lib: rand - Fix random number bounding

diff --git a/src/lib/rand.c b/src/lib/rand.c
index ff7675dcc651d35230f42abea932a91f12adb65b..9fbcac37a7ba3752eff3330f07a716e254a6db76 100644 (file)
--- a/src/lib/rand.c
+++ b/src/lib/rand.c
@@ -31,7 +31,8 @@ uint32_t i_rand_limit(uint32_t upper_bound)
 {
        i_assert(upper_bound > 0);
 
-       uint32_t val, min = -upper_bound % upper_bound;
+       uint32_t val;
+       uint32_t min = ~(upper_bound - 1) % upper_bound;
        while((val = i_rand()) < min);
        return val % upper_bound;
 }