| Type | Bug | Status | tested | Date | 30-Sep-2007 20:31 |
|---|---|---|---|---|---|
| Version | alpha 31 | Category | Unspecified | Submitted by | Jerry |
| Platform | All | Severity | minor | Priority | high |
| Summary | ALIAS allows word! for its name argument |
|---|---|
| Description |
When the second augument is word!, instead of string! >> alias 'print 'pnt == pnt >> pnt 1 ** Script error: pnt has no value The word! type should be disallowed for the name argument. |
| Example code |
| Assigned to | n/a | Fixed in | alpha 79 | Last Update | 31-Jan-2011 06:15 |
|---|
| Comments | |
|---|---|
|
(0000187)
admin 12-Jan-2008 10:58 |
R2 only allows a string for the second arg; R3 should probably do the same (not knowing if there are other issues in allowing words). --Gregg There is definitely an issue with allowing words: If even a set-word! version of a word is loaded, that word can't be used as an alias. Specifying the 'pnt in the example statement loads the word pnt, making it unavailable for alias. The word! datatype needs to be disallowed for the name parameter. -BrianH |
|
(0001004)
Carl 21-Jun-2009 00:29 |
ALIAS works, but words belong to namespaces in R3, different from R2.
>> alias 'print 'pt == pt >> 'pt = 'print == true >> system/contexts/exports/pt ["example" 1] example 1 |
|
(0001447)
BrianH 31-Jul-2009 21:39 |
See #1164 for examples of why this is still a bug, and #1163 and #1165 for related bugs.
I understand that ALIAS is probably used to implement case-preserving words in R3, and thus needs to accept a word argument. However, as a user-space function this can cause major problems. It would be a better idea to have an internal function that does the aliasing for case preserving and such (called by MAKE/TO word!), and a user-level function that only allows words that aren't yet in the symbol table (case-insensitive) to be aliased. The restriction of string! for the second argument would need to be restored for the user-level function. The alternative would have to be either security-restricting ALIAS, or not exporting it at all. |
|
(0001557)
BrianH 21-Aug-2009 20:15 |
As of alpha 79, ALIAS no longer allows a word for its name argument. However, it does not check to see if the name word has been used yet. This means that #1163, #1164 and #1165 can still occur, though are now less likely to do so.
The problem is that ALIAS probably can't check to see if a word has been used yet since there is no direct connection between a word being loaded and being used. In R2, loading a word meant putting it into system/words, which counted as use, so you could block ALIAS for existing words. In R3, ALIAS is used to implement case-preserving words, and you can *guarantee* that the word has been used in that case, every time. With ALIAS word! word! disabled, #1163 and #1165 are less important, but the previously dismissed #1164 now becomes a security issue. ALIAS needs to be used carefully, or it could inadvertantly be used as a denial-of-service attack. Created a ticket for the security issue (#1212). |
|
(0003068)
BrianH 31-Jan-2011 06:15 |
As of alpha 111, the ALIAS function has been removed, so the above issues have been resolved. |
| Date | User | Field | Action | Change |
|---|---|---|---|---|
| 31-Jan-2011 06:15 | BrianH | Comment : 0003068 | Added | - |
| 21-Aug-2009 22:03 | BrianH | Comment : 0001557 | Modified | - |
| 21-Aug-2009 20:15 | BrianH | Comment : 0001557 | Added | - |
| 21-Aug-2009 19:45 | BrianH | Status | Modified | dismissed => tested |
| 21-Aug-2009 19:45 | BrianH | Severity | Modified | not a bug => minor |
| 21-Aug-2009 19:45 | BrianH | Category | Modified | => Unspecified |
| 21-Aug-2009 19:45 | BrianH | Fixedin | Modified | => alpha 79 |
| 1-Aug-2009 00:17 | BrianH | Comment : 0001447 | Modified | - |
| 1-Aug-2009 00:14 | BrianH | Comment : 0001447 | Modified | - |
| 31-Jul-2009 21:39 | BrianH | Comment : 0001447 | Added | - |
| 21-Jun-2009 00:30 | carl | Comment : 0001004 | Modified | - |
| 21-Jun-2009 00:29 | carl | Comment : 0001004 | Added | - |
| 21-Jun-2009 00:21 | carl | Status | Modified | reviewed => dismissed |
| 21-Jun-2009 00:21 | carl | Severity | Modified | trivial => not a bug |
| 26-Feb-2009 08:01 | BrianH | Priority | Modified | normal => high |
| 20-Jan-2009 01:23 | BrianH | Priority | Modified | none => normal |
| 20-Jan-2009 01:23 | BrianH | Version | Modified | => alpha 31 |
| 20-Jan-2009 01:23 | BrianH | Description | Modified | - |
| 20-Jan-2009 01:23 | BrianH | Summary | Modified | Alias not working => ALIAS allows word! for its name argument |
| 2-Dec-2008 18:50 | Admin | Ticket | Added | - |