Bug #8978: Fiddle possibly misuses mprotect

• Status: Closed
• Assignee: tenderlovemaking (Aaron Patterson)
• Target version: 2.1.0
• ruby -v: ruby 2.1.0dev (2013-10-02 trunk 43121) [x86_64-linux]
• Backport: 1.9.3: DONE, 2.0.0: DONE, 2.1: DONE

[mame (Yusuke Endoh)]

Hello Aaron,

Coverity Scan found a possible bug in "initialize" function of ext/fiddle/closure.c:

result = ffi_prep_closure(pcl, cif, callback, (void *)self);
...
i = mprotect(pcl, sizeof(pcl), PROT_READ | PROT_EXEC)

I don't understand the code completely, but the size of the pointer does not seem to make sense.
Perhaps, "sizeof(pcl)" should be "sizeof(*pcl)".

The same applies to dealloc:

munmap(cls->pc1, sizeof(cls->pc1));

BTW, ffi_prep_closure seems deprecated.
We should use ffi_prep_closure_loc instead when it is available.

--
Yusuke Endoh [e-mail]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

Applied in changeset r44731.

---

• ext/fiddle/closure.c: use sizeof(*pcl) for correct sizeof value.
  [ruby-core:57599] [Bug #8978]. Thanks mame!

[tenderlovemaking (Aaron Patterson)]

I took the mprotect example from the ffi man pages. Seems there must be a bug in the example code. Anyway, I've fixed it.

Also, we should be using ffi_prep_closure_loc if it is available:

https://github.com/ruby/ruby/blob/92a7f323678d6070383364f2129a5202b217c5da/ext/fiddle/closure.c#L231-234

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED

[mame (Yusuke Endoh)]

Thank you!

Nagachika, I think r44751 is also needed to backport.

--
Yusuke Endoh [e-mail]

[usa (Usaku NAKAMURA)]

• Backport changed from 1.9.3: REQUIRED, 2.0.0: REQUIRED, 2.1: REQUIRED to 1.9.3: DONE, 2.0.0: REQUIRED, 2.1: REQUIRED

backported into ruby_1_9_3 at r44941.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 1.9.3: DONE, 2.0.0: REQUIRED, 2.1: REQUIRED to 1.9.3: DONE, 2.0.0: DONE, 2.1: REQUIRED

r44731 and r44751 were backported to ruby_2_0_0 at r45008.

[naruse (Yui NARUSE)]

• Backport changed from 1.9.3: DONE, 2.0.0: DONE, 2.1: REQUIRED to 1.9.3: DONE, 2.0.0: DONE, 2.1: DONE

r45122