. However, your user scripts can protect the words in system/contexts/user as you see fit.
REBOL can't prevent you from shooting yourself in the foot. The purpose of the security settings is to prevent other people from shooting you in the foot. |
|
(0001489)
meijeru 14-Aug-2009 20:38 |
How am I to understand the remark that system/contexts/user cannot be protected? It seems to be protected to me...
>> system/contexts/user: 1 ** Script error: protected variable - cannot modify: contexts |
|
(0001490)
BrianH 14-Aug-2009 21:38 |
The word 'user in system/contexts could be protected - the object it refers to (system/contexts/user) can not. SELF in user scripts refers to the same object. You could protect words within that object though.
However, that error you mention is weird: It should be saying "cannot modify: user". The word 'contexts in system should be protected as well, but that is not what you were trying to modify. |
|
(0001491)
Sunanda 14-Aug-2009 22:41 |
We have some inconsistencies with protecting SELF.
Consider: CONSOLE SESSION 1: a: 1 protect 'a set self 'oops ** Script error: protected value or series - cannot modify ===> so creating and protecting A has protected SELF Meanwhile, in a separate console CONSOLE SESSION 2: set self 'oops probe self make object! [ system: 'oops set: 'oops oops: 'oops ... ===> SELF has been modified a: 1 protect 'a set self 'oops2 probe self make object! [ system: 'oops set: 'oops oops: 'oops probe: make function! [[ {Debug print a molded value and returns that same value value [any-type!] ][ print mold :value :value ]] a: 1 protect: make native! [[ {Protect a series or a variable from being modified.} value [word! series! bitset! map! object! module!] /deep "Protect all sub-series as well" /words "Block is a list of words" /hide "Hide variables (avoid binding and lookup)" ]] oops2: unset! ] ===> Protecting A has apparently silently stopped the modification of words that precede it in SELF. This all may mean nothing, or it may be a symptom of some part of word handling that needs fine-tuning. Only the man behind the curtain can say for sure. |
|
(0001518)
Carl 20-Aug-2009 06:02 |
Actually... that all seems correct, because:
set an-object value will attempt to set all the fields of the object. So, SET self will do the same. HOWEVER, if a field of the object is protected, then the SET of the object will fail. (It needs a better error message.) It detects the protection before trying to set any field of the object, so nothing in the object will be set. In A79, the error message has been changed, and you will now see: >> set self 'oop ** Script error: protected variable - cannot modify: a ** Where: set ** Near: set self 'oop I hope that helps. |
| Date | User | Field | Action | Change |
|---|---|---|---|---|
| 21-Aug-2009 20:41 | BrianH | Status | Modified | built => tested |
| 20-Aug-2009 06:07 | carl | Comment : 0001518 | Modified | - |
| 20-Aug-2009 06:07 | carl | Comment : 0001518 | Modified | - |
| 20-Aug-2009 06:06 | carl | Comment : 0001518 | Modified | - |
| 20-Aug-2009 06:05 | carl | Status | Modified | problem => built |
| 20-Aug-2009 06:05 | carl | Fixedin | Modified | => alpha 79 |
| 20-Aug-2009 06:04 | carl | Comment : 0001518 | Modified | - |
| 20-Aug-2009 06:02 | carl | Comment : 0001518 | Modified | - |
| 20-Aug-2009 06:02 | carl | Comment : 0001518 | Added | - |
| 14-Aug-2009 22:41 | sunanda | Comment : 0001491 | Added | - |
| 14-Aug-2009 21:38 | BrianH | Comment : 0001490 | Added | - |
| 14-Aug-2009 20:38 | meijeru | Comment : 0001489 | Added | - |
| 14-Aug-2009 13:50 | BrianH | Comment : 0001488 | Added | - |
| 14-Aug-2009 13:27 | BrianH | Type | Modified | Bug => Issue |
| 14-Aug-2009 13:27 | BrianH | Status | Modified | submitted => problem |
| 14-Aug-2009 13:27 | BrianH | Category | Modified | Unspecified => Security |
| 14-Aug-2009 13:27 | BrianH | Description | Modified | - |
| 14-Aug-2009 12:00 | meijeru | Comment : 0001487 | Modified | - |
| 14-Aug-2009 11:59 | meijeru | Comment : 0001487 | Added | - |
| 14-Aug-2009 09:57 | sunanda | Ticket | Added | - |