Fix for HDFFV-10217 infinite loop in H5VM_power2up().

The function H5VM_power2up() returns the next power of 2 for n.
When n exceeds 2^63, it overflows and becomes 0 causing the infinite looping.
The fix ensures that the function checks for n >= 2^63 and returns 0.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/H5VMprivate.h b/src/H5VMprivate.h
index 4d71b29..decac7e 100644
--- a/src/H5VMprivate.h
+++ b/src/H5VMprivate.h
@@ -460,7 +460,11 @@ H5VM_power2up(hsize_t n)
 {
     hsize_t     ret_value = 1;  /* Return value */
 
-    while(ret_value < n)
+    /* Returns 0 when n exceeds 2^63 */
+    if(n >= (hsize_t)1 << ((sizeof(hsize_t) * CHAR_BIT) - 1))
+        ret_value = 0;
+
+    while(ret_value && ret_value < n)
         ret_value <<= 1;
 
     return(ret_value);