mcstrans: ensure transitivity in compare functions

Ensure comparison functions used by qsort(3) fulfill transitivity, since otherwise the resulting array might not be sorted correctly or worse[1] in case of integer overflows. [1]: https://www.qualys.com/2024/01/30/qsort.txt Signed-off-by: Christian Göttsche <[email protected]> Acked-by: James Carter <[email protected]>
SELinuxProject · Mar 4, 2024 · fc2822a · fc2822a
1 parent 162a088
commit fc2822a
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/mcstrans/src/mcstrans.c b/mcstrans/src/mcstrans.c
@@ -952,9 +952,13 @@ find_in_hashtable(const char *range, domain_t *domain, context_map_node_t **tabl
  return trans;
 }
 
+#define spaceship_cmp(a, b) (((a) > (b)) - ((a) < (b)))
+
 static int
 string_size(const void *p1, const void *p2) {
- return strlen(*(char **)p2) - strlen(*(char **)p1);
+ size_t len1 = strlen(*(const char *const *)p2);
+ size_t len2 = strlen(*(const char *const *)p1);
+ return spaceship_cmp(len1, len2);
 }
 
 static int
@@ -965,7 +969,7 @@ word_size(const void *p1, const void *p2) {
  int w2_len=strlen(w2->text);
  if (w1_len == w2_len)
  return strcmp(w1->text, w2->text);
- return (w2_len - w1_len);
+ return spaceship_cmp(w2_len, w1_len);
 }
 
 static void