[Bug c++/22860] heap buffer overflow in value_contents_copy_raw

["simon.marchi at ericsson dot com" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=22860

Simon Marchi <simon.marchi at ericsson dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |simon.marchi at ericsson dot com

--- Comment #1 from Simon Marchi <simon.marchi at ericsson dot com> ---
I debugged GDB a little bit, and this is due to virtual inheritance I think. 
The layout of the vC structure (when used standalone) is:

0   vtable
4   vtable
8   vc
C   vx
10  vA::va
14  vA::vx

And the layout of the vD structure is

0   vtable?
4   vtable?
8   vd
C   vx
10  vtable?
14  vtable?
18  vB::vb
1C  vB::vx
20  vA::va
24  vA::vx
28  vtable?
2C  vtable?
30  vC::vc
34  vC::vx

Because of virtual inheritance, the vA base of vC is share with the vA base of
vD.  Because of that, the vC object is not contiguous in memory.  In
value_from_component, we are trying to extract the vC object from vD as a 24
bytes contiguous object from its location in vD.  Asan warns when we try to
read the bytes just passed vD.

-- 
You are receiving this mail because:
You are on the CC list for the bug.