Re: [screen-devel] [bug #60030] Screen segfaults by displaying some UTF-8 character combination

[Tavis Ormandy]

On 2021-02-10, Axel Beckert wrote:
> +  else if (i < sizeof combchars / sizeof *combchars) {

This doesn't seem right, I think it should be compared against the
calloc param at the top of utf8_handle_comb(), but I don't really
understand enough about unicode to know where that 0x802 comes from!

I think for sure this code doesn't handle c > 0x801, so maybe that's an
acceptable fix?

i.e.

--- encoding.c  2020-02-05 12:09:38.000000000 -0800
+++ encoding.c  2021-02-10 15:00:05.000000000 -0800
@@ -1357,6 +1357,9 @@
   int root, i, c1;
   int isdouble;
 
+  if (c > 0x801)
+    return;
+
   c1 = mc->image | (mc->font << 8) | mc->fontx << 16;
   isdouble = c1 >= 0x1100 && utf8_isdouble(c1);
   if (!combchars)


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