[kerx] Protext against overflows

This commit is contained in:
Behdad Esfahbod 2018-10-13 11:39:12 -04:00
parent ed2ee78136
commit fc45e698f2
1 changed files with 5 additions and 3 deletions

View File

@ -233,7 +233,7 @@ struct KerxSubTableFormat2
unsigned int offset = l + r;
const FWORD *v = &StructAtOffset<FWORD> (&(this+array), offset);
if (unlikely ((const char *) v < (const char *) &array ||
(const char *) v + v->static_size - (const char *) this > header.length))
(const char *) v - (const char *) this > header.length - v->static_size))
return 0;
return *v;
}
@ -480,9 +480,11 @@ struct KerxSubTableFormat6
unsigned int l = (this+t.rowIndexTable).get_value_or_null (left, num_glyphs);
unsigned int r = (this+t.columnIndexTable).get_value_or_null (right, num_glyphs);
unsigned int offset = l + r;
if (unlikely (offset < l)) return 0; /* Addition overflow. */
if (unlikely (hb_unsigned_mul_overflows (offset, sizeof (FWORD32)))) return 0;
const FWORD32 *v = &StructAtOffset<FWORD32> (&(this+t.array), offset * sizeof (FWORD32));
if (unlikely ((const char *) v < (const char *) &t.array ||
(const char *) v + v->static_size - (const char *) this > header.length))
(const char *) v - (const char *) this > header.length - v->static_size))
return 0;
return *v;
}
@ -494,7 +496,7 @@ struct KerxSubTableFormat6
unsigned int offset = l + r;
const FWORD *v = &StructAtOffset<FWORD> (&(this+t.array), offset * sizeof (FWORD));
if (unlikely ((const char *) v < (const char *) &t.array ||
(const char *) v + v->static_size - (const char *) this > header.length))
(const char *) v - (const char *) this > header.length - v->static_size))
return 0;
return *v;
}