Is it possible to overflow baton->size in dwarf_mark_symbols_computed() in dwarf2read.c?

Daniel Jacobowitz drow@false.org
Fri May 13 15:25:00 GMT 2005


On Fri, May 13, 2005 at 08:18:47AM -0700, Cuthbertson, Reva D. wrote:
> Hello,
> 
> I had a question regarding the following assignment in
> dwarf2_mark_symbol_computed() in dwarf2read.c:
> 
> baton->size = dwarf2_per_objfile->loc_size - DW_UNSND (attr);
> 
> The field "loc_size" in dwarf2_per_objfile is declared to be an unsigned
> integer and attr.u.unsnd (expansion of DW_UNSND (attr)) is declared to
> be an unsigned long but the "size" field in dwarf2_loclist_baton and
> dwarf2_locexpr_baton defined in dwarf2loc.h is defined to be an unsigned
> short.  Is it possible to overflow baton->size with the above
> calculation?

Yes, this seems possible.  Size is used for overflow checking only at
this point; saturating at USHORT_MAX seems reasonable.

Have you encountered this problem?

-- 
Daniel Jacobowitz
CodeSourcery, LLC



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