stb_vorbis: revise CVE-2023-45676 / CVE-2023-45677 fix.

sezero · sezero · commit c1b3d5c8533e · 2023-12-11T08:55:04.000+03:00
c.f.: nothings/stb#1248.
diff --git a/src/codecs/stb_vorbis/stb_vorbis.h b/src/codecs/stb_vorbis/stb_vorbis.h
@@ -986,7 +986,7 @@ static void *make_block_array(void *mem, int count, int size)
 
 static void *setup_malloc(vorb *f, int sz)
 {
-   if (sz < 0 || INT_MAX - 7 < sz) return NULL;
+   if (sz <= 0 || INT_MAX - 7 < sz) return NULL;
    sz = (sz+7) & ~7; // round up to nearest 8 for alignment of future allocs.
    f->setup_memory_required += sz;
    if (f->alloc.alloc_buffer) {

Original file line number	Diff line number	Diff line change
`@@ -986,7 +986,7 @@ static void make_block_array(void mem, int count, int size)`
`986`	`986`
`987`	`987`	`static void setup_malloc(vorb f, int sz)`
`988`	`988`	`{`
`989`		`- if (sz < 0 \|\| INT_MAX - 7 < sz) return NULL;`
	`989`	`+ if (sz <= 0 \|\| INT_MAX - 7 < sz) return NULL;`
`990`	`990`	`sz = (sz+7) & ~7; // round up to nearest 8 for alignment of future allocs.`
`991`	`991`	`f->setup_memory_required += sz;`
`992`	`992`	`if (f->alloc.alloc_buffer) {`