Hi Bernd,
> Are all the places being patched really problematic ones where an input file
> could realistically cause an overflow, or just the string functions?
The loop in demangle_args allows to call the patched register*- and
remember*-methods arbitrarily often. So, those should also overflow at some
point.
Found a few other segmentation faults in libiberty that I’ll report and patch
separately.
> I'm concerned about just returning without any kind of error indication. Not
> sure what we should be calling from libiberty, but I was thinking maybe
> xmalloc_failed.
Done. Now, clients of libiberty freeze for about 80 seconds and consume about
3GB of memory before exiting with "out of memory allocating 2147483647 bytes
after a total of 3221147648 bytes”.
> Might also want to guard against overflow from the first addition.
Done.
Index: libiberty/cplus-dem.c
===================================================================
--- libiberty/cplus-dem.c (revision 234607)
+++ libiberty/cplus-dem.c (working copy)
@@ -55,6 +55,7 @@ Boston, MA 02110-1301, USA. */
void * malloc ();
void * realloc ();
#endif
+#include <limits.h>
#include <demangle.h>
#undef CURRENT_DEMANGLING_STYLE
@@ -4254,6 +4255,8 @@ remember_type (struct work_stuff *work,
}
else
{
+ if (work -> typevec_size > INT_MAX / 2)
+ xmalloc_failed (INT_MAX);
work -> typevec_size *= 2;
work -> typevec
= XRESIZEVEC (char *, work->typevec, work->typevec_size);
@@ -4281,6 +4284,8 @@ remember_Ktype (struct work_stuff *work,
}
else
{
+ if (work -> ksize > INT_MAX / 2)
+ xmalloc_failed (INT_MAX);
work -> ksize *= 2;
work -> ktypevec
= XRESIZEVEC (char *, work->ktypevec, work->ksize);
@@ -4310,6 +4315,8 @@ register_Btype (struct work_stuff *work)
}
else
{
+ if (work -> bsize > INT_MAX / 2)
+ xmalloc_failed (INT_MAX);
work -> bsize *= 2;
work -> btypevec
= XRESIZEVEC (char *, work->btypevec, work->bsize);
@@ -4764,6 +4771,8 @@ string_need (string *s, int n)
else if (s->e - s->p < n)
{
tem = s->p - s->b;
+ if (n > INT_MAX / 2 - tem)
+ xmalloc_failed (INT_MAX);
n += tem;
n *= 2;
s->b = XRESIZEVEC (char, s->b, n);
