Forum: Ruby-core [ruby-trunk - Bug #7325][Open] Marshal#load taints classes if they are referenced in a marsheled obj

Issue #7325 has been reported by urielka (Uriel Katz).

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Bug #7325: Marshal#load taints classes if they are referenced in a 
marsheled object
https://bugs.ruby-lang.org/issues/7325

Author: urielka (Uriel Katz)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:
ruby -v: ruby 1.9.3p327 (2012-11-10 revision 37606) [x86_64-linux]


=begin
= Reproducing steps:
ruby taint.rb

= Output of this script in my computer running 1.9.3-p327:
 Before marshal is tainted?: false
 After marshal is tainted?: true
 Safe level when calling tainted method using call: 4
 Safe level when calling tainted method directly: 0

= Expected:
MyObject#test shouldn't be tainted as it was defined in my own source 
and what was saved into the file is just a reference to MyObject class 
("\u0004\bc\rMyObject")

= Actual:
MyObject#test is tainted and calling it using Method#call will make it 
run in safe-level 4.


= Some background on how I got to this issue:
I wrote some RPC code that accepts a class and method name and does the 
invocation,the way I call the method is getting the method from the 
instance using something like: "cls_instance.method(method_name).call"

I used Rails.cache with FileStore (which uses Marshal#load from file) to 
cache a object that had references to classes.

After reading from the cache all other requests saw the classes as 
tainted and when calling the methods they ran at $SAFE=4 which caused it 
to fail (even puts doesn't work at that level :)

This issue also made me understand that there is 2 potential bugs in 
Rails.
=end

Issue #7325 has been updated by mame (Yusuke Endoh).

Status changed from Open to Assigned
Assignee set to shugo (Shugo Maeda)
Target version set to 2.0.0

Summarized:

  p Integer.tainted? #=> false
  Marshal.load(Marshal.dump(Integer).taint)
  p Integer.tainted? #=> expected: false, actual: true

Indeed, it looks weird.  Shugo-san, what do you think?

--
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Bug #7325: Marshal#load taints classes if they are referenced in a 
marsheled object
https://bugs.ruby-lang.org/issues/7325#change-33844

Author: urielka (Uriel Katz)
Status: Assigned
Priority: Normal
Assignee: shugo (Shugo Maeda)
Category:
Target version: 2.0.0
ruby -v: ruby 1.9.3p327 (2012-11-10 revision 37606) [x86_64-linux]


=begin
= Reproducing steps:
ruby taint.rb

= Output of this script in my computer running 1.9.3-p327:
 Before marshal is tainted?: false
 After marshal is tainted?: true
 Safe level when calling tainted method using call: 4
 Safe level when calling tainted method directly: 0

= Expected:
MyObject#test shouldn't be tainted as it was defined in my own source 
and what was saved into the file is just a reference to MyObject class 
("\u0004\bc\rMyObject")

= Actual:
MyObject#test is tainted and calling it using Method#call will make it 
run in safe-level 4.


= Some background on how I got to this issue:
I wrote some RPC code that accepts a class and method name and does the 
invocation,the way I call the method is getting the method from the 
instance using something like: "cls_instance.method(method_name).call"

I used Rails.cache with FileStore (which uses Marshal#load from file) to 
cache a object that had references to classes.

After reading from the cache all other requests saw the classes as 
tainted and when calling the methods they ran at $SAFE=4 which caused it 
to fail (even puts doesn't work at that level :)

This issue also made me understand that there is 2 potential bugs in 
Rails.
=end

Issue #7325 has been updated by usa (Usaku NAKAMURA).


memo: r38357 is also related.
----------------------------------------
Backport #7325: Marshal#load taints classes if they are referenced in a 
marsheled object
https://bugs.ruby-lang.org/issues/7325#change-34737

Author: urielka (Uriel Katz)
Status: Assigned
Priority: Normal
Assignee: usa (Usaku NAKAMURA)
Category:
Target version:


=begin
= Reproducing steps:
ruby taint.rb

= Output of this script in my computer running 1.9.3-p327:
 Before marshal is tainted?: false
 After marshal is tainted?: true
 Safe level when calling tainted method using call: 4
 Safe level when calling tainted method directly: 0

= Expected:
MyObject#test shouldn't be tainted as it was defined in my own source 
and what was saved into the file is just a reference to MyObject class 
("\u0004\bc\rMyObject")

= Actual:
MyObject#test is tainted and calling it using Method#call will make it 
run in safe-level 4.


= Some background on how I got to this issue:
I wrote some RPC code that accepts a class and method name and does the 
invocation,the way I call the method is getting the method from the 
instance using something like: "cls_instance.method(method_name).call"

I used Rails.cache with FileStore (which uses Marshal#load from file) to 
cache a object that had references to classes.

After reading from the cache all other requests saw the classes as 
tainted and when calling the methods they ran at $SAFE=4 which caused it 
to fail (even puts doesn't work at that level :)

This issue also made me understand that there is 2 potential bugs in 
Rails.
=end