avcodec/diracdec: Tighter checks on CODEBLOCKS_X/Y

Fixes very long but finite loop
Fixes: asan_heap-oob_107866c_42_041.drc
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/diracdec.c

@@ -1004,8 +1004,8 @@ static int dirac_unpack_idwt_params(DiracContext *s)
         /* Codeblock parameters (core syntax only) */
         if (get_bits1(gb)) {
             for (i = 0; i <= s->wavelet_depth; i++) {
-                CHECKEDREAD(s->codeblock[i].width , tmp < 1, "codeblock width invalid\n")
-                CHECKEDREAD(s->codeblock[i].height, tmp < 1, "codeblock height invalid\n")
+                CHECKEDREAD(s->codeblock[i].width , tmp < 1 || tmp > (s->avctx->width >>s->wavelet_depth-i), "codeblock width invalid\n")
+                CHECKEDREAD(s->codeblock[i].height, tmp < 1 || tmp > (s->avctx->height>>s->wavelet_depth-i), "codeblock height invalid\n")
             }
 
             CHECKEDREAD(s->codeblock_mode, tmp > 1, "unknown codeblock mode\n")