Eliminate integer overflow in block_find_suitable

This commit fixes undefined behavior when (*fl + 1 >= 32) in bitmap
operations.

Author: jserv

tlsf.c

@@ -238,7 +238,7 @@ INLINE tlsf_block_t *block_find_suitable(tlsf_t *t, uint32_t *fl, uint32_t *sl)
     uint32_t sl_map = t->sl[*fl] & (~0U << *sl);
     if (!sl_map) {
         /* No block exists. Search in the next largest first-level list. */
-        uint32_t fl_map = t->fl & (uint32_t) (~(uint64_t) 0 << (*fl + 1));
+        uint32_t fl_map = t->fl & ((*fl + 1 >= 32) ? 0U : (~0U << (*fl + 1)));
 
         /* No free blocks available, memory has been exhausted. */
         if (UNLIKELY(!fl_map))
@@ -475,7 +475,7 @@ INLINE tlsf_block_t *block_find_free(tlsf_t *t, size_t *size)
         block = block_find_suitable(t, &fl, &sl);
         ASSERT(block, "no block found");
     }
-    ASSERT(block_size(block) >= size, "insufficient block size");
+    ASSERT(block_size(block) >= *size, "insufficient block size");
     remove_free_block(t, block, fl, sl);
     return block;
 }

tlsf.h

@@ -21,7 +21,7 @@ extern "C" {
 #define _TLSF_FL_MAX 30
 #endif
 #define TLSF_MAX_SIZE (((size_t) 1 << (_TLSF_FL_MAX - 1)) - sizeof(size_t))
-#define TLSF_INIT ((tlsf_t){.size = 0})
+#define TLSF_INIT ((tlsf_t) {.size = 0})
 
 typedef struct {
     uint32_t fl, sl[_TLSF_FL_COUNT];